Grape seed pomace as a valuable source of antioxidant fibers.

BACKGROUND: Grape seed pomace is a valuable by-product from winery/oil extraction industries and a potential source of bioactive compounds. Hot water extraction is the most widely used technology for polysaccharide recovery from plant and seed sources. To obtain an antioxidant fiber-rich extract (AFE) from defatted grape seed pomace, seed:water ratio (1:10-1:20) and extraction temperature (70-90 °C) effects on extraction yield, total sugars, total phenolic compounds and condensed tannins were investigated. RESULTS: The best extraction results were achieved at the highest seed:water ratio and temperature. At these conditions, the extraction yield and total sugar content of the freeze-dried AFE were 100.1 g kg-1 and 725.3 g kg-1 , respectively. The AFE presented high total phenolic content (16.2 g GAE kg-1 ), condensed tannins (515.1 mg CAT kg-1 ), soluble (219.1 g kg-1 ) and insoluble fibers (132.4 g kg-1 ), besides protein (171.1 g kg-1 ) and ash (152.6 g kg-1 ). The antioxidant capacity of the AFE was 382.7, 823.7 and 1439.4 µmol Trolox g-1 for DPPH, ABTS and ORAC methods. CONCLUSION: The AFE was shown to be not only an interesting source of fiber with antioxidant capacity, which could become a potential foodstuff, but also an ecofriendly and sustainable alternative to use grape seed pomace. © 2019 Society of Chemical Industry.

Enzymatic production of xylooligosaccharides from Brazilian Syrah grape pomace flour: a green alternative to conventional methods for adding value to agricultural by- products.

BACKGROUND: The aim of this work was to determine the most favorable conditions for the production of xylooligosaccharides (XOS) from Brazilian Syrah grape pomace. Chemical processes were performed using a rotatable central composite design where the concentration of sulfuric acid or sodium hydroxide and the grape pomace flour/solvent mass ratio were the dependent variables. Enzymatic production was also evaluated using xylanase produced by Aspergillus niger 3T5B8 and Viscozyme® enzymatic commercial cocktail. RESULTS: Chemical extraction allowed to recover 21.8-74.6% and 5.2-96.3% of total XOS for acidic and alkaline processes respectively. Enzymatic production extracted up to 88.68 ± 0.12% of total XOS using xylanase and up to 84.09 ± 2.40% with Viscozyme® . CONCLUSION: The present study demonstrated different feasible methods to produce high-added-value molecules, i.e. XOS, from Syrah grape pomace flour, valorizing this major by-product. The use of enzymatic cocktails demonstrated to be an alternative to the conventional methods, allowing to obtain an eco-friendly and sustainable grape pomace extract. © 2018 Society of Chemical Industry.

Influence of processing conditions on bioactive compound extraction from Vitis vinifera L. var. Alicante Bouschet grape skin.

The aim of this study was to evaluate the effects of process conditions on the solid-liquid extraction of bioactive compounds from the Alicante Bouschet grape skin from the semi-arid region of Brazil. The influence of temperature (23-57 °C), ethanol concentration (16-84%) and citric acid concentration (0-4%) on the total phenolic content, monomeric anthocyanin content and on the antioxidant capacity of the extracts measured by oxygen radical absorbance capacity and cation radical scavenging activity (ABTS·+) methods was investigated. Ethanol concentration and temperature had a significant influence on total phenolic compounds extraction and antioxidant capacity while monomeric anthocyanins extraction was only affected by ethanol concentration. The conditions selected as the most adequate for the extraction were: temperature of 40 °C, 50% v/v ethanol and 2% m/v citric acid.

Antioxidant Compounds Recovery from Juçara Residue by Thermal Assisted Extraction.

This study aimed to recover bioactive compounds by solid-liquid extraction from the agro-industrial residue obtained during juçara fruits processing into pulp. A preliminary study using different solvents (methanol, ethanol and water) indicated ethanol in aqueous solution as the best solvent for antioxidants recovery. Then, a Box-Behnken design was applied considering as independent variables the solvent composition (30-70% ethanol in water), temperature (30-70 °C) and time (30-60 min), in order to evaluate the effects of these factors on antioxidant activity in juçara extract. Results showed that the extracts with higher antioxidant activity were obtained using 30% ethanol at 70 °C for 60 min; measurements included ABTS and DPPH assays, determination of total phenolic content and total monomeric anthocyanins. Furthermore, the effect of pH in antioxidants recovery was evaluated. For this purpose, the 30% ethanol solution was acidified to pH 1 and 2 with HCl. Principal component analysis showed the formation of three distinct groups: one characterized by high bioactive compounds content (pH 1.0), another with superior antioxidant activity (pH 5.75, non-acidified), and finally the group at pH 2 presenting the worst concentrations in the evaluated responses. HPLC analysis showed the presence of cyanidin-3-O-rutinoside and cyanidin-3-O-glucoside in the extracts. Therefore, the conventional solid-liquid extraction using renewable solvent can be successfully applied to recover bioactive compounds from juçara residue, which can be used by different food industries.

Grape by-product extracts against microbial proliferation and lipid oxidation: a review.

The wine industry is responsible for the production of million tons of waste, such as grape skin, stalk, sludge and seeds, which can be considered inexpensive sources of phenolic compound owing to incomplete extraction during wine production. Phenolic compounds, also called polyphenols, comprise the most abundant bioactive compounds in grape and are recognized by their antioxidant and antimicrobial potential. Because of their functional properties, extracts obtained from grape wastes, which are rich in phenolic compounds, can be employed in the development of many products, ranging from medical to food applications, decreasing the growth of spoilage and pathogenic microorganisms and inhibiting lipid oxidation. These characteristics are motivating the research for alternative sources of natural antioxidant and antimicrobial agents, aimed at decreasing the use of artificial additives, which have been associated with some toxic effects. This article provides a review of the use of grape by-product extracts and their bioactive compounds as natural antioxidant and antimicrobial agents in food products. © 2016 Society of Chemical Industry.

Anthocyanin-sensitized gelatin-ZnO nanocomposite based film for meat quality assessment.

Meat is considered a highly perishable food, and the interest in developing tools to monitor meat quality products has increased these years. A novel gelatin-ZnO-anthocyanin ternary nanocomposite film is proposed as a sensitive layer to meat quality monitoring in the present work. The incorporation of anthocyanin (ATH) on gelatin-ZnO (G-ZnO) film induced a sensitivity improvement of films towards ammonia vapor according to impedance measurements. G-ZnO-ATH film presented a good response (38.69 %) to the presence of ammonia vapor at 300 ppm. Also, good selectivity for ammonia was observed in the films. G-ZnO-ATH, applied to minced meat's quality monitoring at different storage conditions, showed a good performance, with a significant (p < 0.05) non-linear Spearman correlation between the response and the total volatile basic nitrogen released during meat spoilage for both storage conditions. The results suggest new perspectives in the developed film as a promising nanocomposite material for meat quality monitoring.

Polymeric nanoparticles as oral delivery systems for a grape pomace extract towards the improvement of biological activities.

Grape pomace (GP) is a major by-product from the wine industry, known for its bioactive compounds and their impact upon gastrointestinal (GI) health. However, bioaccessibility is often poor due to their degradation during digestion. This work aimed to encapsulate bioactive GP extract (GPE) into chitosan (CS) and alginate (Alg) nanoparticles (NPs) to mitigate degradation in the GI tract. Alg and CS NPs were optimized using a rotatable central composite design and NPs were characterized for their size, polydispersity, zeta potential and total phenolics (TP) association efficiency. The best formulations showed sizes ranging 523-853 nm, polydispersity indexes of 0.11-0.36, zeta potential of -15.0-14.9 mV and TP association efficiencies of 68 and 65%. FTIR confirmed that there was no formation of new chemical groups after association of the polymers with GPE. Both formulations improved the bioaccessibility of different phenolics following in vitro GI digestion, leading to increased antioxidant and antimicrobial activities. Moreover, the permeability of bioactive compounds through a Caco-2/HT29-MTX co-culture was reduced, suggesting a higher residence time in the intestine. Cy5.5 was used for tracking the CS NPs, which did not affect the metabolic activity of Caco-2 and HT29-MTX cells. Confocal microscopy images confirmed the adsorption of NPs to the cellular layer and suggested a reduction of the tight junction protein occludin when cells were incubated with Cy5.5-CS in solution. This study suggests that encapsulation of GPE can offer protection against along the GI tract and improve its biological activity with significant impact for oral delivery applications, including functional foods.

Advantages of microfiltration processing of goat whey orange juice beverage.

The objective of this study was to evaluate the microbiological, physicochemical and functional quality of an innovative goat whey orange juice beverage (GOB) processed by microfiltration. The microfiltration (0.2 µm) of the GOBs had a variation on the feed temperature (20, 30, 40, 50 °C) and were compared to the conventional heat treatment LTLT (63 °C/30 min). Microbiological (aerobic mesophilic bacteria, mold and yeast and lactic bacteria), physicochemical (pH, color, rheology and volatile compounds) bioactive compounds (acid ascorbic, total phenolics) and functional activity (DPPH, ACE, α-amilase and α-glucosidase) analysis were performed. The GOB processed by microfiltration using at least 30 °C presented adequate microbial counts (less than 4, 3 and 4 log CFU/mL, for AMB, molds and yeasts and LAB, respectively). In general, the pH, color parameters, volatile and bioactive compounds were not influenced by microfiltration temperature, but presented a difference from the LTLT processing. The rheological parameters were influenced by MF temperature and the utilization of temperatures of 20° and 30 °C maintained the consistency similar to the LTLT sample, preserving the compounds responsible for the texture. Therefore, it is suggested a processing of GOB by microfiltration using mild temperatures (between 30° and 40 °C) to preserve consistency and also obtain a desirable microbial quality, beyond the preservation of many functional properties and volatile compounds.

Impact of in vitro gastrointestinal digestion on the chemical composition, bioactive properties, and cytotoxicity of Vitis vinifera L. cv. Syrah grape pomace extract.

Grape pomace (GP) is a major byproduct worldwide, and it is well known for its bioactive compounds, such as fibers and phenolic compounds, that are popular for their impact upon human health, including gastrointestinal health. The objective of this work was to evaluate the chemical composition and biological activities of an enzymatic GP extract, as well as to investigate how gastrointestinal digestion (GID) modulates these properties. GP extract was previously produced using an enzymatic cocktail with xylanase activity and was then exposed to simulated conditions of GID, characterized for its chemical composition, and screened for antimicrobial, prebiotic, and antioxidant activities. The safety of this ingredient after GID was also assessed. GP extract presented high contents of dietary fiber and other carbohydrates, including xylooligosaccharides, in addition to minerals and phenolic compounds. In vitro simulated GID revealed that xylobiose was resistant to gastric conditions, unlike phenolic compounds. The use of 2% (w/v) of this ingredient proved to be a potential carbon source that could be fermented by Lactobacillus and Bifidobacterium spp, even after digestion. The extract also exhibited strong antioxidant and antimicrobial activities against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa; however, after GID, the antioxidant capacity decreased, and the antimicrobial capacity was strongly reduced or lost. Furthermore, the extract safety was also guaranteed on Caco-2 intestinal cells. This novel and green GP extract proved to be composed of relevant bioactive molecules, including xylooligosaccharides, polyphenols, organic acids, and minerals, which provided different biological properties; it has potential applications in the food industry such that it can be used as an ingredient in the development of new functional foods.

Use of grape pomace for the production of hydrolytic enzymes by solid-state fermentation and recovery of its bioactive compounds.

A cocktail of biomass hydrolytic enzymes was produced by solid-state fermentation (SSF) by the mutant strain Aspergillus niger 3T5B8, using as substrate a mixture of grape pomace and wheat bran, and compared to the production when wheat bran was used as the sole substrate. The two enzymatic cocktails were subsequently used for the extraction of bioactive compounds from grape pomace and the relationship between the activities of the cocktail and the release of phenolic compounds was evaluated. Although the wheat bran SSF process was more effective for enzyme production, the enzymatic cocktail produced by the grape pomace - wheat bran mixture was more effective for the extraction of compounds with higher proanthocyanidins content and higher antioxidant potential (p < 0.05). A significant correlation between the bioactive compounds and enzyme activity was observed.

Cellulose nanocrystals from grape pomace: Production, properties and cytotoxicity assessment.

Cellulose nanocrystals (CNCs) were obtained from grape pomace through chemical and physical pretreatments. Bleached cellulose pulp was subjected to acid hydrolysis (AH) for 30 or 60 min and an ultrasound treatment to obtain CNCs (AH30S and AH60S). Compositional analyses of untreated (UGP) and pretreated (PGP) grape pomace showed the effectiveness of pretreatment in removing non-cellulosic components, recovering 80.1% cellulose in PGP (compared to 19.3% of UGP). Scanning and transmission electron microscopies were used to evaluate the CNCs morphology. AH in combination with ultrasound treatment led to needle-shaped structures and apparently more dispersed suspensions. Crystallinity index and thermal stability were studied by X-ray diffraction and thermogravimetric analysis, respectively. The AH60S sample presented high aspect ratio, crystallinity and thermal stability. CNCs toxicity was evaluated by exposing Caco-2 cells to CNCs suspension and evaluating their viability. Results showed that CNCs are non-toxic, opening the opportunity for their use on food and pharmaceutical applications.

Towards integral utilization of grape pomace from winemaking process: A review.

Grape is the main fruit crop in several countries. Although many grape-based food products can be found in the market, studies have shown that around 75% of the world grape production is destined for the wine industry. Grape pomace is an abundant by-product from the wine industry, which consists of the remaining skin, seeds and stalks and represents around 25% of total grape weight used in the winemaking process. In countries such as Italy, France and Spain, where wine production is more relevant, the annual grape pomace generation can reach nearly 1200 tonnes per year. In order to reach a sustainable winemaking process there is a need of a waste reduction policy. Several studies explore this subject using grape pomace as a source of healthy and technological compounds that could be applied in animal feed, pharmaceutical, cosmetic or food industry to improve stability and nutritional characteristics, and in cosmetic industry, where grape seeds oil is widely used. This review aims to approach the recent winemaking scenario and the benefits achieved when a waste management policy is implemented, as well as to compare available extractive technologies and a wide alternative of uses for grape pomace.

Coupling of ultrafiltration and enzymatic hydrolysis aiming at valorizing shrimp wastewater.

The objective of this work was to obtain a protein hydrolysate from the wastewater generated during shrimp cooking, by coupling ultrafiltration and enzymatic hydrolysis processes. Initially, the effluent was concentrated by ultrafiltration, reaching a protein concentration factor of 3.2. The concentrated effluent was then enzymatically hydrolyzed, aiming at obtaining peptides with antioxidant capacity. The effects of some process variables--temperature (55-75 °C), pH (7-9) and enzyme/substrate (E/S) ratio (0.1-2.5%)--on the degree of hydrolysis and the antioxidant capacity were evaluated. The increase in temperature and pH resulted in lower degree of hydrolysis and higher antioxidant capacity. The conditions selected as the most suitable were: temperature of 75 °C, pH of 9.0 and E/S ratio of 0.1%. The hydrolysates produced at these conditions were also evaluated for total amino acid content and electrophoretic profile, showing a suitable amount of essential amino acids that covers the recommended daily needs.