超声-热处理鲜切莲藕保鲜效果的研究

Study on the Preservation Effect of Ultrasonic-heat Treating Fresh-cut Lotus Root

为探究超声-热(Heat+US)技术对鲜切莲藕的保鲜作用,将鲜切莲藕置于超声水浴(50℃,300 W超声处理9 min)进行预处理,后在贮藏期间测定莲藕的微生物污染情况,蛋白质、抗坏血酸、淀粉等主要营养物质含量以及总还原力。结果表明,采用超声-热处理,4℃下贮藏第9 d,鲜切莲藕的菌落总数和霉菌及酵母菌总数比对照分别下降了2和0.775 CFU/g(P<0.05);可溶性蛋白质和可溶性固形物含量均达到最高,分别为0.60 mg/g FW和5.88%,是对照组的1.13和1.02倍(P<0.05)。此外,鲜切莲藕中抗坏血酸、果胶、可滴定酸和淀粉的含量均高于对照组(P<0.05)。但该处理对可溶性糖含量的影响并不显著(P>0.05)。同时,鲜切莲藕总还原力也显著高于对照组(P<0.05)。用此方法能够延长鲜切莲藕的货架期,对鲜切生产具有指导意义。

In order to explore the regulation effect of ultrasonic-heat(Heat+US)technology on the preservation of fresh-cut lotus root,the fresh-cut lotus root was placed in an ultrasonic water bath(50℃,300 W ultrasonic treatment for 9 min)for pretreatment and storage,and the microorganisms,major nutrient content and total reducing power of lotus root were regularly measured.The results showed that the total number of colonies and the total number of molds and yeasts of fresh-cut lotus root decreased by 2 and 0.775 CFU/g,respectively,compared with the control on the 9th day of storage with Heat+US treatment(P<0.05);The contents of soluble protein and soluble solid matter were the highest,0.60 mg/g FW and 5.88%,respectively,which were 1.13 and 1.02 times that of the control group(P<0.05).In addition,the contents of ascorbic acid,pectin,titratable acid and starch in fresh-cut lotus root were higher than those in the control(P<0.05).However,the treatment had no significant effect on soluble sugar content(P>0.05);meanwhile,the total reducing power of fresh-cut lotus root was also significantly higher than that of the control group(P<0.05).This method can prolong the shelf life of fresh-cut lotus root and has a great significance for fresh-cut production.