Anthocyanin Degradation Research Articles

Effects of energy input modes on energy efficiency and berry quality in continuous microwave drying

To elucidate the effects of energy input modes on energy efficiency and berry quality in continuous microwave drying, four energy input modes with variational working ways of magnetrons were investigated by using numerical simulation and bench experiments in a continuous microwave dryer. Energy efficiency was divided into absorption and conversion efficiency to study the change rule of drying process, and the retention rate of anthocyanins of berry’s representative nutrition ingredient was studied considering both of the temperature and its uniformity. Results indicate that the energy input modes affect the absorption efficiency by changing the distribution uniformity of electric field of material layer, and the conversion efficiency by altering the matching degree between the energy allocation and drying characteristics of berry, which are both determined by the ways of working magnetrons of different energy input modes. The conversion efficiency has a greater influence on the final energy efficiency, so the energy input mode should be paid attention to the provision of microwave energy by selecting proper way of working magnetrons according to the drying characteristics. The effect of temperature uniformity on anthocyanin degradation is more obvious with average temperature increasing gradually, where better uniformity of electric field strength should be provided to guarantee the quality of dried berry by adjusting the energy input mode. The research results provide significant insights to optimize the energy input mode of taking into account both the energy efficiency and dried quality of material.

Interactions between lipid oxidation and anthocyanins from black carrots in ω-3 fatty acid-rich flaxseed oil-in-water emulsions

The application of anthocyanins as red colorants in lipid-containing foods such as oil-in-water emulsions is challenging due to their ability to act as antioxidants and their instability under various environmental conditions. In this study, we investigated the kinetics of black carrot anthocyanin degradation and the subsequent color loss influenced by lipid oxidation reactions in 1% (w/w) flaxseed oil-in-water emulsions stabilized by 0.1% (w/w) sodium dodecyl sulfate (SDS) at pH 2 upon storage at 35 °C for ten days under light and in the dark. Oxidatively stable Miglyol oil-in-water emulsions and SDS solutions were used as reference. The results showed simultaneous formation of lipid hydroperoxides and degradation of anthocyanins. The addition of anthocyanins decreased lipid hydroperoxide formation, confirming the antioxidant activity of anthocyanins through radical scavenging mechanism. The kinetic modelling of lipid oxidation and anthocyanin degradation are particularly important for estimating color stability in colored emulsion-based food systems such as dairy or non-dairy milk or yoghurt drinks.Graphical abstract

Floral Response to Heat: A Study of Color and Biochemical Adaptations in Purple Chrysanthemums.

Chrysanthemums are among the world's most popular cut flowers, with their color being a key ornamental feature. The formation of these colors can be influenced by high temperatures. However, the regulatory mechanisms that control the fading of chrysanthemum flower color under high-temperature stress remain unclear. This study investigates the impact of high temperatures on the color and biochemical responses of purple chrysanthemums. Four purple chrysanthemum varieties were exposed to both normal and elevated temperature conditions. High-temperature stress elicited distinct responses among the purple chrysanthemum varieties. 'Zi Feng Che' and 'Chrystal Regal' maintained color stability, whereas 'Zi Hong Tuo Gui' and 'Zi lian' exhibited significant color fading, particularly during early bloom stages. This fading was associated with decreased enzymatic activities, specifically of chalcone isomerase (CHI), dihydroflavonol 4-reductase (DFR), and anthocyanidin synthase (ANS), indicating a critical period of color development under heat stress. Additionally, the color fading of 'Zi Lian' was closely related to the increased activity of the peroxidase (POD) and polyphenol oxidase (PPO). Conversely, a reduction in β-glucosidase (βG) activity may contribute significantly to the color steadfastness of 'Zi Feng Che'. The genes Cse_sc027584.1_g010.1 (PPO) and Cse_sc031727.1_g010.1 (POD) might contribute to the degradation of anthocyanins in the petals of 'Zi Hong Tuo Gui' and 'Zi Lian' under high-temperature conditions, while simultaneously maintaining the stability of anthocyanins in 'Zi Feng Che' and 'Chrystal Regal' at the early bloom floral stage. The findings of this research provide new insights into the physiological and biochemical mechanisms by which chrysanthemum flower color responds to high-temperature stress.

Impact of Spray Drying on the Properties of Grape Pomace Extract Powder

Incorporating anthocyanins, valuable natural pigments, into a powder can improve their stability, but exposure to high temperatures during processing can cause them to degrade. The purpose of this study was to investigate how the inlet air temperature during spray drying affects the physical and chemical characteristics as well as the flowability of a grape pomace anthocyanin powder obtained through ultrasound-assisted extraction using acidified water as the solvent. An anthocyanin solution containing 13% (w/v) maltodextrin was subjected to spray drying at temperatures ranging from 120 to 170 °C. Tukey’s test was applied to compare the means of the samples. The samples dried at temperatures between 130 and 170 °C were adequate, with a moisture content < 5% and a water activity < 0.3, indicating that the powder was stable. The highest anthocyanin retention (91.94 ± 1.59%) and process yield (50.00 ± 3.06%) were achieved at 140 °C, while higher temperatures resulted in anthocyanin degradation. Furthermore, the powder exhibited poor flowability, indicating cohesive behavior (Hausner ratio > 42.29% and Carr index > 1.73), which is an industrial parameter rarely considered in spray-drying studies. The acidification process was found to promote high anthocyanin retention following high-temperature processing. However, powders obtained from food matrices with low pH and high sugar content may exhibit increased cohesion due to interaction forces. These findings highlight the potential of utilizing grape pomace and green solvents to produce bioactive-rich powders for industrial applications.

Use of vine-shoots stilbene extract to the reduction of SO2 in red and rosé Italian wine: Effect on phenolic, volatile, and sensory profiles

Sulfur dioxide (SO2) is one of the most used additives in wine industry for its antioxidant and antimicrobial activity. However, due to health concerns, consumers’ demand of wines with either reduced or totally replaced SO2 has increased. This study aimed to assess the effect of partial and total replacement of SO2 with a vine-shoots extract rich in stilbenes in rosé (cv. Sangiovese) and red (cv. Negramaro) wines respectively. Color as well as phenolic, volatile, and sensory profiles of wines were evaluated at bottling and during storage.The results showed that the vine-shoots extract increased the levels of trans-resveratrol, catechin, and gallic acid in wines. Moreover, the positive correlation of procyanidin dimers in red wine suggested an increase of the polymerization reactions. The amount of added extract probably provided lower antimicrobial protection compared to SO2, as indicated by the higher levels of ethyl phenol. The decrease of individual anthocyanins and oxidation aldehydes observed in wines with SO2 replacement and the higher levels of caftaric acid in the rosé wine with the extract suggested a shift of the oxidative protection, with a lower protection towards anthocyanin degradation and higher protection towards carbonyl formation and oxidation of readily oxidizable phenolic acids.

Incorporation of microencapsulated polyphenols from jabuticaba peel (Plinia spp.) into a dairy drink: stability, in vitro bioaccessibility, and glycemic response

This work incorporated bioactives extracted from jabuticaba peel in the form of concentrated extract (JBE) and microencapsulated powders with maltodextrin (MDP) and gum arabic (GAP) in a dairy drink, evaluating its stability, in vitro bioaccessibility, and glycemic response. We evaluated the pH, acidity, colorimetry, total phenolics and anthocyanins, antioxidant capacity, degradation kinetics and half-life of anthocyanins, bioaccessibility, and postprandial glycemic physicochemical characteristics response in healthy individuals. The drinks incorporated with polyphenols (JBE, GAP, and MDP) and the control dairy drink (CDD) maintained stable pH and acidity over 28 days. In color, the parameter a*, the most relevant to the study, was reduced for all formulations due to degradation of anthocyanins. Phenolic and antioxidant content remained constant. In bioaccessibility, we found that after the gastrointestinal simulation, there was a decrease in phenolics and anthocyanins in all formulations. In the glycemic response, we observed that the smallest incremental areas of glucose were obtained for GAP and JBE compared to CDD, demonstrating that polyphenols reduced glucose absorption. Then, the bioactives from jabuticaba peel, incorporated into a dairy drink, showed good storage stability and improved the product’s functional aspects.

A Natural Food Colourant from Dioscorea alata (Dandila) in Sri Lanka: Development, Storage Stability and Bio-active Properties

Though anthocyanins are popular as natural food colourants with additional functional properties, their instability limited their utilization in the industry. Therefore, this study aimed to formulate a natural food colourant by the microwave-assisted encapsulation of Dandila (Dioscorea alata) anthocyanins to enhance the storage stability of the pigments in ambient conditions and to study the storage stability and the bio-active properties of the formulated colourant. Acidified water was used as the solvent to extract the anthocyanins from Dandila yams. Maltodextrin and gum Arabic were tested as wall materials at three different ratios to encapsulate the extracted pigments. Storage stability, Total Phenolic content, anti-oxidant activity and anti-bacterial activity were determined using appropriate procedures. The colourant formulation encapsulated with maltodextrin (30 mg/ml) was selected as the best encapsulation treatment for Dandila anthocyanin. Anthocyanin degradation was not significant during the tested 12 months of storage period. Noteworthy values were obtained for Total Phenolic Content and anti-oxidant activity. Among the tested strains in the antimicrobial assay, the natural colourant showed inhibitory activities against Escherichia coli and Streptococcus pneumoniae. The results confirm the successful development of a natural colourant rich in bio-active properties from Dandila anthocyanin while ensuring its storage stability in ambient conditions.

Enhanced stability and bioavailability of mulberry anthocyanins through the development of sodium caseinate-konjac glucomannan nanoparticles

This study was carried out to improve the stability of anthocyanins (ACNs) by developing MA-SC-KGM nanoparticles using a self-assembly method that involved the combination of sodium caseinate (SC) and konjac glucomannan (KGM) with mulberry anthocyanin extract (MA). Atomic force microscopy (AFM) analysis showed SC encapsulated MA successfully. Multispectral techniques demonstrated the presence of hydrogen bonds and hydrophobic interactions in the nanoparticles. MA-SC-KGM ternary mixture improved storage stability, color stability and anthocyanin retention better compared to the MA-SC binary mixture. Notably, MA-SC-KGM nanoparticles significantly inhibited the thermal degradation of ACNs, improved pH stability, and showed stability and a slow-release effect in gastrointestinal digestion experiments. In addition, MA-SC-KGM nanoparticles were effective in scavenging DPPH· and ABTS+ free radicals, with enhanced stability and antioxidant capacity even during the heating process. This study successfully developed a novel MA-SC-KGM protein-polysaccharide composite material that effectively stabilized natural ACNs, expanding the application of ACNs in various industries.

Image recognition technology provides insights into relationships between anthocyanin degradation and color variation during jet drying of black carrot

To identify interesting relationships between anthocyanin degradation and color variation during food processing, black carrot slice (BCS) was dried by air-impingement jet drying (AIJD) and hot air drying (HAD). AIJD was a better technology for drying BCS than HAD. Results of colorimeter determination showed that the color of BCS was significantly changed during AIJD at 50, 60 and 70 °C. UHPLC-QqQ-MS/MS analysis found that AIJD-induced degradations of main BCS anthocyanins, cyanidin-3-xylosyl(feruloylglucosyl)galactoside and cyanidin-3-xylosyl(sinapoylglucosyl)galactoside, belonged to non-spontaneous endothermic reactions, which followed the 0.5- and 1-order kinetic equations, respectively. Anthocyanin content and colors obtained from colorimeter presented strong positive correlation, particularly the a* and chroma values. We further developed a Python script based on image recognition technology to visualize the correlation matrixes between the anthocyanin contents and colors of BSC images. The plots revealed that strong positive correlations between anthocyanins and colors primarily concentrated in the sample's periphery following a concentric pattern.

Kinetic modelling of anthocyanins and vitamin C degradation in a maqui-citrus beverage during storage for different sweeteners and pasteurization treatments

Kinetic models to describe the degradation of anthocyanins (first-order model) and vitamin C (system of ordinary differential equations) in a novel beverage, has been used as a tool to identify the most relevant variables for the degradation kinetics and to support shelf-life estimation. The models were based on an empirical dataset, accounting for the effect of a prior processing treatment (HHP at 400 MPa- 180s; HHP at 600 MPa-180s; thermal treatment at 85 °C for 15s), storage temperature (4 or 20 °C), and the use of two different sweeteners (sucralose or stevia). Using model selection (based on AIC), we conclude that the degradation kinetics depends on a complex combination of process and product parameters. A strong temperature dependence on anthocyanins and vitamin C was observed during pasteurization. Products treated by HHP resulted in higher vitamin C concentrations during storage than those thermally treated. Finally, an interaction with the sweetener resulted in a slight stabilization of bioactive compounds. In conclusion, this study demonstrates the complexity of the degradation process of bioactive compounds in these beverages, advocating that nonlinear kinetic models serve as a tool to identify the most relevant parameters, ultimately supporting product formulation and shelf life estimation.

The degradation and antioxidant capacity of anthocyanins from eggplant peels in the context of complex food system under thermal processing

A model of complex food system composed of dietary fiber, protein, starch (3/2/2), added with anthocyanins extracted from purple eggplant peels was constructed to investigate impacts of thermal treatments (including steaming, boiling, microwave and frying) on the degradation and antioxidant capacity of anthocyanins. The content of anthocyanins was reduced by 84.48% under frying treatment (185 ± 5 °C), and the degradation of anthocyanins was in line with second-order kinetics as with microwave treatment (700 W). Under boiling and steaming conditions, the degradation of anthocyanins followed first-order kinetics. Additionally, the antioxidant capacity was positively correlated with the contents of total anthocyanins and polyphenols. During thermal treatments, anthocyanins were mainly decomposed into gallic acid, phloroglucinaldehyde, and 2,4-dihydroxybenzoic acid (frying), in which phloroglucinaldehyde could be further isomerized into phloroglucinic acid. The results of scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) also supported that frying showed the most robust effect on influencing the structure of anthocyanins during these four thermal treatments.

Isolation, Purification and Tyrosinase Inhibitory Activity of Anthocyanins and Their Novel Degradation Compounds from Solanum tuberosum L.

To explore the composition of anthocyanins and expand their biological activities, anthocyanins were systematically isolated and purified from tubers of Solanum tuberosum L., and their tyrosinase inhibitory activity was investigated. In this study, two new anthocyanin degradation compounds, norpetanin (9) and 4-O-(p-coumaryl) rhamnose (10), along with 17 known anthocyanins and their derivatives, were isolated and purified from an acid-ethanolic extract of fresh purple potato tubers. Their structures were elucidated via 1D and 2D NMR and HR-ESI-MS and compared with those reported in the literature. The extracts were evaluated for anthocyanins and their derivatives using a tyrosinase inhibitor screening kit and molecular docking technology, and the results showed that petanin, norpetanin, 4-O-(p-coumaryl) rhamnose, and lyciruthephenylpropanoid D/E possessed tyrosinase inhibitory activity, with 50% inhibiting concentration (IC50) values of 122.37 ± 8.03, 115.53 ± 7.51, 335.03 ± 12.99, and 156.27 ± 11.22 μM (Mean ± SEM, n = 3), respectively. Furthermore, petanin was validated against melanogenesis in zebrafish; it was found that it could significantly inhibit melanin pigmentation (p < 0.001), and the inhibition rate of melanin was 17% compared with the normal group. This finding may provide potential treatments for diseases with abnormal melanin production, and high-quality raw materials for whitening cosmetics.

Exploring deep eutectic solvent extraction's impact on anthocyanin degradation kinetics in various conditions

This study evaluated the stability of anthocyanins in red cabbage extracts using deep eutectic solvents (DESs) and acidified methanol under thermal and storage conditions. DESs included combinations of choline chloride with malic acid (Ma), xylitol (Xy), lactic acid (La), and glycerol (Gl). Extracts were heat-treated at 40 °C–100 °C and stored at temperatures of 25 °C, 4 °C, and −18 °C for 35 days. Analysis involved pH differential methodology, browning and polymeric color indexes, antioxidant assays (DPPH• and ABTS•+), HPLC, and FT-IR spectroscopy. Results showed that anthocyanin content in all solvents decreased with increasing temperature. Acidified methanol samples experienced a notable reduction from 304.2 mg/L at 40 °C to 246.5 mg/L at 100 °C. Malic acid, lactic acid, xylitol, and glycerol samples also showed significant declines at higher temperatures. Cold storage effectively preserved anthocyanin levels. Kinetic analysis indicated that ChCl-Xy was the most effective solvent in preserving anthocyanins and minimizing browning, while ChCl-Ma led to the highest anthocyanin degradation and color changes. At 25 °C, Ac-MetOH demonstrated the highest antioxidant activity (DPPH• scavenging rate k of 5.66 ± 0.15), but ChCl-Ma exhibited the highest browning index (k of 3.4 ± 0.13) and polymeric color index (k of 5.54 ± 0.12), suggesting lower stability compared to other solvents.

Multi-Omics Analysis Reveals That Anthocyanin Degradation and Phytohormone Changes Regulate Red Color Fading in Rapeseed (Brassica napus L.) Petals.

Flower color is an important trait for the ornamental value of colored rapeseed (Brassica napus L.), as the plant is becoming more popular. However, the color fading of red petals of rapeseed is a problem for its utilization. Unfortunately, the mechanism for the process of color fading in rapeseed is unknown. In the current study, a red flower line, Zhehuhong, was used as plant material to analyze the alterations in its morphological and physiological characteristics, including pigment and phytohormone content, 2 d before flowering (T1), at flowering (T2), and 2 d after flowering (T3). Further, metabolomics and transcriptomics analyses were also performed to reveal the molecular regulation of petal fading. The results show that epidermal cells changed from spherical and tightly arranged to totally collapsed from T1 to T3, according to both paraffin section and scanning electron microscope observation. The pH value and all pigment content except flavonoids decreased significantly during petal fading. The anthocyanin content was reduced by 60.3% at T3 compared to T1. The content of three phytohormones, 1-aminocyclopropanecarboxylic acid, melatonin, and salicylic acid, increased significantly by 2.2, 1.1, and 30.3 times, respectively, from T1 to T3. However, auxin, abscisic acid, and jasmonic acid content decreased from T1 to T3. The result of metabolomics analysis shows that the content of six detected anthocyanin components (cyanidin, peonidin, pelargonidin, delphinidin, petunidin, and malvidin) and their derivatives mainly exhibited a decreasing trend, which was in accordance with the trend of decreasing anthocyanin. Transcriptomics analysis showed downregulation of genes involved in flavonol, flavonoid, and anthocyanin biosynthesis. Furthermore, genes regulating anthocyanin biosynthesis were preferentially expressed at early stages, indicating that the degradation of anthocyanin is the main issue during color fading. The corresponding gene-encoding phytohormone biosynthesis and signaling, JASMONATE-ZIM-DOMAIN PROTEIN, was deactivated to repress anthocyanin biosynthesis, resulting in fading petal color. The results clearly suggest that anthocyanin degradation and phytohormone regulation play essential roles in petal color fading in rapeseed, which is a useful insight for the breeding of colored rapeseed.

Nanoencapsulation of Maqui (Aristotelia chilensis) Extract in Chitosan-Tripolyphosphate and Chenopodin-Based Systems.

Maqui berries contain a high percentage of anthocyanins with high antioxidant and anti-inflammatory capacity but that are unstable in the colonic site. Nanocarriers based on polysaccharides and/or proteins can protect against the degradation of anthocyanins. The aim of this study was the nanoencapsulation of maqui extract (ME) in chitosan-tripolyphosphate (CTPP-ME), chenopodin (CH-ME), and chenopodin-alginate (CHA-ME). A standardised ME was prepared and then encapsulated in the nanosystems. The physicochemical properties, encapsulation parameters, and the interactions of ME with the nanovehicles were characterised. The cyanidin-3-glucoside released and ORAC activity in phosphate buffer at pH 7.4 were evaluated. The content of ME was 8-9 mg of cyanidin-3-glucoside/g of extract. CTPP with ME at 3% obtained the highest encapsulation efficiency (EE = 91%), and no significant differences were observed in size (274-362 nm), PDI (0.5-0.7), and zeta potential (+34-+41 mV) when the concentration of ME changed from 1% to 5%. CH-ME was shown to be smaller (152 nm) than CTPP-ME, and CH-ME and CHA-ME showed lower EE (79% and 54%, respectively) than CTPP-ME. FT-IR revealed a stronger interaction of ME with CTPP-ME than with CH-ME. Both systems showed a significantly lower release than free ME, and the T50 value of CTPP-ME 3% (328 min) was higher than CH-ME (197 min). Both protected the ORAC activity of ME.

Combined effect of electrolyzed water (EW) and sonication with equilibrium modified atmosphere packaging for prolonging storage stability of fresh strawberry.

This research focuses on the effectiveness of electrolyzed water (50 and 100 ppm for 3 min), ultrasonication (80 W for 3 min), and their combinations on fresh strawberries, which are then packaged using microperforated film to enhance their storage stability. The gas composition in the headspace, pH, soluble solids, color (L*, a*, b*, and ΔE* values), anthocyanins, total phenolics, and texture profile was evaluated for the 35 days of storage at +4 °C. The lowest weight loss was measured at about 100 ppm electrolyzed water (EW; 0.47%), and the highest one was in the control group (0.57%) after storage. At the end of the storage, O2 in the headspace decreased from 20.90% to 10.50-8.10% and CO2 was accumulated from 0.03% to 16.4-14.34%. The results showed that soluble solids decreased (9.95 to 8.48-7.85 °Bx) and pH values increased (3.34 to 3.79-3.91) during storage. At the end of the storage, the total phenolics in the control group decreased by the most during storage (from 1209.09 ppm to 808.00 ppm), whereas the 50 ppm EW group had the highest (931.66 ppm). Further, the significantly highest anthocyanin amount was found to be 143.86 ppm in the 100 ppm EW group at the end of 28 days of storage. The EW can significantly delay the degradation of anthocyanin over the storage period. The sonication at 100 ppm EW damages strawberry tissues, reducing their hardness. The lowest decay rate was found in fruits treated with 100 ppm EW (41.67%), followed by 50 ppm EW (58.33%), compared to the control (75.00%). This study reveals that applications of the 50 ppm EW and also 50 pm EW combined with ultrasonication have great potential in the extending storage stability of the fresh strawberries.

The effects of polysaccharides, organic acids and colloids on the stability of anthocyanin in purple corn

SummaryPurple corn anthocyanins have rich nutritional value, but anthocyanins have low stability. The main objective of this study was to screen compounds from the common co‐pigments (polysaccharides, organic acids and colloids) that could improve the stability of anthocyanins and to investigate the effect of different co‐pigments on the stability of anthocyanins in purple corn during heat treatment. There were significant differences in copigmentation effects among different types of co‐pigments. The total anthocyanin retention rate of purple corn without co‐pigments was 15.02%. After copigmentation treatment with different compounds, among the polysaccharides, the total anthocyanin retention rates of 15% fructose and 15% glucose were 37.29% and 52.18% respectively. The copigmentation effects of monosaccharides were better than those of disaccharides, sugar alcohols and cyclodextrins. Among the organic acids, the six co‐pigments were all organic acids containing phenolic rings. The retention rates of anthocyanins were 71.47% and 68.21% for 0.06% tannic acid and 0.1% tartaric acid, respectively, indicating high copigmentation effects. The a* value of purple corn was significantly increased after these treatments, indicating that organic acids had stronger copigmentation effects than polysaccharides. In the colloids, the total anthocyanin retention rate of 2.0% pectin was 43.72%, while 0.5% guar gum had a retention rate of 9.82%. However, low concentrations of guar gum promoted the degradation of anthocyanins, indicating weak copigmentation effects for colloids.

Study of the stability of hydroelectrolytic sports beverages enriched with phenolic extract from jaboticaba peel or blueberry pulp

This study evaluated the impact of light exposure and storage conditions on sports beverages enriched with phenolic extracts from jaboticaba peel and blueberry pulp over a period of 91 days. The analysis encompassed various parameters, including microbial assessments, phenolic content, anthocyanin concentrations, color coordinates, and the stability of anthocyanin compounds. The results indicated that the applied heat treatment effectively maintained the beverages' microbiological safety, with the phenolic-rich extracts showcasing antimicrobial properties. Both beverages exhibited stability in total phenolic content. However, anthocyanin concentrations experienced significant reductions, although certain stabilizing factors, such as interactions between anthocyanins and phenolic compounds, contributed to color preservation. The study highlights the complexities of anthocyanin degradation and its effects on the color, flavor, and antioxidant properties of these enriched sports beverages.

Black bean (Phaseolus vulgaris L. cv. "Tolosa") polyphenolic composition through cooking and in vitro digestion.

In this study, five different black bean (Phaseolus vulgaris L. cv. Tolosa) populations cultivated in different geographical areas including Oiartzun, Andoain, Azkoitia, San Esteban and Amasa Villabona, were studied and their polyphenolic content was determined. Two food products were prepared from the five different bean populations, cooked "Tolosa" beans and a hummus made with "Tolosa" cooked beans. Moreover, the variations of total polyphenol content (TPC), total anthocyanin content (TAC) and free radical scavenging activity by the 1,1-diphenyl-1-picrylhydrazyl (DPPH) method were analyzed for raw beans, cooked beans, and "Tolosa" beans hummus. Polyphenolic detailed composition was determined by means of HPLC-MS-QTOF analysis. The "Tolosa" bean population richest in polyphenols was selected in order to study the effect of in vitro digestion on the polyphenolic content and antioxidant effect and the degradation of the main anthocyanins was followed during the in vitro digestion. Finally, the effect of the different phases of digestion on the cytotoxicity in Caco-2 cells was determined. The results suggest that cooking "Tolosa" black beans results in an increase in the bioaccessibility of polyphenols and their antioxidant activity, which, additionally has a positive effect on Caco-2 intestinal cell viability.

Bunch transpiration is involved in the hastening of grape berry ripening under elevated temperature and low relative humidity conditions

The present study aimed: i) to evaluate the impact of the changes in temperature and relative humidity (RH), projected by the year 2100, on grape ripening, and ii) to assess if bunch transpiration is a key physiological process involved in the advancement in grape development under future climate conditions. Fruit-bearing cuttings of Vitis vinifera L. cv. ‘Tempranillo’ were grown, from fruit set to maturity, in glasshouses under two conditions: 24°C/14°C and 55%/70% RH (day/night) (T) vs 28°C/18°C and 43%/58% RH (T+4). To elucidate the role of bunch transpiration in grape development in a future climate scenario, the bunches of half of the plants in the T+4 glasshouse were sprayed with an antitranspirant (AT+4). T+4 increased bunch transpiration, hastened the ripening process, increasing the rate of total soluble solid (TSS) accumulation and malic acid degradation, and reduced the concentration of total anthocyanins. The application of antitranspirant partially alleviated the effects of combined high temperature and low RH on maturation times, through lower TSS accumulation rates. Berries in AT+4 had the lowest concentrations of anthocyanins and color, likely related to a reduction in light transmittance by the antitranspirant film and to higher anthocyanin degradation due to the longer exposure to elevated temperatures. The results show a negative impact of elevated temperature and low RH on grape composition. The increased bunch transpiration under these conditions played an important role in the changes observed in phenology and sugar accumulation.