Neutral and acidic electrolysed water kept microbial quality and health promoting compounds of fresh-cut broccoli throughout shelf life

Abstract

Abstract The effect of neutral (NEW) and acidic (AEW) electrolysed water (EW) sanitising treatments (both with 70 and 100 mg L− 1 free chlorine) on the bioactive profile and microbial quality of fresh-cut ‘Parthenon’ and kailan-hybrid broccoli throughout 19 days at 5 °C was studied. Disinfection with 100 mg L− 1 NaClO was used as control. EW treatments, particularly NEW100, achieved the best microbial reductions after shelf life, being a promising alternative to chlorine in both broccoli cvs. In addition, all EW-treated samples, regardless of pH or free chlorine levels, showed up to 30% higher total phenolic (TP) contents than chlorine-disinfected ones, which reported values of 556.5 (kailan-hybrid) and 444.0 mg gallic acid kg− 1 fw (‘Parthenon’). The best correlation between total antioxidant capacity (TAC) and TP was attained by the FRAP method with an R2 = 0.65–0.68. Throughout shelf life, TP and FRAP-analysed TAC kept stable values, or even slightly increased. On the processing day, the APX, GPX, CAT and SOD activities of chlorine-treated samples were 105.6/115.4, 3783.2/6791.0, 359.0/433.0 and 798.0/1489.0 U g− 1 protein for kailan-hybrid/‘Parthenon’, respectively. SOD and CAT activities of EW-treated samples were 13–46% lower than those of the NaOCl-disinfected samples. Myrosinase activity in kailan-hybrid was 1.5-fold higher than in ‘Parthenon’. Generally, the myrosinase activity in EW-disinfected samples was kept during shelf life, while in NaOCl-sanitised samples decreased. In general, both EW treatments seem to be promising techniques for keeping good microbial quality in both fresh-cut broccoli cvs. Furthermore, this alternative water sanitising technique showed better bioactive compounds retention in broccoli. Industrial relevance The present study shows for the first time the effects of neutral and acidic electrolyzed water treatments (with two different free Cl concentrations) on the bioactive content (antioxidant capacity, phenolics, and antioxidant enzymes) and microbial quality of two different broccoli cvs. (kailan-hybrid and ‘Parthenon’) throughout 19 days at 5 °C. These results will be useful for the fresh-cut (FC) vegetable industry since the optimum parameters for the EW treatments of two FC broccoli cvs. are hereby provided in order to accomplish the safety and microbial quality aspects. Furthermore, data regarding to enhancing of health-promoting properties of these FC broccoli cvs. after EW treatments are shown. In that way, the FC industries may supply to the consumers a FC vegetable that meet the safety aspects and with improved health-promoting properties.