Inclusion of grape pomace in the diet of pigs on pork quality and oxidative stability of omega-3 enriched fat / Inclusão do bagaço de uva na dieta de suínos sobre a qualidade da carne e a estabilidade oxidativa da gordura enriquecida com ômega-3

ABSTRACT: The objective of this study was to assess the effects of including grape pomace in the diet of pigs on pork quality and oxidative stability of body fat enriched with omega-3 fatty acids. Four treatments were compared: T1) Control diet based on corn and soybean meal; T2) Diet with inclusion of 3% of a canola (50%) and flaxseed (50%) oil blend; T3) Diet with inclusion of 3% of the oil blend and sequential levels of 3 and 5% of grape pomace; T4) Diet with inclusion of 3% of the oil blend and sequential levels of 6 and 10% of grape pomace. Inclusion of grape pomace in the diet led to an increase (P<0.10) of a* value and color saturation index of meat. The omega-3 and polyunsaturated fatty acids (PUFA) content of backfat were increased (P>0.10) with dietary inclusion of oils blend. Neither the inclusion of the oil blend, nor the grape pomace had any effect (P>0.10) on the production of thiobarbituric acid reactive substances (TBARS) in the loin samples, despite the higher PUFA content in the fat of pigs fed the oil blend. Antioxidant effect of grape pomace was not possible to prove when measured by TBARS, but the increased redness of the pork from pigs fed with this ingredient suggested a possible antioxidant effect of grape pomace.

RESUMO: Este trabalho teve como objetivo avaliar a inclusão do bagaço de uva na dieta de suínos sobre a qualidade da carne e, a estabilidade oxidativa da gordura corporal enriquecida com ácidos graxos ômega-3. Foram comparados quatro tratamentos: T1 - Dieta controle baseada em milho e farelo de soja; T2 - Dieta com inclusão de 3% de uma mistura de óleos de canola (50%) e de semente de linho (50%); T3 - Dieta com inclusão de 3% da mistura de óleos e níveis sequenciais de 3 e 5% de bagaço de uva e; T4 - Dieta com inclusão de 3% da mistura de óleos e níveis sequenciais de 6 e 10% de bagaço de uva. A inclusão do bagaço de uva na dieta resultou no aumento (P<0,10) do valor de a* e índice de saturação da cor da carne. O conteúdo de ômega-3 e ácidos graxos poli-insaturados (PUFA) do toucinho aumentaram (P<0,10) em função da inclusão da mistura de óleos na dieta. A mistura de óleos e o bagaço de uva não afetaram a produção de substâncias reativas ao ácido tiobarbitúrico (TBARS) nas amostras de lombo, apesar do maior conteúdo de PUFA na gordura dos suínos que receberam a mistura de óleos na dieta. Não foi possível provar efeito antioxidante do bagaço de uva na carne através da determinação dos valores de TBARS. Porém, a cor vermelha mais intensa na carne dos suínos alimentados com este ingrediente sugere um possível efeito antioxidante do bagaço de uva.

Wine grape pomace flour improves blood pressure, fasting glucose and protein damage in humans: a randomized controlled trial

BACKGROUND: The Mediterranean diet is a healthy diet with positive scientific evidence of preventing chronic diseases. Bioactive components support the healthy properties of the Mediterranean diet. Antioxidants and fiber, two components of the Mediterranean diet, are key functional nutrients for healthy eating and nutrition. Wine grape pomace is a rich source of these dietary constituents and may be beneficial for human health. Our hypothesis was that the intake of red wine grape pomace flour (WGPF) prepared from red wine grapes (Cabernet Sauvignon variety) reduced the metabolic syndrome in humans. To evaluate the effect of WGPF on components of metabolic syndrome we design a 16-week longitudinal intervention study. Thirty-eight males, 30-65 years of age, with at least one component of metabolic syndrome, were randomly assigned to either the intervention group (n = 25) or the control group (n = 13). At lunch, the intervention group was given 20 g of WGPF per day, which contained 10 g of dietary fiber, 822 mg of polyphenols and an antioxidant capacity of 7258 ORAC units. Both groups were asked to maintain their regular eating habits and lifestyles. Clinical evaluation, anthropometric measurements and biochemical blood analyses were done at the beginning and the end of the study. RESULTS: WGPF intake significantly decreased systolic and diastolic blood pressure as well as fasting glucose levels. Plasma γ-tocopherol and δ-tocopherol increased and carbonyl group in plasma protein decreased in WGPT group, significantly. No significant effect was observed for waist circumference, HDL cholesterol, triglycerides, total antioxidant capacity and vitamin C in and between groups. The group-dependent magnitude of the differences between the baseline and final postprandial insulin values and γ-tocopherol concentrations was statistically significant. CONCLUSIONS: The consumption of WGPF-rich in fiber and polyphenol antioxidants, as a food supplement in a regular diet improves blood pressure, glycaemia and postprandial insulin. In addition, increased antioxidant defenses and decreased oxidative protein damage indicating attenuation of oxidative stress. WGPF might be a useful food ingredient for health promotion and chronic disease prevention.

Dual effects of a mixture of grape pomace (Campbell Early) and Omija fruit ethanol extracts on lipid metabolism and the antioxidant defense system in diet-induced obese mice

BACKGROUND/OBJECTIVES: We investigated the effects of a combination of grape pomace (Vitis labrusca, Campbell Early) and Omija fruit (Schizandra chinensis, Baillon) ethanol extracts on lipid metabolism and antioxidant defense system in diet-induced obese mice. MATERIALS/METHODS: Forty male C57BL/6J mice were divided into four groups and fed high-fat diet (control group, CON) or high-fat diet added 0.5% grape pomace extract (GPE), 0.05% Omija fruit extract (OFE) or 0.5% GPE plus 0.05% OFE (GPE+OFE) for 12 weeks. RESULTS: In contrast to the GPE- or OFE-supplemented groups, the GPE+OFE group showed significantly lower body weight and white adipose tissue weights than the CON group. Moreover, GPE+OFE supplementation significantly decreased plasma total cholesterol and increased the plasma HDL-cholesterol/total-cholesterol ratio (HTR) compared to the control diet. The hepatic triglyceride level was significantly lower in the GPE+OFE and GPE groups by increasing beta-oxidation and decreasing lipogenic enzyme compared to the CON group. Furthermore, GPE+OFE supplementation significantly increased antioxidant enzyme activities with a simultaneous decrease in liver H2O2 content compared to the control diet. CONCLUSIONS: Together our results suggest that supplementation with the GPE+OFE mixture may be more effective in improving adiposity, lipid metabolism and oxidative stress in high-fat diet-fed mice than those with GPE and OFE alone.

Effects of grape pomace on the antioxidant defense system in diet-induced hypercholesterolemic rabbits

The effects of grape seeds extract and grape peels extract prepared from grape pomace on the activity of antioxidant enzymes, degree of lipid peroxidation in serum and liver tissue were investigated in rabbits fed on high cholesterol diet. New Zealand white rabbits were divided as follows ; 1) NOR (normal group); 2) CHOL (cholesterol group); 3) GSH (cholesterol + grape seed extract group); 4) GPE (cholesterol + grape peel extract); 5) GSP (cholesterol + grape seed powder); 6) GPP (cholesterol + grape peel powder); 7) GE (cholesterol + grape seed and peel extract); 8) GP (cholesterol + grape seed and peel powder). Eight groups of rabbits were studied for 8 weeks. At the end of the experimental period, rabbits were sacrificed and the liver tissue were removed. Then, GSH, GPx, GST, CAT and MDA in the liver were measured. In liver tissues, total glutathione contents (GSH), glutathione peroxidase (GPx) and catalase (CAT) activity, which was significantly higher by grape seed extract supplementation. The level of malondialdehyde (MDA) was lower in the serum of rabbits fed grape seed extract or grape peel powder plus cholesterol than in the serum of rabbits fed cholesterol alone. It is therefore likely that grape seed extract prepared from grape pomace functioned as antioxidants in vivo, negating the effects of the oxidative stress induced by 1% cholesterol diet. The grape seed extract was found effective in converting the oxidized glutathione into reduced glutathione, and in removing H2O2 that is created by oxidative stress. The grape peel powder was found to have small influence on reduced glutathione content, CAT and GPX activity, but it increased GST activity in liver tissues, resulting in promoting the combination of lipid peroxide and glutathione (GSH), and further, lowering the formation of lipid peroxide in the serum. Therefore, grape pomace (grape seed extract and grape peel powder) supplementation is considered to activate the antioxidant enzyme system and prevent damage with hypercholesterolemia.

Effect of Dietary Grape Pomace on Lipid Oxidation and Related Enzyme Activities in Rats Fed High Fat Diet

The present study was conducted to investigate the effect of dietary supplementation of grape pomace on lipid peroxidation and related enzyme activities of rats fed high fat diet. Male Sprague-Dawley rats weighing about 90 g were assigned to 4 experimental groups of 8 rats on the basis of their body weight. The high fat diet contained additional 15% lard to AIN 93-based diet. Rats were fed experimental diets containing 5% grape pomace for 4 weeks. Dietary supplementation of grape pomace reduced serum concentration of lipid peroxide in rats fed high fat diet. Hepatic concentration of lipid peroxide tended to be lower by feeding grape pomace. Hepatic total glutathione content and GSH/GSSG ratio were increased by grape pomace feeding in normal or high fat diet groups. Hepatic superoxide dismutase activity of grape pomace group with high fat diet was induced significantly compared with high fat diet group without grape pomace. Hepatic catalase activity of high fat fed rats was induced by feeding grape pomace. Grape pomace diet increased glutathione-S-transferase and glutathione peroxidase activities in rat liver fed high fat. Hepatic glucose-6-phosphatase activity was not affected by dietary supplementation of grape pomace in rats fed high fat. These results suggest that dietary supplementation of grape pomace may alleviate lipid peroxidation through antioxidant effect in rats fed high fat.

Effect of Grape Intake on Cadmium Metabolism of Rats during Aging

This study was carried out to investigate the effect of whole grape, grape pomace and grape juice intake on cadmium (Cd) metabolism during aging in thirteen-month-old Sprague-Dawley male rats. One hundred and twenty rats weighing 548.8+/-4.3 g were assigned to eight groups according to body weight and were raised for 3, 5 or 7 months on diets containing 2 % (w/w) dried powders of three different parts of the grape (Campbell Early) and 0.02 % (w/w) CdC12. Food intake tended to decrease with aging, and body weight and epididymal fat pad (EFP) weights of Cd-exposed groups were lower than those of Cd-free groups. Cadmium accumulated in the blood and tissues and Cd concentration was the lowest in the pomace group among Cd-exposed animals. Metallothionein (MT) concentration in the tissues increased through Cd administration. Grape diets, especially grape pomace diets, were effective in decreasing Cd absorption in the tissues by increasing Cd excretion through feces. The intake of grape pomace alleviated the decrease in bone density caused by Cd administration and prevented a decrease in glomerular filtration rates (GFR) with aging. Among the parts of grape, grape pomace, which had highest content of dietary fiber and flavonoids, was the most effective. The results of this study suggest the possibility of using grape pomace as a functional food material, a prospect that previously has been discarded.