Study On Compound Biological Preservatives Application In Pickle Vegetables

Pickle vegetables are absolutely necessary food on the table in China. One of the main problems with pickle vegetables is how to prolong their shelf-life, and the main solution was to use preservatives. However, chemical preservatives which are widely used at present would more or less do harm to people's health, and biological preservatives usually had limited antibacterial spectrum. Therefore, it is very important to develop compound biological preservatives with wide range of antibacterial spectrum in which are used in the pickle vegetable industry.The effectof nisin, phytic acid,and natamycin on shelf-life extending of pickle vegetables was studied. The main conclusions of the experiments were as follows:Ten kinds of bacteria which were all bacilli were isolated from spoiled pickle vegetables, and both Gram-negatives and Gram-positives were five. Six kinds of mildew were isolated with three having Septa hypha and three havingNon-septa hypha; all kinds of the hypha were villous except a floc one; an oval budding microzyme was also isolated; no actinomycosis was found.The experiments of effect on bacteria of preservatives were done when the initial concentration solution bacteria was 103cfu/ml.The best antibacterial concentration was 1mg/ml nisin mixed with 1.5mg/ml phytic acid. The inhibitory effect of the best concentration of nisin and phytic acid used in other bacteria such as E.coli , Staphylococcus aureus from the spoiled pickle vegetables was also remarkable.The inhibitory effect of natamycin on mildew and microzyme inhibition was studied. When the initial concentration of spore suspension of mildew and microzyme solution were both 103cfu/ml, 0.5mg/ml natamycin could completely inhibit the growth of mildew and microzyme. At this concentration of natamycin, Aspergillus Niger and Aspergillus flavus Link were also inhibited.Nisin, phytic acid and natamycin were used as preservatives to inhibit microbe in pickle vegetables. It was found that the growth of microbes could be effectively inhibited with Nisin0.03g/kg, phytic acid 0.045 g/kg and Natamycin 0.008 g/kg and the pickle vegetables remained a good sensory quality. Also biological preservatives had better effect either on the inhibition of microbes or the sensory quality compared with chemical preservatives.After accounting the cost of biological preservatives used in this product, we found that the price was only aboutï¿¥0.07/kg and would not increase the price of the product greatly .Therefore, it is possible in apply this compound biological preservative to the pickle vegetable industry.