Microbiological and functional quality of ready-to-eat arugula as treated by combinations of UV-C and nonconventional modified atmospheres

Abstract

The industry of ready-to-eat vegetables is interested in developing environmentally friendly sanitization techniques such as the ultraviolet light (UV-C). The effect of UV-C (5, 10, 15, 20 and 25 kJ/m(-2)) and nonconventional modified atmospheres (MA) using helium, argon, nitrous oxide and high oxygen were evaluated on arugula leaves inoculated with Escherichia coli. According to preliminary tests, 10 kJ/m(-2) UV-C was the most effective in reducing E. coli. The combinations of UV-C (10 or 15 kJ/m(-2)) with the He or Ar-enriched atmospheres were selected. The UV-C factor significantly affected enterobacteria counts and the total antioxidant activity showed an increase on the second day, mostly for the 15 kJ/m(-2) dose combined either with He or Ar (1.28 and 1.31mg trolox equivalent/g (fw), respectively). UV-C was the determining factor on the effectivity of the combined treatments, delaying the microbial growth and preserving the functional quality of ready-to-eat-arugula.

PRACTICAL APPLICATIONS

There is increasing interest in developing environmentally friendly sanitization techniques as an alternative to chlorine-based washing systems. This study gives an insight with regard to the effect of UV-C light combined with nonconventional modified atmospheres on the microbiological, functional and sensory quality of ready-to-eat arugula. The results demonstrated that UV-C was the determining factor on the effectivity of the combined treatments delaying the microbial growth, preserving the functional and sensory quality of arugula. Therefore, data from this study may be useful for vegetable producers and manufacturers to consider the implementation of a low cost sanitization technology such as UV-C light for extending the shelf life and maintaining the overall quality of ready-to-eat leafy salads.