Brassica napus (canola) seed is a rich source of phytosterols, tocopherols and carotenoids, which all have recognized health benefits, although these are reduced or lost during crude oil refinement. Many studies are now outdated, so new research to monitor bioactive retention through current processing techniques is warranted. In this work, canola seed, in-process seed, and oil samples were collected from the major stages of five commercial canola oil processes. Analysis of phytosterols, tocopherols and carotenoids indicated seed pre-treatment enhanced bioactive concentrations in the crude oil. Although the bleaching step in each process eliminated all carotenoids, high concentrations of phytosterols and tocopherols remained in the refined oil across all processes, with losses notably lower than those found in previous reports. Moreover, crude oil samples from a two-stage cold pressing process showed greatly enriched concentrations of tocopherols (+122%), sterols (+140%) and carotenoids (+217%). The results show that modern Australian canola oil processing retains high phytosterol and tocopherol concentrations and warrants further investigation into bioactive enrichment strategies. Given the growing interest in health-enhanced foods, this study provides opportunities for nutrition and health-enhanced oil products and the potential for adding value in the edible oil industry.
4 February 2023 in International Journal of Food Science and Technology
Summary: Whey protein hydrolysates are important food emulsifiers and bioactive ingredients. This study investigated the stability of whey protein isolate (WPI) bioactive peptide fraction nanoemulsions under representative food processing and storage conditions: pH (3–9), ion concentration (Na+, 0–200 mm and Ca2+, 0–15 mm), thermal treatment (30–90 °C) and freeze–thawing. Bioactive peptide fractions, UC–10 and UP–10, were obtained by ultrafiltration of chymotrypsin or pepsin WPI hydrolysates, respectively. The nanoemulsions produced with these fractions had droplet diameters of 177 ± 3.5 nm (UC–10) and 154 ± 1.6 nm (UP–10). Nanoemulsions destabilised at pH 3–5, around the isoelectric point of WPI proteins but were stable at higher pH values, 6–9. Nanoemulsion instability escalated above critical Na+ (25 mm) and Ca2+ (2.5 mm) concentrations, but Ca2+ accelerated droplet aggregation more strongly than Na+. Furthermore, nanoemulsions were moderately stable to heating and freeze–thawing. Overall, both WPI bioactive peptide‐stabilised nanoemulsions showed consistent stability to the processing conditions. This study expands on designing, producing and utilising nanoemulsions based on WPI bioactive peptides.
29 January 2010 in International Journal of Food Sciences and Nutrition
Changes in acidification and starch behaviour were investigated during co-fermentation of cassava and soybean into gari, an African fermented product. Non-volatile acidity, pH and starch content were evaluated using standard analytical methods. Starch breakdown and pasting characteristics were also analysed using a Brabender viscoamylograph. Fermentation caused significant variations in the pH, non-volatile acidity and starch concentration. The pH decreased with concomitant increases in non-volatile acidity during co-fermentation of the cassava dough. Soy fortification up to 20% caused only minimal effects on the pH, titratable acidity and starch content during the fermentation period. Starch content decreased from 69.8% to 60.4% within the 48 h fermentation time in the unfortified sample, with similar trends noted at all levels of fortification. Starch pasting characteristics showed varied trends in pasting temperature, peak viscosity, viscosity at 95°C and at 50°C-hold with increasing fermentation time and soybean concentration. Cassava could be co-fermented with soybean up to 20% concentration during gari processing without significant effect on its process and product quality characteristics.