Recovery and concentration of antioxidants from winery wastes.

Grape and wine byproducts have been extensively studied for the recovery of phenolic compounds with antioxidant activity and a variety of biological actions. The selective recovery and concentration of the phenolic compounds from the liquid phase separated from further diluted winery wastes has been proposed. Adsorption onto non ionic polymeric resins and further desorption with ethanolic solutions was studied. Several commercial food grade resins were screened with the aim of selecting the most suited for the practical recovery of phenolic compounds with radical scavenging activity. Under the optimized desorption conditions (using Sepabeads SP207 or Diaion HP20 as adsorbents and eluting with 96% ethanol at 50 °C) a powdered yellow-light brown product with 50% phenolic content, expressed as gallic acid equivalents, was obtained. The radical scavenging capacity of one gram of product was equivalent to 2-3 g of Trolox.

Effects of calf diet, antioxidants, packaging type and storage time on beef steak storage.

The effect of basal dietary supplemented with vegetable oils plus vitamin E (sunflower, soybean, linseed and a basal diet control), type of packaging (MAP or vacuum), addition of natural antioxidant (grape seed, rosemary) and storage time (0, 7, 14 and 21 days) on lipid oxidation, color stability, vitamin E content, and total aerobic bacterial counts in steaks of Longissimus thoracis was studied. The triple interaction diet × time × packaging affected oxidative stability, redness and yellowness of the meat. TBARS values did not increase with time in vacuum-packaged samples for all dietary treatments. However, samples from MAP and control showed the highest TBARS values after 21 days of storage (0.72 mg MDA/kg of meat, P<0.05). Both exogenous antioxidant extracts and MAP maintained low total aerobic counts in steaks until the 21st day. Calves should be fed a diet supplemented with L-VE, stored in MAP and treated with grape seed extract to extend the shelf life of their meat.

Processing of Rosa rubiginosa: extraction of oil and antioxidant substances.

In this work, a study about the effect of various operational conditions on the quantity of oil and soluble solids capable of being extracted from rosa mosqueta rosehip seeds is undertaken. Both the particle sizes assayed (0.6mm, 0.6-1mm, and 1-2mm) and the solvent-to-solid ratios (15:1, 25:1, and 50:1) showed a remarkable influence on the extraction efficiency. Extracted substances obtained by using the minor particle size or the maximum solvent-to-solid ratio doubled, at least, those attained by working under any other conditions. A major weight of kinetics upon equilibrium factors can be inferred from the short extraction times and high effective diffusivity values (being the lower one 1.97x10(-11)m(2)s(-1)) assessed for any condition. The antioxidant power of extracts was evaluated by ability to scavenge the DPPH radical. Results noteworthy depended on the solvent used to extract; whilst an approximately 80% DPPH inhibition percentage was reached in ethanol extracts, values of 52.2% or 41% were found in methanol and aqueous extracts, respectively. Even so, antioxidant capacity of Rosa rubiginosa extracts was much higher than that reported for other agricultural matrixes.

Tissue accretion and milk content of docosahexaenoic acid in female rats after supplementation with different docosahexaenoic acid sources.

BACKGROUND: Docosahexaenoic acid (DHA) is highly concentrated in the mammalian nervous and visual system. The fatty acid, which is required by the fetus and the newborn, is supplied by the mother from their tissue reservoirs. It has been suggested that mother's supplementation with DHA during pregnancy and even before pregnancy. Different sources of DHA are available for supplementation such as: single-cell algae triglycerides (TG), egg's yolk phospholipids (PL), DHA ethyl esther (EE), and sn-2 DHA monoacylglyceride (MG). We evaluated comparatively the effectiveness of these different DHA sources to produce tissue DHA accretion and to increase milk DHA content. METHODS: Female Wistar rats fed a diet which provided no DHA, were daily supplemented by 40 days before mating (BM) and during the pregnancy with either TG, PL, EE, or MG to an amount which provided 8 mg/kg b.w. of DHA. Samples of blood plasma, erythrocytes, hepatic and adipose tissue were obtained from rats at the BM condition and after the delivery (AD), and milk samples were also obtained from the gastric content of the pups nursed by the rats at day 3, 11 and 20 of suckling. Samples were processed to assess DHA and arachidonic acid (AA) content by gas-chromatography. RESULTS: TG, PL, EE, and MG supplementation produced a similar intestinal absorption of DHA as estimated from the plasma DHA at the BM condition. However, PL and MG supplementation produced a higher accretion of DHA into erythrocytes, hepatic, and adipose tissue than TG and EE supplementation at the BM condition. AA content was not modified by the different supplementing oils. A reduction of the DHA content of plasma, erythrocytes, hepatic and adipose tissue at the AD condition was observed, and a reduction of AA for the hepatic and adipose tissues was also observed, suggesting the importance of these tissues as DHA and AA reservoirs. Milk secretion from PL and MG supplemented rats showed a higher DHA content than secretion from TG- and EE-supplemented rats. CONCLUSIONS: We conclude that PL and MG supplementation provides higher tissue DHA accretion and higher milk DHA content than TG and EE supplementation. However, we were not able to visualize the comparative advantages derived from PL vs. MG supplementation.

Effect of solvent, temperature, and solvent-to-solid ratio on the total phenolic content and antiradical activity of extracts from different components of grape pomace.

Grape byproducts were subjected to an extraction process under various different experimental conditions (namely, solvent type, temperature, solvent-to-solid ratio, time contact, and raw material) in order to study the effect of these conditions on the yield of phenolic compounds and the corresponding antiradical activity of extracts. Although the order of decreasing capacity to extract soluble materials was ethanol > methanol > water, methanol was the most selective for extracting phenolic compounds. Temperature and solvent-to-solid ratio were found to have a critical role in extraction efficiency; values of 50 degrees C (between 25 and 50 degrees C) and 1:1 (between 1:1 and 5:1) maximized the antiradical activity of phenolic extracts. In addition, extracts from grape samples previously subjected to distillation reached higher antiradical values in comparison to those coming directly from pressing; in both cases, seed extracts showed better results than those of stem when ethanol or water was employed, whereas the opposite occurred in the case of methanol. These differences were attributed to the different phenolic compositions of the considered fractions.