Enrichment of Whole Wheat Cocoa Biscuits with Encapsulated Grape Skin Extract.
ABSTRACT: Grape pomace is one of the major waste products generated by the wine-making process and it contains seeds and skins still rich in bioactive compounds. Skins can be separated from the seeds and valorised for the recovery of antioxidant extracts with different potential applications. The aim of this study was to evaluate the influence of the addition of an extract obtained from waste grape skins and encapsulated in maltodextrins on the antioxidant properties and sensory acceptability of whole wheat cocoa biscuits. Different levels of enrichment (1.2, 2.3, and 3.5% on dough weight) were tested, and the obtained doughs and biscuits were analysed for total phenols content and antioxidant capacity (based on different radical assays). Extract addition increased the phenolic content (up to 134% increase) and antioxidant capacity (up to 244%) of both doughs and biscuits. Extract containing biscuits were also characterised by a different colour. However, oxidation stability, evaluated at accelerated temperature and oxygen conditions, was not improved by the extract incorporation. Cooking led to an average (not always significant) 16% decrease in phenolic content for both enriched and reference recipes. The enrichment level significantly influenced the sensory acceptability, with identification of two clusters of consumers, with one cluster preferring the biscuits with the highest enrichment level and one cluster preferring the biscuits with the lowest level. The results showed that whole wheat cacao biscuits represent an appropriate food matrix to develop pleasant novel products enriched in phenolic compounds from waste grape skins and likeable for regular biscuits consumers.
Project description:Agro-industry byproducts can still contain large amounts of phenolic compounds, and one of the richest sources are grape skins and seeds as grape pomace, both fermented (red winemaking) and unfermented (white winemaking). The residual polyphenolic content depends on various factors such as grape variety, vintage, and winemaking technique. In this work, four red grape varieties cultivated in northern Italy were studied: Albarossa, Barbera, Nebbiolo, and Uvalino. The work was aimed at studying the polyphenolic composition of skins and seeds from fresh grapes and from the corresponding pomace after fermentative maceration, to assess the actual importance of the varietal differences when processing winemaking byproducts for the extraction of phenolic compounds. The skin and seed extracts were prepared by solvent extraction with a 50% hydroalcoholic solution. The polyphenolic composition of all extracts was determined by spectrophotometry and high-performance liquid chromatography (HPLC); the content and the monomer composition of condensed tannins were determined by phloroglucinolysis; the antioxidant capacity was measured with the ABTS (2,2'-azinobis-(3-ethylbenzothiazoline-6- sulfonate)) method. The antioxidant capacity was higher for the seeds than for the skins, and it was positively correlated with the condensed tannins content. Significant differences in polyphenolic composition of fresh grape skins and seeds were observed between the different cultivars. In particular, Barbera and Albarossa skins were significantly distinguished from Nebbiolo and Uvalino skins for a higher content of anthocyanins and a lower content of vanillin-reactive flavans and condensed tannins; regarding seeds, Barbera and Albarossa had a lower content of vanillin-reactive flavans, proanthocyanidins, and condensed tannins than Nebbiolo and Uvalino. The winemaking process extracted the phenolic compounds to a different extent from skins and seeds, regardless of the cultivar. The differences between cultivars in the polyphenolic profile disappeared after fermentative maceration.
Project description:The aim of this study was to isolate, identify and quantify soluble free phenolics, conjugated acid-hydrolysable phenolics (AHP) and alkaline-hydrolysable phenolics, and bound phenolics (BP) fractions from two tomato varieties (saladette and grape) and an industrial tomato by-product, as well as, to determine their antioxidant capacity. Phenolic composition was determined using Folin-Ciocalteu's method and HPLC-DAD. AHP were predominant in grape and saladette tomato extracts (91.47?±?17.28 mg gallic acid equivalents (GAE) per g dry extract (DE) and 57.41?±?8.80 mg GAE per g DE, respectively), while BP form was predominant in tomato by-product (51.30?±?10.91 GAE per g DE). AHP extract of grape tomato presented the highest antioxidant capacity by DPPH assay (252.35 ± 42.55 ?mol trolox equiv (TE) per g DE). In the case of ORAC assay, AHP fractions from both grape (1005.19?±?138.52 ?mol TE per g DE) and saladette tomatoes (804.16?±?131.45 ?mol TE per g DE), and BP fraction from by-product (852.40?±?71.46 ?mol TE per g DE) showed the highest ORAC values. Caffeic acid was the most abundant phenolic acid and it was found mainly in its conjugated forms. Naringenin was the most abundant flavonoid and it was mainly detected in bound form. Our analysis allowed a better characterization of phenolic compounds in whole tomato and by-product, remarking the importance of the fractionation. The valorization of the industrial tomato by-product, through the use of its different fractions of phenolic antioxidant compounds, could generate additional income to the tomato industry and reduce the waste disposal problem.
Project description:In this study, grapes (Vitis vinifera L.) were systematically sampled across the main grape-producing areas in a nationwide survey of China. Grapes from special regions, such as heavy metal polluted areas (e-waste dismantling area) and pesticide free areas (courtyard) were also collected to make a comparison. Grape skins and pulps were separated to evaluate influence of accumulation behavior, environmental transport and water cleaning efficiency to heavy metals. Levels of copper in grape skins (5.02?±?3.18??g/g) were higher than in pulps (3.74?±?1.48??g/g). Only high level of copper in two grape skins (sampled from an e-waste dismantling area) showed obvious decrease during water clean-up procedure, indicating the influence of air deposition. Statistical analysis showed no significant difference in the copper levels of grapes from markets, courtyards and e-waste dismantling areas. Concentrations and sources of chromium (Cr), manganese (Mn), nickel (Ni), cadmium (Cd), lead (Pb) and arsenic (As) were also analyzed. Higher levels of these heavy metals were observed in grape skins than pulps. Finally, we evaluated the risk of ingesting heavy metal through grapes using the estimated daily intake (EDI). No health risk was found by consuming grapes according to the data from this study.
Project description:Skin and seed grape extracts of three red varieties (Merlot, Tannat, and Syrah) at different stages of ripening were studied for their total phenolic content (TPC) by using the Folin-Ciocalteu assay and for their total antioxidant capacity (TAC) by using spectrophotometric and electrochemical assays. Flavanol and anthocyanin compositions were also investigated using Ultra Performance Liquid Chromatography coupled with Mass Spectrometry (UPLC-MS). Results showed that seeds had the highest phenolic content and the highest antioxidant potential compared to skins at all stages of ripening. The highest TPC and TAC values were measured in seeds at close to veraison and veraison ripening stages. In skins, the highest values were found at the green stage, it was in accordance with the flavanols content. The voltammetric measurements were carried out using disposable single walled carbon nanotubes modified screen-printed carbon electrodes (SWCNT-SPCE). Three peaks on voltammograms were obtained at different oxidation potentials. The first anodic peak that oxidized at a low potential describes the oxidation of ortho-dihydroxy phenols and gallate groups, the second peak corresponds to the malvidin anthocyanins oxidation and the second oxidation of flavonoids. The third voltammetric peak could be due to phenolic acids such as p-coumaric acid and ferulic acid or the second oxidation of malvidin anthocyanins. The high linear correlation was observed between antioxidant tests and flavanols in skins (0.86 ? r ? 0.94), while in seeds, 'r' was higher between electrochemical parameters and flavanols (0.64 ? r ? 0.8).
Project description:Largely produced agri-food byproducts represent a sustainable and easily available source of phenolic compounds, such as lignins and tannins, endowed with potent antioxidant properties. We report herein the characterization of the antioxidant properties of nine plant-derived byproducts. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays indicated the superior activity of pomegranate peels and seeds, grape pomace and pecan nut shell. An increase in the antioxidant potency was observed for most of the waste materials following a hydrolytic treatment, with the exception of the condensed tannin-rich pecan nut shell and grape pomace. UV-Vis and HPLC investigation of the soluble fractions coupled with the results from IR analysis and chemical degradation approaches on the whole materials allowed to conclude that the improvement of the antioxidant properties was due not only to removal of non-active components (mainly carbohydrates), but also to structural modifications of the phenolic compounds. Parallel experiments run on natural and bioinspired model phenolic polymers suggested that these structural modifications positively impacted on the antioxidant properties of lignins and hydrolyzable tannins, whereas significant degradation of condensed tannin moieties occurred, likely responsible for the lowering of the reducing power observed for grape pomace and pecan nut shell. These results open new perspectives toward the exploitation and manipulation of agri-food byproducts for application as antioxidant additives in functional materials.
Project description:In order to analyze and compare the phenolic characteristics of red wine grapes with diverse genetic backgrounds, skin phenolics among 21 different cultivars belonging to Vitis vinifera L., East Asian and North American Vitis species and hybrids, as well as 2 varieties of muscadine grapes were estimated by HPLC-MS/MS. There were 45 anthocyanins, 28 flavonols, 8 flavan-3-ols, 9 cinnamic acids, 5 benzoic acids, 5 ellagic acids and 2 stilbenes detected in all the samples. Total contents of each phenolic type varied significantly among the different grape cultivars investigated. There was also a large variability in the phenolic compositions of different grape groups. The differences in anthocyanin composition were obvious between V. vinifera and non-V. vinifera grapes and also between the grapes originating from Eurasia and North America. Quercetin-3-glucuronide and quercetin-3-glucoside were marker flavonol compounds for Euvitis grape skins. Flavan-3-ol monomers were dominant in the skins of muscadine and non-V. amurensis East Asian grapes, whereas polymers were more common in V. vinifera and North American grapes. The muscadine grapes were very rich in flavonols, flavan-3-ols and ellagic acids. Via principal component analysis, these grape cultivars were clustered into three groups according to their characteristic phenolic content and composition.
Project description:The aim of this study was to explore the potential of the agroindustrial waste from two Colombian mango cultivars as sources of bioactive phenolic compounds. Phenolic extracts from mango waste (peels, seed coats, and seed kernels) of 'sugar mango' and 'Tommy Atkins' cultivars were obtained. The bioactive properties of the phenolic extracts were accessed by measuring their free radical scavenging activity and antioxidant effects against lipid oxidation in food products; moreover, their antiproliferative effects against some cell lines of human cancer were explored. It is observed that the agroindustrial waste studied provides promising sources of bioactive phenolics. 'Sugar mango' waste provided extracts with the highest antioxidant effect in food products and antiproliferative activity; these extracts reduced lipid oxidation and cell growth by more than 57% and 75%, respectively. The seed kernel from 'sugar mango' supplied the extract with the best bioactive qualities; in addition, some recognized bioactive phenolics (such as mangiferin and several galloyl glucosides) were observed in this extract and related with its properties. The results obtained suggest that 'sugar mango' waste may be considered a source of bioactive phenolics, with promising uses in food and pharmaceutical products. Thus, a suitable alternative for the use and valorization of agroindustrial waste from Colombian mango cultivars is presented.
Project description:Phenolics present in grapes have been explored as cosmeceutical principles, due to their antioxidant activity and ability to inhibit enzymes relevant for skin ageing. The winemaking process generates large amounts of waste, and the recovery of bioactive compounds from residues and their further incorporation in cosmetics represents a promising market opportunity for wine producers and may contribute to a sustainable development of the sector. The extracts obtained from grape marc and wine lees, using solid-liquid (SL) extraction with and without microwave (MW) pretreatment of the raw material, were characterized in terms of antioxidant activity through chemical (ORAC/HOSC/HORAC) and cell-based (keratinocytes-HaCaT; fibroblasts-HFF) assays. Furthermore, their inhibitory capacity towards specific enzymes involved in skin ageing (elastase; MMP-1; tyrosinase) was evaluated. The total phenolic and anthocyanin contents were determined by colorimetric assays, and HPLC-DAD-MS/MS was performed to identify the main compounds. The MW pretreatment prior to conventional SL extraction led to overall better outcomes. The red wine lees extracts presented the highest phenolic content (3 to 6-fold higher than grape marc extracts) and exhibited the highest antioxidant capacity, being also the most effective inhibitors of elastase, MMP-1 and tyrosinase. The results support that winemaking waste streams are valuable sources of natural ingredients with the potential for cosmeceutical applications.
Project description:The increasing demand for healthy baked goods boosted studies on sourdough microbiota with beneficial metabolic traits, to be used as potential functional starters. Here, 139 yeasts isolated from cereal-based fermented foods were in vitro characterized for their phytase and antioxidant activities. The molecular characterization at strain level of the best 39 performing isolates showed that they did not derive from cross contamination by baker's yeast. Afterwards, the 39 isolates were in vivo analyzed for their leavening ability, phytase activity and polyphenols content using five different wholegrain flours, obtained from conventional and pigmented common wheat, emmer and hull-less barley. Combining these findings, through multivariate permutation analysis, we identified the 2 best performing strains, which resulted diverse for each flour. Doughs singly inoculated with the selected strains were further analyzed for their antioxidant capacity, phenolic acids, xanthophylls and anthocyanins content. All the selected yeasts significantly increased the total antioxidant activity, the soluble, free and conjugated, forms of phenolic acids and anthocyanins of fermented doughs. This study revealed the importance of a specific selection of yeast strains for wholegrain flours obtained from different cereals or cultivars, in order to enhance the pro-technological, nutritional and nutraceutical traits of fermented doughs.
Project description:Grapes are widely known for health benefits due to their antioxidant content. In wine production, grape stems are often discarded, though they has a higher content of antioxidants than the juice. The effectiveness of using an environmentally friendly solvent, ethanol, as a superheated liquid and supercritical fluid to extract antioxidant compounds from grape stems of organically grown Crimson Seedless grapes was evaluated. The Ferric Reducing Ability of Plasma (FRAP) assay and the Total Phenolic Content (TPC), or Folin-Ciocalteu assay, were used to quantify the antioxidant power of grape stem extracts. The extractions were performed at temperatures between 160°C and 300°C at constant density. It was found that the optimal extraction temperature was 204°C, at superheated liquid conditions, with a FRAP value of 0.670 mmol Trolox Equivalent/g of dry grape stem. The FRAP values were higher than other studies that extracted antioxidants from grape stems using single-pass batch extraction.