真空包装年糕保鲜剂研究

Study on preservatives of vacuum-packed Chinese New Year rice cake

为了有效地抑制真空包装水磨年糕腐败微生物的生长,延长其保质期,首先分离并鉴定真空包装年糕中的腐败微生物;针对该菌种选取相应的保鲜剂,并通过测定单体和复配保鲜剂的最低抑制质量浓度和协同增效作用,确定适用于真空包装年糕的复配保鲜剂.结果表明:导致真空包装年糕腐败的微生物主要为芽孢杆菌属(Bacillus);针对该类微生物的适宜复配保鲜剂配方为w(单甘油月桂酸酯)∶w(柠檬酸)∶w(脱氢醋酸钠)=1∶1∶1;经过实验室和工厂大试检测表明,添加1.5g/kg该复配物,同时在95℃灭菌60min,能将真空包装水磨年糕的保质期由原来在37℃下7d左右提高到20d.说明用该配方不仅能有效地延长年糕的保质期,且其品质不会受到影响;单甘油月桂酸酯还可降低年糕的硬度.

Water milled Chinese New Year rice cake（NYRC） is a kind of delicious and nutritive Chinese traditional food. But the short shelf life of the NYRC restricts its industrialization development. The purpose of the study is to inhibit the growth of spoilage microorganisms effectively and to extend the shelf life of the vacuum-packed NYRC. There were four main steps： 1） the spoilage microorganisms were separated and characterized from vacuum-packed NYRC. 2） Six commonly used antibacterial agents were chosen against the spoilage microorganisms, and the minimum inhibitory concentrations （MIC） were determined. 3） The synergistic effects between glycerol monolaurate （GML） and other preservatives were measured. 4） In order to investigate application effect of chosen food preservatives, lab and factory testes were taken in NYRC product. The moisture, hardness and colour （L value） of the vacuum-packed NYRC were determined. The main results were as follows： 1） The spoilage microorganisms which led to corruption of vacuum-packed NYRC were two kinds of Bacillus. 2） Among the tested preservatives, GML had the lowest MIC which was 32 μg/mL. 3） There was synergistic effect of GML and sodium dehydroacetate, and the fractional inhibitory concentration index （FICI） was 0. 531. The compound preservative made up of GML, citric acid and sodium dehydroacetate at the mass ratio of 1 ： 1 ： 1 was selected against the Bacillus. 4） Adding the selected compound preservative of 1.5g/kg could extend the shelf life from about 7 d to 20 d at 37 ℃. The compound preservative not only had no adverse effect on the moisture and color of NYRC, but also could reduce the hardness efficiently. In NYRC products, the compound preservative shows significantly better effect than the monomer GML. In addition, while prolonging the shelf life of the vacuum-packed NYRC, the compound preservative had no adverse effect on its quality.