The application of subcritical water treatments to valorize certain plant-based agricultural waste is reviewed with a focus on the extraction of phenolic compounds and the production of oligosaccharides. Phenolic compounds can be efficiently extracted by raising the temperature to an optimal value; however, many phenolic compounds are decomposed at high temperatures. Nevertheless, some degradation products of phenolic compounds also show high antioxidant activity. The conversion of polysaccharides from plant-based agricultural waste into smaller polysaccharides or oligosaccharides may be an alternative method for the preparation of ingredients with health benefits.
Thermal aggregation of whey proteins has been the topic of extensive research work. Blocking of disulfide bonds is quite important for the understanding of aggregation mechanism and, specifically, the role of disulfide interchange reaction. In this work, chemical blocking of disulfide bonds by Dithiothreitol (DTT) was compared with physical blocking (at pH 3), when molecules at both conditions were subjected to thermal aggregation at 80℃ for 1 hr. Results indicate differences in molecular properties at the two aggregation conditions. Aggregates that were formed via thermal treatment in the presence of chemical blocking reagents (DTT) produced larger aggregates of spherical, collapsed macromolecules. However, aggregate formed when disulfide bonds were physically blocked - at pH 3- produced smaller aggregates of spherical, wormlike macromolecules.
Acyl ascorbates are ascorbic acid derivatives, which are possibly used as antioxidants in oil systems. The effect of stearoyl ascorbate at different amounts in model cookies containing iron, in terms of lipid autoxidation, was studied. A kinetic model describing the formation and degradation of lipid hydroperoxides (expressed as peroxide value) was developed to compare the antioxidant abilities. Results showed that addition of 25 mg of stearoyl ascorbate to 250 μL of soybean oil resulted in the longest induction time among the tested systems. Additionally, stearoyl ascorbate showed much higher antioxidant ability compared to palmitoyl and behenoyl ascorbates.