열수 마이크로버블 병용 세척이 절단 양상추의 품질에 미치는 영향

Abstract

The effects of different washing techniques, including the combined use of heated water and microbubbles water, on fresh-cut lettuce leaves (Lactuca sative var, capitata) were examined. The outer leaves were removed from the lettuce and cut into squares with dimensions of approximately 1–2 cm. The lettuce leaf samples were then washed with either tap water (Tap), microbubbles water (MB, Contains 70% or more of microbubbles with a diameter of 10μm or less), heated water (HWT, 40°C, 45°C or 50°C), or heated microbubbles water (HWT+MB, 40°C, 45°C or 50°C) for 1 min. After washing, the microbiological properties (i.e., total viable bacteria, coliform and fungi) and quality of the samples were measured. The total viable bacteria level of the HWT-50°C sample was <1 log CFU/g, representing the most effective washing technique, although the freshness decreased rapidly during storage. In addition, HWT+MB-40°C treatment was less effective in reducing the microbiological levels, although the decay rate was maintained at 0% for the initial 2 d of storage, and showed the lowest value of 11% after 6 d. Furthermore, the decay rate for the sample treated with MB was <30% after 10 d, and a similar result was obtained for the HWT+MB-40°C sample. It was apparent that a combined heat and microbubbles treatment, and in particular at a temperature of 40°C, was effective for maintaining the freshness and quality of fresh-cut lettuce during storage.