Microbial Decontamination of Mung Bean Sprouts Using Electrolyzed Water and Its Effects on The Physicochemical and Sensory Properties of The Sprouts

Abstract

Electrolyzed water (EW) was used to decrease the levels of microbial contaminants in commercial mung bean sprouts. High contamination levels of aerobic bacteria as well as yeasts and mold were observed in raw mung bean sprouts (on average 7.67 ± 0.22 and 7.70 ± 0.07 log CFU/g, respectively). Mung bean sprouts were treated with EW produced at varying flow rates of brine and deionized water streams. Acidic electrolyzed water (AEW) with a pH of 3.66 and a chlorine concentration of 230 mg/L exhibited the best performance in reducing the contaminant levels. Compared to untreated or tap water (TW)-treated sprouts, sensory qualities (appearance, color, and flavor) of AEW-treated mung bean sprouts were not significantly different (P > 0.05) for up to cumulative treatment time of 40 s. In addition, no significant (P > 0.05) alterations were observed in the levels of moisture content, reducing sugars content, and total phenolic contents of mung bean sprouts by AEW treatment during the same period. On the other hand, the 2,2-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of the sprouts was significantly improved following AEW treatment. In addition, compared with untreated or TW-treated samples, an improved shelf life was noted for AEW-treated (cumulative submerged time: 40 s) mung bean sprouts during storage at 4 and 25 °C. The research results can be applied to design AEW-based mung bean sprout sanitation system.