Influence of different processing and storage conditions on in vitro bioaccessibility of polyphenols in black carrot jams and marmalades

Starch-based composite formulation of chickpea flour and black carrot (Daucus carota l.) pomace in extruded snacks: In vitro gastrointestinal behavior and stability of bioactive compounds

Black carrot pomace (BCP) is a by-product of colorant production, containing various valuable components with the health promoting effects. In this study, for the first time, BCP was incorporated into a starch-based extruded snack formulation using wheat semolina and corn starch. Total phenolic content, total antioxidant capacity, phenolics, and anthocyanins after processing and in vitro gastrointestinal digestion were investigated, and physical and textural properties of the snack products were determined. Incorporating BCP significantly raised the TPC and antioxidant levels, notably achieving peak levels in snacks enriched with 20 % BCP. The phenolic acids and anthocyanins were increased significantly (48-382 %) (p < 0.05) with simulated gastric digestion whereas no anthocyanins were detected after simulated intestinal digestion. On the other hand, the extrusion process resulted in a negative impact on anthocyanin concentrations, particularly marked by a significant reduction in some cyanidin derivatives indicating the detrimental effect of extrusion on the molecular integrity of anthocyanins under high temperature and pressure, leading to their degradation. In the final product, the snacks displayed lower expansion indices, water absorption index, water solubility index, and lightness; but had higher hardness and redness values compared to the control and turned slightly darker. The study proposes to evaluate BCP as a value-added ingredient that imparts functional properties to foods along with the utilization of starch in the extrusion process. Additionally, the integration of wheat semolina and corn starch contributed to the structural integrity and texture of the extruded snacks, highlighting the importance of polysaccharides in the formulation.

Combined application of high pressure and ultrasound in fig paste: effect on bioactive and volatile compounds

The combined impact of high-hydrostatic pressure (HHP) and ultrasound (US) on the cyanidin-3-O-rutinoside (C3R), quercetin-3-O-rutinoside (Q3R), and volatile compounds from fig (Ficus carica) paste was investigated. The HHP increased the content of C3R and Q3R, from 70 to 133 mg/kg fw and 31 to 44 mg/kg fw, respectively. The combination of HHP and US further enhanced the extraction of these bioactive compounds. Specifically, processing fig paste with US for 5 min at 40 °C yielded approximately 250 mg of C3R/kg fw and 45 mg of Q3R/kg fw, after 20 min. More than 25 volatile compounds were identified, with benzaldehyde being the predominant compound, accounting > 75%. Trace amounts of hydroxymethylfurfural (< 0.36 mg/100 g fw) were detected in HHP-processed fig paste. The application of HHP at mild temperatures and short time, combined with US, effectively promotes the content of bioactive compounds present in fig paste without adversely affecting the fruit's volatile compounds.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01410-1.

Insights into the current status of bioactive value, postharvest processing opportunities and value addition of black carrot

Black carrots are a type of carrot that is naturally dark purple or black in color. They are a good source of antioxidants, vitamins, and minerals, and have been shown to have several health benefits, including reducing the risk of cancer, heart disease, and diabetes. This review article discusses the bioactive compounds present in black carrot, including anthocyanins, phenolic acids, carotenoids, and organic acids and sugars. It also compares the bioactive compounds and antioxidant capacity of black carrot with other carrot varieties. Furthermore, it discusses various postharvest processing methods, both conventional and novel, such as encapsulation, drying, and microbial decontamination, highlighting their effects on preserving and stabilizing the bioactive compounds. The review also emphasizes the incorporation of black carrot into different food products, including dairy items, beverages, and baked goods, and their impact on nutritional enhancement. The article provides knowledge on utilizing black carrot for improved nutritional and functional outcomes.

Pectin conformation influences the bioaccessibility of cherry laurel polyphenols and gut microbiota distribution following in vitro gastrointestinal digestion and fermentation

Interactions between dietary fiber and phenolic compounds in foods can influence their gastrointestinal fate. This study aimed to examine the effect of four types of pectin on the polyphenols of cherry laurel puree and human gut microbiota during a simulated in vitro gastrointestinal digestion and large intestine fermentation. Results revealed that the combined addition of different pectins and pectinase to cherry laurel puree significantly affected the content and bioaccessibility of phenolics. The addition of pectins and pectinase distinctively impacted the phenolic subclasses in both raw and post-digested/fermented cherry laurel puree, suggesting differential interactions due to structural features. Both pectins and pectinase modulated the composition of fecal microbiota after in vitro fermentation, increasing bacterial diversity following pectinase treatment. The combined addition of pectins followed by pectinase had differential impacts on polyphenol bioaccessibility and gut microbiome diversity, hence having a potential outcome in terms of human health.

Effect of Inclusion of Date Press Cake on Texture, Color, Sensory, Microstructure, and Functional Properties of Date Jam

Date press cake (DPC) is a by-product of the date syrup industry with a high content of dietary fibers, minerals, and antioxidant compounds. Accordingly, the present study aimed to evaluate the inclusion of DPC on the color parameters, texture profile, sensory evaluation, microstructure properties, total phenolics, and antioxidant capacity of date jam. The DPC was included in the preparation of date jam in an increasing level of 0, 3, 6, 9, and 12% (w/w). The results revealed that increasing DPC levels significantly increased the hardness, cohesiveness, adhesiveness, and chewiness properties of date jam. The increase in DPC inclusion levels significantly decreased the L* values and increased the a*, b*, and ΔE values of the jam. The DPC addition significantly increased the phenolics content and antioxidant capacity in a dose-dependent manner and the highest value reported in the jam contained 12% DPC by 40.02 and 11.50% compared to the control, respectively. The scanning electron microscopy results revealed that the addition of DPC up to 9% resulted in a jam surface with a denser network, homogeneous structure, and without cracks and pores, indicating improvement in the morphological properties. The sensory evaluation results showed that date jam prepared with 9% DPC had the highest overall acceptability score. This study revealed the potential use of DPC in date jam formulation up to 9% as a natural, functional, and low-cost ingredient to improve the jam’s textural properties, antioxidant capacity, and overall acceptability.

Effect of geographical location, processing and simulated digestion on antioxidant characteristics of quince (Cydonia oblonga)

Quince fruit (Cydonia oblonga Miller) is an important source of bioactive compounds, especially of phenolic compounds, that's why it is considered a good source of antioxidants. However, it is known that the antioxidant characteristics and the beneficial effect of foods are affected by the variety, geographical origin, processing and gastrointestinal digestion. In this work, the effects of the geographical origin, processing, and simulated digestion of quince jam on its antioxidant characteristics were studied. Phenolic composition and antioxidant capacity were determined in quince fruit and jam from four different locations in San Juan, Argentina. The results showed that quince fruit samples from St. Lucia had the highest total phenolic content (5.13 mg GAE/g; p < 0.05) and in vitro antioxidant capacity measured by ferric-reducing antioxidant power assay (FRAP) and radical-scavenging capacity assay (DPPH· and ABTS·+ ). With regard to quince jam, a positive effect was observed on its antioxidant characteristics after processing. Twenty-one phenolics were detected in jam, being most of them derivatives of hydroxycinnamic acids (eg. 5-caffeoylquinic acid; 4-caffeoylquinic acid and quinic acid). Studies on stability and bioaccessibility of quince phenolics showed that less than 25% of the initial phenolics in jam were detected after digestion being quinic acid and hydroxycinnamic acids the most resistant. The in vitro antioxidant capacity showed, in general, a similar trend to the phenolics content throughout the digestion process. The results obtained showed that the antioxidant activity of quince and jam is related to the type and amount of phenolics in the samples, which depends on the geographical origin, processing, and gastrointestinal digestion. These variables are not always taken into account when studying the probable antioxidant activity of food, even though they should be considered for a complete nutritional evaluation of a food.

Medlar Jam Production (Mespilus germanica) with the Use of Sous Vide Method

The aim of this study was to evaluate the influence of sous vide technology on the chemical properties of fruit jams produced with medlar fruit (Mespilus germanica L.). The fruit jams were produced using sous vide technology at different temperatures: 60 °C, 70 °C, and 80 °C. The fruit jams were also produced at 100 °C using the traditional cooking method. Experimentally produced samples were evaluated by the following methods: total polyphenols content, ferric reducing antioxidant power assay (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and organic acid determination. Among sous vide-processed samples, the samples with the highest (p < 0.05) antioxidant activity were processed at 80 °C, containing pectin; the results were the following: phenols content 0.56 ± 0.01 mg gallic acid/kg; FRAP antioxidant activity 0.32 ± 0.01 µmol Trolox/g; DPPH antioxidant activity 21.39 ± 0.33%. The obtained results showed that fruit jam production with the use of sous vide technology can affect antioxidant capacity of this food commodity. The research also provided important information about non-traditional fruit, such as medlar fruit (Mespilus germanica L.), and its processing by sous vide technology. Certainly, more analyses are necessary to give a clearer picture of the changes in medlar fruit during processing at different temperatures, and processing technologies, especially because there are presently no publications about the use of medlar fruit as a raw material in fruit jam preparation.

The effects of drying and fermentation on the bioaccessibility of phenolics and antioxidant capacity of Thymus vulgaris leaves

Fresh thyme leaves (Thymus vulgaris L.) were dried at 45 °C for 5 h and naturally fermented at 20 °C in a brine solution containing salt and vinegar for 18 days. The ethanolic extracts of fresh (FT), dried (DT), and fermented-pickled (PT) thyme leaves were assessed in terms of total phenolic content (TPC), total flavonoid content (TFC), antioxidant capacity values and subjected to in vitro gastrointestinal digestion. TPC, TFC, and antioxidant capacity values of fermented thyme leaves were found significantly higher than of dried and fresh samples. The bioaccessibility index (BI) value for TPC and TFC was highest for PT and lowest for DT, indicating that both processes had different effects on the structure of phenolic compounds present in the thyme leaves. Similarly both Recovery and BI values of DPPH antioxidant capacity were highest for PT, but lowest for fresh samples. When CUPRAC assay was applied, the recovery % for FT and PT was similar, and the BI was higher for FT. Results showed that compared to the results of fresh thyme leaves, drying and pickling had a considerable effect on the initial phenolic compounds extracted and their fate during in vitro digestion.

Assessment of Bioactive Compounds under Simulated Gastrointestinal Digestion of Bee Pollen and Bee Bread: Bioaccessibility and Antioxidant Activity

Bee pollen and bee bread have always been regarded as excellent natural resources for application in food and pharmaceutical fields due to their rich nutrient content and diversity of bioactive compounds with health-improving properties. Extensive studies on both bee products as ingredients for a healthy diet were reported, although the data concerning their metabolization on the gastrointestinal tract is quite limited. Here, we report, at each digestive stage, the bioactive profile for both bee products, their bioaccessibility levels and the antioxidant activity evaluation. The findings indicated that the average bioaccessibility level of total phenolic and total flavonoid content for bee pollen was 31% and 25%, respectively, while it was 38% and 35% for bee bread. This was reflected in a decrease of their antioxidant capacity at the end of in vitro gastrointestinal digestion, both in free radicals scavenging capacity and in reducing power. Moreover, within the 35 phytochemicals identified, the most affected by gastrointestinal digestion were phenylamides, with a complete digestibility at the end of the intestinal phase. Overall, our results highlight that bioactive compounds in both raw products do not reflect the real amount absorbed in the intestine, being bee bread more accessible in bioactive content than bee pollen.

Antioxidant Activity and Bio-Accessibility of Polyphenols in Black Carrot (Daucus carota L. ssp. sativus var. atrorubens Alef.) and Two Derived Products during Simulated Gastrointestinal Digestion and Colonic Fermentation

Black carrot has been attracting increasing thanks to its high bioactive compound content. This study presents the polyphenol bio-accessibility of black carrot and two derived products (black carrot snack (BC snack) and black carrot seasoning (BC seasoning)) after in vitro gastrointestinal digestion and colonic fermentation. Additionally, antioxidant activity was measured by 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS), 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) assays. Nine flavonoids and eight anthocyanins were determined by ultra high-performance liquid chromatography high resolution mass spectrometry (UHPLC-HRMS) analysis, the predominant compounds being the hydroxycinnamic acids 3-O-feruloylquinic acid, 4-O-feruloylquinic acid and chlorogenic acid. The BC snack (108 µmol/g DW) presented the highest total polyphenol content, followed by BC seasoning (53 µmol/g DW) and black carrot (11.4 µmol/g DW). The main polyphenols still bio-accessible after in vitro digestion were the hydroxycinnamic acids, with mean recovery rates of 113 % for black carrot, 69% for BC snack and 81% for BC seasoning. The incubation of black carrot and its derived products with human faecal bacterial resulted in the complete degradation of anthocyanins and in the formation of mainly 3-(4′-hydroxyphenyl)propanoic acid as the major catabolic event. In conclusion, our results suggest that the black carrot matrix impacts significantly affects the bio-accessibility of polyphenols and, therefore, their potential health benefits.

Bioaccessibility of Tudela artichoke (Cynara scolymus cv. Blanca de Tudela) (poly)phenols: the effects of heat treatment, simulated gastrointestinal digestion and human colonic microbiota

The aim of this study was to evaluate the bioaccessibility of (poly)phenolic compounds in Tudela artichokes (Cynara scolymus cv. Blanca de Tudela) after an in vitro gastrointestinal digestion and the effect of the human colonic microbiota. A total of 28 (poly)phenolic compounds were identified and quantified by LC-MS/MS in raw, boiled, sous vide and microwaved Tudela artichokes. Out of these, sixteen were phenolic acids, specifically caffeoylquinic acids (CQAs) and other minor hydroxycinnamic acid derivatives, ten flavonoids belonging to the family of flavones (apigenin and luteolin derivatives) and two lignans (pinoresinol derivatives). Sous vide and microwaving caused mainly transesterification reactions of CQAs but maintained or even augmented the total (poly)phenolic contents of artichokes, while boiling decreased (poly)phenolic compounds by 25% due to leaching into the boiling water. Heat treatment exerted a positive effect on the bioaccessibility of (poly)phenols after gastrointestinal digestion. In raw artichokes, only 1.6% of the total (poly)phenolic compounds remained bioaccessible after gastrointestinal digestion, while in artichoke samples cooked by sous vide, boiled and microwaved, the percentage of bioaccessibility was 60.38%, 59.93% and 39,03% respectively. After fecal fermentation, 20 native (poly)phenolic compounds and 11 newly formed catabolites were quantified. 48 h of fecal fermentation showed that native (poly)phenols are readily degraded by colonic microbiota during the first 2 h of incubation. The colonic degradation of artichoke (poly)phenols follows a major pathway that involves the formation of caffeic acid, dihydrocaffeic acid, 3-(3'-hydroxyphenyl)propionic acid, 3-phenylpropionic acid and phenylacetic acid, with 3-phenylpropionic acid being the most abundant end product. The catabolic pathways for colonic microbial degradation of artichoke CQAs are proposed.

Urinary and Plasma Antioxidants in Behavioral Symptoms of Individuals With Autism Spectrum Disorder

The balance between antioxidant capacity and oxidative stress-induced free radicals may be crucial in the pathophysiological development factor of autism spectrum disorder (ASD). We measured the following urinary and plasma biomarker levels of oxidative stress and antioxidants. As urinary biomarkers, (1) hexanoyl-lysine (HEL), which is a new biomarker of oxidative stress, (2) the total antioxidant capacity (TAC), and (3) 8-hydroxy-2'-deoxyguanosine (8-OHdG), as a product of oxidative modifications to DNA; and the plasma levels of (4) the antioxidant protein superoxide dismutase (SOD), which is the crucial defense again oxygen reactive species, and (5) transferrin and (6) ceruloplasmin, which are biomarkers of iron and copper neurotransmission and oxidant-antioxidant systems. We examined the relationship between these urinary and plasma biomarkers and behavioral symptoms in 19 individuals with ASD (mean age, 10.8 ± 5.2 years) and 10 age-matched healthy controls (mean age, 14.2 ± 7.0 years). Behavioral symptoms were estimated using the Aberrant Behavior Checklist (ABC). Urinary TAC levels were significantly lower, whereas urinary HEL levels were significantly increased in the ASD group as compared with the control group. The five ABC subscale and total scores were significantly raised in the autism group than in the control group. The results of a linear regression analysis revealed that plasma SOD levels may be a more accurate predictor of differences in ABC scores between individuals with ASD and control individuals. The present study firstly revealed the important findings that the cooperation between the urinary antioxidant TAC and plasma SOD levels may contribute to the ABC subscale scores of stereotypy. Urinary TAC activity and antioxidant protein SOD may be associated with incomplete mineral body store and antioxidant-related transcription factor and browning reactions. Consequently, a critical imbalance between TAC urinary levels and plasma SOD levels may be an important contributor to autistic behavioral symptoms.

Effect of Ultrasound on In Vitro Bioaccessibility of Phenolic Compounds and Antioxidant Capacity of Blackberry (Rubus fruticosus) Residues cv. Tupy

Agro-industries residues of fruit are a source of antioxidant compounds with a possible health impact. The aim of this study was to evaluate the total phenolic content (TPC), total monomeric anthocyanins (TMA), individual phenolic compounds (IPC), antioxidant capacity and in vitro intestinal bioaccessibility from blackberry residues (BR), and ultrasonicated blackberry residues (US-BR). The results showed that BR had higher TPC (4,016.43 mg GAE/100 g DM), TMA (364.53 mg Cy-3-Gl/100 g) antioxidant capacity by ABTS (5,422.38 mg AAE/100 g DM) and FRAP (12511.44 μmol Fe(II)/100 g DM) than US-BR. TPC and TMA obtained by US-BR were more bioaccessible (70 and 51%, respectively) compared to BR (37 and 34%, respectively). The use of ultrasound can aid the extraction of total phenolic compounds and improve their bioaccessibility. After acid hydrolysis, a high amount of individual phenolic compounds (IPC) in US-BR (chlorogenic acid, caffeic acid, apigenin, luteolin and kaempferol) was obtained compared with BR. Before in vitro digestion, total individual compounds (TIC) content was lower in the BR (29.49 mg/100 g DM) than US-BR (92.36 mg/100 g DM) and there was 5 and < 1%, respectively. Therefore, the food industry would use residues of blackberry fruits as a source of antioxidant compounds with possible health benefits.

Carrot Anthocyanins Genetics and Genomics: Status and Perspectives to Improve Its Application for the Food Colorant Industry

Purple or black carrots (Daucus carota ssp. sativus var. atrorubens Alef) are characterized by their dark purple- to black-colored roots, owing their appearance to high anthocyanin concentrations. In recent years, there has been increasing interest in the use of black carrot anthocyanins as natural food dyes. Black carrot roots contain large quantities of mono-acylated anthocyanins, which impart a measure of heat-, light- and pH-stability, enhancing the color-stability of food products over their shelf-life. The genetic pathway controlling anthocyanin biosynthesis appears well conserved among land plants; however, different variants of anthocyanin-related genes between cultivars results in tissue-specific accumulations of purple pigments. Thus, broad genetic variations of anthocyanin profile, and tissue-specific distributions in carrot tissues and organs, can be observed, and the ratio of acylated to non-acylated anthocyanins varies significantly in the purple carrot germplasm. Additionally, anthocyanins synthesis can also be influenced by a wide range of external factors, such as abiotic stressors and/or chemical elicitors, directly affecting the anthocyanin yield and stability potential in food and beverage applications. In this study, we critically review and discuss the current knowledge on anthocyanin diversity, genetics and the molecular mechanisms controlling anthocyanin accumulation in carrots. We also provide a view of the current knowledge gaps and advancement needs as regards developing and applying innovative molecular tools to improve the yield, product performance and stability of carrot anthocyanin for use as a natural food colorant.

Silage Fermentation: A Potential Biological Approach for the Long-Term Preservation and Recycling of Polyphenols and Terpenes in Globe Artichoke (Cynara scolymus L.) By-Products

An economic and effective method for storage is necessary to make full use of the nature of active components in artichoke by-products and ease environmental pressure. In this paper, the potential of silage fermentation for the preservation and recycling of polyphenols and terpenes in artichoke by-products is evaluated. The silage of artichoke by-products is characterized by lactic acid bacteria fermentation. Silage distinctly increases the abundance of lactic acid bacteria in artichoke by-products, such as Lactobacillus, Lactococcus, Serratia, and Weissella, and greatly increases the abundance of Firmicutes. The improvement of the microorgan structure and composition is of great significance for the quality of artichoke by-products. Polyphenols in the stems and leaves of artichokes are preserved well in silage. Among the 18 polyphenol compounds detected by high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (HPLC-QqQ-MS/MS), the contents of 11 phenolic acids and four flavonoids increased significantly. For terpenes detected by gas chromatography-mass spectrometry (GC-MS), the contents of four pentacyclic triterpenoids increased significantly, while two sterols were kept stable in the silage process. Silage is a potential biotechnology for the long-term preservation of bioactive components, such as polyphenols and terpenes in artichoke by-products, and the results provide a scientific basis for the efficient utilization of by-products.

Bioaccessibility of Antioxidants and Fatty Acids from Fucus Spiralis

Fucus spiralis is an edible brown seaweed (SW) found in the Portuguese Coast. It has been reported to have high antioxidant activity, which may elicit a potential use for the food industry. However, little information is available on how the SW behaves during the digestive process and how the freeze-drying process might affect the bioaccessibility of the different compounds. Therefore, antioxidant activity, total polyphenols, lipid, and fatty acid contents were measured before and after in vitro simulation of the human digestive process, both in fresh and freeze-dry SW. F. spiralis had a lipid content of 3.49 ± 0.3% of dry weight (DW), which is a usual amount described for this SW genus. The total lipid bioaccessibility was 12.1 ± 0.1%. The major omega-3 fatty acid detected was eicosapentaenoic acid, 7.5 ± 0.1%, with a bioaccessibility percentage of 13.0 ± 1.0%. Four different methods—total phenolic content (TPC), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and 1,1-diphenyl-2-picryl-hydrazyl (DPPH)—were used to assess the antioxidant activity of F. spiralis. The bioaccessibility of the antioxidants studied, ranged between 42.7% and 59.5%, except the bioaccessibility of polyphenols in freeze-dried SW (23.0% ± 1.0%), suggesting that the freeze-drying process reduces the bioaccessibility of these compounds.

Comparison of the phenolic profiles and physicochemical properties of different varieties of thermally processed canned lychee pulp

Lychee pulp is rich in phenolics and has a variety of biological activities. However, the changes in the phenolic profile under heat treatment are unknown. The effect of the heat treatment temperature on commercial varieties (Guiwei and Nuomici) of canned lychee was investigated by comparing samples that were either unheated (UH), underwent 70 °C heat treatment (HT70) or underwent 121 °C heat treatment (HT121) and then were stored at room temperature. The results showed that the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of the UH, HT70 and HT121 samples were significantly decreased after storage at room temperature for 9 d, 13 d and 25 d, respectively. However, the TPC, TFC and antioxidant activity of HT121 canned lychee were still significantly higher than those of the UH and HT70 samples. However, the texture characteristics of the HT121 samples were worse than those of the UH and HT70 samples, and the color of the canned lychee was darker after the HT121 treatment. Nine individual phenolic compounds were detected in the canned lychee by HPLC-DAD. The gallic acid content was increased after HT121 treatment. In particular, (−)-gallocatechin was generated by HT121 thermal processing. However, after storage at room temperature for 9 d, the contents of (−)-gallocatechin in canned Guiwei and Nuomici were decreased by 96.27% and 94.04%, respectively, and (−)-gallocatechin disappeared after 25 d. In summary, the phenolic contents and antioxidant activity of canned lychee are increased by high-temperature treatment.

Lychee pulp is rich in phenolics and has a variety of biological activities.

A Micromethod for Polyphenol High-Throughput Screening Saves 90 Percent Reagents and Sample Volume

There is ample evidence that polyphenols are important natural substances with pronounced antioxidative properties. This study aimed to develop a fast and reliable method to determine total polyphenol content (TPC) in foodstuffs and human samples. The microtitration format offers the advantage of low sample volumes in the microlitre range, facilitating high-throughput screening with 40 samples simultaneously. We accordingly adjusted the so-called Folin–Ciocalteu method to a microtitre format (polyphenols microtitre—PPm) with 90% reduction of reagents. The assay was standardized with gallic acid in the range between 0.1 and 3 mM, using a 20 µL sample volume. The intra-assay coefficient of variation (CV) was less than 5%, and inter-assay CV was in the range of 10%. Wavelength was measured at 766 nm after two hours of incubation. This micromethod correlates significantly with both the classical Folin–Ciocalteu method and High-Performance Thin-Layer Chromatography (HPTLC) (r² = 0.9829). We further observed a significant correlation between PPm and total antioxidants (r² = 0.918). The highest polyphenol concentrations were obtained for red, blue, and black fruits, vegetables, and juices. Extracts of red grapes could be harvested almost sugar free and might serve as a basis for polyphenol supplementation. Beer, flour, and bread contained polyphenol concentrations sufficient to meet the minimal daily requirement. We conclude that PPm is a sensitive and reliable method that detects polyphenols even in samples diluted 10-fold. The literature strongly recommends further investigations on the effects of polyphenol uptake on human and animal health.

Grown to be Blue-Antioxidant Properties and Health Effects of Colored Vegetables. Part I: Root Vegetables

During the last few decades, the food and beverage industry faced increasing demand for the design of new functional food products free of synthetic compounds and artificial additives. Anthocyanins are widely used as natural colorants in various food products to replenish blue color losses during processing and to add blue color to colorless products, while other compounds such as carotenoids and betalains are considered as good sources of other shades. Root vegetables are well known for their broad palette of colors, and some species, such as black carrot and beet root, are already widely used as sources of natural colorants in the food and drug industry. Ongoing research aims at identifying alternative vegetable sources with diverse functional and structural features imparting beneficial effects onto human health. The current review provides a systematic description of colored root vegetables based on their belowground edible parts, and it highlights species and/or cultivars that present atypical colors, especially those containing pigment compounds responsible for hues of blue color. Finally, the main health effects and antioxidant properties associated with the presence of coloring compounds are presented, as well as the effects that processing treatments may have on chemical composition and coloring compounds in particular.

Stability of Anthocyanins, Phenolics and Color of Tart Cherry Jams

The aim of this work was to assess the effect of a set storage period on the phenolics, anthocyanins, antioxidant activity, color, and texture of three types of jams made from tart cherry. The prepared samples of tart cherry jams were: (1) regular jam; (2) extra jam; and (3) light jam. The samples were stored at room temperature for eight months. Results of the investigated parameters after storage were compared with the results after sample preparations, and between the different jam samples. The light jam had the highest phenolic content and anthocyanin content (3.34 g/kg and 985.52 mg/kg). Consequently, the light jam had the highest antioxidant activity determined by ABTS (2,2’-azinobis(3-ethylbenzothiazoline sulfonic acid)) and DPPH (2,2-diphenyl-1-picrylhydrazil) method. After storage, the highest retention of the phenolics had regular jam and extra jam (85%), while the lowest retention (74%) were found in the light jam. Anthocyanin stability was the highest in the regular jam, then the extra jam (15%), and then the light jam, with retention of 22%, 15%, and 12%, respectively. Color parameters and textural parameters also depended on jam type, as well as on storage conditions. Since the investigated types of jams differed in content of fruit and water, these are the most important factors that cause the change in the retention of phenolics and anthocyanins, as well as a change in color and textural parameters.

Identification of phenolic compounds from a unique citrus species, finger lime (Citrus australasica) and their inhibition of LPS-induced NO-releasing in BV-2 cell line

In this study, a unique citrus species (Citrus australasica) was selected, and its fruit characteristics, phenolic compounds and ability to inhibit inflammation were preliminarily studied. Finger lime fruits showed distinctive features in shape, size, weight, colour, total soluble solids, water-soluble pectin, sugar and acids contents. Combining UPLC-HRMS and UPLC-DAD analysis, 31 phenolics, 1 secoiridoid derivative and 1 neolignan glycoside were preliminarily identified and quantified. The phenolics composition of finger limes showed cultivar and tissue specificity. Antioxidant evaluation showed that extracts from finger lime cultivar of 'XiangBin' exhibited better antioxidant capacities than cultivar of 'LiSiKe', especially in peel. LPS-induced NO-releasing model was performed in the mouse microglia BV-2 cell line. Results illustrated that finger limes inhibited the NO-releasing and the inflammation-related cytokines including IL-1β, IL-6 and TNFα elevation. QRT-PCR revealed that finger lime extracts alleviated LPS-induced upregulation of iNOS, IL-6, JAK2, TNFα, TLR2, TLR4, IL-1β, NF-κB and LPS-induced downregulation of IκBα. This study may expand our knowledge on the physiochemical characteristics and bioactive properties of citrus fruits.

Monkey orange fruit juice improves the nutritional quality of a maize-based diet

This paper studied the nutritional impact of the use of juice from Strychnos cocculoides (monkey orange) in a maize-based porridge. Monkey orange juice is traditionally used to supplement maize porridge - a staple breakfast cereal especially for vulnerable groups. Monkey orange fruits contain high amounts of micronutrients and phenolic compounds and are widely distributed throughout sub-Saharan Africa. The valuable components can be efficiently extracted by traditional and pectinase maceration techniques. The bioaccessibility of minerals and main phenolic compounds in maize porridge (5 g maize meal) supplemented by monkey orange juice (100 ml) were assessed after in-vitro digestion together with the kinetics of starch degradation. Caffeic and protocatechuic acids exceeded 100%, and chlorogenic acid 81% bioaccessibility after simulated intestinal digestion. Rutin was undetected after the simulated intestinal phase due to precipitation in the pellet. In-vitro bioaccessibility of minerals ranged from 12 to 62% in monkey orange enriched porridge. A 50-70% decrease of starch hydrolysis was observed at the end of the simulated intestinal digestion of monkey orange maize porridge confirming the known potential of phenolic compounds to decrease the glycaemic index of starch-rich foods. Consequently monkey orange juice appeared a suitable ingredient to enrich staple maize porridge thanks to its micronutrients and health benefit potential. Similar relationships of other fruits and starchy foods warrant study as a means to improve the nutritional quality of the diets of malnourished populations.

Influence of freezing on the bioaccessibility of beetroot (Beta vulgaris) bioactive compounds during in vitro gastric digestion

BACKGROUND

The effect of freezing (in liquid nitrogen at -196 °C , at -80 °C and at -20 °C) on the food matrix structure and the consequent effect on the bioaccessibility of total polyphenol content (TPC) and antioxidant activity (AA) of beetroot was investigated by an in vitro digestion method. The in vitro digestion involved incubation in simulated saliva followed by incubation in simulated gastric juice. Bioaccessibility of bioactive compounds was evaluated by measuring the TPC and the AA during in vitro digestion in both the beetroot matrix and the gastric juice.

RESULTS

Release of TPC and AA of beetroot was higher in frozen samples (55 ± 5% for TPC and 68 ± 5% for AA) than in the fresh beetroot sample (∼46% for TPC and ∼53% for AA). The mass transfer kinetics were described by using a Weibull model with mean relative errors lower than 8.5% contributing to a better understanding of the influence of freezing on the bioaccessibility of bioactive compounds.

CONCLUSIONS

From the treatments tested in this study, freezing with liquid nitrogen resulted in the greatest increase in bioaccessibility of the antioxidant and phenolic compounds of beetroots. © 2018 Society of Chemical Industry.

Effects of convective drying and freeze-drying on the release of bioactive compounds from beetroot during in vitro gastric digestion

Drying may alter the microstructure of vegetables and influence the release of bioactive compounds during digestion.

Physico-Chemical Changes of Composite Whey Protein Hydrogels in Simulated Gastric Fluid Conditions

Polysaccharide blended whey protein isolate (WPI) hydrogels were developed for the delivery of black carrot ( Daucus carota) concentrate as bioactive agent in simulated gastric fluid (SGF). Pectin (PC), gum tragacanth (GT), and xanthan gum (XG) were blended as additional polymers to modulate the release characteristics of the WPI hydrogels. Experiments showed that sole whey protein (C), XG, and GT blended hydrogels possessed restricted release profiles 67%, 61%, and 67%, respectively, whereas PC samples attained higher release rates (83%) ( p < 0.05). Interactions between polymers and aqueous medium were analyzed by nuclear magnetic resonance relaxometry. C (82 ms) and GT (84 ms) hydrogels attained higher T₂ values than PC (74 ms) and XG (73 ms) samples in SGF. Hardness of only XG hydrogels increased from 1.9 to 4.1 N after gastric treatment. Physicochemical changes within hydrogels during release were also investigated, and hydrogels were proved to be appropriate for desired delivery purposes.

The uniaxial and coaxial encapsulations of sour cherry (Prunus cerasus L.) concentrate by electrospinning and their in vitro bioaccessibility

Sour cherry (Prunus cerasus L.) is rich in polyphenols which are known to be protective agents against several diseases. Polyphenols are highly sensitive against temperature, pH, oxygen, and light conditions, leading to low bioaccessibility. In this study, polyphenols of sour cherry concentrate (SCC) were encapsulated by uniaxial or coaxial electrospinning with gelatin or gelatin-lactalbumin. Results showed that phenolic acids had higher encapsulation efficiencies than anthocyanins. Encapsulation efficiencies were found as 89.7 and 91.3% in terms of phenolic acids and 70.3 and 77.8% in terms of flavonoids for the uniaxially electrospun samples with gelatin and gelatin-lactalbumin, respectively. The content of polyphenols in SCC decreased after intestinal tract whereas all electrospun samples showed improved bioaccessibility. According to in vitro digestion results, electrospinning encapsulation provided 8 times better protection of cyanidin-3-glucoside compared to the non-encapsulated SCC. Results showed that especially coaxial electrospinning encapsulation is an effective method for sour cherry polyphenols.

Comparison of chemical, color stability, and phenolic composition from pericarp of nine colored corn unique varieties in a beverage model

The objective was to compare the chemical stability and color of nine unique anthocyanin-rich colored corn varieties named/coded as V1, V2, V3… V9. Extracts were added to a beverage model and stored at 4 °C, 22°C, or 32°C for 12weeks. After 12 weeks of storage at 32°C, variety V6 [high condensed form (CF), high cyanidin-3-O-glucoside (C3G)] had the longest anthocyanin half-life, based on the quantification by HPLC. V3 [high pelargonidin (Pg), high acylated form (C3-mal)] and V5 (high CF, high C3G, high C3-mal) had the most favorable hue. V5 and V6 had some of the smallest changes in color over time. These findings suggest that an abundance of condensed forms with C3G in corn extracts could contribute to the improved stability. Beverage storage parameters also influenced color parameters; low temperatures and low pH enhanced color and anthocyanin stability. The most promising corn varieties for future experiments are V3, V5, and V6 based on color retention.

Molecular Mechanisms and Pathways as Targets for Cancer Prevention and Progression with Dietary Compounds

A unique feature of bioactive food ingredients is their broad antioxidant function. Antioxidants having a wide spectrum of chemical structure and activity beyond basic nutrition; display different health benefits by the prevention and progression of chronic diseases. Functional food components are capable of enhancing the natural antioxidant defense system by scavenging reactive oxygen and nitrogen species, protecting and repairing DNA damage, as well as modulating the signal transduction pathways and gene expression. Major pathways affected by bioactive food ingredients include the pro-inflammatory pathways regulated by nuclear factor kappa B (NF-κB), as well as those associated with cytokines and chemokines. The present review summarizes the importance of plant bioactives and their roles in the regulation of inflammatory pathways. Bioactives influence several physiological processes such as gene expression, cell cycle regulation, cell proliferation, cell migration, etc., resulting in cancer prevention. Cancer initiation is associated with changes in metabolic pathways such as glucose metabolism, and the effect of bioactives in normalizing this process has been provided. Initiation and progression of inflammatory bowel diseases (IBD) which increase the chances of developing of colorectal cancers can be downregulated by plant bioactives. Several aspects of the potential roles of microRNAs and epigenetic modifications in the development of cancers have also been presented.

Food processing strategies to enhance phenolic compounds bioaccessibility and bioavailability in plant-based foods

Phenolic compounds are important constituents of plant-based foods, as their presence is related to protective effects on health. To exert their biological activity, phenolic compounds must be released from the matrix during digestion in an absorbable form (bioaccessible) and finally absorbed and transferred to the bloodstream (bioavailable). Chemical structure and matrix interactions are some food-related factors that hamper phenolic compounds bioaccessibility and bioavailability, and that can be counteracted by food processing. It has been shown that food processing can induce chemical or physical modifications in food that enhance phenolic compounds bioaccessibility and bioavailability. These changes include: (i) chemical modifications into more bioaccessible and bioavailable forms; (ii) cleavage of covalent or hydrogen bonds or hydrophobic forces that attach phenolic compounds to matrix macromolecules; (iii) damaging microstructural barriers such as cell walls that impede the release from the matrix; and (iv) create microstructures that protect phenolic compounds until they are absorbed. Indeed, food processing can produce degradation of phenolic compounds, however, it is possible to counteract it by modulating the operating conditions in favor of increased bioaccessibility and bioavailability. This review compiles the current knowledge on the effects of processing on phenolic compounds bioaccessibility or bioavailability, while suggesting new guidelines in the search of optimal processing conditions as a step forward towards the design of healthier foods.

Processing black mulberry into jam: effects on antioxidant potential and in vitro bioaccessibility

BACKGROUND

Black mulberries (Morus nigra) were processed into jam on an industrialised scale, including the major steps of: selection of frozen black mulberries, adding glucose-fructose syrup and water, cooking, adding citric acid and apple pectin, removing seeds, and pasteurisation. Qualitative and quantitative determinations of antioxidants in black mulberry samples were performed using spectrophotometric methods, as well as HPLC- and LC-QTOF-MS-based measurements. These analyses included the determination of total polyphenolic content, % polymeric colour, total and individual anthocyanin contents, antioxidant capacity, and in vitro bioaccessibility in processing samples.

RESULTS

Jam processing led to a significant reduction in total phenolics (88%), total flavonoids (89%), anthocyanins (97%), and antioxidant capacity (88-93%) (P < 0.05). Individual anthocyanin contents, determined using HPLC analysis, also showed a significant decrease (∼99% loss). In contrast, % recovery of bioaccessible total phenolics, anthocyanins, and antioxidant capacity (ABTS assay) increased after jam processing (16%, 12%, and 37%, respectively).

CONCLUSION

Fruit processing resulted in losses of polyphenols, anthocyanins, and antioxidant capacity of black mulberry jam. Optimisation of food processing could help to protect the phenolic compounds in fruits which might be helpful for the food industry to minimise the antioxidant loss and improve the final product quality. © 2016 Society of Chemical Industry.

Antioxidant Capacity, Anticancer Ability and Flavonoids Composition of 35 Citrus (Citrus reticulata Blanco) Varieties

Citrus (Citrus reticulate Blanco) is one of the most commonly consumed and widely distributed fruit in the world, which is possessing extensive bioactivities. Present study aimed to fully understand the flavonoids compositions, antioxidant capacities and in vitro anticancer abilities of different citrus resources. Citrus fruits of 35 varieties belonging to 5 types (pummelos, oranges, tangerines, mandarins and hybrids) were collected. Combining li quid chromatography combined with electrospray ionization mass spectrometry (LC-ESI-MS/MS) and ultra-performance liquid chromatography combined with diode array detector (UPLC-DAD), a total of 39 flavonoid compounds were identified, including 4 flavones, 9 flavanones and 26 polymethoxylated flavonoids (PMFs). Each citrus fruit was examined and compared by 4 parts, flavedo, albedo, segment membrane and juice sacs. The juice sacs had the lowest total phenolics, following by the segment membrane. Four antioxidant traits including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC) and cupric reducing antioxidant capacity (CUPRAC) were applied for the antioxidant capacities evaluation. Three gastric cancer cell lines, SGC-7901, BGC-823 and AGS were applied for the cytotoxicity evaluation. According to the results of correlation analysis, phenolics compounds might be the main contributor to the antioxidant activity of citrus extracts, while PMFs existing only in the flavedo might be closely related to the gastric cancer cell line cytotoxicity of citrus extracts. The results of present study might provide a theoretical guidance for the utilization of citrus resources.