Polyphenols from guaraná after in vitro digestion: Evaluation of bioacessibility and inhibition of activity of carbohydrate-hydrolyzing enzymes.

Guaraná (Paullinia cupana) is a typical product from Amazon biota that exerts antioxidant capacity due to the presence of phenolic compounds, such as catechin, epicatechin and proanthocyanidins. The objective of this study was to evaluate the potential inhibitory activity of guaraná extracts, after digestion in vitro, on carbohydrates-metabolism enzymes and to assess the bioacessibility of guaraná polyphenols. The guaraná samples before and after enzymatic digestion, were compared for total phenolic content and phenolic profile. Furthermore, we investigated the uptake of polyphenols from guarana, using Caco-2 cells, and the effect of digested guaraná on carbohydrate metabolism enzymes. The amount of total phenolic compounds extracted from guaraná decreased after digestion in vitro, and native phenolics were not identified after cell permeation. On the other hand, polyphenols from guaraná were able to inhibit α-glucosidase and α-amylase activities. In conclusion, guaraná can be considered as a dietary source with anti-hyperglycemic potential.

Effect of natural antioxidant combinations on lipid oxidation in cooked chicken meat during refrigerated storage.

The effect of combinations of sage, oregano and honey on lipid oxidation in cooked chicken meat during refrigeration at 4°C for 96h was determined. Chicken samples (thigh and breast) were then separated into five groups: control; butylated hydroxytoluene; oregano+sage; oregano+sage+5%honey and oregano+sage+10%honey. Quantitative measurements of thiobarbituric acid reactive substances, conjugated dienes, hexanal, fatty acids, cholesterol and cholesterol oxides were used as indicators of lipid oxidation. Acceptability and preference were also evaluated. The effectiveness of the natural antioxidants for reducing the velocity of lipid oxidation in cooked chicken thigh and breast was demonstrated after 48 and 96h of refrigeration at 4°C. The treatments that presented the lowest hexanal values after 96h of refrigeration were oregano+sage+5%honey and oregano+sage+10%honey. Only traces of free cholesterol oxides were found (25-OH, 7-k, 7α-OH and 7ß-OH). The natural antioxidants protected cooked chicken meat from oxidation processes and resulted in great acceptability.

Biochemical pharmacology of functional foods and prevention of chronic diseases of aging.

The major mechanisms and consequences of free radicals in foods and biological systems that result in the occurrence of chronic diseases of aging (atherosclerosis, cataract, cancers, diabetes, neurological diseases, immune-inflammatory disorders) are described. The main antioxidant defense mechanisms from foods and cells and tissues are also reported. Many nutraceutical substances, with their respective beneficial actions (antioxidant, detoxifying, apoptotic actions) and effects, and most common food sources are also described. There are many options of foods to prevent cancer and chronic diseases, to improve life's quality in maturity.