Effects of orange winemaking variables on antioxidant activity and bioactive compounds

AbstractAscorbic acid, carotenoids and polyphenols stand out among the orange juice natural antioxidants. The winemaking process affects their bioavailability and bioactivity. Antioxidant activities (AA) were estimated in different process conditions to asses those properties. The AA and their correlation with ascorbic acid, total phenolics and carotenoids content were calculated. The variables and levels analyzed were: pasteurized and natural must (PJ and NJ), pH 3.5 and 4.0 and fermentation temperatures at 10°C and 20°C. Statistically significant differences (α=0.05) were found among bioactive compounds concentrations. Antioxidant compounds concentration was higher in raw material than in orange wine. Juice pasteurization caused the major losses while subsequent vinification affects them to a lesser extent. Highest antioxidants retention was measured in wines from JN fermented at pH 3.5 and 10 °C (JN-3.5-10) followed by wines from JP and fermented at the same conditions (JP-3.5-10). AA determined by DPPH showed a positive and close correlation with FRAP, while ABTS showed a low correlation with former assays. Juice pasteurization process and fermentation temperature influenced bioactive compound reduction which correlates with the AA variation.

Effect of different stress conditions on the stability of quercetin-loaded lipid microparticles produced with babacu ( Orbignya speciosa ) oil: evaluation of their potential use in food applications

Lipid micro and nanoparticles have been extensively investigated as carriers for hydrophobic bioactives in food systems because they can simultaneously increase the dispersibility of these lipophilic substances and help improve their bioavailability. In this study, lipid microparticles of babacu oil and denatured whey protein isolate were produced, and their ability to protect quercetin against degradation was evaluated over 30 days of storage. Additionally, the lipid microparticles were subjected to the typical stress conditions of food processing (presence of sucrose, salt, and thermal stresses), and their physico-chemical stability was monitored. The data show that the babacu microparticles efficiently avoided the oxidation of quercetin because 85% of the initial amount of the flavonoid was preserved after 30 days. The particles were notably stable up to a temperature of 70 °C for 10 minutes at relatively high concentrations of salt and sucrose. The type of stirring (mechanical or magnetic) also strongly affected the stability of the dispersions.