【作者】 于见亮；

【导师】 李开雄；

【作者基本信息】 石河子大学 ， 农产品加工及贮藏工程， 2008， 硕士

【摘要】 本课题对导致新疆塔城地区冷却羊肉腐败的主要微生物进行了分离与初步鉴定,并对其初始菌相的构成及菌相在贮存过程中的变化规律进行了研究,同时以冷却羊肉中优势腐败菌为目标菌,研究乳酸链球菌素(nisin)、茶多酚、壳聚糖、丁香、桂皮五种天然防腐剂的抑菌性能,采用响应曲面法对其进行复配和优化,确定复合天然防腐剂最佳配比,并研究了该复合天然防腐剂对冷却羊肉的保鲜效果。主要结论如下:1、从新疆塔城地区冷却羊肉中分离和初步鉴定出典型腐败菌株11株,有7株鉴定到种,其中肠杆菌科3株,分别是拉氏西地西菌、弗氏埃希氏菌、产气肠杆菌;乳杆菌2株,分别是植物乳杆菌和鼠李糖乳杆菌;假单胞菌属2株,分别是荧光假单胞菌(天然变种Ⅱ)和类产碱假单胞菌;4株鉴定到属,热死环丝菌2株、葡萄球菌属和酵母菌各1株。2、假单胞菌属、乳酸菌、葡萄球菌、肠杆菌科、热死环丝菌是构成新疆塔城地区冷却羊肉初始菌相的主要微生物。4℃真空冷藏条件下,乳酸菌所占细菌总数的比例呈快速上升趋势,并逐步成为绝对优势菌群;肠杆菌科和热死环丝菌增长缓慢,假单胞菌的含量明显下降,但仍占较大比例;葡萄球菌的菌数明显减少。3、单因素抑菌试验表明,茶多酚、壳聚糖、乳酸链球菌素、丁香和桂皮浸提液对冷却羊肉中主要腐败菌具有不同的抑制作用。应用响应曲面试验设计对这5种天然防腐剂进行优化配比,通过多元回归分析获得多元回归方程,经失拟项和决定系数检验,证明预测模型可靠性较好。结果表明茶多酚与丁香、桂皮浸提液之间存在显著的交互效应(P<0.01),它们的抑菌效果依次为茶多酚>壳聚糖>丁香、桂皮浸提液>nisin。复合防腐剂最佳配比分别是nisin0.117%,茶多酚0.243%,壳聚糖1.16%,丁香、桂皮浸提液4.19%。4、用复合天然保鲜液浸泡处理冷却羊肉和刷包装袋内膜处理羊肉在(3±1)℃真空包装条件下的货架期分别为16天和11天,这两种处理分别比对照组延长货架期9天和4天。更多还原

【Abstract】 In this thesis, the dominant spoilage microorganisms of chilled mutton made in Tacheng district were isolated and identified.The composition of the initial microflora and changes of microflora during storage under vacuum were analyzed. The antibacterial activities of nisin, tea polyphenols,chitosan, the extraction of clove and cinnamon were compared and the optimum combinations of the five natural preservatives for the preservation of chilled mutton were researched by using the response surface methodology.The effects of the optimum combination of the five natural preservatives for the preservation of chilled mutton were also researched. The results included several parts as follows:1. Eleven strains dominant microorganisms of chilled mutton made in Tacheng were isolated and preliminary identified. They were Cedecea lapagei, E. fergusonii, Enterobacter aerogenes, L. plantarum, L. rhamnosus, P. fluorescens, P. paseudoalaligenes, two strains Brochothrix thermosphactas ,one strain Staphylococcus and one strain Yeast.2. Pseudomonas, Lactobacillus, Staphylococcus, Enterobacteriaceae and Brochothrix thermosphacta were the dominant microorganisms in the chilled mutton made in Tacheng district. Lactobacillus increased progressively and became predominant microflora during storage in 4℃under vacuum; Enterobacteriaceae and Brochothrix thermosphacta increased slowly, but Staphylococcus decreased gradually.3. Effective antibacterial effects of nisin, tea polyphenols,chitosan, the extraction of clove and cinnamon were found based on single factor experiments.The optimization of the combination of the five natural preservatives was focused on the preservation of chilled mutton by Response surface methodology. Quadratic polynomial equation was obtained through multiple regression analysis. The predicted model was proven adequate when tested by the lack of fit and coefficient of determination (R2). The results revealed that antibacterial effects of tea polyphenols were more positive than that of chitosan, the extraction of clove and cinnamon, and nisin. There was a significant synergy between tea polyphenols and the extraction of clove and cinnamon (p <0.01). The results of regression analysis showed that the optimum proportion of the combination of nisin, tea polyphenols, chitosan and the extraction of clove and cinnamon was 0.117%, 0.243%, 1.16% and 4.19% respectively.4. The effects of the optimum combination of the five natural preservatives for the preservation of chilled mutton were evaluated. The results revealed that shelf life of vacuum packaged chilled mutton, stored at (3±1)℃and treated using the compound natural preservatives solution by soaking treatment and brushing packaging bag treatment, were 16 days and 11days respectively, while the contrast could preserve 7 days. The compound natural preservatives were proved effective for the preservation of chilled mutton.更多还原