Winery by‑products as a feed source with functional properties:dose–response effect of grape pomace,grape seed meal,and grape seed extract on rumen microbial community and their fermentation activity in RUSITEC

Background Grape and winery by-products have nutritional values for cattle and also contain functional compounds like phenols,which not only bind to protein but can also directly affect microbiota and their function in the rumen.We characterized the nutritional and functional effects of grape seed meal and grape pomace as well as an effective dosage of grape phenols on ruminal microbiota and fermentation characteristics using a rumen simulation technique.Results Six diets(each n=8)were compared including a control diet(CON,no by-product),a positive control diet(EXT,CON+3.7%grape seed extract on a dry matter(DM)basis),two diets with grape seed meal at 5%(GS-low)and 10%(GS-high),and two diets with grape pomace:at 10%(GP-low)and 20%(GP-high),on a DM basis.The inclusion of the by-product supplied total phenols at 3.4%,0.7%,1.4%,1.3%,and 2.7%of diet DM for EXT,GS-low,GS-high,GP-low,and GP-high,respectively.Diets were tested in four experimental runs.All treatments decreased ammonia concentrations and the disappearances of DM and OM(P<0.05)compared to CON.EXT and GP-high lowered butyrate and odd-and branch-chain short-chain fatty acids while increased acetate compared to CON(P<0.05).Treatments did not affect methane formation.EXT decreased the abundance of many bacterial genera including those belonging to the core microbiota.GP-high and EXT consistently decreased Olsenella and Anaerotipes while increased Ruminobacter abundances.Conclusion The data suggest that the inclusion of winery by-products or grape seed extract could be an option for reducing excessive ammonia production.Exposure to grape phenols at a high dosage in an extract form can alter the rumen microbial community.This,however,does not necessarily alter the effect of grape phenols on the microbial community function compared to feeding high levels of winery by-products.This suggests the dominant role of dosage over the form or source of the grape phenols in affecting ruminal microbial activity.In conclusion,supplementing grape phenols at about 3%of diet DM is an effective dosage tolerable to ruminal microbiota.

Selection of Relevant Variables to the Enzyme Production on Red Grape Pomace by Solid-State Fermentation

With the aim of to valorise red grape pomace and to reduce its environmental impact, the production of enzymatic preparations appear as an interesting choice. Statistical experimental Plackett-Burman designs were applied for the selection of relevant medium components and culture conditions for cellulase, xylanase, polygalacturonase and tannase production by Aspergillus awamori, in solid-state fermentation on red grape pomace. Ten variables were tested： initial moisture content （IMC）, particle size （PS）, temperature, initial pH, time of cultivation, mixing （Mx）, and additions of： fructose, tannic acid, sodium phosphate, and ammonium sulphate （ASA）. Results indicate that the production of each enzyme was affected in a distinct way by the different variables. Also, for each of the enzyme activities considered, IMC must be carefully controlled, and optimized above 65%; PS and Mx, must not be taken into account and ASA must be discarded. The other variables studied, must be selected according to the enzyme activity that will be favored.

Grape Pomace Aqueous Extract (GPE) Prevents High Fat Diet-Induced Diabetes and Attenuates Systemic Inflammation

Diabetes mellitus is a group of metabolic syndromes with a hallmark of hyperglycemia. Serious long-term complications from diabetes are a major cause of hospitalization and death. We recently discovered that grape pomace, the by-product from the waste of the wine and juice industries, had great potential to prevent diabetes. In this study, we examined the potential use of grape pomace in controlling high blood glucose in the form of Cabernet Franc Grape pomace aqueous extract (GPE). Both streptozotocin (STZ;1 × 150 mg/kg)-treated mice and non-STZ treated mice were fed with high fat diet that was supplemented with 2.4 g/kg GPE for 12 weeks. GPE had no significant effect on the blood glucose levels in STZ-treated mice. However, GPE significantly reduced blood glucose levels by 16.1% (p < 0.05) in non-STZ treated mice following a 10-week HFD feeding period when compared with high fat diet controls. GPE reduction of hyperglycemia also promoted a significant reduction of GHbA1c accumulation. Circulating peptide hormones related to glucose homeostasis, including GLP-1, glucagon, DPP-4 and insulin, were drastically altered by GPE. Moreover, GPE attenuated the expressions of insulin, glucagon, and several gut hormones at the mRNA level. In addition, GPE significantly down regulated 5 biomarker genes for systematic inflammation. Taken together, our results highlight a role of GPE as a potential alternative approach to control diabetes epidemic.

Structural composition of oligomeric and polymeric proanthocyanidins from diff erent parts of grape pomace

Grape pomace is one of the most abundant solid by-products generated during winemaking,rich in bioactive compounds,i.e.,proanthocyanidins.The major objective of this work was to characterize structurally oligomeric and polymeric proanthocyanidins of diff erent parts of grape pomace(seed,skin,and stem).Column chromatography techniques were used to isolate oligomeric and polymeric proanthocyanidins fractions from diff erent parts of grape pomace.The purifi ed grape seed proanthocyanidins were used to assess the effi ciency of the three most frequently-used acidic degradation methods,using benzyl mercaptan,phloroglucinol,and cysteamine as nucleophiles.The structural characterization of proanthocyanidins in the different parts of grape pomace was further performed by the phloroglucinolysis and ESI-MS analysis.The results showed signifi cant diff erences in the structural composition of proanthocyanidins among diff erent parts of pomace.A positive correlation was found between the mean degree of polymerization and percentage of galloylation,in both oligomeric and polymeric fractions.The results provided useful information for the preparation of diff erent proanthocyanidins products from grape pomace.

In vitro Evaluating the Influence of Grape Seed Polyphenol Extract on the Digestibility of Macronutrients

Interaction between dietary polyphenol and proteins including digestive enzymes may result in reduced digestibility of food macronutrients, thus lowering absorption of nutrients that contributing to high energy accumulation in human body. The objective of this study was to investigate the effect of grape seed polyphenol extract （GSPE） on the digestibility of starch, food lipid and food protein by digestive enzymes such as u-amylase, lipase, pepsin and trypsin. The digestion of each substrate was conducted at the optimal pH and temperature of specific enzyme. Bread containing different amount of grape pomace was used as a real food model and its digestion was conducted under simulated digestion condition. Concentrations of reducing sugar, fatty acid and amino acids in enzyme digested mixtures were determined as indicators of starch, lipid and protein digestions, respectively. Results indicate that GSPE significantly inhibited the digestion of starch, cooking oil and casein, but did not inhibit digestion of whey protein and egg white protein. Instead, the digestion of egg white and whey protein by trypsin was moderately enhanced in the presence of GSPE. However, under simulated human digestion condition, the grape pomace in the bread significantly reduced the digestibility of bread starch and protein.

Biochar from grape pomace,a waste of vitivinicultural origin,is effective for root-knot nematode control

Root-knot nematodes(RKNs)are obligate endoparasites that feed on their host plants to complete its life cycle,representing a major threat to agriculture and economy worldwide.The development of new management strategies becomes essential as effective chemical nematicides are progressively being restricted.Hence,we analysed grape pomace-derived biochars,pyrolysed at 350°C(BC350)and 700°C(BC700),focusing on their potential for RKN control.The thermal treatment of grape pomace caused an increase in the concentration of carbon and plant macro-and micronutrients,which were largely present in a water-soluble form.Synchrotron radiation-based Fourier transform infrared microspectroscopy data showed a general loss of carboxylic functional groups during pyrolysis,partially contributing to the alkalinisation of both biochars,mostly in BC700.Scanning electron microscopy coupled with energydispersive X-ray spectroscopy analysis revealed a highly porous structure filled with different crystals composed of elements such as K,Ca,Mg,P,Si or Al,which could be a suitable environment for the growth of microorganisms.Biochar-derived aqueous extracts showed phytotoxicity to tomato seedlings at high concentrations,and disappeared upon dilution,but no toxic effect was observed on the nematode’s infective stage.However,the infective and reproductive traits of a Meloidogyne javanica population in tomato were significantly reduced(i.e.egg masses and eggs per plant)in washed-biochar-treated soil in pots(0.75%;BC350W).Therefore,the large amount of grape waste generated after wine production can be transformed into a valuable product such as biochar,effective for RKNs control,thus reducing the waste management problem and contributing to a circular economy.

Supplementation of grape pomace(Vitis vinifera) in broiler diets and its effect on growth performance, apparent total tract digestibility of nutrients,blood profile,and meat quality

This experiment was conducted to explore the efficacy of grape pomace(Vitis vinifera) on growth performance, apparent total tract digestibility of nutrients, blood profile, and meat quality in commercial broilers.Four hundred broiler chicks(3-d-old) were randomly allotted to 4 dietary treatments for 28 d.Each treatment had 5 replicates with 20 birds per replicate.The dietary treatments were 1) control, 2)5 g/kg grape pomace(GP), 3) 7.5 g/kg GP, and 4) 10 g/kg GP supplemented in diets after drying.Supplementation of GP did not show linear effects(P > 0.05) on body weight(BW) gain, however, quadratic effects(P < 0.05) on BW gain were observed during d 0 to 7 and d 8 to 14.Body weight gain, feed intake,and feed conversion ratio remained unaffected during d 22 to 28 and overall period.The nutrient digestibility studies conducted at the end of the feeding trial did not show(P > 0.05) any effect due to GP supplementation, except a quadratic trend(P=0.07) for digestibility of ash was observed.Serum levels of glucose, triglyceride, and high-density lipoprotein cholesterol were not affected(P > 0.05), however,total cholesterol and serum immunoglobulin G levels showed quadratic effects(P < 0.05) due to GP supplementation.The thio-barbituric acid reactive substances values in breast meat linearly decreased(P < 0.01) in supplemented groups at 0, 5, and 10 d of storage showing linear effects due to GP supplementation, and quadratic effects were also observed at 5 and 10 d of storage.The meat color value such as redness was also decreased(P < 0.05) in supplemented groups showing both linear and quadratic effects.Overall, it could be concluded that GP supplementation showed quadratic effects on BW gain during early growth stages and was effective in reducing serum cholesterol level and improving meat quality parameters in broilers.

Pisco grape pomace:Iron/copper speciation and antioxidant properties,towards their comprehensive utilization

The pisco and wine industry produces hundreds of tons of grape pomace each year in Chile,generating environmental problems,and demanding urgent strategies for its management.The aim of this work was to study the pisco grape pomace based on a physicochemical characterization,an iron/copper speciation analysis,and the optimization for polyphenols recovery,establishing the polyphenolic profile,antioxidant properties,and the Fe^(2+)/Cu^(2+) chelating activity,to promote their revalorization as an ingredient with potential application in the food industry.The chemical characterization showed mainly high values for crude protein(15.36%dw)and potassium(9240.66 mg/kg).The Fe/Cu speciation depicted that iron and copper soluble forms in pisco pomace flour represented 70.57%and 52.18%,respectively,regarding total content.The optimized extract showed mainly pyrogallol,catechin and epicatechin,with concentrations of 1078.43±60.14μg/g,883.20±7.57μg/g and,751.76±23.04μg/g,respectively,with a relevant antioxidant capacity by Oxygen Radical Absorbance Capacity(ORAC)of 1402.15μmol TE/g dw GPE and,a better chelating ability to complex Fe^(2+) than Cu^(2+).The pisco pomace was for the first time chemically characterize,showing it as a potential source of minerals and antioxidant biocompounds,making it a good candidate for nutritional applications,as a rich source of organic matter or even could be potentially utilized to produce value-added commodities,toward a circular economy.