Effect Of Grape Research Articles

Effect of Grape and its Derivatives on Cognitive Function: A Systematic Review of Clinical Trials

Background: According to the world health organization (WHO), in 2019, around 50 million people suffer from dementia, worldwide; and approximately 60% live in low- and middle-income countries. Dementia has physical, psychological, social, and economic effects on dementia sufferers, their caregivers, families, and the community.
 Objectives: This systematic review investigated the effect of short-term and long-term interventions with grapes and their derivatives on different cognitive functions, such as executive function, memory, attention and language in all people.
 Methods: Pubmed, Scopus, and Proquest were searched until June 12, 2020 for English studies. Clinical trials in which grapes and its derivatives were considered as an intervention and changes of cognition and its components as an outcome, were selected. Two independent individuals assessed the quality of the articles according to Jadad checklist and extracted the information of the articles with inclusion criteria based on a specific table. The differences were resolved with the discussion and opinion of a third person.
 Results: Nine Studies (211 individuals) were included in the content analysis, of which 3 studies had short-term intervention and 6 studies had long-term intervention with grape juice, freeze-dried grape powder, and a syrup made from grapes (Enoant Syrup). It can be said that the consumption of grapes and its derivatives improved various cognitive components (such as attention, executive function, immediate spatial memory, learning, and driving skill) between groups.
 Conclusion: In general, long-term intervention with grapes and their derivatives has led to the improvement of some cognitive functions, but its short-term intervention is not very effective and only 2 studies showed improvement in attention speed. However, the included studies were highly heterogeneous and more research is needed using similar cognitive assessment tools.

Grape seed proanthocyanidin alleviates left ventricular remodeling by regulating systolic pressure, oxidative stress and vasoactive substances in spontaneously hypertensive rats

Purpose: To study the effect of grape seed proanthocyanidin (GSP) on left ventricular remodeling in spontaneously hypertensive rats, and the underlying mechanism.
 Methods: Spontaneously hypertensive rats were randomly divided into two groups, with 12 rats per group. One group was injected with GSP. Systolic pressure in each group was measured at baseline (before treatment), and at 3, 6 and 9 weeks after treatment. Whole heart index and left heart index were calculated. Histopathological changes in myocardium and left ventricular posterior wall thickness of rats in each group were measured. The cross-sectional area of myocardial cells and myocardial collagen volume fraction were assessed. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), nitric oxide (NO), renin, angiotensin II (Ang II), endothelin-1 (ET-1) and endothelial nitric oxide synthase (eNOS) in each group of rats were assayed.
 Results: Compared with the spontaneous hypertension group, whole heart mass index, left heart mass index, left ventricular posterior wall thickness, cross sectional area of myocardial cells, myocardial collagen volume fraction, and levels of MDA, renin, Ang II and ET-1 in GSP group were significantly decreased, while the expression levels of SOD, CAT, NO and eNOS were markedly increased in GSP group (p < 0.05). Cell hypertrophy in the GSP group was significantly mitigated, when compared with that in the spontaneous hypertension group.
 Conclusion: GSP mitigates left ventricular remodeling in rats by reducing systolic blood pressure, improving antioxidant capacity and regulating levels of vasoactive substances, thus suggesting its potential for the management of hypertension.

Role of extraction procedures on the concentration of varietal thiol precursors in Grillo white grape must

Background and Aims Varietal thiol precursors (VTPs) decrease strongly after the pre-fermentative operations. The effect of grape must extraction steps on the concentration of S-3-(hexan-1-ol)-L-glutathione (G-3SH), S-3-(hexan-1-ol)-L-cysteine (Cys-3SH) and S-3-(hexanal)-glutathione (G-3SHal) was investigated. Methods and Results Must produced on a commercial scale was sampled throughout the pre-fermentation steps. Must was also prepared in the laboratory for assessing the role of copper, sulfite and air. In commercial must fractions, over 95% of G-3SHal was lost because of sulfite addition, while the concentration of G-3SH and Cys-3SH increased along with must yield, and it exceeded the concentration found in berries. No Cys-3SH was found in the intact grape; instead a trace concentration of G-SHal, and a high concentration of glutathione and even cysteine was determined when sulfite was added. A large amount of G-3SHal was formed when copper was depleted. Conclusions Our data suggest that Cys-3SH and G-3SHal are promptly and mainly formed in grape must upon grape pressing. Sulfite and copper prevented the formation of VTPs, while settling of must led to a loss of VTPs. Significance of the Study Varietal thiol precursors can be preserved through the proper management of pressing with particular attention to must contact with air, extraction conditions, contact time with solids and addition of sulfite.

The Effects of Grape, pomegranate, Sesame Seed Powder and Their Oils on Probiotic Ice Cream: Total phenolic contents, antioxidant activity and probiotic viability

The present study aimed to produce probiotic ice cream, containing Lactobacillus rhamnosus and Bifidobacterium animalis subps. lactis BB12 as the starter cultures, by adding vegetable seed pulp powder (sesame, pomegranate seed, and grape seed) and oils of these seeds to the ice cream mixtures and to examine the effects of these additions on pH, acidity, total phenolic content, flavonoid content, antioxidant capacity and the probiotic viability of Lactobacillus rhamnosus and Bifidobacterium animalis subps. lactis BB12 in ice cream samples stored at −20 °C for 90 days. Total phenolic content, flavonoid content, and antioxidant capacity were evaluated on the first and last day of the storage. Vegetable seed powders and oils did not affect the pH and acidity values of the ice cream samples. The pulp powders and oils used contributed to preserving the viability of probiotic bacteria during storage. Among the seed pulp powders, the grape seed had the highest phenolic content and antioxidant activity. Especially, ice creams containing grape seed powder, grape seed powder + seed oil, and pomegranate seed powder promoted the development of probiotic microorganisms in these ice cream samples due to the high phenolic components and antioxidant activity. The total phenolic content and antioxidant activity of seed powders and oils were parallel to the total phenolic content and antioxidant activity of ice creams produced using these powders and oils. It can be concluded that grape seed powder and its oil can be used as a natural ingredient to develop a novel ice cream with high nutritional antioxidant activity.

Synergistic Effects of Exogenous Grape Seed Extract and α-Tocopherol on Lipid Oxidation in Refrigerated and Frozen Rainbow Trout (Oncorhynchus Mykiss) and Pork Loin (Longissimus Dorsi) Muscle

The objective of this study was to assess the antioxidative effectiveness of Grape Seed Extract (GSE) with and without exogenous a-tocopherol in two raw meats that are particularly susceptible to lipid oxidation, rainbow trout (Oncorhynchus mykiss) and pork loin (longissimus dorsi).

Grape seed proanthocyanidin extract suppresses oxidative stress in the rat pancreas of type-1 diabetes

Aim This study aimed to elucidate the effects of grape seed proanthocyanidin extract (GSPE) on oxidative stress (OS), antioxidant enzymes, free radicals and cytokines in the pancreas of T1DM rats. Methods Two-month-old Wistar rats were assigned to the control (CON), CON + GSPE (CON + PA), diabetics (STZ, 60 mg/kg b.w.), diabetes + GSPE (STZ + PA), diabetes + insulin (STZ + INS, 3 U/day) and diabetics + GSPE and INS (STZ + INS + PA) groups. GSPE (75 mg/kg b.w.) was administered daily either alone or with INS for 8 weeks. Results Glutathione was lowest in diabetics while it increased in the STZ + INS + PA (p < .001) group, similar to catalase activity (p < .05). Hydrogen peroxide, superoxide and lipid peroxidation increased with iNOS, TNF-α and IL-1β in the diabetic pancreases, while GSPE decreased (p < .001). Further, reduced β-cells/islet number was improved in diabetics (p < .001) with treatment. Conclusion This study suggests that GSPE with INS is effective in minimising OS and pancreatic degeneration in T1DM rats.

The Effect of Grape Seed Extract Mouth Rinse on the Caries Activity, Dental plaque and Gingivitis

The Effect of Grape Seed Extract Mouth Rinse on the Caries Activity, Dental plaque and Gingivitis

Study of the effect of grape seed extract on the harmful effects of Monosodium Glutamate on chicken embryo Development

Study of the effect of grape seed extract on the harmful effects of Monosodium Glutamate on chicken embryo Development

Grape Seed and Physalis Extracts as Anti- Inflammatory Agents in Cetuximab Induced Tongue Mucositis in Rats

Background: Oral mucositis induced by cancer therapy alters cancer patient’s life. Nutraceuticals these days is for their various activities which could neutralize the toxicity induced by cancer treatment. Purpose: Comparision between the effect of grape seed and fruits of Physalis peruviana methanol extract in reduction of mucositis induced by Cetuximab drug. Study Design: Animal study. Methods: 60 male rats divided into 6 groups as 10 in each group. Control group of rats with no intervention given. The other 5 groups were given Cetuximab drug alone or with grape seed extract (simultaneously or 1 week before Cetuximab drug) or Physalis extract (simultanously or 1 week before Cetuximab drug). After sacrifice, tongue was dissected and tissue preparation was done for all samples. Digital counting was done by image analyzer computer system for (a) filliform papillae in H&E stained sections, (b) mast cells in mast cell tryptase stained sections to assess inflammation. The area percent for bax immune-expression in other immune stained sections were also measured done to assess apoptosis. Results: The difference between the groups was assessed for statistical significance (P<0.0001) by ANOVA test. The greatest mean number of filiform papillae was recorded in control group I. Greatest mean number of mast cells and the greatest mean area percent of bax immune expression were recorded in group II. Conclusion: Grape seed extract and Physalis extract could neutralize the harmful effect of cancer therapy. Physalis extract had more potent effect in reducing the inflammation induced by Cetuximab drug.

Effect of grape ( Vitis vinifera L.) varieties and harvest periods on bioactive compounds, antioxidant activity, phenolic composition, mineral contents, and fatty acid compositions of Vitis leave and oils

Total phenolic contents of immature and mature vine leaves changed between 38.45 (Cabernet Sauvignon) and 78.66 mg GAE/g (Michele Palieri) to 19.49 (Cabernet sauvignon) and 47.76 mg GAE/g (Michele Palieri), respectively. In addition, antioxidant values (DPPH) of immature and mature vine leaves changed between 17.24 µmolTE/g (Chairette) and 30.24 µmol TE/g dw (Trakya İlkeren) to 14.54 µmol TE/gdw (Gamay) and 23.65 µmolTE/g dw (Narince), respectively. Immature and mature vine leaves contained 11.20 g/kg (Michele Palieri) and 34.90 g/kg (Gamay); 24.18 g/kg (Hamburg Misketi) and 60.76 g/kg (Gamay) fructose, respectively. The highest 3,4-dihydroxybenzoic acid and (+)-catechin contents of immature and mature leaves were found in Trakya İlkeren and Michele Parieri (14.15 mg/kg and 387.86 mg/kg) and Cincaut and Hamburg misketi (11.30 mg/kg and 168.73 mg/kg) vine leaves, respectively. The major fatty acids of vine leave oils were palmitic, linoleic, arachidic, and linolenic acids. Therefore, the results obtained will create a detailed database of these materials. Practical applications Stuffed grape leaf picked fresh from the vine has been a famous dish of Turkish, Balkan, and Middle East Nations cuisine for centuries. Vine leaves are rich in sugars, organic acids, and phenolic compounds. The vine leaves are composed of a wide range of phenolic compounds. The Mediterranean coast has benefited from by-products of grape. The grape leave oils are rich in palmitic, oleic, and linoleic acid. Brined vine leaves have a significant place in human nutrition.

The protective effects of grape seed oil on induced osteoarthritis of the knee in male rat models

BackgroundOsteoarthritis (OA), though being treated via various methods and medicines, is still a major healthcare concern mostly due to the increase in diagnosis of these age-related diseases. The present study aimed at investigating the effects of oral and intra articular injection of grape seed oil on OA in male rat models.Methods and materialsSeventy male rats were selected and their anterior cruciate ligament was cut to induce OA. They were divided into 7 groups (n = 10): C1, no treatment; C2, receiving 300 mg/day of Piascledine per os (PO); C3, 1 mg sodium hyaluronate intra-articularly in days 1, 7, 14; C4, 1 mg methyl-prednisolone acetate intra-articularly; E1, avocado and grape seed oil combination (2:1, 300 mg/day) PO; E2, 500 mg/day of grape seed oil PO; E3, 200 mg/day grape seed oil intra-articularly. After 10 weeks, the rats were anesthetized and evaluated radiologically and histopathologically. P value ≤ 0.05 was considered as statistically significant.ResultsAll the groups made significant differences with C1 regarding all inspected radiological criteria (P ≤ 0.05). E1 and E3 showed significantly better effects on medial femoral condyle, medial tibial condyle, joint space width, total osteophyte, and OA scores (P ≤ 0.04).Joint surface, matrix, cell distribution, cell population viability, calcification, and subchondral bone in treatment groups had significantly better scores versus C1 (P ≤ 0.04). E1 and E3 had significantly superior results regarding joint surface, cell viability, and calcification (P ≤ 0.04).ConclusionsGrape seed oil has protective effects, both in injectable form and PO in combination with avocado, on OA in rats. Further clinical trials are necessary.

Effects of grape and pomegranate waste extracts on poultry carcasses microbial, chemical, and sensory attributes in slaughterhouse.

Contamination of poultry carcasses is considered as a critical point in the evaluation of poultry meat safety. The present study aimed at determining the decontamination effects of natural antimicrobial derived from grape waste extract and pomegranate waste extract (GWE and PWE) on poultry carcasses in a slaughterhouse. Poultry carcasses were treated in chiller with concentrations of 0, 2, 4 and 6% of pomegranate and grape waste extracts. Pomegranate and grape waste extracts contained 432.20 and 328.43 mg GAE/g total phenolic compounds. These extracts showed significant antimicrobial effect on the main poultry bacteria in vitro. On the first day of cold storage, significant reduction in total bacterial counts (p < .05) was observed in treated carcasses. After 3 days of storage time, total bacteria, Staphylococcus aureus, and Escherichia coli reduced significantly (p < .05) compared to untreated samples. At sixth and ninth days of storage time, significant reduction in total volatile nitrogen (TVN), total bacteria counts, Staphylococcus aureus, coliforms, and Escherichia coli were observed. Sensory attributes in treated carcasses with PWE and GWE have been enhanced significantly compared to untreated during acceptable shelf time (p < .05). Based on the results, pomegranate and grape waste extracts can be used to preserve and improve the shelf life of the poultry carcasses close to the standard range until the ninth day of storage. Application of pomegranate and grape waste extracts in slaughterhouse could be considered as an environmentally, natural and safe decontamination intervention in integral food safety system.

Effectiveness of grape seed extract-based intracanal dressings against Enterococcus Faecalis and its influence on dentin microhardness and bond strength of filling material

The aim of this study was to evaluate the effectiveness of grape seed extract (GSE)-based intracanal dressings against Enterococcus faecalis (E. faecalis) and its influence on dentin microhardness and bond strength of the filling material. The root canals of 126 human teeth were distributed into three test groups: antimicrobial activity (60 teeth), dentin microhardness (30 teeth) and bond strength (36 teeth). In all three groups, specimens were subdivided into six groups, according to intracanal dressing protocols: G1 – distilled water (DW); G2 – 2% chlorhexidine gel (CHX); G3 – calcium hydroxide (Ca[OH]2)+DW; G4 – GSE+DW; G5 – Ca(OH)2+CHX; G6 – GSE+CHX. The counting of colony-forming units (CFUs), the Vickers microhardness tester and the push-out test were performed to evaluate the antimicrobial activity, dentin microhardness and bond strength, respectively. Specific statistical analysis was performed for each evaluation (α=5%). The greatest bacterial reduction was observed in G5 (Ca[OH]2+CHX) and G6 (GSE+CHX) (p&lt;0.05). There was no statistically significant difference among groups in the dentin microhardness evaluation (p&lt;0.05). The highest bond strength in the immediate evaluation was observed in G4 (GSE+DW) and G6 (GSE+CHX), whereas the highest bond strength after 12 months of storage was observed in G2 (CHX), G3 (Ca[OH]2+DW), G4 (GSE+DW), and G6 (GSE+CHX) (p&lt;0.05). After the storage period, bond strength was increased in G2 (CHX) and G3 (Ca[OH]2+DW), and remained unchanged in G4 (GSE+DW) and G6 (GSE+CHX) (p&lt;0.05). GSE-based intracanal dressings have antimicrobial potential against E. faecalis, have no influence in dentin microhardness and preserve the high bond strength of filling materials for root dentin over time.

Macro and Microscopic Gastroprotective Effects of Grape Seed Extract on the Gastric Ulcer Experimentally Induced by Alcohol

Alcohol administration has been widely correlated with gastric injuries involving gastric ulcers. Grape seed extract (GSE) is a rich source of phenolics and flavonoids with marked antioxidant and anti-inflammatory characteristics that might give it a potential impact on the gastric ulcer. Polyphenolics are naturally occurring antioxidants that protect our bodies from ROS damage and their intake has probable health advantages involving protection from many ailments. Thus, this study intended to illustrate the probable protective actions of grape seed extract against alcohol induced gastric ulcers in rats. The total phenolics and the total flavonoids content in grape seed extract have been quantified. The total phenolic content was found to be 284.11±0.01 mg of gallic acid equivalent (GAE) per g of grape seed extract. Meanwhile, the total flavonoid content was 8.02±0.08 mg of quercetin equivalent (QE)/g extract. Pretreatment with grape seed extract (100 mg kg-1 p.o.) reduced the serious effect of alcohol gastric mucosal damage as illustrated by decreasing the size of macroscopic lesions and alleviating the histopathologic aberrations. These studies were similar to those applied by the standard antiulcer omeprazole. These results could be ascribed to the antioxidant action of grape seed extract as it notably restored the gastric catalase level to the normal range. These outcomes highlight the protection effects of grape seed extract on the gastric ulcer induced by alcohol.

English

English

Effects of Grape (Vitis vinifera L.) Seed Oil and St John’s Wort (Hypericum perforatum L.) Extract Supplementation into Diets of Laying Hens at Different Levels on Performance, Egg Quality and Some Blood Parameters

This study set out to determine the effects of dietary supplementation of grape seed oil and Hypericum perforatum L. extract to the laying hens (Lohmann White, 40 weeks of age) on performance, egg quality and some blood parameters. For this purpose, a total of 336 hens were randomly distributed to the control and other treatment groups, 12 replicates/group with 4 hens/replication. Birds were fed with basal diet only (control group) and the basal diet supplemented with different levels (100, 200, 300 mg/kg) of grape seed oil (GSO-1, GSO-2, GSO-3) and Hypericum perforatum L. extract (HPE-1, HPE-2, HPE-3). Dietary treatments had no significant effect on performance parameters. GSO-3 and HPE-1 supplemental groups presented with increased shell weight (p&amp;lt;0.01) while only GSO-1 group showed increased egg albumen index (p&amp;lt;0.01) and Haugh unit (p&amp;lt;0.05). Among blood parameters, except for serum HDL and total protein, the other blood parameters (serum triglyceride, total cholesterol, LDL, AST, Ca and P) were not affected by the treatments. In conclusion, results showed a partial improvement in some egg quality traits, however, further studies are needed to fully investigate the beneficial effects of these additives in laying hens reared under different stresses.

Investigating effects of grape seed extract on neuropathic pain in the streptozotocin-induced diabetic mice.

Diabetes mellitus is a complicated and serious health problem involving peripheral neuropathy. This situation causes to loss of senses, tingle and pain. Diabetic peripheral neuropathy (DPN) affects 236 million people around the World. Hence there is a need to investigate alternative ways of cure focusing on DPN. Flavonoids have potential on pain due to their permeability characteristic in the capillary microcirculation system and in lowering blood pressure. Flavonoids are common in grape seed. The main flavonoids of grape seed involve proanthocyanidins which might be an effective agent in cure of pain in DPN. The purpose of this study is to investigate effects of grape seed extract on neuropathic pain in the Streptozotocin-induced diabetic mice. In the study, 50 eight-week old BALB-C strain mice in five different groups (Control, Diabetic Control, Control+25 mg/kg, Diabetes+25 mg/kg and Diabetes+50 mg/kg) were used. To induce diabetes in thirty of these animals, single dose Streptozotocin (180 mg/kg) was administered intraperitoneally. After diabetes was observed, grape seed extract (25 mg/kg and 50 mg/kg body weight) was administered by oral gavage in three groups (Cont­rol+25 mg/kg, Diabetes+25 mg/kg and Diabetes+50 mg/kg) during six weeks. At the end of the second and sixth weeks, pain threshold measurements in hot plate test were performed in line with a predetermined thermal pain model. Also the tissues of the sciatic nerve and abdominal aorta from the animals were histologically investigated. As a result hot plate measurements, pain threshold values of the animals in Diabetes+50mg/kg group significantly differed from the measurements of the animals in control group in the first measurements and from the animals in Diabetes+25 mg/kg group in the second measurements (p<0.05). However pain threshold values of the animals in Diabetes+25 mg/kg group differed significantly from the values of the animals in control+25 mg/kg group and control group. It means pain threshold values of the animals in Diabetes+50 mg/kg and Diabetes+25 mg/kg groups were significantly lower than the values of the animals in the other groups. The results of histological investigations showed that degenerations of myelin sheet and axons in diabetic control group were decreased significantly in Diabetes+50 mg/kg and Diabetes+25 mg/kg groups. Moreover degenerations of aorta tissues of animals in diabetic group were not seen in the animals of Dia­betes+50 mg/kg except for tunica adventitia inflammation. It can be said that grape seed extract decreased threshold of neuro­pathic pain in the Streptozotocin-induced diabetic mice and prevented degenerations of myelin sheet and axons, and aorta tissues.

Efficiency of modern fungicides in protection of vineyards from fungal diseases

Goal. To investigate the effectiveness of the fungicide prosper 300 CS, SK (spiroxamin 300 g/l) and the fungicide Serenade ASO SC, SC (Bacillus subtilis, strain QST 713) on the susceptibility of vine plants with oidium and Botrytis.&#x0D; Methods. Field, in the vineyards of the Odessa region. Soil — South cerebrospinale black earth, humus content 3.2% and soil pH 6.9—7.0. The nutrition area of the bushes 3 ќ 1.5 m, forming — Wallpaper of vysokooktanovyj twoplace horizontal cordon. Treatment of the soil at fallow without irrigation. Event for care experienced areas — spring pruning bushes, garter green shoots of chip topping green shoots, chasing, side-shoot removing. Determined the effectiveness of drugs in different doses against powdery mildew (pathogen Uncinula necator Berk.) and gray mold (causative agent Botrytis cinerea Pers.). The counts were performed according to standard techniques, using experimental methods in Phytopathology and plant protection.&#x0D; Results. The use of the fungicide prosper 300 CS, SK, for two-time spraying of vineyards in the consumption rate of 1.2 l/ha showed the effectiveness of grape against pathogen oidium on the leaves — 85.0%, the brushes of 84.1%. The biopesticide Serenade ASO SC, CS showed the best results against the pathogen Botrytis at a rate of 6.0 to 8.0 l/ha. Efficacy on grapes was 82.9—85%.&#x0D; Conclusions. The use of the fungicide prosper 300 CS, SK (1.2 l/ha) and the fungicide Serenade ASO SC, KS (6.0 to 8.0 l/ha) reduced the manifestation of diseases on grape bushes and control their further spread during the growing season. Restrictions on the development and destruction of oidium and Botrytis in the vineyards, for the use of investigational drugs, provided higher yields and quality parameters of wine.

Grape seed extract supplement increases bone callus formation and mechanical strength: an animal study

BackgroundThe positive effects of grape seed proanthocyanidin extract (GSPE) on bone health, which is a potent antioxidant, are known but its effects on fracture healing are not sufficiently covered in the literature. This study aims to investigate the effects of GSPE on fracture healing and biomechanics of healing bone.Materials and methodsSixty-four adult Wistar-Albino male rats were divided into 8 groups of 8 animals in each group. Osteotomy was performed to the right femurs of all groups except the negative control (G1) and positive control (G2) groups, and intramedullary Kirchner wire was used for fixation. GSPE was given to half of the rats (G2-G4-G6-G8) 100 mg/kg/day by oral gavage. The rats were sacrificed on the tenth (G3–G4), twentieth (G5–G6), and thirtieth (G1–G2–G7–G8) days, respectively, and histopathological, radiological, and biomechanical examinations were performed.ResultsHistopathological examination of the specimens from the callus tissues revealed that bone healing was more prominent in the groups supplemented with GSPE (G4, G6, G8). There was a statistically significant improvement in radiological recovery scores and callus volumes in groups with GSPE. When biomechanical strengths were evaluated, it was found that GSPE increased bone strength not only in fracture groups but also in the positive control group (G2).ConclusionsAs a result, this study showed that GSPE, a potent anti-oxidant, had a positive effect on bone healing and improved mechanical strength of the healing bone.

Effect of grape must polyphenols on yeast metabolism during alcoholic fermentation.

In red winemaking, polyphenols from grape berry pericarp and seed are extracted during fermentation and their interactions with yeast have been widely demonstrated. However, information concerning the impact of extracted polyphenols on yeast metabolism during fermentation is missing. The aim of this study was to further explore interactions between yeasts and polyphenols and to identify their effects on yeast metabolism and fermentation kinetics. This impact was studied in synthetic musts for four commercial Saccharomyces cerevisiae wine strains, using polyphenols purified from a thermovinification must, in both stressed (phytosterol deficient medium) and non-stressed conditions. Interactions between grape polyphenols and yeast cells were substantiated from the early stage of fermentation by means of epifluorescence and confocal microscopy. If these interactions were limited to yeast cell walls in non-stressed conditions, the passage of polyphenols through yeast envelope and their accumulation in the intracellular space of living cells was shown in phytosterol-deficient medium. Whatever the conditions used (stressed and non-stressed conditions) and for all strains, the presence of polyphenols led to a significant decrease of cell growth (50%), CO2 production rate (60 to 80%) and nitrogen consumption (3 to 4 times less), resulting in increased fermentation lengths. The perturbation of yeast growth and metabolism due to polyphenol compounds was likely mostly linked to their interactions with the yeast plasma membrane. From the mid-stationary phase to the end of the fermentation, an adaptive response was exhibited by yeast, resulting in lower mortality. This work evidenced a strong impact of polyphenols on yeast fermentative capacity and highlighted the importance of a better knowledge of the mechanisms involved to improve the management of fermentations in the context of red winemaking.