An off-on fluorescence method for acid phosphatase assay based on the inner filter effect of MnO2 nanosheets on vitamin B2

Fluorescence analysis has attracted much attention due to its rapidity and sensitivity. The present work describes a novel fluorescence detection method for acid phosphatase (ACP) on the basis of inner-filter effect (IFE), where MnO2 nanosheets (MnO2 NSs) and vitamin B2 (VB2) are served as absorbers and fluorophores, respectively. In the absence of ACP, the absorption band of MnO2 NSs overlaps well with the excitation band of VB2, resulting in effective IFE and inhibition of VB2 fluorescence. In the presence of ACP, 2-phospho-L-ascorbic acid trisodium salt (AAP) is hydrolyzed to generate ascorbic acid (AA), which efficiently trigger the reduction of MnO2 NSs into Mn2+ ions, causing the weakening of the MnO2 NSs absorption band and the recovery of VB2 fluorescence. Further investigation indicates that the fluorescence recovery degree of VB2 increases with the increase of ACP concentration. Under selected experimental conditions, the proposed method can achieve sensitive detection of ACP in the ranges of 0.5-4.0 mU/mL and 4.0-15 mU/mL along with a limit of detection (LOD) as low as 0.14 mU/mL. Finally, this method was successfully applied for the detection of ACP in human serum samples with satisfactory recoveries in the range of 95.0 %-108 %.

Effect of SO2, glutathione, and glutathione-rich inactive dry yeast on the color, phenolic compounds, ascorbic acid, and antioxidant activity of Roxburgh rose wine

Conventional methods for inhibiting browning in wine are not suitable for cili (Roxburgh rose) wine, which is naturally rich in ascorbic acid and subject to restrictions on SO2 addition. In this study, the capacity of various additives to suppress the browning of cili wine caused by ascorbic acid degradation was investigated. SO2, pure reduced glutathione (GSH), regular inactive dry yeast (IDY), and IDY with various levels of glutathione enrichment (g-IDY) were separately introduced into cili wine following the completion of alcoholic fermentation. Over a period of 12 months, the color parameters, levels of ascorbic acid, phenolic compounds, antioxidant activity, and GSH content of the aged cili wine were analyzed. Among the investigated additives, g-IDY exhibited the strongest inhibitory effect on browning. Moreover, adding 800 mg L-1 g-IDY increased the total reducing power and residual GSH content by factors of 1.52 and 2.44, respectively, with respect to those of the SO2-treated cili wine, thus enhancing its antioxidant capacity. Using ultra-performance liquid chromatography-tandem mass spectrometry analysis, a total of 22 monomeric phenolic compounds were identified. After g-IDY treatment, the contents of 15 easily oxidizable o-diphenols decreased, preventing the depletion of ascorbic acid as an antioxidant. As a result, the levels of ascorbic acid and total phenolics were 1.5-fold and 1.17-fold higher than those in the SO2-treated wine, respectively. This study demonstrates that g-IDY provides a new approach to preventing the browning of wine caused by ascorbic acid degradation. PRACTICAL APPLICATION: Cili wine, characterized by its high ascorbic acid content, can decelerate cellular senescence and bolster immune function, which has contributed to its popularity. Ascorbic acid, a potent antioxidant, can be spiked into white wines to significantly enhance their antioxidative properties. Nevertheless, the high ascorbic acid content in cili wine renders it susceptible to oxidation under both aerobic and anaerobic conditions, which alters the wine's hue from golden to dark brown, thus diminishing its commercial value. Overcoming this browning associated with ascorbic acid degradation is therefore of considerable importance and could facilitate the advancement of the cili industry.

Comparative elucidation of bioactive and antioxidant properties of red dragon fruit peel as affected by electromagnetic and conventional drying approaches

The effects of near-infrared (NIRD), mid-infrared (MIRD), far-infrared (FIRD), microwave (MWD), and hot air drying (HAD) on drying kinetic, colour, phytochemical composition, and antioxidant activity of red dragon fruit peel (RDFP) was evaluated. Results indicated that drying methods induced varying microstructural and chemical changes on RDFP, significantly influencing moisture removal rates and phytochemical retention. The lowest drying time was observed for MWD, while MIRD presented the highest drying time. FIRD drying was more favourable for retaining TPC, TFC, betacyanin and betaxanthin, while the ascorbic acid content was better retained during MIRD and NIRD. Enhancements in ABTS, CUPRAC and reducing power were associated with FIRD, and NIRD and MIRD enhanced DPPH and HRSA. Overall, chemical modifications induced by drying improved the phytochemical and antioxidant properties but presented adversative effects on ascorbic acid and DPPH. The study presented an essential background for the optimal drying of RDFP.

Quantification of flavonoids, minerals, and pigments present in "Nanicão" bananas during the ripening process

Banana is one of the most consumed and popular fruits in all regions of the world, being cultivated mainly in tropical countries. It is not only a rich source of vitamins A, C, and B, calcium, iron, potassium, phosphorus, and other vitamins and nutrients, but it also contains several types of antioxidants with high nutritional value. In this context, the current study aimed to quantify the content of ascorbic acid, flavonoids, pigments, and minerals present in "Nanicão" bananas during the ripening process. As demonstrated, the level of flavonoids was higher in ripe and overripe fruits, whereas the mineral composition was high only at ripening stage 4 (more yellow than green) a stage that should be prioritized when recommending fruit consumption to the population deficient in these minerals. Regarding pigments, there was a reduction in chlorophylls a and b and an increase in carotenoids and anthocyanins in peels and pulps. PRACTICAL APPLICATION: Flavonoids are phenolic, bioactive compounds with proven antioxidant and anti-inflammatory activity and products of the plant's secondary metabolism. The degradation of chlorophylls and synthesis of carotenoids and anthocyanins, and as a consequence of the latter pigment, the increase in flavonoids in the pulp was evident during the monitoring of ripening, mainly in the fruit peels in relation to pigments. Minerals are essential elements, the main ones provided in balanced diets and important for dietary and nutritional health.

Short-term anaerobic treatment maintained the quality of Actinidia arguta by activating the antioxidant defense system

BACKGROUND

This study aimed to investigate the effect of 6, 12, and 24 h short-term anaerobic treatment on kiwiberry quality and antioxidant properties at 5 °C.

RESULTS

Short-term anaerobic treatment was found to delay ripening and softening in kiwiberries, evident from changes in ethylene release, total soluble solids, starch, protopectin, and fruit texture. The 24 h treatment group exhibited the lowest decay rate of 12% on day 49, a 38% reduction compared with the control group. Anaerobic treatment reduced flesh translucency and decay in the fruit. The 12 h and 24 h treatments enhanced the activities of superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase, and increased the level of total phenolics, flavonoids, anthocyanins, and ascorbic acid. Moreover, it lowered oxidative damage in cell membranes, evidenced by reduced malondialdehyde content and relative conductivity.

CONCLUSION

These results indicate that anaerobic treatment maintains the fruit quality by stimulating its antioxidant defense system. Therefore, short-term anaerobic treatment emerges as a promising method for kiwiberry storage. © 2024 Society of Chemical Industry.

Effect of tropospheric ozone and its protectants on gas exchange parameters, antioxidant enzymes and quality of Garlic (Allium sativum. L)

An experimental study was conducted to assess the detrimental effect of ground-level ozone (O3) on garlic physiology and to find out appropriate control measures against ground-level O3, at TNAU-Horticultural Research farm, Udhagamandalam. Elevated ground ozone levels significantly decreased garlic leaf chlorophyll, photosynthetic rate, stomatal conductance, total soluble solids and pungency. The garlic chlorophyll content was highest in ambient ozone level and lowest in elevated ozone@200 ppb, highest stomatal conductance was recorded in ambient ozone with foliar spray of 3%Panchagavya, and the lowest was observed in elevated ozone@200 ppb. Since the elevated O3 had reduced in garlic photosynthetic rate significantly the lowest was observed in elevated O3@200 ppb and the highest photosynthetic rate was observed in ambient Ozone with foliar spray 3% of panchagavya after a week. The antioxidant enzymes of garlic were increased with increased concentration of tropospheric ozone. The highest catalase (60.97 µg of H2O2/g of leaf) and peroxidase (9.13 ΔA/min/g of leaf) concentration was observed at 200 ppb elevated ozone level. Garlic pungency content was highest in ambient ozone with foliar spray of 0.1% ascorbic acid and the lowest was observed under elevated O3@200 ppb. Highest total soluble solids were observed in ambient ozone with foliar spray of 3%Panchagavya and the lowest observed in elevated ozone@200 ppb. Thus, tropospheric ozone has a detrimental impact on the physiology of crops, which reduced crop growth and yield. Under elevated O3 levels, ascorbic acid performed well followed by panchagavya and neem oil. The antioxidant such as catalase and peroxidase had positive correlation among themselves and had negative correlation with chlorophyll content, stomatal conductance, photosynthetic rate, pungency and TSS. The photosynthetic rate has high positive correlation with chlorophyll content, pungency and TSS. Correlation analysis confirmed the negative effects of tropospheric ozone and garlic gas exchange parameters and clove quality. The ozone protectants will reduce stomatal opening by which the entry of O3 in to the cell will be restricted and other hand they also will alleviate ROS and allied stresses.

Biochemical and metabolomics analyses reveal the mechanisms underlying ascorbic acid and chitosan coating mediated energy homeostasis in postharvest papaya fruit

Papaya is a climacteric fruit that undergoes rapid ripening and quality deterioration during postharvest storage, resulting in significant economic losses. This study employed biochemical techniques and targeted metabolomics to investigate the impact of exogenous AsA + CTS application on the energy metabolism regulation of papaya fruit during postharvest storage. We found that AsA + CTS treatment significantly increased the levels of key metabolic compounds and enzymes, such as adenosine triphosphate (ATP), adenosine diphosphate (ADP), and the energy charge, as well as the succinic acid content and the activities of succinic dehydrogenase (SDH), cytochrome c oxidase (CCO), H+-ATPase, and Ca2+-ATPase. Moreover, AsA + CTS coating augmented the nicotinamide adenine dinucleotide kinase (NADK) activity and increased the NADH and NADPH concentrations. Regarding sugar metabolism, it increased the activities of 6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenase and raised d-glucose-6-phosphate levels. These findings suggest that AsA + CTS coating application can mitigate the metabolic deterioration and sustain a primary metabolism homeostasis in papaya fruit by enhancing the tricarboxylic acid (TCA) cycle and pentose phosphate pathway (PPP), thereby preserving their quality attributes during postharvest storage.

Comparison of vitamin C and flavanones between freshly squeezed orange juices and commercial 100% orange juices from four European countries

Knowing the true levels of nutrients and dietary bioactives in fruit juices at the point of consumption is key to properly understand their potential health benefits. The objective was to characterise the vitamin C and flavanone content in commercial orange juices consumed in Europe, compared with fresh-squeezed juices. Commercial juices were a rich source of vitamin C (>30% of the Nutrient Reference Value). Vitamin C in fresh-squeezed juices, at the end of their shelf-life, remained 33% higher than the levels found in the commercial juices. Flavanones had similar values from both commercial and fresh juices, except for fresh samples stored for 48 h, where fresh juices had higher values (22.36 mg/100 mL). Thus, orange juices preserve their bioactive compounds during storage, with very little influence of the brand, country, industrial process or storage conditions. Main bioactive compounds in commercial juices are present at nutritionally significant levels to the freshly-squeezed ones.

Efficient Electrochemical Microsensor for the Simultaneous Measurement of Hydrogen Peroxide and Ascorbic Acid in Living Brains

Hydrogen peroxide (H2O2) and ascorbic acid (AA), acting as two significant indicative species, correlate with the oxidative stress status in living brains, which have historically been considered to be involved mainly in neurodegenerative disorders such as Alzheimer's disease, Huntington's disease, and Parkinson's disease (PD). The development of efficient biosensors for the simultaneous measurement of their levels in living brains is vital to understand their roles played in the brain and their interactive relationship in the progress of these diseases. Herein, a robust ratiometric electrochemical microsensor was rationally designed to realize the determination of H2O2 and AA simultaneously. Therefore, a specific probe was designed and synthesized with both recognition units responsible for reacting with H2O2 to produce a detectable signal on the microsensor and linkage units helping the probe modify onto the carbon substrate. A topping ingredient, single-walled carbon nanotubes (SWCNTs) was added on the surface of the electrode, with the purpose of not only facilitating the oxidation of AA but also absorbing methylene blue (MB), prompting to read out the inner reference signal. This proposed electrochemical microsensor exhibited a robust ability to real-time track H2O2 and AA in linear ranges of 0.5-900 and 10-1000 μM with high selectivity and accuracy, respectively. Eventually, the efficient electrochemical microsensor was successfully applied to the simultaneous measurement of H2O2 and AA in the rat brain, followed by microinjection, and in the PD mouse brain.

Effect of the Drying Method and Storage Conditions on the Quality and Content of Selected Bioactive Compounds of Green Legume Vegetables

This study aimed to determine the effect of the drying method (freeze-drying, air-drying), storage period (12 months), and storage conditions (2-4 °C, 18-22 °C) applied to two legume species: green beans and green peas. The raw and dried materials were determined for selected physical parameters typical of dried vegetables, contents of bioactive components (vitamin C and E, total chlorophyll, total carotenoids, β-carotene, and total polyphenols), antioxidative activity against the DPPH radical, and sensory attributes (overall quality and profiles of color, texture, and palatability). Green beans had a significantly higher content of bioactive components compared to peas. Freeze-drying and cold storage conditions facilitated better retention of these compounds, i.e., by 9-39% and 3-11%, respectively. After 12 months of storage, higher retention of bioactive components, except for total chlorophyll, was determined in peas regardless of the drying method, i.e., by 38-75% in the freeze-dried product and 30-77% in the air-dried product, compared to the raw material.

How to achieve adequate quenching for DBP analysis in drinking water?

Quenching is an important step to terminate disinfection during preparation of disinfected water samples for the analysis of disinfection byproducts (DBPs). However, an incomplete quenching might result in continued reactions of residual chlorine, whereas an excessive quenching might decompose target DBPs. Therefore, an adequate quenching to achieve simultaneous disinfection termination and DBP preservation is of particular importance. In this study, the two-stage reaction kinetics of chlorine and three commonly used quenching agents (i.e., ascorbic acid, sodium thiosulfate, and sodium sulfite) were determined. Stopping quenching during the first stage prevented interactions of residual chlorine with natural organic matter. Complete quenching was achieved by minimizing the quenching time for ascorbic acid and sodium sulfite, while limiting the quenching time to less than 3 min for sodium thiosulfate. At the optimized quenching times, the molar ratios (MRs) of quenching agent to chlorine were 1.05, 1.10, and 0.75 for ascorbic acid, sodium sulfite, and sodium thiosulfate, respectively. The destructive effects of the three quenching agents on total organic halogen (TOX) followed the rank order of ascorbic acid (33.7-64.8 %) < sodium sulfite (41.6-72.8 %) < sodium thiosulfate (43.3-73.2 %), and the destructive effects on aliphatic DBPs also followed the rank order of ascorbic acid (29.5-44.5 %) < sodium sulfite (34.9-51.9 %) < sodium thiosulfate (46.9-53.2 %). For total organic chlorine (TOCl) and aliphatic DBPs, the quenching behavior itself had more significant destructive effect than the quenching agent type/dose and quenching time, but for total organic bromine (TOBr), the destructive effect caused by quenching agent type/dose and quenching time was more significant. High-dose, long-duration quenching enhanced the reduction of TOX, but had little effect on aliphatic DBPs. Additionally, the three quenching agents reduced the levels of halophenols (except for tribromophenol), while maintained or increased the levels of tribromophenol, halobenzoic/salicylic acids, and halobenzaldehydes/salicylaldehydes. To achieve adequate quenching for overall DBP analysis in chlorinated water samples, it is recommended to use ascorbic acid at a quenching agent-to-chlorine MR of 1.0 for a quenching time of < 0.5 h.

Evaluation of AgNCs@PEI and their integrated hydrogel for colorimetric and fluorometric detection of ascorbic acid

A dual-mode colorimetric and fluorometric sensor based on water soluble silver nanoclusters (AgNCs@PEI) is developed for quantitative and visual detection of ascorbic acid (Asc A). The detection method relies on the Asc A induced aggregation of AgNCs@PEI, which resulted in fluorecsence quenching of the sensor. The clusters exhibited a unique combination of static and collisional quenching with a wide range of dynamic detection (1-105 µM) Linear relationship was observed in the concentration range 102-103 µM using fluorescence and 0.2 × 102-5 × 103 μM using absorbance spectroscopy with respective detection limits of 10.65 μM and 2.49 μM. The corresponding colorimetric and fluorometric changes can be easily monitored by the naked eye with a visual detection limit of 103 μM. AgNCs@PEI were further integrated within a hydrogel for developing a solid-state visual detection platform. Notably, the sensing response of the clusters towards Asc A remained unaltered even after hydrogel integration. Additionally, digital image analysis was adopted, which improved the sensitivity of instrument-free fluorescence detection of Asc A. Analysis by the developed sensor showed excellent recovery percentages of Asc A in spiked urine samples, which further underscores the practical applicability of the sensor.

A facile double moving redox boundary model for visual electrophoresis titration of ascorbic acid

In this work, we proposed a double moving redox boundary (MROB) model to realize the colorless analyte electrophoresis titration (ET) by the two steps of the redox reaction. Single MROB has been proposed for the development of ET sensing (Analyst, 2013, 138, 1137. ACS Sensor, 2019, 4, 126.), and faces great challenges in detecting the analyte without color change during redox reaction. Herein, a novel model of double-MROB electrophoresis, including its mechanisms, equations, and procedures, was developed for titration by using ascorbic acid as a model analyte. The first MROB was created with ferric iron (Fe3+) and iodide ion (I-) in which Fe3+ was reduced as Fe2+ and I- was oxidized as molecular iodine (I2) used as an indicator of visible MROB due to blue starch-iodine complex. The second boundary was then formed between the molecular iodine and model analyte of ascorbic acid. Under given conditions, there was a quantitative relationship between velocity of MROB (VMROB(ii)) and ascorbic acid concentration (CVit C) in the double-MROB system (1/VMROB(ii) = 0.6502CVit C + 4.5165, and R = 0.9939). The relevant relative standard deviation values of intraday and inter-day were less than ∼5.55% and ∼6.64%, respectively. Finally, the titration of ascorbic acid in chewable vitamin C tablets was performed by the developed method, the titration results agreed with those via the classic iodometric titration. All the results briefly demonstrated the validity of the double MROB model, in which Vit C was used as a model analyte. The developed method had potential use in quantitative analysis of redox-active species in biomedical samples.

Effect of post-harvest cold plasma treatment on physicochemical properties and inactivation of Penicillium digitatum in Persian lime fruit

Cold atmospheric plasma (CAP) treatment is used in this study to inactivate Penicillium digitatum in lime fruit at post-harvest. Limes were inoculated manually withP. digitatum spore (106 CFU/fruit) and then were treated with CAP at 30, 60, 90, and 120 s and compared with untreated samples. The results showed that increasing the exposure time of CAP reduced spores to less than 7 CFU/fruit in 120 s on the lime peel. In the treated samples, antioxidant activity had an upward trend. In addition, phenolic compounds, vitamin C, density, soluble solid content (SSC), color, and pH of the lime juice were increased (P < 0.05). Compared to the control sample, no significant changes were observed in the juice yield percentage, texture, acidity, chlorophyll, and carotenoid (P > 0.05). The best exposure for CAP treatment was 60 s since it increased phenolic compounds, antioxidant activity, and vitamin C content in the lime juice.

A fluorescence "turn-on" sensor for ascorbic acid in fruit juice and beverage based on ascorbate oxidase-like activity of citric acid-derived carbon dots

Citric acid-derived carbon dots (CA-CDs) without any modifications were found to have the ascorbate oxidase (AAO)-like activity. The CA-CDs have high affinity for ascorbic acid (AA), which is similar to natural AAO. The robustness of CA-CDs is greater than that of AAO. Based on the AAO mimetic activity of CA-CDs, a sensitive turn-on mode and natural enzyme-free fluorescence detection method has been developed for AA in some fruit juice and beverage samples with satisfied recoveries. This study provides CDs-based AAO mimetic nanozymes to replace the expensive natural enzymes or heavy metal-based nanozymes, which will show great potential in biological and food assays.

Kinetic models applied to quality change and shelf-life prediction of fresh-cut pineapple in food cold chain

This study developed a predictive model of the remaining shelf-life of fresh-cut pineapple by considering microbial, chemical, and sensory indicators under storage temperatures.The effect of temperature on quality indices (Ea)was29.57-96.8 kJ/mol. The acceptable limits for vitamin C loss and weight loss for fresh-cut pineapple were 27.71 mg/100 g fresh weight and 4.32 %, respectively, in accordance with cutoffs determined on the basis of sensory changes. Key quality indicators that could predict the remaining shelf-life between 5 °C and 25 °C were the TVC and WL. Vitamin C loss was only suitable when storage temperature was above 10 °C. The remaining shelf-life in a real supply chain in terms of the TVC, vitamin C loss, and WL were 9.9, 3.5, and 4 days, respectively. Overall, the shelf-life prediction model developed using selected key indicators may help in managing temperature in the fresh-cut fruit supply chain and improving storage shelf-life.

Xanthan gum coatings augmented with lemongrass oil preserve postharvest quality and antioxidant defence system of Kinnow fruit under low-temperature storage

Kinnow mandarin is an important citrus fruit that undergoes various postharvest qualitative losses. Therefore, the present study aimed to investigate the effect of polysaccharide-based xanthan gum (XG) coatings and lemongrass essential oil (LG) on the nutritive quality of Kinnow mandarins stored at 5-7 °C, 90-95 % RH for 75 days. The results revealed that in comparison to control the coatings maintained the fruit titratable acidity (TA), soluble solid content (SSC), ascorbic acid (AsA) content, total flavonoid content (TFC), and juice content, along with reduced weight loss and spoilage incidence. The coated fruits also exhibited higher sensory quality, total antioxidant activity (TAA), and activities of enzymes; catalase (CAT), peroxidase (POD), and phenylalanine ammonia-lyase (PAL). At the end of storage, the fruits coated with XG 1.0 % + LG 1.0 % exhibited maximum TA (0.69 %), AsA content (203.5 mg L-1), and TFC (0.21 mg g-1) with minimum weight loss (7.57 %) and spoilage (3.01 %) and SSC (11.87 %). The scanning electron microscopic (SEM) images of the coated fruits also exhibited smooth surfaces with closed stomata pores. Overall, XG 1.0 % + LG 1.0 % proved as a potential postharvest treatment for maintaining the nutritive quality of Kinnow under low-temperature storage.

New insight into interference-free and highly sensitive dopamine electroanalysis

Early diagnosis of Parkinson's disease and hyperprolactinemia based on electrochemical dopamine (DA) sensing appears as an efficient and promising practical diagnostic method. However, the coexistence of DA in real samples with ascorbic acid (AA) and uric acid (UA), which oxidize at potentials close to its own, prevents the accurate electrochemical DA sensing and therefore, hinders the effective diagnosis of these diseases. In this work, we successfully combined the electrostatic proprieties of GO, the electron transfer properties of an AuNPs@MWCNTs nanocomposite and the ability of thiol group of the amino acid l-cysteine to react chemically with carbonyl groups of UA, to develop a novel approach that enabled complete suppression of interference from AA and UA and hence, accurate DA electroanalysis in the conditions close to those of human blood serum. The chemical reaction between l-cysteine and UA was evidenced by monitoring the DPV responses of UA under different conditions. XRD, Raman spectroscopy, XPS and FE-SEM revealed the successful synthesis of GO and AuNPs@MWCNTs. The study of the electrode material (GO-AuNPs@MWCNTs) morphology via FE-SEM and HR-TEM showed that AuNPs@MWCNTs are distributed throughout the exfoliated GO layers. The fabricated sensor was calibrated in the concentration range of 0.5-5 μM, in the presence of the highest blood concentrations of AA and UA for healthy individuals. A linear relationship was observed and the LOD was found to be 1.31 nM (S/N = 3). Furthermore, the sensor showed good electron transfer kinetics, good repeatability and reproducibility, satisfactory long-term stability, and recoveries in human blood serum.

Carnauba wax-based edible coatings retain quality enhancement of orange (Citrus sinensis cv. Moro) fruits during storage

Fruit coatings serve a dual purpose in preserving the quality of fruits. Not only do they act as a barrier against water evaporation and fungal infiltration, but they also enhance the fruit's visual appeal in the market. Yet, their influence on the fruit's quality components, which play a crucial role in determining its nutritional value, taste, and overall flavor, has remained relatively unexplored. This study aimed to evaluate the effects of carnauba wax coating on the quality of Moro oranges during storage. The selected fruits were meticulously chosen for uniformity in size. The experiment involved applying carnauba wax, a commonly used type among local producers, at four different concentrations: 0%, 0.5%, 1%, and 1.5%. These treatments were applied during various storage periods, including immediately after fruits were harvested and after 40 and 80 days. Following the application of these treatments, the oranges were stored in a controlled environment (morgue) at a temperature of 4 ± 1 °C. Subsequently, several physicochemical parameters of both the fruit flesh and skin were examined. The results unveiled a decline in the overall ascorbic acid content of the fruits. In terms of phenol content, a general decreasing trend was observed after harvesting. At each sampling interval during storage, the phenol content in uncoated fruits consistently exceeded that of their waxed counterparts. Significant reduction in fruit weight was observed throughout the storage period. Both vitamin C and total acidity levels in the fruit exhibited decreases during the storage period. As time passed, fruit firmness gradually declined, while fruit decay increased during the 40- and 80-day storage periods for untreated Moro oranges. The anthocyanin content showed an increasing trend. The study also unveiled a decline in the antioxidant capacity of citrus fruits during storage. Strong significant positive correlations were observed between total phenol content and key parameters, such as antioxidant activity (0.941**), MDA (0.364*), vitamin C content, and total carbohydrate content (0.475**). Skin radiance showed a perfect correlation with chroma and hue (1.000**). Principal component analysis revealed that the first principal component accounted for 34.27% of the total variance, out of a total of five principal components that explained 77.14% of the variance. Through cluster analysis, the variables were categorized into three distinct groups; one associated with weight loss and another with ion leakage. Considering these findings, carnauba wax-based coating emerges as a promising solution for preserving Moro oranges. It effectively mitigates fruit weight loss and helps maintain fruit firmness during storage, making it a valuable tool for fruit preservation.

Acerola (Malpighia emarginata) Anti-Inflammatory Activity-A Review

The manuscript provides an overview of recent scientific reports on the properties and range of health-promoting effects of acerola (Malpighia emarginata DC) fruits and leaves. Acerola is a natural raw material that, in its unprocessed form, is known to be a rich source of vitamin C and polyphenolic compounds. For this reason, the consumption of acerola may provide a number of health-promoting benefits, particularly related to its strong anti-free radical effects. The review discusses anti-inflammatory and anticancer effects of acerola fruit and leaves as well as its therapeutic effects on selected physiological processes in the human system. Their biochemical mechanisms are also explained. Recommendations for the consumption of acerola in the prevention of inflammatory and free radical diseases are presented. The part of the article devoted to anticancer effects of acerola describes the possibilities of using the edible parts of this raw material to obtain products and preparations of potential use in cancer prevention and therapy.

Impact of 24-epibrassinoliode and methyl jasmonate on quality of Red Delicious apples

BACKGROUND

Changes in apple fruit quality indices in response to foliar spray with 24-epibrassinolide (EBL) at 0 and 1 μmol L-1 and methyl jasmonate (MeJA) at 0 and 0.5 μmol L-1 , as well as the combination of these phytohormones, were investigated at harvest and during cold storage.

RESULTS

Both phytohormones synergistically enhanced the fruit firmness, specific weight, size, fresh weight, water content, total antioxidant activity, total phenolics, ascorbic acid, total anthocyanins, total soluble solids/titratable acidity ratio and precocity. In addition, the fruit abscission pattern was changed in response to different treatments. Treated fruit exhibited lower weight loss and internal breakdown symptoms and higher total soluble solids index, firmness and phytochemicals during cold storage. A negative correlation was seen between fruit mass, firmness, specific weight, antioxidant activity, total phenolics and vitamin C content with internal breakdown occurrence and weight loss.

CONCLUSION

Foliar spray with EBL and MeJA during the growth season is a good environmental friendly and safe method for enhancing the apple fruit different quality parameters, marketability and postharvest life. © 2023 Society of Chemical Industry.

Development and evaluation of earth air heat exchanger cum evaporative cool system as an energy-efficient method for storage of tomatoes

BACKGROUND

The lack of adequate on-farm storage facilities is one of the leading causes of enormous postharvest losses of fresh commodities, negatively affecting farmers' livelihoods and the sector's economic contribution. The aim of the current study was to develop and evaluate a solar-powered earth air heat exchanger cum evaporative cooling (EAHE-EC) system as an energy-efficient method for the storage of fresh produce for smallholders.

RESULTS

The postharvest quality parameters of tomatoes stored under ambient storage (AS) and in an EAHE-EC system were assessed at regular time intervals during storage. These include weight loss, total soluble solids, titratable acidity, fruit firmness, color, pH, ascorbic acid, lycopene content, total phenolic acid, and antioxidant activity. The average temperature and relative humidity inside the EAHE-EC system varied from 20.59 to 22.61 °C and 82.60% to 89.43%, respectively, in comparison with AS (26.39-39.21 °C and 22.09-43.58%). Storage methods and time had a significant (P < 0.05) effect on tomato quality. Based on the retention of the overall quality until the end of the storage period, the shelf life of tomatoes was recorded as 21 days in the EAHE-EC system, which was 1.5 times more than AS (14 days).

CONCLUSIONS

The extra shelf-life gained by tomatoes in the EAHE-EC system may provide a sufficient buffer period for smallholders for retailing and marketing. This suggests that the developed system can maintain postharvest quality and increase the shelf life of tomatoes. It therefore has potential as an energy-efficient system for the storage of fruits and vegetables, including tomatoes. © 2023 Society of Chemical Industry.

Antioxidant Activity Analysis of Native Actinidia arguta Cultivars

Kiwiberry (Actinidia arguta) is a perennial fruit tree belonging to the family Actinidiaceae. Kiwiberries are known to have an extremely high concentration of sugars, phenolics, flavonoids, and vitamin C, and possess delicious taste and health-promoting properties. Numerous studies have focused on kiwiberry fruits, demonstrating that they possess a higher phytochemical content and greater antioxidant activities than other berry fruits. The purpose of this study was to compare the phytochemical content and antioxidant potential of leaf, stem, root, and fruit extracts from twelve kiwiberry cultivars grown in Wonju, Korea, characterized by a Dwa climate (Köppen climate classification). In most kiwiberry cultivars, the total phenolic (TPC) and total flavonoid (TFC) phytochemical content was significantly higher in leaf and stem tissues, while the roots exhibited higher antioxidant activity. In fruit tissues, the TPC and TFC were higher in unripe and ripe kiwiberry fruits, respectively, and antioxidant activity was generally higher in unripe than ripe fruit across most of the cultivars. Based on our results, among the 12 kiwiberry cultivars, cv. Daebo and cv. Saehan have a significantly higher phytochemical content and antioxidant activity in all of the tissue types, thus having potential as a functional food and natural antioxidant.

Ultrasound treatment alleviates external pericarp browning and improves fruit quality of pomegranate during storage

BACKGROUND

Ultrasound treatment has a beneficial role in horticultural production from harvest to consumption. The quality traits and microbiological load in pomegranate fruit were explored during 30 days' storage at 20 °C after 10 min and 30 min ultrasound treatments.

RESULTS

Ultrasound treatment significantly reduced the microbiological load during storage, providing a relatively clean and suitable storage environment. This was especially true for the 30 min treatment, which also maintained relatively lower weight loss and kept the browning rate below 5% during storage. Meanwhile, the fruit treated with ultrasound had higher ascorbic acid and anthocyanin content, which provided better antibacterial properties and higher nutraceutical properties until the end of storage. The 30 min ultrasound treatment significantly delayed the decrease in catalase (CAT) enzyme activity and the increase in peroxidase (POD) enzyme activity. Combined with weighted gene co-expression network analysis (WGCNA), and correlation analysis, color indicators and antioxidant activity induced by ultrasound treatment were responsible for the relatively higher fruit quality of pomegranate.

CONCLUSION

Ultrasound treatment can improve the sensory quality and nutritional characteristics of pomegranate fruits during storage, and reduce the microbiological load. Ultrasound for 30 min was better than 10 min for prolonging the storage life of pomegranate. Our results will provide valuable information for ultrasound application in other horticultural products. © 2023 Society of Chemical Industry.

Arabinan-rich pectic polysaccharide fraction from Malpighia emarginata fruits alleviates inflammatory pain in mice

Malpighia emarginata (Malpighiaceae), popularly known as "acerola", is a tropical and subtropical fruit native to the Americas. Despite its high vitamin C content, which gives it a high antioxidant property, soluble dietary fibers, such as polysaccharides, are also abundant constituents of acerola (10% of the dried fruit). The acerola cold-water soluble (ACWS) fraction presented anti-fatigue and antioxidant effects in vivo and in vitro. To infer further systemic effects of ACWS, this study aimed to investigate the antinociceptive, anti-inflammatory, and antioxidant effects of ACWS in murine models of pain. In formalin-induced nociception, ACWS (0.1, 1, and 10 mg/kg) reduced only the inflammatory phase, and also (10 and 30 mg/kg) attenuated the acetic acid-induced writhing and leukocyte migration in the peritoneal cavity. The mechanical allodynia and paw edema induced by intraplantar injection of carrageenan were greatly reduced by ACWS (10 mg/kg). At the inflammatory pick induced by carrageenan (4 h), ACWS significantly reduced myeloperoxidase activity, TNF-α, IL-1β, and PGE2 levels, and restored IL-10 levels. ACWS also exhibited antioxidant properties by decreasing lipid hydroperoxides content, increasing GSH levels, and restoring superoxide dismutase and catalase activities in the carrageenan model and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay. Collectively, these results support the antinociceptive, anti-inflammatory, and antioxidant effects of ACWS and reveal a promising candidate for the treatment of inflammatory pain conditions.

Stability of vitamin C, carotenoids, phenols, and antioxidant capacity of pasteurised orange juice with resistant maltodextrin storage

Resistant maltodextrin (RMD) was added at increasing concentrations (0%, 2.5%, 5% and 7.5%) before pasteurisation to orange juice to analyse its potential protective effect on the health-related bioactive compounds of pasteurised orange juice throughout its storage time. Samples were characterised in terms of basic physico-chemical properties and bioactive compounds at the beginning of the storage. Higher concentrations of RMD proved to better preserve the bioactive compounds of orange juice, thus obtaining a higher antioxidant capacity (AC). Stability of all samples was determined by measuring the same parameters at days 0, 15, 45, 75, 105, 136 and 170 of storage. °Brix and pH were very stable in all samples along storage, while all bioactive compouds had negative variations. However, RMD addition slightly improved ascorbic acid, vitamin C, total phenols, and total carotenoids retention, improving then its AC. This effect was greater in the 5% RMD-added samples. All bioactive compounds showed a positive Pearson's correlation coefficient with AC. Colour variations were also measured at days 105 and 170. All samples had a positive variation of all colour parameters, being this clearer at day 170. This work enlights the potential functionality of RMD to better preserve the health-related compounds of pasteurised orange juice.

Development of silver nanoparticles based on the method using quince seed mucilage for ascorbic acid determination

INTRODUCTION

Nanoparticles are used in various fields such as chemistry, pharmacy, biotechnology, and food science since they provide higher sensitivity than traditional optical detection methods. Recently, synthesis of nanomaterials using green chemistry has become popular. Many phytochemical components are used in the synthesis of nanoparticles, including vitamins, proteins, polysaccharides, glycosides, essential oils and phenolic compounds.

OBJECTIVE

A novel green nanotechnology-based method using quince seed mucilage (QSM) was designed for the determination of ascorbic acid in pharmaceutical preparations. QSM, a natural polysaccharide, was used as a bioreducing and stabilizing reagent in the proposed silver nanoparticle (SNP)-based method.

METHOD

In the first stage of the developed method, silver(I) is reduced to silver(0) via QSM and spherical, homogeneous SNPs were prepared (QSM-SNPs). In the second stage of the developed method, SNPs nuclei were enlarged with the addition of ascorbic acid. The developed method was validated by performance parameters (linearity, recovery, and precision). Ascorbic acid determination was performed by measuring increase in absorbance at 420 nm.

RESULTS

The limit of detection and limit of quantification for ascorbic acid were, respectively, found to be at 0.27 and 0.90 μM. The QSM-SNP-based method was successfully applied to effervescent tablets containing ascorbic acid. The standards of the excipients frequently used in pharmaceutical preparations did not interfere with the developed method.

CONCLUSION

The developed QSM-SNP-based method satisfies the requirements of green nanotechnology. The developed QSM-SNP-based method is simple, fast, eco-friendly and low-cost.

An opportunity for acerola pulp (Malpighia emarginata DC) valorization evaluating its performance during the block cryoconcentration by physicochemical, bioactive compounds, HPLC-ESI-MS/MS, and multi-elemental profile analysis

The present study evaluated the effect of cryoconcentration of pulp blocks of acerola (Malpighia emarginata DC). The study evaluated cryoconcentration in three stages. The cryoconcentrated samples, the ice fractions, and the initial pulp were evaluated for physicochemical composition, bioactive composition, and multielement profile. The cryoconcentrated sample obtained in the third stage of cryoconcentration showed the best results for the concentration factor, process efficiency, total soluble solids content, red color intensity, and increasing of the macro and micronutrients: Cu, Ca, S, Sr, K, Mn, Na, P, Mg, Fe. All stages presented good performance in the total soluble solids content, increase in the titratable acidity of the concentrates, and progressive increase in the intensity of the red color. Generally, higher levels of total phenolic and antioxidant activity were found for the 2nd and 3rd concentrates. The phenolic activity showed an increase of 166.90% in the 3rd stage concentrate compared to fresh pulp, and the antioxidant activity was 112.10% by the ABTS method and 131.60% by the DPPH method, both in the 3rd stage concentrate. The major individual polyphenols were Ferulic acid, Protocatechuic acid, and Taxifolin, with significant increases in the concentration of the compounds in the 2nd and 3rd stage concentrates. In addition, the contents of potentially toxic metals were below detection limits. During the cryoconcentration process, there was a decrease in the values ​​of vitamin C content, moisture content, density, and elements Cu, Sr, and Zn.

Determination of vitamin c in raw fruit and vegetable homogenates: dietary exposure and health effects of excess intake in adults and children

Objective

The aim of the study was to determine Vitamin C content in some fruits and vegetables (FAV) including apple, banana, orange, pineapple, watermelon, carrot and cucumber, sold in the local markets in Awka, Anambra State, Nigeria as well as Vitamin C content in two-component and three-component homogenates FAV. The work was also designed to investigate the dietary exposure and health effects of excess vitamin C intake in adults and children.

Material and methods

Vitamin C as total ascorbic acid (AA) after reduction of dehydroascorbic acid was analyzed using both titrimetric and spectrophotometric methods. The titrimetric method involved iodometric back-titration while the spectrophotometric method was done at an absorbance of 530 nm. The dietary exposure was evaluated as the total FAV intake multiplied by chemical concentration in the FAV whereas the health effect of excess vitamin C intake was conducted using the hazard quotient (HQ).

Results

The results revealed that Vitamin C for single fruits ranged from 11.76 - 41.17 mg/L for spectroscopic method and 16.9 - 31.84 mg/L for titrimetric method. Fruit homogenates showed Vitamin C concentrations of 14.70 - 220.58 mg/L and 17.23 - 209.09 mg/L for two-components homogenates: 29.41-132.35 mg/L and 31.05-113.10 mg/L for tri-components homogenates for spectrophotometric and titrimetric methods respectively. The results of dietary exposure and the health effects of excess vitamin C intake showed that children are more susceptible to health issues than adults in illnesses such as nausea, gastrointestinal pains, increased kidney stones and hyperactivity.

Conclusion

There is therefore the need for a national recommended dietary allowance for total ascorbic acid (AA) in FAV homogenates from a stakeholder point of view in Nigeria.

Characterization and bioaccessibility assessment of bioactive compounds from camu-camu (Myrciaria dubia) powders and their food applications

Camu-camu (Myrciaria dubia) is a tropical fruit known for its content of bioactive compounds. This study aimed to evaluate physicochemically, morphologically, andsensorialpowders from camu-camu obtained by spray-drying at two inlet temperatures (150 °C and 180 °C) with three encapsulating agents (maltodextrin, whey protein and a 50:50 mixture of both) and by freeze-drying of whole fruit. The use of maltodextrin protected bet anthocyanins (cyanidin-3-glucoside (C3G) and delphinidin-3-glucoside (D3G)), but whey protein showed a better protective effect on ascorbic and malic acids. These facts were confirmed during the storage stability test, finding that relative humidity is a critical variable in preserving the bioactive compounds of camu-camu powders. The powders with the highest content of bioactive compounds were added to a yogurt and a white grape juice, and then sensory evaluated. The bioaccessibility studies in gastric and intestinal phases showed better recovery percentages of bioactive compounds in camu-camu powders (up to 60.8 %) and beverages (up to 90 %) for C3G, D3G, ascorbic acid, and malic acid than in the fruit juice. Dehydration of camu-camu (M. dubia) is a strategy to increase the bioactive compounds stability, modulate the fruit sensory properties, and improve their bioavailability after incorporation in food matrices.

Comparison of several HPLC methods for the analysis of vitamin C

Ascorbic acid is a water-soluble vitamin common in food and dietary supplements. A usual problem with ascorbic acid analysis is the lack of stability of its samples and standard solutions owing to oxidation. A procedure to protect ascorbic acid from oxidation using mercaptoethanol is described in this study in connection with the comparison of three HPLC measuring methods. Two reversed-phase columns were evaluated for the separation. One technique uses UV detection, and two others use MS/MS detection. The methods were calibrated for quantitation on different ranges of concentrations. The LC-UV method covers the range 3.9 μg/ml to 500 μg/ml, one LC-MS/MS the range 80 ng/ml to 20 μg/ml, and the other 0.1 ng/ml to 20 μg/ml. As a proof of functionality all three methods were utilized for measuring vitamin C in energy drinks and chews (gummies). The sensitivity of LC-MS/MS methods was not necessary for the analysis of those samples, but the high sensitivity can be beneficial for other types of sample such as environmental or biological, where the levels of ascorbic acid are very low. The study showed that the formation of 2,3-diketogulonic acid is not a likely path for ascorbic acid oxidation following hydrolysis as reported in some studies.

Development of a biodegradable microfluidic paper-based device for blood-plasma separation integrated with non-enzymatic electrochemical detection of ascorbic acid

In the present article, we developed an electrochemical microfluidic paper-based device (EμPAD) for the non-enzymatic detection of Ascorbic Acid (AA) concentration in plasma using whole human blood. We combined LF1 blood plasma separation membrane and Whatman grade 1 filter paper to separate plasma from whole blood through wax printing. A screen-printed electrode (SPE) was modified with spherical-shaped MgFe2O4 nanomaterial (n-MgF) to improve the catalytic properties of SPE. The n-MgF was prepared via hydrothermal method, and its material phase and morphology were confirmed via XRD, FTIR, TEM, SEM, and AFM analysis. The fabricated n-MgF/SPE/EμPAD exhibited detection of AA ranging from 0 to 80 μM. The obtained value of the detection limit, limit of quantification, sensitivity, and response time are 2.44 μM, 8.135 μM, 5.71 × 10-3 mA μM-1 cm-2, and 10 s, respectively. Our developed n-MgF/SPE/EμPAD shows marginal interference with the common analytes present in plasma, such as uric acid, glutamic acid, glucose, urea, lactic acid, and their mixtures. Overall, our low-cost, portable device with its user-friendly design and efficient plasma separation capability offers a practical and effective solution for estimating AA concentration from whole human blood in a single step.

Impact of refrigerated storage on (bio)chemical conversions of health-related compounds in pretreated, pasteurized Brussels sprouts and leek

Vegetable processing often consists of multiple processing steps. Research mostly focused on the impact of individual processing steps on individual health-related compounds. However, there is a need for more holistic approaches to understand the overall impact of the processing chain on the health potential of vegetables. Therefore, this work studied the impact of pretreatment (relatively intact versus pureed vegetable systems), pasteurization and subsequent refrigerated storage (kinetic evaluation) on multiple health-related compounds (vitamin C, vitamin K1, carotenoids, glucosinolates and S-alk(en)yl-L-cysteine sulfoxides (ACSOs)) in Brussels sprouts and leek. It could be shown that differences introduced by different types of pretreatment were not nullified during pasteurization and refrigerated storage. Clearly, enzymatic conversions controlled during pretreatment resulted in different health-related compound profiles still observable after pasteurization. Moreover, about -42% and -100% relative concentration differences of ACSOs and dehydroascorbic acid, respectively, were detected immediately after pasteurization, while glucosinolates concentrations decreased by about 47% during refrigerated storage. All other compounds were stable during pasteurization and refrigerated storage.

Changes in bioactive compounds and antioxidant activity of three Amaranthus L. genotypes from a model to household processing

Amaranthus L. leaves are consumed as vegetables and are a rich source of secondary plant metabolites. The phenolic profiles of the three analyzed genotypes by LC-Q-TOF-MS/MS and HPLC-DAD were characterized by high amounts of hydroxycinnamic glucaric and -isocitric acids. 'Gartenfuchsschwanz' (A. hybridus L.) and 'Red Callaloo' (A. tricolor L.) had similar profiles. 'Gemüse-Amaranth' (A. tricolor L.) had a high amount of caffeoylglucaric acid 4, which was isolated, and afterward identified by NMR. Its antioxidant activity, measured by TEAC, DPPH, and TPC, was similar to 5-caffeoylquinic acid, common in many plant species. The antioxidant activity of Amaranthus L. can be explained rather by their different phenolic- and ascorbic acid concentrations than by their species. Household cooking reduces antioxidant activity due to oxidation processes while leaching into cooking water could be neglected. Amaranthus L. baked into a wheat-dough-matrix showed lower phenolic concentrations, presumably due to the formation of phenol-protein-bounds and thermal degradation.

Coffee grounds-derived carbon quantum dots as peroxidase mimetics for colorimetric and fluorometric detection of ascorbic acid

In this study, we reported the eco-responsible synthesis of iron-doped carbon quantum dots (Fe-CQDs) from waste coffee grounds through a simple hydrothermal method. The Fe-CQDs exhibited high peroxidase-like activity, which could convert 3,3',5,5'-tetramethylbenzidine (TMB) into blue ox-TMB in the presence of H2O2. After adding ascorbic acid (AA) to above system, the blue solution faded. Based on this phenomenon, a colorimetric method for visual monitoring of H2O2 and AA was developed. Meanwhile, the fluorescence of Fe-CQDs can be quenched by the formed ox-TMB via inner filter effect (IFE), followed by the recovery upon the addition of AA. Therefore, Fe-CQDs can be acted as a fluorescent probe to detect H2O2 and AA through the "on-off-on" mode. Furthermore, the dual-recognition methods based on Fe-CQDs were used to measure AA content in beverage samples. Thus, this work would shed much light on converting waste into biomass CQDs and their potential applications in biomolecular detection.

A novel SERS sensor array based on AuNRs and AuNSs inverse-etching for the discrimination of five antioxidants

Antioxidants play an important role in life health and food safety. Herein, an inverse-etching platform based on gold nanorods (AuNRs) and gold nanostars (AuNSs) for high-throughput discrimination of antioxidants was constructed. Under the action of hydrogen peroxide (H2O2) and horseradish peroxidase (HRP), 3,3',5,5'-tetramethylbenzidine (TMB) would be oxidized to TMB+ or TMB2+. HRP reacts with H2O2 to release oxygen free radicals, which then react with TMB. Au nanomaterials can react with TMB2+, at the same time, Au was oxidized into Au (I), leading to the etching of the shape. Antioxidants, with good reduction ability, would prevent the further oxidation of TMB+ to TMB2+. So the presence of antioxidants will prevent further oxidation while avoiding the etching of Au in the catalytic oxidation process, thereby achieved inverse etching. Distinctive surface enhanced Raman scattering (SERS) fingerprint of five antioxidants were obtained based on the differential ability to scavenge free radicals. Five antioxidants, including ascorbic acid (AA), melatonin (Mel), glutathione (GSH), tea polyphenols (TPP), and uric acid (UA) were successfully distinguished by using linear discriminant analysis (LDA), heat map analysis and hierarchical cluster analysis (HCA). The study exhibits an effective inverse-etching based SERS sensor array for the response of antioxidants, which has great reference value in the field of human disease and food detection.

A robust and facile label-free method for highly sensitive colorimetric detection of ascorbic acid in fresh fruits based on peroxidase-like activity of modified FeCo-LDH@WO3 nanocomposite

Many compounds such as amino acids and oligonucleotides have been shown to effectively change peroxidase-like activity of nanoparticles. While a few studies have focused on mimicking the active site of natural enzymes on nanozymes and thus increasing their substrate affinity. Therefore, in this work, the surface of FeCo@WO3 nanocomposite was modified using guanosine triphosphate (GTP) to mimic the histidine of peroxidase enzyme's active site and its modification was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FT-IR). Then, the peroxidase-mimicking activity of the modified nanocomposite was tested using a colorimetric method, based on the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2). It was found that GTP improves the activity of FeCo@WO3 as a natural peroxidase active site's distal histidine residue. Ascorbic acid (AA) is a powerful antioxidant that induces the reduction of blue color (oxidized TMB) ox-TMB to colorless TMB. The colorimetric method was applied for the sensitive detection of AA in common fruits. The linear range of AA was 10-100 μM with a limit of detection (LOD) of 0.27 μM, which provides a rapid and sensitive method for testing AA in the field of food analysis.

Fruit Juices of Etcho (Pachycereus pecten-aboriginum) and Giant Cardon (Pachycereus pringlei) are Sources of Health-Promoting Ingredients with Potential Anticancer Properties

Mexico is one of the main diversification centers of cacti in the world, with more than 500 endemic species, most of which remain nutritionally and functionally uncharacterized. The columnar cacti of the genus Pachycereus comprise five underutilized endemic Mexican species, whose nutraceutical properties have only been studied in the P. weberi species. Therefore, this study aimed to evaluate the nutritional quality and bioactive properties of etcho (P. pecten-aboriginum) and giant cardon (P. pringlei) fruit. The physical, chemical, and nutritional composition of etcho and giant cardon fruits were characterized, as well as the profile and content of bioactive compounds, antioxidant activity (ABTS•+ and DPPH•), and antiproliferative capacity in cervical (HeLa) and breast cancer (MDA-MB-231, MCF-7, and T-47D) cell lines. Our results suggest that etcho and giant cardon fruits are rich sources of essential nutrients and bioactive phytochemicals (including K, Mg, P, dietary fiber, polyphenolic compounds, vitamin C, betalains, and myo-inositol) with antioxidant and anticancer potential by inhibiting the proliferation of all evaluated cell lines with IC50 values in the range of 198 to 287 µg of gallic acid equivalents/mL. Therefore, etcho and giant cardon fruits could be used for nutraceutical purposes, and their consumption could promote health benefits.

Global Research Trends on the Utilization of Nopal (Opuntia Sp) Cladodes as a Functional Ingredient for Industrial Use

Although nopal cladodes are a valuable bioactive compound source, they have historically been underused. This review draws a parallel between quantitative and qualitative data from the most outstanding scientific research concerning nopal cladodes in the last five years by implementing a bibliometric analysis. Italy, Mexico, Brazil, and Morocco accounted for approximately 55% of the 111 articles selected for this review. Nopal cladodes are a great source of nourishing ingredients such as mucilage, pectin, insoluble fibers, minerals, ascorbic acid, and bioactive compounds such as carotenoids (e.g., β-carotene, lutein, and cryptoxanthin), flavonoids (e.g., isorhamnetin, quercetin, rutin, and catechin), phytosterols (e.g., β-sitosterol and β-campesterol). Additionally, they offer technological benefits as a food ingredient, allied to good sensory acceptability. The findings suggest that medium-aged cladodes (20 days) have the highest concentration of soluble fiber, protein, and bioactive compounds, rendering them the optimal maturity stage for consumption and processing. Therefore, nopal cladodes can be exploited for several industries, including biotechnology, cosmetics, and pharmaceuticals, and they have attracted attention as a promising ingredient for the food industry in the concept of the next generation of innovative and functional vegetable foods.

Reveal the relationship between the quality and the cuticle composition of Satsuma mandarin (Citrus unshiu) by postharvest heat treatment

To investigate the influence of heat treatment (HT) on Satsuma mandarin fruit's postharvest quality and cuticle composition, we immersed the fruit for 3 min in hot water at 52°C and subsequently stored them at room temperature (25°C) for 28 days, and fruit quality parameters, such as good fruit rate, weight loss rate, firmness, total soluble solids, total titratable acidity, and ascorbic acid content, were monitored. Additionally, changes in the peel's cuticle composition were analyzed, and wax crystal morphologies on the fruit surface were examined using scanning electron microscopy (SEM). The findings revealed that appropriate HT effectively preserved fruit quality. The main compositions of wax and cutin on the fruit's surface remained consistent between the HT and the CK during storage. The total content of wax and cutin initially increased, peaking on the 14th day of storage, and then decreased, falling below the levels observed on day 0. Notably, the total amount of cutin in the HT group exceeded that of the control group. Specifically, ω-hydroxy fatty acids with mid-chain oxo groups and mid-oh-ω-hydroxy fatty acids constituted approximately 90% of the total cutin content. Moreover, the HT group exhibited higher (p < 0.05) total wax content in relation to the control. Fatty acids and alkanes were the predominant components, accounting for approximately 87.5% of the total wax. SEM analysis demonstrated that HT caused wax crystals to melt and redistribute, effectively filling wax gaps. It suggests that HT holds promising potential as a green, safe, and eco-friendly commercial treatment for preserving the postharvest quality of Satsuma mandarin. PRACTICAL APPLICATION: In this study, Satsuma citrus (Citrus unshiu) underwent heat treatment (HT) and was subsequently preserved at room temperature (25°C) for 28 days. The findings revealed that HT significantly improved fruit quality compared to the control group. These findings provide valuable insights into the advancement of eco-friendly and pollution-free citrus preservation methods, offering essential strategies and process parameters for their practical application.

Nano and chelated iron fertilization influences marketable yield, phytochemical properties, and antioxidant capacity of tomatoes

Iron (Fe) is one of the limiting micronutrients essential for crop productivity. The goal of our study was to evaluate the effects of different sources and rates of Fe fertilization on the marketable yield, physical and chemical properties, and phytochemical quality of fresh market tomatoes (Solanum Lycopersicum L., cv. Sunbrite). A factorial experiment under a drip-irrigated plasticulture system was conducted in a completely randomized design with two sources of Fe (nano vs. chelated) and four rates of application (0, 10, 20, and 40 mg/L) with four replications. Results indicated that relative chlorophyll concentration in the leaf (SPAD index) increased significantly (by 24 to 27%) with 10 and 20 mg/L of both nano- and chelated Fe fertilization compared to the control. Increasing Fe fertilization decreased the leaf SPAD readings. The total fruit yield of tomato was 1.6 to 1.8 times higher under the chelated- and nano Fe fertilization and the increase in yield was significantly higher under the chelated Fe fertilization, when compared to the control. In contrast, the tomato harvest index was highest under 10 and 20 mg/L of nano Fe than under other Fe treatments. While the chelated Fe fertilized tomatoes had significantly higher concentrations of vitamin C (34%), ß-carotene (6%), total carotene (25%), flavonoid (17%), and polyphenol (66%), the nano Fe, in contrast, increased ß-carotene, total carotene, and polyphenol concentrations by 25, 33, 51, and 7%, respectively, compared to the control. The 20 mg/L chelated Fe significantly increased the vitamin C, total carotene, flavonoid, polyphenol concentration, and antioxidant capacity more than any other Fe treatments. Based on the principal components analyses, vitamin C, lycopene, and anthocyanin were identified as the core indicators of the tomato nutrition quality index (NQIndex). The NQIndex ranged from 47 to 54, falling within the medium level of nutritional quality (40 to <70). In conclusion, the chelated Fe, when applied at 20 mg/L, was the most appropriate rate based on highly correlated connectivity for the phytochemicals syntheses associated with the improved tomato antioxidant capacity.

Environmental pollution biomonitoring around a cement factory based on the Air Pollution Tolerance Index of some tree species

The present study examined the ability of Quercus castaneifolia C.A.M., Parrotia persica C.A.M., and Carpinus betulus L. for environmental pollution biomonitoring based on the Air Pollution Tolerance Index (APTI). Four leaf traits, total leaf chlorophyll content, leaf extract pH, ascorbic acid content, and relative water content of leaf, were used to compute the APTI values. The study was conducted at five sites in the Hyrcanian forests at different distances from a cement factory close to the Neka city, northern Iran. Based on the results, a 22.5, 30.1, and 25.8% decrease was thus recorded in total chlorophyll content for Q. castaneifolia, P. persica, and C. betulus, respectively, compared to the reference site. However, ascorbic acid content shows an increment of 179.8, 116.8, and 97.3% for P. persica, C. betulus, and Q. castaneifolia, respectively, in the polluted sites as compared to the reference site. The relative water content of P. persica was significantly higher than of Q. castaneifolia and C. betulus in all studied sites. APTI was significantly different among the species, and P. persica was highly tolerant to air pollution, with the highest values of APTI ranging from 11.8 to 16.9. The APTI values of Q. castaneifolia ranged from 9.5 to 11.3 and showed an intermediate tolerance to air pollution. Also, the most sensitive species to air pollution was C. betulus, with a range of 6.6-7.9 in APTI values. Based on APTI values, it can be suggested that P. persica can be used as a biomonitor, while C. betulus can be used as a bioindicator for atmospheric dust deposition and heavy metal pollution.

In vitro anticholinergic and antiglycaemic properties of frost-hardy Actinidia fruit extracts and their polyphenol profile, L-ascorbic acid content and antioxidant capacity

The aim of this study was to investigate the inhibitory effects of Actinidia arguta ('Weiki', 'Skarlet September Kiwi') and Actinidia kolomikta ('Lande') fruit extracts against advanced glycation end-products (AGEs) formation and acetylcholinesterase (AChE) activity. The extracts were also tested regarding polyphenol profile and Lascorbic acid content (UHPLC-DAD-MS), and antioxidant capacity (DPPH, ABTS). 'Scarlet September Kiwi' showed the strongest anti-AGEs activity studied with BSAGLU (IC50 = 2.68) and BSA-MGO (IC50 = 18.06) models. The highest anti-AChE activity was found for the 'Lande' extract (IC50 = 4.56). 'Lande' showed the highest L-ascorbic acid content (8271.96 µg/g dw), ABTS (312.42 µmol TE/g dw) and DPPH (282.01 µmol TE/g dw) values. 'Scarlet September Kiwi' revealed the highest individual phenolics concentration (2321.43 µg/g dw). The contents of (+)-catechin and L-ascorbic acid were significantly correlated with anti-AChE activity. This research sheds new light on the bioactivity of Actinidia arguta and Actinidia kolomikta fruit elucidating the role of (+)-catechin and L-ascorbic acid in prevention of Alzheimer's disease.

Effect of dielectric barrier discharge nonthermal plasma treatment on physicochemical, nutritional, and phytochemical quality attributes of pineapple [Ananas comosus (L.)] juice

Forward feed multilayered perception and central composite rotatable design were used to model the nonthermal plasma (NTP) experimental data in artificial neural network (ANN) and response surface methodology, respectively. The ANN was found to be more accurate in modeling the experimental dataset. The NTP process parameters (voltage and time) were optimized for pineapple juice within the range of 25-45 kV and 120-900 s using an ANN coupled with the genetic algorithm (ANN-GA). After 176 generations of GA, the ANN-GA approach produced the optimal condition, 38 kV and 631 s, and caused the inactivation of peroxidase (POD) and bromelain by 87.24% and 51.04%, respectively. However, 100.32% of the overall antioxidant capacity and 89.96% of the ascorbic acid were maintained in the optimized sample with a total color change (ΔE) of less than 1.97 at all plasma treatment conditions. Based on optimal conditions, NTP provides a sufficient level of POD inactivation combined with excellent phenolic component extractability and high antioxidant retention. Furthermore, plasma treatment had an insignificant effect (p > 0.05) on the physicochemical attributes (pH, total soluble solid, and titratable acidity) of juice samples. From the intensity peak of the Fourier-transform infrared spectroscopy analysis, it was found that the sugar components and phenolic compounds of plasma-treated juice were effectively preserved compared to the thermal-treated juice.

Integration of metabolomics and transcriptomics analyses reveals the mechanism of nano-selenium treated to activate phenylpropanoid metabolism and enhance the antioxidant activity of peach

Foliar spraying to improve the quality of fruits is a general approach nowadays. In this study, 10 ppm nano-selenium (nano-Se) diluted with distilled water was sprayed on peach leaves every 10 days for a total of 7 sprays during the fruit set period. And then their fruit quality was compared with that of control group. It was found that the firmness, soluble solid concentration, total phenol, and proanthocyanidin content of the peaches were raised after the nano-Se treatment. Moreover, the ascorbic acid glutathione loop (ASA-GSH loop) was fully activated in the nano-Se treated group, and the associated antioxidant capacity and enzyme activity were significantly increased. Metabolomics revealed that nano-Se could upregulate some metabolites, such as phenylalanine, naringenin, and pinocembrin, to fully activate the metabolism of phenylpropanoids. Further, based on transcriptomics, nano-Se treatment was found to affect fruit quality by regulating genes related to phenylpropanoid metabolism, such as arogenate/prephenate dehydratase (ADT), genes related to abscisic acid metabolism such as (+)-abscisic acid 8'-hydroxylase (CYP707A), and some transcription factors such as MYB. Based on the comprehensive analysis of physicochemical indicators, metabolomics, and transcriptomics, it was found that nano-Se improved fruit quality by activating phenylpropanoid metabolism and enhancing antioxidant capacity. This work provides insights into the mechanism of the effect of nano-Se fertilizer on peach fruit quality. PRACTICAL APPLICATION: The firmness and soluble solid concentration of peaches are higher after nano-Se treatment, which is more in line with people's demand for hard soluble peaches like "Yingzui." The antioxidant capacity, antioxidant substance content, and antioxidant enzyme activity of nano-Se-treated peaches are higher, with potential storage resistance and health effects on human body. The mechanism of nano-Se affecting peach quality was analyzed by metabolomics and transcriptomics, which is a reference and guide for the research and application of nano-Se.

The effect of layers of high tunnel covering and soil mulching on tomato fruit quality

BACKGROUND

High tunnels (HT) and plastic mulch can increase yield, extend growing seasons, protect plants from harsh weather conditions, and produce more marketable and attractive tomatoes. However, plastic covering reduces solar radiation, which may affect the quality of tomatoes. This study investigated the effects of single-layer versus double-layer HT and plastic mulch versus bare soil on the quality of fully ripe tomato fruits. The study was conducted over 2 years (2021 and 2022). The fruit color (L*, a*, and b*), vitamin C, pH, total titratable acid (TTA), total soluble solids (TSS), and lycopene content of the two tomato cultivars (Brandywine and Rebelski) were quantified.

RESULTS

The results showed that quality parameters varied with the plastic layers of HT, plastic mulch, and planting year. The double-layer HT only showed a slight but significant influence on the color of tomatoes of both cultivars in the same year (P < 0.05). Brandywine tomatoes grown in the double-layer HT had significantly lower pH and lycopene content than those grown in single-layer HT, regardless of mulching. The effect of plastic layers on TTA, TSS, and lycopene depended on whether the soil was mulched. Tomatoes grown on bare soil had higher TTA and TSS values than those grown on mulched soil in double-layer HT. Tomatoes grown in single-layer HTs had significantly higher vitamin C content than those in the double-layer HT for both cultivars regardless of mulching.

CONCLUSION

This study demonstrates that double-layer HT is unnecessary for the improvement of the overall quality of tomatoes. © 2023 Society of Chemical Industry.

Catechol oxidase nanozyme based colorimetric sensors array for highly selective distinction among multiple catecholamines

In order to effectively monitor multiple catecholamine (CA) neurotransmitters with extreme similar structures, a rapid, sensitive and selective detection strategy has become an urgent problem to be solved. In this paper, a novel colorimetric sensors array based on CuNCs protected by various ligands such as tannic acid, ascorbic acid and polymethylacrylic acid (CuNCs@TA, CuNCs@AA and CuNCs@PMAA) was constructed. All of these CuNCs could mimic catechol oxidase to selective catalyze catechol-type analogues (such as CAs) to corresponding quinones along with color changes. Furthermore, experiments and theory calculations demonstrated that Cr6+-modification on the surface of CuNCs facilitated the steady-state kinetics of enzymatic activity. Based on these CuNCs as sensing probes, this sensors array can quickly detect different CAs (such as epinephrine (EP), including dopamine (DA), norepinephrine (NE) and l-dopa) with similar structures. When those analogues were added to the CuNC-based colorimetric array sensors, different absorbance changes were produced at 485 nm. Linear discriminant analysis (LDA) showed that the tri-probe colorimetric array sensors could recognize and distinguish these analogues, and corresponding binary and ternary mixtures could be well categorized. The value of Factor 1 of an array with varied CA concentrations had a good linear correlation, and the detection limit (LOD) was as low as 10-8∼10-9 mol/L. Four CA analogues in real samples were identified by CuNCs-based colorimetric array sensors. This work provides a fast and convenient experimental basis for monitoring the complex structure CAs neurotransmitters.

Using Cu2+ to regulate the emission feature of near-infrared fluorescent sensor with AIE: To detect ascorbic acid in food samples and its application in bioimaging

Conventional ascorbic acid (AA) detection methods such as chromatography, capillary electrophoresis, colorimetry, electrochemical detection, and enzymatic analysis require expensive equipment and complicated operation. Simple, rapid, and accurate AA detection is essential to inspect food quality, diagnose diseases, and assess immunity in humans. In this study, the first near-infrared fluorescence sensor DBHM with aggregation-induced emission was developed to detect AA under the involvement of Cu2+. The DBHM + Cu2+ sensor showed high sensitivity to AA with a limit of detection of 2.37 μM. The AA detection mechanism was investigated by optical studies, 1H NMR titration, high-resolution mass spectrometry, and infrared spectroscopy. AA was detected qualitatively and quantitatively by the DBHM + Cu2+ sensor in beverages, fruits, and Vitamin C tablets using a dual-mode (fluorescence and smartphone app) sensing platform. The new sensing system also showed low toxicity and excellent bioimaging in HeLa cells, C. elegans, and mice. This sensor could advance AA detection technology in the food industry and has potential bioimaging applications.

Effect of ultra violet (UV-C) and cold storage on orange juice quality

The effect of the UV-C treatment on the physico-chemical characteristics, pectin methylesterase activity (PME) as well as microbial quality of orange juice, compared to fresh juice, was studied. The juice samples were UV-C (254 nm) irradiated for different exposure times (15, 30, 45 and 60 min) and stored at 4 ± 1 °C for 30 days. UV-C treatment didn't significantly (p ≤ 0.05) affect pH values, titratable acidity, TSS (%), ascorbic acid content and PME activity in both fresh and stored samples. Increasing the exposure time from 5 to 60 min. showed no significant effect (p ≤ 0.05) on L* and a* values for both the fresh and the stored samples. On the contrary, negative relationship was observed between UV-C exposure time and b* values. Total bacterial counts were significantly (p ≤ 0.05) reduced from 2.69 to 0.93 log10 CFU/mL when the exposure time was increased from 0 to 60 min. The UV-C treatment showed similar trend on yeast and mold counts but to a lesser extend due to their resistance to UV. The sensory characteristics, i.e. odour, colour, taste, consistency and overall acceptability didn't change (p ≤ 0.05) as a result of UV-C treatment at any tested exposure times.

Porous carbon nanosheets derived from two-dimensional Fe-MOF for simultaneous voltammetric sensing of dopamine and uric acid

It is of great significance for electrochemical sensors to simultaneously detect dopamine (DA) and uric acid (UA) related to biological metabolism. In this work, two-dimensional (2D) porous carbon nanosheets (CNS) was prepared as electrocatalysts to improve the sensitivity, the selectivity, and the detection limit of the simultaneous detection. First, 2D amorphous iron-metal organic frameworks (Fe-MOF) was synthesized with Fe3+and terephthalic acid via a facile wet chemistry method at room temperature. And then, CNS was prepared by pyrolysis and pickling of Fe-MOF. CNS had large specific surface area, good electrical conductivity and lots of carbon defects. The response currents of the CNS modified electrode was larger than those of the control electrodes in the simultaneous determination. The simultaneous determination was measured via differential pulse voltammetry to reduce the effect of capacitive currents on quantitative analysis. The CNS modified electrodes showed high sensitivity and low detection limit for the simultaneous detection of DA and UA. The modified electrodes have been successfully used to detect DA and UA in normal human serum.