Effect of refrigerated storage on the bioactive compounds and microbial quality of Brassica oleraceae sprouts

Abstract

Brassica sprouts are a healthy and convenient food product. Due to a great number of species and varieties, the knowledge about the bioactive composition and stability of the quality during storage of different Brassica oleracea sprouts is still scarce. In this work, the glucosinolate and phenolic profile of four varieties of B. oleracea sprouts (red cabbage, broccoli, Galega kale and Penca cabbage) grown under different light conditions was monitored during 12 days of storage (at 4°C). Their microbial quality was assessed by monitoring the microbial load of mesophilic bacteria, total coliforms, yeasts and molds and presence of Salmonella. The presence of biogenic amines was also monitored to guaranty the safety of this product. As expected, the content of bioactive compounds suffered significant (p<0.05) changes during storage, especially after 7 days of storage. The two Portuguese varieties (Galega kale and Penca cabbage) had a high content of aliphatic glucosinolates (as glucoraphanin and sinigrin), having the sprouts grown under darkness a more stable content of these compounds. The phenolic profile was characterized by a prevalence of hydroxycinnamic acids derivatives, and in sprouts grown without light in particular. Sprouts did not show any contamination by Salmonella and were considered as microbiologically safe during the studied period.