Development and validation of a liquid chromatographic method to quantify sucrose, glucose, and fructose in tubers of Solanum tuberosum Group Phureja

Green synthesized gold nanoparticles and CuO-based nonenzymatic sensor for saliva glucose monitoring

Glucose, essential for brain and muscle functions, requires careful monitoring in diabetes and other chronic disease management. While blood glucose monitoring provides precise information about these diseases, it remains an invasive method. Saliva glucose monitoring could offer an alternative approach, but the glucose concentration in saliva is very low. In this work, we report a simple, low-cost, highly sensitive nonenzymatic electrochemical glucose sensor. We developed this sensor using green synthesized gold nanoparticles (AuNPs) and wet chemical synthesized copper oxide (CuO) nanoparticles on a screen-printed carbon electrode (Au/CuO/SPCE). The sensor's high sensitivity results from dual amplification strategies using AuNPs and CuO nanomaterials, each demonstrating catalytic activity towards glucose. This shows promising potential for saliva glucose monitoring. The AuNPs were synthesized using an Au precursor and orange peel extract (OPE), yielding stable colloidal AuNPs with a mean diameter of about 37 nm, thus eliminating the need for additional capping agents. Under optimal conditions, amperometric tests revealed that the sensor responded linearly to glucose concentrations ranging from 2 μM to 397 μM with a sensitivity of 236.70 μA mM-1 cm-2. Furthermore, the sensor demonstrated excellent reproducibility, stability and high selectivity for glucose in the presence of different biomolecules. We validated the sensor's efficacy by measuring glucose in human saliva, showing its potential for noninvasive glucose monitoring. This research advances the development of point-of-care devices, positioning the sensor as a promising tool for noninvasive glucose monitoring and improved diabetes management.

Soluble Carbohydrates in Several Transylvanian Potato Cultivars

This paper is the first to report the soluble carbohydrate content at harvest for eight Transylvanian potato cultivars: Christian, Cumidava, Kronstadt, Riviera, Roclas, Rustic, Tampa and Zamolxis. The aim of this study is to explore the soluble carbohydrate composition of the above-mentioned cultivars, since such quantitative information is important for breeding programs, consumers and processing units. High performance liquid chromatography was used for analysis, separations being achieved using a Prominence Shimadzu system with a refractive index detector, under isocratic conditions with a mobile phase consisting of acetonitrile: water (80:20%) delivered at 1 mL/min; baseline separations of the target analytes were accomplished with an EC 250/4 Nucleodur 100-5 NH₂ RP column in less than 10 min. The carbohydrate concentrations were found to range from 24.03 mg/100 g (Zamolxis) to 76.58 mg/100 g (Riviera) for fructose, while the corresponding range was from 52.78 mg/100 g (Zamolxis) to 232.97 mg/100 g (Riviera) for glucose and from 238.41 mg/100 g (Zamolxis) to 378.45 (Cumidava) for sucrose. Chromatographic data were then subjected to chemometric analysis; the association of these complementary techniques allowed a fast selection of cultivars with low-reducing carbohydrate content for food processing purposes-the cultivars Zamolxis, Kronstadt, Christian and Roclas were outlined exhibiting both the lowest reducing carbohydrate content and the lowest sucrose content.

Elucidating the role of MaBAM9b in starch degradation

Banana is a typical starch conversion fruit. The high content of starch at harvest is quickly digested and converted to soluble sugars during the postharvest ripening process, ultimately contributing to fruit flavor. This process is regulated in a complex manner by genes and environmental factors. MaBAM9b is one of the main enzyme genes previously found by transcriptomic analysis to be highly expressed in banana fruit. However, its exact role in starch degradation remains unclear. Here, full-length MaBAM9b was isolated from banana fruit, and its subcellular localization, protein expression, and transient expression in banana fruit slices were investigated. In addition, sense and anti-sense MaBAM9b were transformed into rice (Oryza sativa L. japonica. cv. 'Nipponbare') to identify the function of MaBAM9b. MaBAM9b was 1599 bp and encoded 532 amino acids. It contained two conserved domains of PLN02803 and glycosyl hydrolase family 14 and was localized in the chloroplast. The protein expression pattern of MaBAM9b remained consistently high throughout banana fruit ripening and starch degradation. Transient overexpression or inhibition of MaBAM9b in banana fruit greatly improved or suppressed starch degradation. Genetic modification of rice indicated that overexpression of MaBAM9b greatly improved starch degradation and seed germination, while inhibition of its expression suppressed these biological processes. These results support the key role of MaBAM9b in starch degradation and provide a target gene for banana fruit quality improvement and biological breeding.

Analysis of edible characteristics, antioxidant capacities, and phenolic pigment monomers in Lilium bulbs native to China

Lilium is cherished for its health-promoting properties in China. The bulbs of Lilium are rich in phenolic compounds, which are associated with antioxidant capacity. However, no systematic evaluation on phenolic compositions and antioxidant capacities for the edible Lilium native to China has been conducted. Herein, bulbs of 56 wild populations and three cultivars were collected. Their edible characteristics, antioxidant capacities, and pigments have been investigated and analyzed. The results showed that phenolic compounds contributed to the major colors (red, yellow and white) in Lilium bulbs. The seven phenolic pigment monomers responsible for the color of bulbs-cyanidin-3-O-rutinoside, isoquercitrin, regaloside B, regaloside C, regaloside H, regaloside A and regaloside D-were identified by the combination of HPLC-MS and NMR analysis. The population Lilium regale E. H. Wilson (Maoxian County, Sichuan Province) had the highest antioxidant capacity. According to the quantification results, Lilium bulbs with darker and redder colors possessed larger biomass, better nutrient compositions, significantly higher bioactive constituents, and higher antioxidant capacities than the three currently consumed cultivars of edible lily bulbs. Overall, these findings suggest that the mountainous area of southwest China could be the fourth source of edible lilies with the bulb-colored Lilium species.

High performance liquid chromatographic method with post-column detection for quantification of reducing sugars in foods

A novel liquid chromatographic analysis method with post-column detection for sugars was developed to improve existing methods in regard to operation time, selectivity, and sensitivity. This method involves separation of reducing sugars on HPLC column at 30 °C and 0.8 mL min^-1 flow rate, post-column reaction of sugars with Cu(II)-neocuproine (Nc) reagent at 80 °C and 0.3 mL min^-1 flow rate, and measurement of Cu(I)-Nc product at 450 nm. The proposed assay was applied to glucose, fructose, maltose, and lactose as reducing sugars. Non-reducing sucrose was determined indirectly, after conversion to its constitutive monomers glucose and fructose by hydrolysis, and analysis with a relative error from -2.41 to 2.09%. Honey, apple juice, and milk samples were evaluated as commercial products. The results obtained with the proposed assay compared to those of the alkaline Cu(II)-Nc reference method were found close to each other, and compatible with the label values of commercial products. The accuracy of the developed method was performed by spiking glucose to honey and lactose to milk samples using two different concentrations. The obtained recoveries with respect to the post-column HPLC method were between 97 and 105% for honey and 96-107% for milk. The method gave linear responses against sugar concentration with correlation coefficients greater than 0.996 for the four analytes (glucose, fructose, maltose and lactose) in a range of 9.0 - 342.3 mg L^-1 with LOD values ≤ 7.4 mg L^-1. With the developed method, it was possible to sensitively determine reducing sugars in various food samples at a lower temperature of post-column reaction (compared to literature values) with easy application of low cost reagents requiring minimal preliminary operation.

Impact of microencapsulated watermelon (Citrullus lanatus) and beetroot (Beta vulgaris L) on storage stability of l-citrulline and dietary nitrate

The aim the current study was to developed a watermelon rind powder (WRP), watermelon pulp powder (WPP), and beetroot powder (BP), in order to compare the stability of L-citrulline and nitrate with that of watermelon rind juice (WRJ), watermelon pulp juice (WPJ), and beetroot juice (BJ), respectively. The stability was evaluated during 32 days at 25, 4 and - 20 ºC. L-arginine and L-ornithine content were also evaluated. At day 0, a significantly higher L-citrulline and L-ornithine content in WRP was observed when compared to WPP. However, a significantly lower L-arginine content in WRP was observed when compared to WPP. L-citrulline content in WRP and WRJ was stable over 32 days in all temperatures evaluated, whereas it reduced in WPP in 32 days at 25 ºC and it is reduced in in WPJ in day 16 and day 32 at 25 °C. L-arginine content in WRP and WPP was stable over 32 days in all temperatures evaluated. A reduction was observed in WRJ at day 2, 4 and 32 at 25 °C and in WPJ at day 2, 4, 8, 16 and 32 days at 25 °C. L-ornithine content in WRP and WPP was stable over 32 days in all temperatures evaluated. An increase was observed in WRJ at day 2, 4 and 32 at 25 °C and in WPJ in day 2, 4, 8, 16 and 32 at 25 °C. Nitrate content in BP was stable over 32 days in all temperatures evaluated, while nitrate content in beetroot juice was reduced in day 2 at 25 °C and day 8 at 4 °C. In conclusion, L-citrulline of the microencapsulated watermelon rind and nitrate of the microencapsulated beetroot were stable throughout storage.

Transcription factor MaMADS36 plays a central role in regulating banana fruit ripening

Bananas are model fruits for studying starch conversion and climactericity. Starch degradation and ripening are two important biological processes that occur concomitantly in banana fruit. Ethylene biosynthesis and postharvest fruit ripening processes, i.e. starch degradation, fruit softening, and sugar accumulation, are highly correlated and thus could be controlled by a common regulatory switch. However, this switch has not been identified. In this study, we transformed red banana (Musa acuminata L.) with sense and anti-sense constructs of the MaMADS36 transcription factor gene (also MuMADS1, Ma05_g18560.1). Analysis of these lines showed that MaMADS36 interacts with 74 other proteins to form a co-expression network and could act as an important switch to regulate ethylene biosynthesis, starch degradation, softening, and sugar accumulation. Among these target genes, musa acuminata beta-amylase 9b (MaBAM9b, Ma05_t07800.1), which encodes a starch degradation enzyme, was selected to further investigate the regulatory mechanism of MaMADS36. Our findings revealed that MaMADS36 directly binds to the CA/T(r)G box of the MaBAM9b promoter to increase MaBAM9b transcription and, in turn, enzyme activity and starch degradation during ripening. These results will further our understanding of the fine regulatory mechanisms of MADS-box transcription factors in regulating fruit ripening, which can be applied to breeding programs to improve fruit shelf-life.

Chemical constituents of fresh-cut potato as affected by cultivar, age, storage, and cooking

Certain changes in phenolics and sugars can occur during the storage of potatoes, where particularly amounts of sugars represent the critical factor as they are involved in potentially harmful acrylamide (AA) formation during frying. This research investigates the impact of cultivars (Birgit and Lady Claire), tuber's age (1, 5, and 9 months), and storage duration (1, 5, and 8 days at 10 °C) on the content of phenolics and sugars in raw, boiled, and fried fresh-cut potato (FCP). The influence of these factors on the formation of AA in fried FCP was also assessed. Significant differences in phenolics and sugars were observed between cultivars (cv. Birgit contained 5.77 mg of phenolics 100 g^-1 of dry weight (DW) and 1.75 g of sugars 100 g^-1 DW, while cv. Lady Claire contained 10.13 mg of phenolics 100 g^-1 DW and 0.65 g of sugars 100 g^-1 DW). The content of phenolics significantly decreased, while sugars increased during tubers' aging. FCP storage time had no significant influence on the content of phenolics and sugars. The phenolics and sugars were the highest in the raw samples and the lowest in the boiled ones. Although the AA level in fried samples was significantly influenced by cultivar (Birgit > Lady Claire) and it increased with FCP storage time, it was below European Food Safety Authority (EFSA) regulation's approved maximum value (750 µg kg^-1 FW) in both cultivars. Therefore, cvs. Birgit and Lady Claire could be considered as promising FCP cultivars and for frying purposes. PRACTICAL APPLICATION: The results of this research reveal that quantitative changes of chemical constituents occurring during storage and cooking of fresh-cut slices of potato cultivars Birgit and Lady Claire are not a concern. This is of particular importance to fresh-cut producers and customers. Phenolics were reduced during storage, but they were still present in all cooked samples independently of the cooking method. The analysis of sugars showed that tubers as old as 9 months could be used for fresh-cut potato processing, providing safe frying without critical levels of acrylamide.

Physiological, Biochemical and Yield-Component Responses of Solanum tuberosum L. Group Phureja Genotypes to a Water Deficit

Water deficits are the major constraint in some potato-growing areas of the world. The effect is most severe at the tuberization stage, resulting in lower yield. Therefore, an assessment of genetic and phenotypic variations resulting from water deficits in Colombia germplasm is required to accelerate breeding efforts. Phenotypic variations in response to a water deficit were studied in a collection of Solanum tuberosum Group Phureja. A progressive water deficit experiment on the tuberization stage was undertaken using 104 genotypes belonging to the Working Collection of the Potato Breeding Program at the Universidad Nacional de Colombia. The response to water deficit conditions was assessed with the relative chlorophyll content (CC), maximum quantum efficiency of PSII (F_v/F_m), relative water content (RWC), leaf sugar content, tuber number per plant (TN) and tuber fresh weight per plant (TW). Principal Component Analysis (PCA) and cluster analysis were used, and the Drought Tolerance Index (DTI) was calculated for the variables and genotypes. The soluble sugar contents increased significantly under the deficit conditions in the leaves, with a weak correlation with yield under both water treatments. The PCA results revealed that the physiological, biochemical and yield-component variables had broad variation, while the yield-component variables more powerfully distinguished between the tolerant and susceptible genotypes than the physiological and biochemical variables. The PCA and cluster analysis based on the DTI revealed different levels of water deficit tolerance for the 104 genotypes. These results provide a foundation for future research directed at understanding the molecular mechanisms underlying potato tolerance to water deficits.

Cultivating Multidisciplinarity: Manufacturing and Sensing Challenges in Cultured Meat Production

Meat cultivation via cellular agriculture holds great promise as a method for future food production. In theory, it is an ideal way of meat production, humane to the animals and sustainable for the environment, while keeping the same taste and nutritional values as traditional meat and having additional benefits such as controlled fat content and absence of antibiotics and hormones used in the traditional meat industry. However, in practice, there is still a number of challenges, such as those associated with the upscale of cultured meat (CM). CM food safety monitoring is a necessary factor when envisioning both the regulatory compliance and consumer acceptance. To achieve this, a multidisciplinary approach is necessary. This includes extensive development of the sensitive and specific analytical devices i.e., sensors to enable reliable food safety monitoring throughout the whole future food supply chain. In addition, advanced monitoring options can help in the further optimization of the meat cultivation which may reduce the currently still high costs of production. This review presents an overview of the sensor monitoring options for the most relevant parameters of importance for meat cultivation. Examples of the various types of sensors that can potentially be used in CM production are provided and the options for their integration into bioreactors, as well as suggestions on further improvements and more advanced integration approaches. In favor of the multidisciplinary approach, we also include an overview of the bioreactor types, scaffolding options as well as imaging techniques relevant for CM research. Furthermore, we briefly present the current status of the CM research and related regulation, societal aspects and challenges to its upscaling and commercialization.

Revitalizing the ethanologenic bacterium Zymomonas mobilis for sugar reduction in high-sugar-content fruits and commercial products

The excessive consumption of sugars can cause health issues. Different strategies have been developed to reduce sugars in the diets. However, sugars in fruits and commercial products may be difficult to reduce, limiting their usage among certain populations of people. Zymomonas mobilis is a generally recognized as safe (GRAS) probiotic bacterium with the capability to produce levan-type prebiotics, and thrives in high-sugar environments with unique characteristics to be developed for lignocellulosic biofuel and biochemical production. In this study, the sugar reduction capabilities of Z. mobilis ZM4 were examined using two fruits of pear and persimmon and three high-sugar-content commercial products of two pear pastes (PPs) and one Chinese traditional wine (CTW). Our results demonstrated that Z. mobilis ZM4 can utilize sugars in fruits with about 20 g/L ethanol and less than 5 g/L sorbitol produced within 22 h using pears, and about 45 g/L ethanol and 30 g/L sorbitol produced within 34 h using persimmons. When PPs made from pears were used, Z. mobilis can utilize nearly all glucose (ca. 60 g/L) and most fructose (110 g/L) within 100 h with 40 ~ 60 g/L ethanol and more than 20 g/L sorbitol produced resulting in a final sorbitol concentration above 80 g/L. In the high-sugar-content alcoholic Chinese traditional wine, which contains mostly glucose and ethanol, Z. mobilis can reduce nearly all sugars with about 30 g/L ethanol produced, resulting in a final ethanol above 90 g/L. The ethanol yield and percentage yield of Z. mobilis in 50 ~ 60% CTW were 0.44 ~ 0.50 g/g and 86 ~ 97%, respectively, which are close to its theoretical yields-especially in 60% CTW. Although the ethanol yield and percentage yield in PPs were lower than those in CTW, they were similar to those in fruits of pears and persimmons with an ethanol yield around 0.30 ~ 0.37 g/g and ethanol percentage yield around 60 ~ 72%, which could be due to the formation of sorbitol and/or levan in the presence of both glucose and fructose. Our study also compared the fermentation performance of the classical ethanologenic yeast Saccharomyces cerevisiae BY4743 to Z. mobilis, with results suggesting that Z. mobilis ZM4 had better performance than that of yeast S. cerevisiae BY4743 given a higher sugar conversion rate and ethanol yield for sugar reduction. This work thus laid a foundation for utilizing the advantages of Z. mobilis in the food industry to reduce sugar concentrations or potentially produce alcoholic prebiotic beverages.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1186/s40643-021-00467-2.

Screen-Printed Glucose Sensors Modified with Cellulose Nanocrystals (CNCs) for Cell Culture Monitoring

Glucose sensors are potentially useful tools for monitoring the glucose concentration in cell culture medium. Here, we present a new, low-cost, and reproducible sensor based on a cellulose-based material, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidized-cellulose nanocrystals (CNCs). This novel biocompatible and inert nanomaterial is employed as a polymeric matrix to immobilize and stabilize glucose oxidase in the fabrication of a reproducible, operationally stable, highly selective, cost-effective, screen-printed glucose sensor. The sensors have a linear range of 0.1–2 mM (R² = 0.999) and a sensitivity of 5.7 ± 0.3 µA cm⁻²∙mM⁻¹. The limit of detection is 0.004 mM, and the limit of quantification is 0.015 mM. The sensor maintains 92.3 % of the initial current response after 30 consecutive measurements in a 1 mM standard glucose solution, and has a shelf life of 1 month while maintaining high selectivity. We demonstrate the practical application of the sensor by monitoring the glucose consumption of a fibroblast cell culture over the course of several days.

Electrochemical flow injection analysis for the rapid determination of reducing sugars in potatoes

Non-enzymatic electrochemical sensors for the monitoring of reducing sugars in foods has great potential as a rapid in-situ detection method. This development involved the assembly of a nanoporous platinum structure on a screen-printed carbon electrode (SPCE). The modified electrode was then employed as an amperometric sensing element in a flow injection analysis (FIA) manifold. The system was successfully applied to the rapid detection of reducing sugars in potatoes, without the need for sample preparation. Optimal signals were achieved in phosphate buffer (pH 7.4) at a flow rate of 0.5 mL min^-1 and an applied potential of 0.6 V. Experimental results demonstrated the sensor's long-term stability and high selectivity for reducing sugars. This method provides high sample throughput due to a rapid response time of less than five seconds. Reducing sugar values determined were in good agreement with those recorded using a commercially available enzymatic assay kit.

Prediction of internal compositions change in potato during storage using visible/near-infrared (Vis/NIR) spectroscopy

Visible/Near-infrared (Vis/NIR) spectroscopy at a range of 450–1000 nm was used to predict the values of three qualitative variables (starch, reducing sugar, and moisture content) on 200 potato tubers from 2 potato genotypes (‘Agria’ and ‘Clone 397009–8’) stored in both traditional and cold storages. After spectroscopy measurements, these variables were measured using reference methods. Then, Partial Least Square (PLS) models were developed. To evaluate developed models, Root Mean Square Error of calibration and cross validation (RMSEC and RMSECV), as well as coefficient of determination for calibration and cross validation (R2C and R2CV), and Residual Predictive Deviation (RPD) were used. The best prediction belonged to reducing sugar with statistical values of R2C = 0.99, R2CV = 0.98, RMSEC = 0.029, RMSECV = 0.037, and RPD = 7.57 in ‘Clone’ genotype stored under cold storage. The weakest prediction was related to moisture content with statistical values of R2C = 0.93, R2CV = 0.92, RMSEC = 0.268, RMSECV = 0.279, and RPD = 6.45 in stored ‘Clone’ genotypes under cold storage. Results of the study showed that, Vis/NIR spectroscopy as a non-destructive, fast, and reliable technique can be used for prediction of inner compositions of stored potatoes.

Morphological and physiological responses of the potato stem transport tissues to dehydration stress

Adaptation of the xylem under dehydration to smaller sized vessels and the increase in xylem density per stem area facilitate water transport during water-limiting conditions, and this has implications for assimilate transport during drought. The potato stem is the communication and transport channel between the assimilate-exporting source leaves and the terminal sink tissues of the plant. During environmental stress conditions like water scarcity, which adversely affect the performance (canopy growth and tuber yield) of the potato plant, the response of stem tissues is essential, however, still understudied. In this study, we investigated the response of the stem tissues of cultivated potato grown in the greenhouse to dehydration using a multidisciplinary approach including physiological, biochemical, morphological, microscopic, and magnetic resonance imaging techniques. We observed the most significant effects of water limitation in the lower stem regions of plants. The light microscopy analysis of the potato stem sections revealed that plants exposed to this particular dehydration stress have higher total xylem density per unit area than control plants. This increase in the total xylem density was accompanied by an increase in the number of narrow-diameter xylem vessels and a decrease in the number of large-diameter xylem vessels. Our MRI approach revealed a diurnal rhythm of xylem flux between day and night, with a reduction in xylem flux that is linked to dehydration sensitivity. We also observed that sink strength was the main driver of assimilate transport through the stem in our data set. These findings may present potential breeding targets for drought tolerance in potato.

Gold and silver nanoparticles in resonance Rayleigh scattering techniques for chemical sensing and biosensing: a review

This review (with 116 refs.) summarizes the state of the art in resonance Rayleigh scattering (RRS)-based analytical methods. Following an introduction into the fundamentals of RRS and on the preparation of metal nanoparticles, a first large section covers RRS detection methods based on the use of gold nanoparticles, with subsections on proteins (albumin, bovine serum albumin and ovalbumin, glycoproteins, folate receptors, iron binding-proteins, G-proteins-coupled receptors, transmembrane proteins, epidermal growth factor receptors), on pesticides, saccharides, vitamins, heavy metal ions (such as mercury, silver, chromium), and on cationic dyes. This is followed by a section on RRS methods based on the use of silver nanoparticles, with subsections on the detection of nucleic acids and insecticides. Several Tables are presented where an RRS method is compared to the performance of other methods. A concluding section summarizes the current status, addresses current challenges, and gives an outlook on potential future trends. Graphical Abstract Change in the resonance Rayleigh scattering (RRS) intensity when mixing the nanoparticles with the specific analyte.

Natural fruit beverages fortified by biologically active substances of grape vines

Based on the study of general knowledge of biochemical and all subsequent developmental studies of organic matter, especially products of grapevine and selected fruit products, a comprehensive study of processing technologies is prepared. Use of a combination of vine products and fruit products in the form of natural grapes. Beverages are researched and developed to be purely natural on the basis of grape musts, blue and white, either individually and again separately in targeted combinations, both biochemically, organoleptically and colorfully, with fruit sources. The core of grape value of biologically active substances is an integral and essential new part and condition of designing these beverages. Their increased biological values, which create the preconditions for containment and if properly managed on the basis of scientific knowledge, may in some cases almost result in the elimination of synthetic additives. It should be noted that 20 - 25% of the adult population suffers from many unexpected allergies, for example, to the sulphite content, although its content in the final product does not exceed the health-approved normatives. And there are many other, interrelated relationships. Beverages are technologically dealt with both without alcohol fermentation and with this fermentation, but only based on their compositional natural resources. They are therefore suitable for the entire population profile. The whole set contains 7 variants and a combination of natural beverages from different fruits. Including natural beverages with or without alcoholic fermentation from the must of white wine grapes, the juice of apple puree with those of biologically active substances from the products grapevine. Three months of monitoring and determination of basic (oenological) values and biologically active substances were performed on these products. The high-performance liquid chromatography method with a refractometric detector determined amount of sugar and alcohol, whilst titrating determined total and volatile acids and free sulfur dioxide. Yeast assimilable nitrogen, total anthocyanins and polyphenols were determined by spectrophotometry, antioxidant activity by DPPH and ABTS methods.

Liquid Chromatography Analysis of Common Nutritional Components, in Feed and Food

Food and feed laboratories share several similarities when facing the implementation of liquid-chromatographic analysis. Using the experience acquired over the years, through application chemistry in food and feed research, selected analytes of relevance for both areas were discussed. This review focused on the common obstacles and peculiarities that each analyte offers (during the sample treatment or the chromatographic separation) throughout the implementation of said methods. A brief description of the techniques which we considered to be more pertinent, commonly used to assay such analytes is provided, including approaches using commonly available detectors (especially in starter labs) as well as mass detection. This manuscript consists of three sections: feed analysis (as the start of the food chain); food destined for human consumption determinations (the end of the food chain); and finally, assays shared by either matrices or laboratories. Analytes discussed consist of both those considered undesirable substances, contaminants, additives, and those related to nutritional quality. Our review is comprised of the examination of polyphenols, capsaicinoids, theobromine and caffeine, cholesterol, mycotoxins, antibiotics, amino acids, triphenylmethane dyes, nitrates/nitrites, ethanol soluble carbohydrates/sugars, organic acids, carotenoids, hydro and liposoluble vitamins. All analytes are currently assayed in our laboratories.

IRMOF-3: A fluorescent nanoscale metal organic frameworks for selective sensing of glucose and Fe (III) ions without any modification

The amine functionalized isoreticular metal-organic framework-3 (IRMOF-3) is synthesized by hydrothermal method. Till now, it's widely used in the area of gas separation, adsorption, and catalysis due to large surface area, structural stability, and tunability. Here, we have reported the use of fluorescent nanoscale IRMOF-3 for highly selective detection of glucose as well as Fe³⁺ ions without any modification. This is due to NH₂ and COOH groups are present on the surface of IRMOF-3 to bind cis-diols of the glucose molecule via host-guest interaction, and Fe³⁺ ions via ligand to metal charge transfer. The Synthesized IRMOF-3 has average diameter of 160 ± 20 nm and interestingly possess deep blue fluorescent emission spectra at 460 nm with quantum yield 17.3%. Using fluorometric assay, the limit of detection (LOD) of glucose and Fe³⁺ ions was found to be 0.56 μM and 4.2 nM respectively. More importantly, the synthesized IRMOF-3 is also utilized for detection of glucose and Fe³⁺ ions in bio-environmental samples.

Fructose recognition using new “Off–On” fluorescent chemical probes based on boronate-tagged 1,8-naphthalimide

A fluorescent probe with a planar structure was designed based on a PET mechanism to detect fructose with lower LOD than analytical methods.

Determination of Single Sugars, Including Inulin, in Plants and Feed Materials by High-Performance Liquid Chromatography and Refraction Index Detection

The exact and reliable detection of sugar monomers and fructans provides important information for the evaluation of carbohydrate metabolism in plants and animals. Using the HPLC method; a large number of samples and single sugars; with both high sensitivity and selectivity; may be analysed. It was shown that the described method—using a Nucleosil column loaded with Pb2+ ions; a refractive index detector (RID); and HPLC-grade water as the eluent—gives precise and reproducible results regarding the detection of individual sugars in extracts of plants and feed materials. The method can be applied for the detection of sucrose; maltose; lactose; xylose; glucose; galactose; arabinose; fructose; ribose; and mannitol. Furthermore; depending on the plant material; the sugars verbascose; stachyose; and raffinose can be separated. The peaks were well resolved and the reproducibility of the analysis; with 94–108% of recovery (RC) and relative standard deviation (RSD) of up to 5%; was very good. The method was successfully applied to a variety of green forages and samples of sugar beet pulp silages. It is also possible to determine fructan with inulin as a standard; together with the other sugars; or alone by a different protocol and column.

Novel SNP markers in InvGE and SssI genes are associated with natural variation of sugar contents and frying color in Solanum tuberosum Group Phureja

Background

Potato frying color is an agronomic trait influenced by the sugar content of tubers. The candidate gene approach was employed to elucidate the molecular basis of this trait in Solanum tuberosum Group Phureja, which is mainly diploid and represents an important genetic resource for potato breeding. The objective of this research was to identify novel genetic variants related with frying quality in loci with key functions in carbohydrate metabolism, with the purpose of discovering genetic variability useful in breeding programs. Therefore, an association analysis was implemented with 109 SNP markers identified in ten candidate genes.

Results

The analyses revealed four associations in the locus InvGE coding for an apoplastic invertase and one association in the locus SssI coding for a soluble starch synthase. The SNPs SssI-C_45711901T and InvGE-C_2475454T were associated with sucrose content and frying color, respectively, and were not found previously in tetraploid genotypes. The rare haplotype InvGE-A_2475187C_2475295A_2475344 was associated with higher fructose contents. Our study allowed a more detailed analysis of the sequence variation of exon 3 from InvGE, which was not possible in previous studies because of the high frequency of insertion-deletion polymorphisms in tetraploid potatoes.

Conclusion

The association mapping strategy using a candidate gene approach in Group Phureja allowed the identification of novel SNP markers in InvGE and SssI associated with frying color and the tuber sugar content measured by High Performance Liquid Chromatography (HPLC). These novel associations might be useful in potato breeding programs for improving quality traits and to increase crop genetic variability. The results suggest that some genes involved in the natural variation of tuber sugar content and frying color are conserved in both Phureja and tetraploid germplasm. Nevertheless, the associated variants in both types of germplasm were present in different regions of these genes. This study contributes to the understanding of the genetic architecture of tuber sugar contents and frying color at harvest in Group Phureja.

Electronic supplementary material

The online version of this article (doi:10.1186/s12863-017-0489-3) contains supplementary material, which is available to authorized users.

Sun dried Corinthian currant (Vitis Vinifera L., var. Apyrena) simple sugar profile and macronutrient characterization

Corinthian currant simple sugar profile was determined by high-pressure liquid chromatography coupled with refractive index detection; the content in other macroconstituents was also assessed. Corinthian currants analyzed were obtained over three consecutive crop years, while the effect of cultivation area altitude was also evaluated. Sugar extraction was optimized with respect to solvent, process, and time. Simple sugar chromatographic analysis was validated for linearity (R²>0.999), limits of detection (6.23-186.66mg/L) and quantification (18.89-565.65mg/L), precision (%RSD<2.67), and recovery (97.99-101.99%). Fructose, glucose, sucrose, maltose, and total sugar content was 32±1%, 32.5±0.6%, 0.40±0.04%, 0.72±0.07% and 66±2%, respectively; moisture, ash, fat, and protein content was 13.8±0.5%, 2.6±0.7%, 0.43±0.06%, and 2.2±0.4%, respectively. Relatively small variations in sugar and other macroconstituent content were detected over the consecutive crops. Cultivation area altitude affected Corinthian currant sugar, fat, and protein content, yet with no remarkable differences.

Natural variation of sucrose, glucose and fructose contents in Colombian genotypes of Solanum tuberosum Group Phureja at harvest

BACKGROUND

Potato frying quality is a complex trait influenced by sugar content in tubers. Good frying quality requires low content of reducing sugars to avoid the formation of dark pigments. Solanum tuberosum Group Phureja is a valuable genetic resource for breeding and for genetic studies. The sugar content after harvest was analyzed in a germplasm collection of Group Phureja to contribute to the understanding of the natural variation of this trait.

RESULTS

Sucrose, glucose and fructose genotypic mean values ranged from 6.39 to 29.48 g kg(-1) tuber dry weight (DW), from 0.46 to 28.04 g kg(-1) tuber DW and from 0.29 to 27.23 g kg(-1) tuber DW, respectively. Glucose/fructose and sucrose/reducing sugars ratios ranged from 1.01 to 6.67 mol mol(-1) and from 0.15 to 7.78 mol mol(-1) , respectively. Five clusters of genotypes were recognized, three of them with few genotypes and extreme phenotypic values.

CONCLUSION

Sugar content showed a wide variation, representing the available variability useful for potato breeding. The results provide a quantitative approach to analyze the frying quality trait and are consistent with frying color. The analyzed germplasm presents extreme phenotypes, which will contribute to the understanding of the genetic basis of this trait. © 2016 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Adsorption efficiency of poly(ethylene glycol)/chitosan/CNT blends for maltene fraction separation

Poly(ethylene glycol)/chitosan (PEG/CH) hydrogel and its composite containing carbon nanotubes (PEG/CH/CNTs) were prepared using a simple blending method. The effect of the PEG/CH ratio on the water uptake was studied and optimized. And the prepared hydrogels were characterized by XRD, SEM, and FTIR. Also, the ability of each of the prepared hydrogels to adsorb and separate maltene fractions was compared using saturates, aromatics, resins, and asphaltenes (SARA) method. From the results, it was noticed that the adsorption capacity and separation ability of PEG/CH/CNT are better than that of PEG/CH. But the released amount of alkane fractions using these hydrogels is higher than that in the reference (without using hydrogel). This may be attributed to degradation of maltene residue to alkanes and that degradation is better by using PEG/CH adsorbent than PEG/CH/CNT. Although, from a practical point of view, where PEG/CH/CNT hydrogel may be favorable, it has an acceptable ability to adsorb and separate the maltene fractions.