【作者】 郭亚萍；

【导师】 靳烨； 孙宝忠；

【作者基本信息】 内蒙古农业大学 ， 农产品加工及贮藏工程， 2005， 硕士

【摘要】 采用 0～5kGy 的不同剂量的 60Co-γ射线对鲜熟水饺进行了辐照处理,研究了辐照及贮存对鲜熟水饺中细菌总数、大肠菌群、感官品质、理化特性、营养价值等安全与品质性状的影响规律与辐照保鲜鲜熟水饺技术工艺。结果表明: 1 0～4℃冷鲜贮存水饺,细菌总数、大肠菌群、TBA 值、过氧化值、挥发性盐基氮、酸度等随贮存期延长呈现增长趋势,pH 值、水分含量、水分活度、色泽和香气等感官指标均呈现下降趋势,鲜熟水饺冷鲜贮存货架期为 7 天。 2 辐照能有效降低鲜熟水饺细菌总数和大肠菌群数量,鲜熟水饺中细菌总数和大肠菌群的 D10值分别为 2.04 kGy 和 1.25kGy,D 值分别为 4.00 kGy 和 2.00kGy;0～5kGy 辐照鲜熟水饺 TBA 值随辐照剂量增加而增加,5kGy 辐照已使之超过国家行业标准限量要求;辐照鲜熟水饺过氧化值、挥发性盐基氮、色差 a 值、色差 b值存在随辐照剂量增加而增加的趋势、水分含量存在下降趋势,但变化未达到显著水平(p<0.05);对酸度、氨基酸态氮、水分活度、游离脂肪酸含量等其他理化指标没有显著影响;较高剂量辐照使产品感官质量降低,却都在可接受范围内; 4kGy 辐照使维生素 B1下降 31.94%,对维生素 E、蛋白、脂肪、氨基酸、不饱和脂肪酸含量无显著影响。 3 X-射线衍射图谱分析表明,1～5kGy 剂量辐照处理可明显降低水饺皮的相对衍射强度,3kGy 辐照水饺的相对衍射强度最低;背景线强度最大值的角度位置(2θ)有随辐照量增加而增加的趋势,辐照对水饺皮淀粉老化有一定的抑制作用。 4 0～4℃冷鲜贮存条件下,各辐照处理产品贮存过程中安全质量变化存在差异。未辐照处理产品贮存至 7 天时挥发性盐基氮含量超标,除 5kGy 辐照产品的 TBA 值在贮存前期超标外,其他各辐照处理产品各项安全质量指标在 21 天贮存期内均未超标;与对照样比,剂量越高,所分析指标变化越小;对照样只有 7天的货架期;2 和 3kGy 辐照在 14 天时感官评分值降至可接收值底限;4kGy 表现出最佳贮藏效果,可获得 21 天的货架期。 5 添加抗氧化剂能显著降低鲜熟水饺的 TBA 值,抑制了脂肪氧化。 本研究建议鲜熟水饺用 4.0kGy 辐照,可获得 21 天的货架期。更多还原

【Abstract】 The effects of irradiation and storage on the survival of total bacteria, E. coli, the sensory,nutritional and physicomical characteristics of the dumpling under chill state (0～4℃ ) were studied. The results showed as the followings: The total bacteria, E.coli, thiobarbituric acid reactive substances (TBA), POV, volatile basic nitrogen, and total acidity of dumpling showed a increasing tendency under chill state (0～4℃ ). The value of pH, Aw, moisture, color difference and sensory evaluation showed a tendency of decrease. The shelf life of boiled dumpling was 7 d under chill state. The total bacteria and E. coli of the treated boiled dumplings were decreased significantly by irradiation. The values of D10 and D for the total bacteria in boiled dumplings under chill state were 2.04 kGy and 4.00 kGy, the value of D10 and D for E. coli were 1.25 kGy and 2.00 kGy. TBAS were increased significantly and excessed the trade standard by 5 kGy γ-irradiation. However, the TBAS would be decreased with addition of antioxidants. Lipid peroxide,volatile basic nitrogen, “a” value of color and “b” value of color showed a tendency of increase, and moisture content and Aw showed a tendency of decrease, which did not achieve a significant level(p<0.05) by 1 to 5 kGy doses of γ-irradiation. Total acidity, amino acid nitrogen and free fatty acid showed no significant differences between treated and control samples. Sensory evaluation values were decreased and were all well within the acceptable level by 1 to 5 kGy doses of γ- irradiation. 4 kGy dose of γ-irradiation decreased content of vitamin B1 significantly and did not had a significant effect on the content of vitamin E, protein, fat, amino acid and unsaturate fatty acid. The results of x-ray diffract grams revealed that the relatively diffraction intensity tended to decrease and the diffraction angle (2θ) tended to increase with the increase of irradiation dose. γ- irradiation treatment restrained the degree of crystallinity of starch in dumpling’s skin. The dose of γ-irradiation had significant influences on shelf life of boiled dumplings under chill state. The value of volatile basic nitrogen of control sample excessed the trade standard after one week. The value of total acidity of control sample excessed the trade standard after four weeks.However ,except TBA of sample treated with 5 kGy excessed the trade standard after irradiation, other properties of treated sample were all well within the acceptable level throughout storage period. The shelf life of control sample was 7 days and the shelf life of 2 and 3 kGy irradiated samples were 14 days for its sensory quality decreased, and the shelf life of 4 kGy irradiated sample was 21 days. According to the research results, the suitable dose of γ-irradiation for the boiled dumpling under chilled state should be 4kGy and it may extend the shelf life of boiled dumpling from 7d to 21 d.更多还原