Quality changes after vacuum-based and conventional industrial cooking of kailan-hybrid broccoli throughout retail cold storage

The microbial, physical, sensory and nutritional quality changes of kailan-hybrid broccoli after industrial boiling, steaming, sous vide (SV), microwaving (MW), SV-MW and grilling throughout 45 days at 4 °C were studied. Boiling, SV-MW and MW induced the highest total colour differences. Boiling and steaming produced the greatest stem softening. Based on the overall sensory quality, the commercial life was established in 45 days, except grilling (14 days) and SV (21 days). Apparently, cooking increased the total phenolic content up to 2.0 and 1.7-fold for grilling and MW, respectively, owing to a better extraction. SV-MW, SV and MW produced the highest total antioxidant capacity increases around 5.4-4.7-fold, contrary to the low enhancements of boiling and grilling (2.9-fold). The best chlorophylls retention was attained by boiling. The total carotenoids content was enhanced up to 1.5-2-fold. Conclusively, these treatments generally showed an excellent microbial reduction and nutritional quality, which, in some cases, was enhanced after 45 days.

► Shelf life was 45 days at 4 °C, except grilled and sous vide (14 and 21 days). ► The apparent increase in total polyphenols content is due to a better extraction. ► Similarly, the increase in total carotenoids content is due to a better extraction. ► However, the antioxidant capacity was enhanced by the heat treatments. ► Boiling achieved the best chlorophyll retention and sous vide the lowest.