Effect of steaming and sous vide processing on the total phenolic content, vitamin C and antioxidant potential of the genus Brassica

Abstract

This study evaluated the effect of thermal processing on the antioxidant potential, vitamin C, and total phenoliccontent of various parts, including edible co-products, of severalBrassicavegetables. Overall, no significantdifferences were observed in the lightness of the samples after thermal processing, although the greenness andh0values of the samples were affected (p< 0.05). Similar profiles were observed for the leaves, inflorescences, andstalks of the studied crucifers. The stalks of some varieties, including broccoli cv. Parthenon and kale cv. Crispa,showed higher vitamin C contents compared to that of their inflorescences (p< 0.05). Both steaming andsous-videprocessing significantly reduced the vitamin C and total phenolic content of the crucifers studied(p< 0.05). The results demonstrated thatBrassicaco-products contain valuable and health-promoting sub-stances that can be lost during thermal processing; this must be considered when calculating the dietary intake ofthese compounds from cooked vegetables.Industrial relevance:The results obtained herein suggest thatBrassicastalks are as nutritious and healthy as theflorets or leaves, which are more commonly consumed as part of our diet. In addition, this study demonstratesthe potential ofBrassicaco-products as a resource for the extraction of antioxidant compounds and opens newcommercial opportunities for their use beyond their current applications in the food industry. The results alsohighlight that these compounds are mostly lost during processing and that the processing conditions should becarefully optimized to minimize their degradation.