常压低温等离子体对黄瓜表面大肠杆菌杀菌效果及品质的影响

采用常压低温等离子体(Atmospheric Pressure Low-Temperature Plasma,APLTP)对鲜切黄瓜表面进行杀菌处理,研究APLTP对鲜切黄瓜表面大肠杆菌的杀菌效果。在单因素的实验基础上,利用响应面分析方法建立大肠杆菌杀菌率的二次项数学模型,利用模型对处理电压、处理时间和处理极距及其相互作用进行分析,并在最佳工艺条件下处理鲜切黄瓜,研究其品质的变化。结果表明:APLTP能有效杀死鲜切黄瓜表面的大肠杆菌,各因子对杀菌率的影响大小依次是处理电压处理极距处理时间,最佳工艺条件为处理电压170 V,处理时间5 min,处理极距2.5 cm,此时杀菌率高达99.65%,与预测值99.60%接近,提高了鲜切黄瓜食用安全性。APLTP处理前后黄瓜的水分含量、可溶性固形物、pH值、色泽、相对电导率、丙二醛及Vc含量变化均不显著(P0.05),较好的保持了黄瓜的水分、糖度、酸度和颜色,同时维持了细胞膜的通透性及抗氧化能力。

Effect of atmospheric pressure low temperature plasma on sterilization rate of escherichia coli on sliced cucumber surface and quality attributes

The surface of fresh cucumber was sterilized by atmospheric pressure low temperature plasma to study sterilization effect of atmospheric pressure low temperature plasma on Escherichia coli (E. coli) on the fresh sliced cucumber surface. On the basis of single factor test, a quadratic polynomial mathematical model for the sterilization rate of E.coli was established by response surface methodology to analyze the effects of processing voltage, time and pole distance, and their pairwise interactions, and the quality of cucumber was studied under the optimum conditions. The experimental results showed that E.coli on the fresh sliced cucumber surface could be effectively killed by atmospheric pressure low temperature plasma. Factors influencing the sterilization rate were in order as processing voltage>processing pole distance>processing time. The conditions were optimized as follows: processing voltage 170 V, processing time 5 min, processing pole distance 2.5 cm. the sterilization rate reached to 99.65% under these conditions, which closed to the predicted value of 99.60%, and improved the edible safety of fresh sliced cucumber. The factors, include water content, soluble solids, pH value, color, relative conductivity, malondialdehyde and Vc content of cucumber, were not significantly changed (P>0.05). The fresh sliced cucumber remained the moisture, sugar, acidity and color, as well as the cell membrane permeability and antioxidant capacity.