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Treatment with low-concentration acidic electrolysed water combined with mild heat to sanitise fresh organic broccoli (Brassica oleracea)

Liu, Qin, Cedric Tan, Chih Shen, Yang, Hongshun, Wang, Shifei
Lebensmittel-Wissenschaft + [i.e. und] Technologie 2017 v.79 pp. 594-600
Brassica oleracea, Escherichia coli O157, Listeria monocytogenes, acidity, antioxidants, broccoli, chlorine, electrolyzed water, firmness, heat, heat treatment, microorganisms, organic foods, oxygen radical absorbance capacity, pathogens, pectins, product quality
The effects of low-concentration electrolysed water (LcEW) (4 mg/L free available chlorine) combined with mild heat on the safety and quality of fresh organic broccoli (Brassica oleracea) were evaluated. Treatment with LcEW combined with mild heat (50 °C) achieved the highest reduction in naturally occurring microorganisms and pathogens, including inoculated Escherichia coli O157:H7 and Listeria monocytogenes (P < 0.05). In terms of the antioxidant content of the treated broccoli, the total phenolic levels and ferric reducing antioxidant power remained unchanged; however, the oxygen radical absorbance capacity of the treated broccoli was higher than that of the untreated control. In addition, mild heat treatment resulted in an increase in firmness. The increased firmness was attributed to changes in the pectin structure, including the assembly and dynamics of pectin. The results revealed that mild heat induced an antiparallel orientation and spontaneous aggregation of the pectin chains. This study demonstrated that LcEW combined with mild heat treatment was effective to reduce microbial counts on fresh organic broccoli without compromising the product quality.