Red cabbage washing with acidic electrolysed water: effects on microbial quality and physicochemical properties

Abstract

The effects of acidic electrolysed water (AEW) as ‘green’ technology on the microbiological and physicochemical properties of fresh-cut red cabbages were studied. Fresh-cut red cabbages and artificially inoculated red cabbages with Salmonella typhimurium DT104 were washed with distilled water (DW) and different available chlorine concentrations (ACC) of AEW for different times. AEW treatments significantly reduced the populations of native aerobic bacteria, molds, and yeasts, and artificially inoculated S. typhimurium DT104 compared with the DW-treated and untreated red cabbage samples. The effectiveness of AEW treatments was greatly enhanced with increasing ACC and treatment times. S. typhimurium DT104 were not detected in the washing water that were collected after the red cabbages treated by AEW. The surface colour, pH, and total phenolic contents did not significantly change when the red cabbages were washed with DW and AEW containing 100 mg/L available chlorine for 3 min. The anthocyanin contents and antioxidant activities of red cabbage were significantly reduced by 18.5 per cent for cyanidin, 22.1 per cent for pelargonidin, and 11.2 per cent for 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, however, the impacts on the nutritional benefits of red cabbage were considered as limited and acceptable. The optimal process condition of AEW for washing red cabbage was 100 mg/L ACC for 3 min. In these conditions, most of the native microflora were inactivated, and artificially inoculated S. typhimurium DT104 on the red cabbage were reduced by 40.2 per cent [3.67 log CFU/g (log10 colony-forming units per gram)] and with minimal losses of nutrients and antioxidant activity, as well as no requirement of decontamination treatment on the washing water after AEW treatment.