Combined Effect of UV-C and Ozone on Bioactive Compounds and Microbiological Quality of Fresh-Cut Rocket Leaves

Abstract

The separate application of UV-C (25 kJ/m 2 , 380 s) and O 3 gaseous (2.5 mg/L for 10 min) treatments and of their combination (25 kJ/m 2 UV-C with 2.5 mg/L O 3 ) were studied to evaluate the effect of combined treatments of UV-C and O 3 on microbial counts, bioactive profile and sensory changes of fresh-cut rocket leaves throughout shelf life to determine whether these treatment have additive or synergistic. The separate application of UV-C and O 3 and of their combination UV-C + O 3 did not affect the sensorial quality, total chlorophyll contents, phenolic compound nor antioxidant capacity of fresh-cut rocket leaves. However, these treatments controlled better the growth of epiphytic microbes than untreated samples. The UV-C treatment had better effect at reducing microorganisms present and not significant differences were found as to the combined treatment. Therefore, applying the combined treatment UV-C + O 3 had neither synergistic nor additive effect in the extension of the fresh-cut rocket leaves shelf life.

Biodegradable Food Packaging of Wild Rocket (Diplotaxis tenuifolia L. [DC.]) and Sea Fennel (Crithmum maritimum L.) Grown in a Cascade Cropping System for Short Food Supply Chain

“…Before washing, microbial load was between 1.7-2.3 and 6.0-6.4 log CFU g −1 for total mesophilic aerobic bacteria; between 0.9-1.5 and non-detected log CFU g −1 for psychrophilic; and between 0.3-1.3 and 4.3-6.2 log CFU g −1 for yeasts and moulds for wild rocket and sea fennel, respectively, while Enterobacteriaceae were not detected in any vegetable or in any treatment (data not shown) (Figure 2). Initial values of microbial counts for wild rocket before disinfection were low and typical for soilless cultivated vegetables when compared with standard cultivation [37] except for psychrophiles, and with lower values when compared with sea fennel. Washing with NaClO was highly effective for decreasing counts to undetectable levels in wild rocket.…”