Polyphenolic content and in vitro antioxidant characteristics of wine industry and other agri-food solid waste extracts

Polyphenolic Composition and In Vitro Antioxidant Activity of Red Grape Seeds as Byproducts of Short and Medium-Long Fermentative Macerations

The polyphenolic composition and antioxidant activity of grape seeds, as byproducts of red winemaking, depend on various factors, such as grape cultivar, vintage effect, grape maturity and winemaking methods. In the present work, the influence of the maceration length on the polyphenolic and antioxidant characteristics of the seeds of four Italian red grape cultivars (‘Barbera’, ‘Grignolino’, ‘Nebbiolo’, and ‘Uvalino’), sampled from the fermentation tanks after short (two days) and medium-long (7–21 days) macerations, was studied with spectrophotometric methods, high-performance liquid chromatography (HPLC), and three different antioxidant assays (2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), ferric reducing antioxidant power (FRAP) and 2,2 diphenyl-1-picrylhydrazyl (DPPH)). The total polyphenolic content (gallic acid equivalent (GAE)) of the seeds sampled after short macerations ranged between 24.5 and 60.1 mg/g dry weight (DW), and it dropped to 20.0–37.5 mg/g DW after medium-long macerations. The polyphenolic profile of the shortly macerated seeds was related to the varietal characteristics, while, after longer macerations, the influence of the maceration length prevailed on the cultivar effect. The multiple in vitro antioxidant activity tests (ABTS, FRAP and DPPH), although based on different mechanisms capable of highlighting behavioral differences between the different polyphenolic compounds, were highly correlated with each other and with the polyphenolic parameters; the qualitative differences between the matrices in the polyphenolic profile were probably less important than the quantitative differences in the polyphenolic content. The relations with the polyphenolic content were linear, except for the Efficient Concentration (EC₂₀) parameter, whose relation was better described by a hyperbolic equation.

Green processing and biotechnological potential of grape pomace: Current trends and opportunities for sustainable biorefinery

Grape pomace is a high quality biodegradable residue of the winery industry. It is comprised of grape seed, skin and stalks, and is blessed with substantial quantities of phenols, flavonoids and anthocyanins with high antioxidant potential. Currently, there is huge emphasis on the isolation of bioactive molecules of grape pomace using green technologies such as microwave, ultrasound, supercritical fluids, high voltage discharge, enzymatic methods and other hybrid techniques. The major applications of these bioactives are contemplatedas nutraceuticals and extension in shelf-life of perishable foodstuffs. Alternatively, the crude form of grape pomace residues can be used for the production of energy, biofertilizers, biochar, biopolymers, composites, feed for ruminants and also, mushroom cultivation through microbial processing. This review discusses value-addition to grape pomace through biotechnological interventions and green processing, providing state-of-art knowledge on current scenario and opportunities for sustainability.

Polymeric Hydrogel Systems as Emerging Biomaterial Platforms to Enable Hemostasis and Wound Healing

Broad interest in developing new hemostatic technologies arises from unmet needs in mitigating uncontrolled hemorrhage in emergency, surgical, and battlefield settings. Although a variety of hemostats, sealants, and adhesives are available, development of ideal hemostatic compositions that offer a range of remarkable properties including capability to effectively and immediately manage bleeding, excellent mechanical properties, biocompatibility, biodegradability, antibacterial effect, and strong tissue adhesion properties, under wet and dynamic conditions, still remains a challenge. Benefiting from tunable mechanical properties, high porosity, biocompatibility, injectability and ease of handling, polymeric hydrogels with outstanding hemostatic properties have been receiving increasing attention over the past several years. In this review, after shedding light on hemostasis and wound healing processes, the most recent progresses in hydrogel systems engineered from natural and synthetic polymers for hemostatic applications are discussed based on a comprehensive literature review. Most studies described used in vivo models with accessible and compressible wounds to assess the hemostatic performance of hydrogels. The challenges that need to be tackled to accelerate the translation of these novel hemostatic hydrogel systems to clinical practice are emphasized and future directions for research in the field are presented.

Tandem absorbance and fluorescence detection following liquid chromatography for the profiling of multiclass phenolic compounds in different winemaking products

A liquid chromatography method coupling diode-array and fluorescence detectors (DAD and FLD, respectively) has been developed for the simultaneous quantification of 32 phenolic compounds (PCs) in winemaking products. With the combination of both detectors it was possible to determine phenolic acids, flavanols, flavonols, stilbenes and other PCs in the matrices under study. An excitation wavelength of 290 nm was selected and three different emission wavelengths (315, 360 and 400 nm) were recorded. The method provided detection and quantification limits (LODs and LOQs) within the ranges of 0.01-1.46 mg/L and 0.03-4.9 mg/L, respectively. The LODs and LOQs using FLD for flavanols, stilbenes and phenyl ethanol analogues were improved between 65 and 1000% as compared with DAD. The combination of DAD with FLD increased both, sensitivity and the ability to reduce interfering signals. The developed method was applied for the characterization of PCs of wines, bunch stems and grape canes.

Dried fruit pomace inclusion in poultry diet: growth performance, intestinal morphology and physiology

Background

Fruit pomaces are by-products rich in polyphenol compounds and dietary fiber. They seem to play an important role in regulating the gut microbiota, morphology and physiology. The aim of this study was to assess whether apple (A), blackurrant (B) or strawberry (S) pomaces could be suitable ingredients in broiler diets and their effect on gut health. A total of 480 male broilers were randomly allotted to 8 dietary treatments with lower (3%-L) or higher (6%-H) dietary fiber content: two control groups (CL/CH), two A diets (AL/AH), two B diets (BL/BH), two S diets (SL/SH). Diet and fruit pomaces were chemically analyzed to assess polyphenol concentration and fibre fraction content. After the evaluation of growth performance, 6 birds/group were slaughtered at 35 days of age. Morphometric and histopathological investigations were performed on duodenum, jejunum and ileum. Excreta were collected to perform microbiota evaluation by 16S DNA sequencing. Weight, viscosity, enzymatic activity, short chain fatty acid (SCFAs) and ammonia concentration were determined in ileum and/or ceca content.

Results

A pomace and A diets showed the lowest polyphenol content and the highest content of soluble fibre fraction. No significant differences were observed for growth performance, gut morphometry and histopathology (P > 0.05). Dietary fruit pomace inclusion increased the weight of ileum and ceca and the ileum digesta viscosity (P < 0.05). In the ileum, A and S groups showed lower bacterial α-glucosidase activity than C groups. Moreover, small intestine SCFAs concentration was higher in fruit pomaces diets (P < 0.05). In ceca, B and S groups showed lower ammonia concentration and higher SCFAs than C. Dietary treatments also influenced the activity of α-glucosidase, α-galactosidase, β-galactosidase β-glucuronidase and xylase. Regarding microbiota, at phylum level, Firmicutes were differentially abundant across treatment (maximum for C and minimum in S, FDR > 0.05). At genus level, an increase of Weissella in AH and Erwinia in S/B diets, as well as a decrease of Lactobacillus in all fruit pomace groups were recorded (P < 0.05).

Conclusions

Fruit pomaces could be suitable ingredients in poultry nutrition even if further studies are needed to better understand which doses is more recommended to avoid negative effects on gut microbiota.

Recovery of Bioactive Compounds from Unripe Red Grapes (cv. Sangiovese) through a Green Extraction

Unripe grapes are a potential source of bioactive compounds which can exert antioxidant and antimicrobial activity. However, very little information is available about the composition of unripe grapes extracts and their extraction techniques. This study aims to evaluate the recovery of bioactive compounds and the antioxidant activity of the extract from unripe Sangiovese grapes obtained at an industrial-scale and the composition of the extract during processing. The extraction yield was approximately 75%. During the extraction, the total phenol (TP), antioxidant activity (AA) total anthocyanin (TAnt), pantothenic acid and choline content significantly increased. High concentrations of TP (2522 mgCATeq/L), AA (8227 μmolTEAC/L) and total water-soluble vitamins (1397 μg/L) were reached at the end of process. The antioxidant activity of the extract was positively correlated with all the phenol compounds and the highest correlations were found with procyanidin B1 (r = 0.994; p-value < 0.004), procyanidin B2 (r = 0.989; p-value < 0.004), kaempferol 3-O-glucoside (r = 0.995; p-value < 0.004) and quercetin 3-O-hexoside (r = 0.995; p-value < 0.071). Our findings contribute to the knowledge of the bioactive composition of unripe grapes. An efficient industrial-scale "green" extraction method, ready to be transferred to the wine sector, was developed to obtain a safe extract with a high concentration of bioactive compounds.

Recent advances in extracting phenolic compounds from food and their use in disease prevention and as cosmetics

Phenolic compounds in plants are essential components of human nutrition, which provide various health benefits. However, some missing links became the research in phenolic compounds structures and potential applications in a challenging work. Despite universal extraction methods with mixtures of different organic solvents are generally adopted in the analysis of phenolic compounds, a need for establish a specific procedure is still open. The great heterogeneity in food and food by-products matrices and the lack of standardized methods which combine chromatographic with spectrophotometric techniques to calculate the amount of phenolic compounds joined with the absence of specific standards hamper to accurate know the real amount of phenolic compounds. Indeed, the high complexity in nature and chemistry of phenolic compounds clearly difficult to establish a daily intake to obtain certain healthy outcomes. Hence, despite the potential of phenolic compounds to use them in cosmetic and healthy applications have been widely analyzed, some concerns must be considered. The chemical complexity, the interactions between phenolic compounds and other food components and the structural changes induced by food processing joined with the lack in the understanding of phenolic compounds metabolism and bioavailability undergo the need to conduct a comprehensive review of each factors influencing the final activity of phenolic compounds. This paper summarizes the potential of phenolic compounds for disease prevention and cosmetics production, as well as their many other uses derived from their antioxidant activity. This paper illustrates the potential of phenolic compounds for disease prevention and cosmetics production, as well as their many other uses derived from their antioxidant activity.

Developing a Sufficient Protocol for the Enhancement of α-Glucosidase Inhibitory Activity by Urena lobata L. Aeroponic Hairy Roots Using Exogenous Factors, a Precursor, and an Elicitor

Aeroponics is considered as a potential method for the culture of herbal plants due to the high growth rate, quantity and quality enhancement of secondary metabolites, and substantial environmental progress associated with this method. The aim of this study was to develop a sufficient protocol for successful Urena lobata hairy root induction by Agrobacterium rhizogenes ATCC 15834, using a precursor and elicitor to enhance α-glucosidase inhibitory activity (GIA) of aeroponic hairy roots (AHRs) in greenhouse conditions. In this study, we found that the optimized procedure (10 min, Woody plant medium (WPM), 1/25 salt strength) had an outstanding effect with a reduction in the rooting time (RT), promotion of the rooting rate (RR), and increase in the fresh weight (FW) and dry weight (DW) compared with the original procedure (30 min, Murashige and Skoog (MS) medium, 1/25 salt strength) after 30 days of culture. The highest DW, GIA, flavonoid (FLA) and phenolic (PHEL) contents were observed for individual addition of 10 mM phenylalanine (PA) or 50 mM chitosan (CS) in the late exponential phase (eighth week) with 15 days of elicitation compared to the control AHRs. However, individual treatment was less effective than the combination of the two. Positive correlations among the GIA, FLA and PHEL indicate that AHRs accumulated phenolic compounds, leading to an increase in the GIA by a synergistic effect. In conclusion, the culture of Urena lobata AHRs with PA and CS is an efficient procedure to produce GIA material in greenhouse conditions.

Nutrigenomic Effects of Long-Term Grape Pomace Supplementation in Dairy Cows

Simple Summary

The aim of this study was to evaluate the effect of grape pomace (GP), the polyphenol-rich agricultural by-product, on dairy cows’ whole-blood transcriptome, milk production and composition. Twelve lactating Holstein-Friesian cows were randomly assigned to two groups; the first received a GP-supplemented diet for 60 days (group GP), whereas the second was given only a basal diet (CTR). The results reveal 40 protein-coding genes differentially expressed in the GP group when compared with the CTR group, but no effects were noticed on milk production, concentrations of crude protein, fat, casein, lactose and urea, or somatic cell count. Compared to CTR, GP had a transcriptomic signature mainly reflecting a reinforced immunogenic response.

Abstract

The increasing demand for more animal products put pressure on improving livestock production efficiency and sustainability. In this context, advanced animal nutrition studies appear indispensable. Here, the effect of grape pomace (GP), the polyphenol-rich agricultural by-product, was evaluated on Holstein-Friesian cows’ whole-blood transcriptome, milk production and composition. Two experimental groups were set up. The first one received a basal diet and served as a control, while the second one received a 7.5% GP-supplemented diet for a total of 60 days. Milk production and composition were not different between the group; however, the transcriptome analysis revealed a total of 40 genes significantly affected by GP supplementation. Among the most interesting down-regulated genes, we found the DnaJ heat-shock protein family member A1 (DNAJA1), the mitochondrial fission factor (MFF), and the impact RWD domain protein (IMPACT) genes. The gene set enrichment analysis evidenced the positive enrichment of ‘interferon alpha (IFN-α) and IFN-γ response’, ‘IL6-JAK-STAT3 signaling’ and ‘complement’ genes. Moreover, the functional analysis denoted positive enrichment of the ‘response to protozoan’ and ‘negative regulation of viral genome replication’ biological processes. Our data provide an overall view of the blood transcriptomic signature after a 60-day GP supplementation in dairy cows which mainly reflects a GP-induced immunomodulatory effect.

Recovery of bioactive compounds from white grape (Vitis vinifera L.) stems as potential antimicrobial agents for human health

The grape is a matrix rich in bioactive compounds and its production generates large quantities of by-products, such as grape stems, which, to date, present low commercial value. However, there is a growing interest in the application of this material as a source of phenolic compounds. Therefore, the present study aims at assessing the phytochemical profile of (poly)phenolic extracts of white Portuguese grape stem varieties produced in the Região Demarcada do Douro (Portugal). The antioxidant activity determined by several assays, as well as the antimicrobial activity using the disc diffusion method against human gastrointestinal pathogenic bacteria of the hydromethanolic extracts, were evaluated. This work presents very positive results as the rich composition in phenolic compounds (94.71–123.09 mg GA⁻¹ and 0.02–73.79 mg g⁻¹ for the total phenol content and for individual phenolics, respectively) presented by grape stems can explain the high antioxidant (0.37–1.17 mmol Trolox g⁻¹) and antimicrobial activities against, essentially, Gram-positive bacteria, and in some cases with higher efficacy than commercial antibiotics. Thus, demonstrating that this wine by-product should deserve greater attention from the pharmaceutical industries due to its excellent biological properties and characteristics not yet applied.

Dietary Grape Pomace Supplementation in Dairy Cows: Effect on Nutritional Quality of Milk and Its Derived Dairy Products

Grape pomace (GP) is the main solid by-product of winemaking and represents a rich source of potent bioactive compounds which could display a wide range of beneficial effects in human health for their association with reduced risk of several chronic diseases. Several studies have proposed the use of GP as a macro-ingredient to obtain economically worthwhile animal feedstuffs naturally enriched by polyphenols and dietary fibers. Moreover, the research carried out in this field in the last two decades evidences the ability of GP to induce beneficial effects in cow milk and its derived dairy products. First of all, a general increase in concentration of polyunsaturated fatty acids (PUFA) was observed, and this could be considered the reflection of the high content of these compounds in the by-product. Furthermore, an improvement in the oxidative stability of dairy products was observed, presumably as a direct consequence of the high content of bioactive compounds in GP that are credited with high and well-characterized antioxidant functions. Last but not least, particularly in ripened cheeses, volatile compounds (VOCs) were identified, arising both from lipolytic and proteolytic processes and commonly associated with pleasant aromatic notes. In conclusion, the GP introduction in the diet of lactating cows made it possible to obtain dairy products characterized by improved nutritional properties and high health functionality. Furthermore, the presumable improvement of organoleptic properties seems to be effective in contributing to an increase in the consumer acceptability of the novel products. This review aims to evaluate the effect of the dietary GP supplementation on the quality of milk and dairy products deriving from lactating dairy cows.

Microwave-Assisted Extraction and Ultrasound-Assisted Extraction of Bioactive Compounds from Grape Pomace

The grape pomace is a by-product from the industrial processing of grape juice, which can be used as a source of bioactive compounds. The aim of this study was to separate the phenolic compounds from grape pomace using an acidic aqueous solution with 2 % citric acid as a solvent, using both ultrasound-assisted extraction, with powers of 250, 350 and 450 W and times of 5, 10 and 15 min, and microwave-assisted extraction using powers of 600, 800 and 1,000 W and times of 5, 7 and 10 min. The results showed that for both methods of extraction, the contents of total phenolic compounds and antioxidant activity by ABTS and DPPH increased with time, and microwave at 1,000 W for 10 min corresponded to the best extraction condition. However, the contents of phenolic compounds and antioxidant activity were lower than exhaustive extraction using acidified methanol solution.

Compositional Characterization of Different Industrial White and Red Grape Pomaces in Virginia and the Potential Valorization of the Major Components

To better evaluate potential uses for grape pomace (GP) waste, a comprehensive chemical composition analysis of GP in Virginia was conducted. Eight commercial white and red pomace samples (cv. Viognier, Vidal Blanc, Niagara, Petit Manseng, Petit Verdot, Merlot, Cabernet Franc, and Chambourcin) obtained from different wineries in Virginia, USA were used. For extractives, GPs contained 2.89%-4.66% titratable acids, 4.32%-6.60% ash, 4.62%-12.5% lipids with linoleic acid being the predominant (59.0%-70.9%) fatty acid, 10.4-64.8 g total phenolic content (gallic acid equivalents)/kg GP, 2.09-53.3 g glucose/kg GP, 3.79-52.9 g fructose/kg GP, and trace sucrose. As for non-extractives, GPs contained 25.2%-44.5% lignin, 8.04%-12.7% glucan, 4.42%-7.05% xylan, and trace amounts of galactan, arabinan, and mannan (less than 3% in total). Potential usages of these components were further examined to provide information on better valorization of GP. Considering the valuable extractives (e.g., polyphenols and oil) and non-extractives (e.g., lignin), designing a biorefinery process aiming at fully recover and/or utilize these components is of future significance.

Secondary metabolites profile and physiological leaf traits in wild and cultivated Corylus avellana under different nutritional status

Leaf secondary metabolites production and physiological leaf traits were analyzed in Corylus avellana wild type (WT) and cultivar (cv. 'Tonda Gentile Trilobata', TGT) under different nutrient supplies. Three treatments were applied: control treatment with no fertilizer supply (WT_C and TGT_C), low nutrient treatment (WT_LN and TGT_LN) and high nutrient treatment (WT_HN and TGT_HN). The analysis of leaf extracts showed a higher concentration of Quercitrin and Myricitrin, with the highest concentrations of both the compounds in WT than TGT. This result can be related to the ecological role of flavonoids, including also antimicrobial properties, which resulted more useful in the understory forest form which hazelnut wild type originates. Therefore, their lower concentration in TGT can be relate to the genetic background of TGT cultivar with a lesser intrinsic need to produce such compounds and justified by a usual growth under more controlled environmental conditions, including also pest and disease control.

Exploring the Synergy Between HPTLC and HPLC-DAD for the Investigation of Wine-Making By-Products

Both environmental and economic issues are increasingly pushing for the revalorization of agri-food by-products, including those arising from wine industry. Wastes produced from wine-making processes are important sources of biologically active compounds, mainly phenolic acids and flavonoids, which could be re-used for several applications, for example as additive surrogates or new ingredients in foodstuffs and/or pharmaceuticals. Therefore, the development of methods aimed at isolating, characterizing and quantifying molecules present in winery by-products acquires considerable importance in view of their re-utilization on a large scale. In this connection, this study demonstrated that high-performance thin-layer chromatography (HPTLC) and high-performance liquid chromatography with diode array detection (HPLC-DAD) can operate in synergy for the investigation of pomace and seed materials arising from both white and red cultivars of Vitis Vinifera. By virtue of fingerprint profiling, mass spectrometry (MS) interfacing and band comparison method, HPTLC enabled detection and identification of phenolic acids, non-anthocyanic flavonoids and anthocyanins. On the contrary, only anthocyanins could be identified by HPLC-DAD, and their subsequent quantification showed that malvidin-3-O-glucoside (oenin) was the most abundant one. In parallel, HPTLC has allowed to detect and quantify proanthocyanidins (PAC), showing that only catechin was present in the test samples. Both quantitative analytical methods were validated in terms of linearity, detection and quantification limits and precision.

Polyphenolic Characterization of Grape Skins and Seeds of Four Italian Red Cultivars at Harvest and after Fermentative Maceration

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.

Microwave-assisted extraction for recovery of polyphenolic antioxidants from ripe mango (Mangifera indica L.) peel using lactic acid/sodium acetate deep eutectic mixtures

The present study investigates recovery of polyphenolic compounds from ripe mango ( Mangifera indica L.) peel using deep eutectic solvents based on microwave-assisted extraction method. Lactic acid/sodium acetate/water (3:1:4) screened out from eight different types of deep eutectic solvent systems was used as extractant. A Box–Behnken design along with response surface methodology was applied to optimize the effect of microwave power (W), time (min), and liquid-to-solid ratio (mL g−1) on polyphenol extraction. The optimized conditions determined were power of 436.45 W, time of 19.66 min, and liquid-to-solid ratio of 59.82 mL g−1. Under the optimal conditions, the recovery of total phenolic content, ferric reducing antioxidant power, and 2,2-diphenyl-1-picrylhydrazyl scavenging activity was 56.17 mg gallic acid equivalent g−1 dw, 683.27 µmol ascorbic acid equivalent g−1 dw, and 82.64 DPPHsc%, respectively. High Performance Liquid Chromatography (HPLC) analysis revealed mangiferin as the prominent phenolic compound in the mango peel extracts. Microwave-assisted deep eutectic solvent extraction showed remarkable effects on the extraction efficiency of phenolic compounds as revealed from scanning electron microscopy analysis. Rancimat test results revealed that the oxidative stability almost doubled upon addition of purified mango peel extracts to the sunflower oil and thus paving way for the use of mango peel waste as a potential source of antioxidants.

Kinetic Improvement of Bioactive Compounds Extraction from Red Grape (Vitis vinifera Moldova) Pomace by Ultrasonic Treatment

Grape pomace from a red grape variety (Vitis vinifera Moldova) cultivated in the northeastern region of Romania has been studied as a source for the extraction of total monomeric anthocyanin (TMA) and total phenolic content (TPC) using ultrasonic treatment. The method of extraction described here uses two different solvents, namely 2-propanol and methanol. For each of the extraction solvents, we evaluated the singular influence and the impact of interactions between process parameters (solvent concentration, ultrasonic frequency, temperature, and extraction time) on the extraction yields of anthocyanins and phenolic compounds. Response surface methodology was implemented via a Box–Behnken design to optimize the extraction of TMA and TPC from grape pomace. According to the optimization, in order to achieve the highest yield of TPC (62.487 mg gallic acid equivalent (GAE)/g (d = 1.0)), the following conditions are necessary: solvent—2 propanol, solvent concentration 50%, temperature −50 °C and extraction time 29.6 min.

Grape Infusions: The Flavor of Grapes and Health-Promoting Compounds in Your Tea Cup

Traditionally, tea, a beverage made from the processed leaves of the tea plant, Camellia sinensis, and herbal infusions have been primarily consumed for their pleasant taste. Nowadays, they are also consumed because they contain nutraceutical compounds, such as polyphenols. Grapes and grape/wine sub-products such as non-fermented/semi-fermented or fermented grapes, skins, and seeds are a rich source of health-promoting compounds, presenting a great potential for the development of new beverages. Therefore, these grape/wine sub-products are used in the beverage sector for the preparation of infusions, tisanes, and decoctions. Besides polyphenols, fermented grapes, skins, and seeds, usually discarded as waste, are enriched with other health-promoting/nutraceutical compounds, such as melatonin, glutathione, and trehalose, among others, which are produced by yeasts during alcoholic fermentation. In this review, we summarize the benefits of drinking herbal infusions and discuss the potential application of some grapevine fermentation waste products in the production of healthy beverages that we can call grape infusions.

Effects of the supplementation of distillers' grape residues on ruminal degradability, whole tract digestibility and nitrogen metabolism in sheep

Five ruminally and duodenally cannulated Kazakh male lambs (30 ± 2.75 kg) maintained singly in a metabolic cage were used in a 5 × 5 Latin square experiment to investigate the effect of supplementing a ration with five different levels of distillers' grape residue (DGR) on ruminal degradability, whole tract digestibility and nitrogen (N) metabolism of growing lambs. The rations were isoenergetic and isonitrogenous and contained 0, 3.85, 7.70, 11.55 and 15.41% DGR (DM basis). Each experimental period lasted for 18 d: 10 d for adaptation to the dietary treatment and 8 d for faecal, urinary, ruminal and duodenal digesta sample collections. The outflow rate of ruminal digesta increased (p = 0.032) linearly with the increased level of dietary neutral detergent fibre content, caused by the supplementation of DGR. As a result, the effective degradability of dry matter and crude protein decreased significantly with the treatments. Although the dietary intake of N, duodenal flow of total N, and the endogenous N at the duodenum were not affected by experimental treatments, N fractions in the digesta were altered. Ruminal microbial N decreased (p < 0.01) linearly; in contrast, ruminal un-degradable protein increased linearly (p < 0.01) in response to the increased addition of DGR. Although there was no significant difference in faecal N among treatments, N retention was increased linearly (p = 0.014), owing to the remarkable reduction (p = 0.016) of urinary N excretion with an increasing level of DGR. The results indicate that the DGR has some potential benefits of increasing the supply of bypass protein and of improving the utilisation efficiency of N for sheep. Therefore, the supplementation of DGR in ruminant feeding is recommended at levels not exceeding 10% of the diet.

Grape peel (Syrah var.) jam as a polyphenol-enriched functional food ingredient

In this study, we evaluated the effects of the storage time on the physicochemical properties, bioactive compound content, and antioxidant capacity of jam prepared from grape peel extract to explore its potential as a supplementary food and/or functional ingredient. The ethanolic extract from Syrah var. grape peel exhibited high bioactive compound concentrations and antioxidant activity. The jam stability (prepared with 8.9% of extract) at 14°C was evaluated at 0, 15, 30, 45, and 60 days. The jam was found to contain high concentrations of polyphenolic compounds (137.0 ± 3.2 mg of gallic acid equivalent/100 g), total flavonoids (128.5 ± 23.0 mg of equivalent/100 g), and total anthocyanins (92.5 ± 4.0 mg of cyanidin equivalent/100 g). However, a large reduction in the flavonoid (70%-90%), anthocyanin (29%-35%), and phenolic (23%-30%) content was observed during storage. The free radical-scavenging activity (DPPH-), ferric reducing antioxidant power (FRAP), and β-carotene-linoleic acid assays revealed the great antioxidant potential of the jam prepared from grape peel extract, which exhibited significant levels of radical-neutralizing activity, especially as determined by the DPPH method with EC50 values ranging from 2.3 ± 0.1 to 3.9 ± 0.1 µg/ml. High R 2 values (p > 0.90) were obtained for the correlation between the DPPH results and the concentrations of the compounds of interest. In summary, the high bioactive compound contents and antioxidant capacity of the jam produced from grape peel suggest that it may provide health benefits as a source of natural antioxidants upon incorporation to several food industry products.

Bioactive Multilayer Polylactide Films with Controlled Release Capacity of Gallic Acid Accomplished by Incorporating Electrospun Nanostructured Coatings and Interlayers

The present research reports on the development of bi- and multilayer polylactide (PLA) films by the incorporation of electrospun nanostructured PLA coatings and interlayers containing the antioxidant gallic acid (GA) at 40 wt% onto cast-extruded PLA films. To achieve the bilayer structures, submicron GA-loaded PLA fibers were applied on 200-µm cast PLA films in the form of coatings by electrospinning for 1, 2, and 3 h. For the multilayers, the cast PLA films were first coated on one side by electrospinning, then sandwiched with 10-µm PLA film on the other side, and the resultant whole structure was finally thermally post-treated at 150 °C without pressure. Whereas the bilayer PLA films easily delaminated and lacked transparency, the multilayers showed sufficient adhesion between layers and high transparency for deposition times during electrospinning of up to 2 h. The incorporation of GA positively contributed to delaying the thermal degradation of PLA for approximately 10 °C, as all films were thermally stable up to 345 °C. The in vitro release studies performed in saline medium indicated that the GA released from the bilayer PLA films rapidly increased during the first 5 h of immersion while it stabilized after 45–250 h. Interestingly, the PLA multilayers offered a high sustained release of GA, having the capacity to deliver the bioactive for over 1000 h. In addition, in the whole tested period, the GA released from the PLA films retained most of its antioxidant functionality. Thus, during the first days, the bilayer PLA films can perform as potent vehicles to deliver GA while the multilayer PLA films are able to show a sustained release of the natural antioxidant for extended periods.

Recovery of phenolic antioxidants from Syrah grape pomace through the optimization of an enzymatic extraction process

Phenolic compounds are highly valuable products that remain trapped in grape pomace, an abundant winery by-product. Therefore, efficient extraction procedures of these compounds represent a route for grape pomace valorisation. Here we performed a screening of the factors affecting the aqueous enzymatic extraction of phenolic compounds from Syrah grape pomace, including the following independent variables: temperature, pH, pectinase, cellulase and tannase; and a subsequent optimization through response surface methodology. At the optimal region, the enzymatic treatment enhanced the extraction yield of phenolics by up to 66% and its antioxidant capacity by up to 80%, reducing the incubation time and enzyme doses in respect to previous studies. We found that tannase raises the antioxidant capacity of the extract by the liberation of gallic acid, while cellulose favours the liberation of p-coumaric acid and malvidin-3-O-glucoside. We also tested the procedure in different grape pomace varieties, verifying its wide applicability.

Evaluation of the Antioxidant and Wound-Healing Properties of Extracts from Different Parts of Hylocereus polyrhizus

Hylocereus polyrhizus cultivation started in Taiwan around the 1980s. The pulp of the fruit is edible and contains small, black, and soft seeds. The peel of the fruits are covered with bracts. The H. polyrhizus fruit is known to be rich in nutrients and minerals. To evaluate the potential applications of the agricultural wastes of H. polyrhizus, the stem, peel, and flower of H. polyrhizus were extracted with solutions of ethanol and water mixed in different ratios. Data was collected for the H. polyrhizus extract including the yield of total phenolics, the total flavonoids, and antioxidant activity, as determined by the 2-2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assay. The protective effects of H. polyrhizus extract on DNA was investigated using an assay with the pUC19 plasmid. The cell proliferation and migration effects were evaluated in the NIH-3T3 fibroblast cell line. The greatest yield of extract from the stem of H. polyrhizus was 44.70 ± 1.77% which was obtained using 50% aqueous ethanol and the greatest yield of extract from the peel was 43.47% using distilled water. The stem extract, which was prepared with 95% aqueous ethanol, had the highest composition of phenolics and flavonoids as well as the best DPPH radical scavenging activity. The stem extract had excellent ABTS radical scavenging activity as well. The stem, peel, and flower extracts, which were prepared using 95% aqueous ethanol, showed excellent results in protecting themselves from DNA damage, similar to the effect of 0.3 mg/mL ferulic acid. None of the extracts were able to promote cell proliferation at concentrations of 250 μg/mL to 2,000 μg/mL in a 24 h period. The 1000 μg/mL stem and flower extracts in 95% aqueous ethanol promoted considerable cell migration after a 24 h period.

Produção de biomassa e lipídios pela levedura Rhodotorula mucilaginosa utilizando a manipueira como substrato

Resumo Devido à elevada e intensa atividade industrial, todos os dias são gerados milhares de toneladas de resíduos agroindustriais. Um desses resíduos, a manipueira, é um líquido obtido durante o processamento da mandioca. Assim, este estudo objetivou avaliar o efeito da variação da concentração de manipueira sobre a produção de biomassa e lipídios pela levedura Rhodotorula mucilaginosa. Foram produzidos 4,1, 6,95, 5,77 g.L -1 de biomassa e 13,33%, 7,71% e 8,47% de lipídios nos cultivos com 50%, 75% e 100% de manipueira, respectivamente. No cultivo realizado em meio sintético, produziram-se 9,39 g.L-1 de biomassa e 41,92% de lipídios. O cultivo com 100% de manipueira apresentou o melhor coeficiente de conversão de açúcares redutores em biomassa e o cultivo em meio sintético o melhor coeficiente para lipídios. Dessa forma, a manipueira mostrou ser um bom substrato para o crescimento da levedura Rhodotorula mucilaginosa e para a produção de lipídios, sendo que essa produção ainda pode ser otimizada.

Grape pomace as a source of phenolic compounds and diverse bioactive properties

The bio-residues resulting from the wine industry (grape pomace made up of skins, seeds and stems) are often undervalued but constitute a potential source of bioactive phenolic compounds that can be applied in several industries. In this context, the aim of the present study was to evaluate the phenolic profile of Vitis vinifera L. grape pomace (skins, seeds and their mixture), and correlate them with its antioxidant, cytotoxic and antibacterial activities. The seeds showed the highest amount of phenolic compounds and also the highest antioxidant, cytotoxic and antibacterial activities. The skins revealed the highest levels of anthocyanins and p-coumaric acid hexoside. Strong correlations were observed between the presence of phenolic compounds and all the bioactivities studied. These by-products are good sources of phenolic compounds with high antioxidant and antibacterial activity, and also presenting a moderate cytotoxicity activity. These added-value by-products have great applicability in food, pharmaceutical and cosmetic industries.

Natural extracts from fresh and oven-dried winemaking by-products as valuable source of antioxidant compounds

Winemaking by-products are a natural source of antioxidant components; however, due to their highly perishable and seasonal nature, they may require a prior conservation step before being processed. Natural extracts from fresh and oven-dried red grape agro-industrial by-products were obtained by ultrasound assisted extraction (UAE), using a hydroalcoholic solution as extracting solvent. Extracts were analyzed by HPLC-DAD-ESI-MS, to know the feasibility of winemaking by-products as natural sources of phenolic compounds, as well as the effect of the oven-drying treatment on the phenolic composition. Oven-drying at 45°C caused a significant decrease on the total phenolic content, which implied a reduction of the antioxidant capacity of the extracts. Also, it produced a decrease in total and individual flavan-3-ols, stilbenes, and flavonols, being greater in those extracts from stems. Respect to anthocyanins, which were only identified in grape pomace extracts, oven-drying caused an important decrease, being the peonidin-3-O-glucoside the more thermosensitive compound. Natural extracts from fresh or oven-dried winemaking by-products could be used in other food industries as a valuable source of phenolic compounds with antioxidant properties. However, further studies on other drying methods are required for addressing the preservation of phenolic compounds from winery by-products successfully.

A Naturally Occurring Antioxidant Complex from Unripe Grapes: The Case of Sangiovese (v. Vitis vinifera)

The wine industry is well known for its production of a large amount of wastes and by-products. Among them, unripe grapes from thinning operations are an undervalued by-product. Grapes are an interesting source of natural antioxidants such as flavonoids, non-flavonoids and stilbenes. A potential strategy to exploit unripe grapes was investigated in this study. Juice from unripe grapes, v. Sangiovese, was obtained by an innovative technique of solid-liquid extraction without the use of solvents. The juice was dried by a spray-drying technique with the addition of arabic gum as support to obtain powder; juice and powder were characterized for antioxidant activity, phenolic concentration and profile. Phenolic acids, flavonols, flava-3-ols, procyanidins and resveratrol were detected in the juice and powder. The powder was used as anti-browning additive in white wine to test the potential re-use of the unripe grapes in the wine industry. The results indicated that the antioxidant complex from unripe grapes contributed to increasing the anti-browning capacity of white wine. Other applications, such as food and nutraceutical products development, can be considered for the antioxidant complex extracted from unripe grapes. In conclusion, the method proposed in this study may contribute to the exploitation of unripe grapes as a by-product of the winemaking process.

Integrated Evaluation of the Potential Health Benefits of Einkorn-Based Breads

Nowadays the high nutritional value of whole grains is recognized, and there is an increasing interest in the ancient varieties for producing wholegrain food products with enhanced nutritional characteristics. Among ancient crops, einkorn could represent a valid alternative. In this work, einkorn flours were analyzed for their content in carotenoids and in free and bound phenolic acids, and compared to wheat flours. The most promising flours were used to produce conventional and sourdough fermented breads. Breads were in vitro digested, and characterized before and after digestion. The four breads having the best characteristics were selected, and the product of their digestion was used to evaluate their anti-inflammatory effect using Caco-2 cells. Our results confirm the higher carotenoid levels in einkorn than in modern wheats, and the effectiveness of sourdough fermentation in maintaining these levels, despite the longer exposure to atmospheric oxygen. Moreover, in cultured cells einkorn bread evidenced an anti-inflammatory effect, although masked by the effect of digestive fluid. This study represents the first integrated evaluation of the potential health benefit of einkorn-based bakery products compared to wheat-based ones, and contributes to our knowledge of ancient grains.

Tannic Acid-Based Multifunctional Hydrogels with Facile Adjustable Adhesion and Cohesion Contributed by Polyphenol Supramolecular Chemistry

Adhesiveness of hydrogels depends on the balance and synergy of their cohesion and adhesion. However, it is a challenge to fabricate catechol-based hydrogels with high adhesiveness because the required condition for cohesion and adhesion of these hydrogels is in conflict with each other: strong cohesion (gelation) requires a weak basic condition, whereas strong adhesion requires an acidic condition. Here, we demonstrated that by utilizing polyphenol supramolecular chemistry, the coexistence of strong cohesion and adhesion can be achieved in a hydrogel via the one-pot method. Poly(dimethyl diallyl ammonium chloride)/tannic acid (PDDA/TA) hydrogel has been studied as a proof of concept. Compared with catechol moieties that covalently grafted on polymer chains, TA can bring high density of pyrogallol/catechol functional groups for polymers via a noncovalent pathway, as well as high acidity in the system. As a result, the cohesion of the hydrogel is enhanced significantly, the highest storage moduli can reach up to ca. 0.15 MPa; besides, the high acidity of the hydrogel prevents pyrogallol/catechol groups from oxidation and guarantees strong adhesion; thus, the hydrogel can adhere to diverse substrates steadily, including tissues, glass, metals, and plastic. Moreover, because of the adjustable adhesiveness via changing the pH, the PDDA/TA hydrogel becomes a unique system with patternable adhesiveness. In addition, the hydrogel has rapid self-healing and high ionic conductivity (∼4.3 S m-1). This study demonstrates that utilizing polyphenol chemistry in the construction of hydrogels opens a new path toward multifunctional hydrogels with improved properties.

Antimicrobial Intervention by Photoirradiation of Grape Pomace Extracts via Hydroxyl Radical Generation

The annual production of grape worldwide amounts to almost 70 million tons, and around 80% is used for winemaking. The two major wastes from winemaking process, pomace and lees account for 20 and 7% of the grapes, respectively. They have been expected as a valuable resource to be recycled because they are rich in polyphenols. Polyphenols possess prooxidatve activity as well as antioxidative one just like a two sides of a coin. A typical example of the prooxidative activity is antibacterial activity of catechins. The activity is exerted through oxidation of phenolic hydroxyl moiety coulpled with reduction of dissolved oxygen leading to hydrogen peroxide (H₂O₂) generation. In addition, once the oxidation of phenolic hydroxyl moiety is augmented by photoirradiation, highly reactive hydroxyl radical (·OH) is generated. Accordingly, there have been several reports showing that photoirardiation of polyphenols exerts bactericidal activity via ·OH generation. This review focuses mainly on antimicrobial intervention by photoirradiation of grape pomace extract in relation to ·OH generation analyzed by an electron spin resonance-spin trapping method.