Mariane Lutz

Phenolics and antioxidant capacity of table grape (Vitis vinifera L.) cultivars grown in Chile.

UNLABELLED Grapes (Vitis vinifera L.) possess health-promoting effects attributed to their supply of a wide variety of bioactive phenolics. Juice and skin fractions of 4 varieties of table grapes: Red Globe, Crimson Seedless, Autumn Royal, and Ribier were prepared to determine and compare their total phenolics content, antioxidant capacity (DPPH, FRAP, and ORAC), anthocyanins, and specific phenolics (caffeic acid, gallic acid, resveratrol, and catechin) content, since a series of positive health benefits are expected from the intake of any of these fractions. Higher amounts of total phenolics and antioxidant capacity were observed in the skin fractions (P < 0.05). Blue grapes (Autumn Royal and Ribier) exhibited higher phenolics content and antioxidant capacity (P < 0.05) than red grapes. The most abundant phenolic compound observed was catechin (P < 0.05). Significant correlations between the antioxidant capacity and total phenolics were observed in grape juice and skin fractions. Autumn Royal juice provides a very high amount of phenolics, anthocyanins, and exhibits the highest antioxidant capacity, offering the best health promoting properties compared with the other grape varieties studied. PRACTICAL APPLICATION Grapes possess health-promoting effects attributed to their supply of a wide variety of bioactive phenolics. Grape juice made with blue grapes (Autumn Royal, Ribier) exhibit higher phenolics content and antioxidant capacity than juice elaborated with red grapes (Red Globe, Crimson Seedless). The skin is a good source of phenolics and has a high antioxidant capacity. Specific health-promoting phenolics are more abundant in blue grapes, mainly in their skin fraction, which should not be discarded.

Effect of Dietary Oils, Cholesterol and Antioxidant Vitamin Supplementation on Liver Microsomal Fluidity and Xenobiotic-Metabolizing Enzymes in Rats

This study was undertaken to compare the effects of four oils: corn (C), olive (O), hazelnut (H) or fish (F), and the intake of two supplements: cholesterol, 1% (Ch) or dl-α-tocopherol acetate, 500 mg/kg, and β-carotene, 30 mg/kg (V), on liver microsomal fluidity, cyt P450 content and aniline hydroxylase (AH), aminopyrine-N-dimethylase (AND) and UDP-glucuronyltransferase (UDP-GT) activities. Male Sprague-Dawley rats (n = 6/group) were fed semipurified diets containing 15% oil, without or with Ch or V, for 20 days. Dietary intake and feed efficiency were lower in rats fed F. Relative liver weight was higher in animals fed F, similar in O and H, and lower in the group fed C. The intake of V increased feed intake in C+V group and decreased the relative liver weight of F+V group, which also decreased with the intake of F+Ch. Ch intake increased the relative liver weight in all groups consuming vegetable oils. Cyt P450 content was higher in rats fed F. Decreased cyt P450 content was observed in C+Ch and F+Ch groups, while it augmented in H+Ch group. Mixture V increased cyt P450 in rats fed C+V, F+V and O+V. The highest membrane fluidity was observed in rats fed F. Fluidity was also higher in group H versus O or C. The intake of Ch decreased microsomal fluidity in all groups, while V induced an increase in microsomal fluidity in group O+V. Rats fed F exhibited higher enzyme activities. AND activity increased with V only in rats fed H+V, while AH activity increased with V intake in groups F+V and O+V. In the C+V group, fluidity was not affected by V, while the cyt P450 content and UDP-GT activity increased. The O+V group exhibited lower UDP-GT activity and higher fluidity and cyt P450 content. The activity of AH decreased in groups F+Ch and C+Ch. UDP-GT activity was higher in rats fed F. It diminished after the intake of Ch in H+Ch and F+Ch. These results indicate that although AH and AND act in the same microsomal metabolic pathway, their localization into the membrane may be determinant of their activity and the response to dietary lipids. It is shown that F intake exerts the most significant effects upon liver microsomal properties, e.g. higher fluidity, cyt P450 content and enzymatic activities, an effect that prevails over the intake of the supplements tested.

Comparison of three drying processes to obtain an apple peel food ingredient

Apple peel, a waste product from dried apple manufacture, has a high content of bioactive phenolic compounds. In Chile ca. 9000 ton of apple peel are generated each year. To obtain a novel food ingredient, we compared three drying processes on Granny Smith apple peel: oven (60°C), drum dryer (110°C), and freeze drying. The influence of each drying technology on the chemical characteristics and antioxidant capacity on fresh and dried peel fractions were determined. The results indicate that all the drying processes affected the chemical characteristics and the color of the ingredient. Total phenolics content and antioxidant capacity decreased significantly in all the products during drying. The preservation of phenolics in apple peel was higher using freeze drying (92%). The drum-drying process retained over 70% putatively healthy phenolics. In addition, this is the most economical system suitable to obtain the apple peel ingredient.

Phenolic content and antioxidant capacity in fresh and dry fruits and vegetables grown in Chile

The study evaluated the impact of dehydration on the total phenolic content (TPC) and antioxidant capacity (AC) of fruits and vegetables (F&V). Fresh small fruits (berries) had the highest TPC, anthocyanin contents, and AC (2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC)). The lowest TPC were observed in carrot and tomato and the lowest anthocyanins were observed in fresh sweet peppers (green and red), red apple, carrot, and tomato. Dehydrated blackberry and eggplant exhibited the highest TPC and anthocyanins. The retention of phenolics after drying ranged from 38.5% (spinach) to 92.1% (red apple). TPC increased in dehydrated tomato and green apple. The lowest DPPH and ORAC were obtained in dried carrot and tomato. DPPH retention ranged from 16.4% (tomato) to 64.7% (blackberry). Dehydrated small fruits and sweet peppers presented lower AC (ORAC) retention, while most dehydrated F&V increased ORAC, ranging from 9.5% (carrot) to 52.9% (eggplant). Dehydrated F&V represent good quality functional foods or ingredients.

Bioavailability of phenolic compounds in grape juice cv. Autumn Royal

The bioavailability of major phenolics in Autumn Royal grape juice was measured in 16 subjects distributed into two groups: the experimental group (n = 8 receiving 300 mL of juice) and the placebo group (n = 8 receiving 300 mL of artificial beverage). Blood was obtained before and after 30, 90, 180, and 300 min after juice or placebo intake and 24-h urine was collected. At 30 min, catechin and gallic acid levels were 3.18 ± 0.06 and 0.33 ± 0.06 nmol/mL plasma (p < 0.01), respectively. The maximal plasma levels of catechin and gallic acid observed at 180 min were 7.11 ± 0.53 and 1.56 ± 0.07 nmol/mL, respectively. After 300 min, gallic acid was not detected and only two subjects exhibited measurable levels of catechin. After juice intake, urinary catechin and gallic acid contents were significantly higher than the basal values (p < 0.001). After a regular serving of grape juice, catechin and gallic acid are bioavailable and thus potentially capable of exerting their expected biological effects.

Phenolics content and antioxidant capacity of Chilean grapes cv. País and Cabernet Sauvignon

Grapes (Vitis vinifera L.) are a source of phenolics and exhibit a high antioxidant capacity. In this study, the total phenolics content and the antioxidant capacity of ground grapes, juice, and skin fractions of two varieties of red grapes widely produced in Chile (Cabernet Sauvignon and País) were analyzed and specific phenolics (caffeic acid, gallic acid, resveratrol and catechin) were determined. The total phenolics content and antioxidant capacity were higher in Cabernet Sauvignon grapes vs. País, mainly in the skin fraction. The predominant phenolic species in all grape fractions was catechin, except in the skin of Cabernet Sauvignon, where resveratrol prevailed. Phenolic acids were not detected in grape juices, probably due to the absence of skin. Significant high correlations between specific phenolics, total phenolics content and antioxidant capacity were observed. The study presents practical data on some relevant chemical characteristics of grape fractions that are associated to potential health benefits.

Dietary fats and cholesterol supplementation effects on aortic and lipid response in rats

Abstract The experiment was designed to elucidate the effects of feeding four dietary oils (corn, hazelnut, olive, and fish), and cholesterol supplementation on plasma, liver lipids, and aortic smooth muscle response to drugs. Male Sprague Dawley rats were fed semipurified diets containing one of the above oils (15% wt/wt), either with or without cholesterol supplementation (1% wt/wt), for 20 days. Hazelnut oil-fed rats showed the highest plasma total cholesterol level, while animals fed fish oil exhibited the lowest plasma total and high density lipoprotein cholesterol concentrations. Hepatic cholesterol content was not affected by dietary oils. Liver lipids increased when dietary cholesterol was added to any of the oils used. Acetylcholine pD 2 was elevated in fish oil- and hazelnut oil-fed rats, but rats fed all dietary oils showed maximal relaxation. Cholesterol supplementation reduced aortic maximal relaxation caused by acetylcholine. These results indicate that the type of dietary oil and cholesterol intake differentially raise plasma and liver lipid levels and modulate aortic smooth muscle response in the rat.

Fatty acid composition of microsomal phospholipids in rats fed different oils and antioxidant vitamins supplement 1

The aim of the study was to examine effects of feeding diets containing different oils and antioxidant vitamins supplementation on the fatty acid composition of hepatic microsomal phospholipids in the rat. Forty-eight male Sprague Dawley rats were fed for 20 days diets containing 15% corn, olive, fish, or hazelnut oil, without or with the addition of β-carotene (30 mg/kg) and dl-α-tocopherylacetate (500 mg/kg), n = 6 per group. Microsomal phospholipids of rats fed corn oil exhibited higher content of linoleic, arachidonic, and docosatetraenoic acids (P < 0.05). Compared with corn oil (control group), olive oil intake increased palmitic, oleic, and vaccenic acids in phosphatidylcholine and phosphatidylserine + phosphatidylinositol, and vaccenic acid in phosphatidylethanolamine (P < 0.05). Fish oil intake increased the level of n-3 long-chain polyunsaturated fatty acids, and decreased arachidonic acid in all phospholipids (P < 0.05). On the other hand, the intake of hazelnut oil increased palmitoleic and oleic acids in phosphatidylcholine and phosphatidylethanolamine, and palmitoleic and vaccenic acids in phosphatidylserine + phosphatidylinositol (P < 0.05). Vitamin supplementation increased microsomal retinol in rats fed corn oil, and α-tocopherol in all groups fed vegetable oils (P < 0.05). The intake of vitamins supplement induced slight modifications of the fatty acid profile of microsomal phospholipids: a higher level of monounsaturated fatty acids, mainly oleic acid, with a reduction of polyunsaturated fatty acids was observed. These results manifest that the composition of microsomes is affected by the fatty acid profile of dietary oils and the intake of antioxidant vitamins supplements.

Influence of dietary lipids on fatty acid composition of nervous membranes (Myelin and synaptosomes) in rats

Abstract The present investigation was designed to evaluate the comparative effects of the intake of a mixture of vegetable oils (peanut and rapeseed oils, 1:1) or salmon oil on the fatty acid relative composition of myelin and synaptosomes in rats. On the second generation of Wistar rats fed semipurified diets containing 6% (wt/wt) vegetable oils mixture or salmon oil, brain membranes were isolated and the relative fatty acid composition was determinated by gas-liquid chromatography. The results demonstrate that the fatty acid composition of myelin and synaptosomes was influenced by dietary oils. Brain membranes of rats fed salmon oil exhibited significantly lower n−6/n−3 ratio in relation to animals fed vegetable oils mixture, with an increment in the n−3 content. The results also indicate that the degree of unsaturation of myelin and synaptosomes was kept constant, independently of the dietary fat source.

Cholestasis and biliary excretion of lipids induced by ethinylestradiol in rats fed polyunsaturated oils

Abstract Pharmacologic doses of ethinylestradiol are known to cause intrahepatic cholestasis in the rat. This is associated with a decrease in liver plasma membranes fluidity and a modification of the activity of membrane-bound enzymes related to bile flow. The intake of a diet containing highly polyunsaturated fats could modify the effects of estrogen, by increasing membranes fluidity due to their incorporation into structural phospholipids. To evaluate this action, rats were fed semipurified diets containing 17% corn (Zea mais) oil or rose hip (Rosa moschata Mill) seed oil during 20 days. Following this period, a group of animals were injected with ethinylestradiol during 5 days, while a control group and a pair fed group were included. Cholestasis was similar between corn and rose hip oils fed to ethinylestradiol treated rats. The biliary excretion of cholesterol was higher in rose hip oil compared to corn oil-fed control rats. Biliary cholesterol/phospholipids ratio decreased in estrogen-treated rats compared to control animals. Our results show that the intake of highly polyunsaturated fatty acids did not modify the expected action of ethinylestradiol in rats.