壳寡糖对冷鲜牛肉保鲜效果的影响

Effects of chitosan oligosaccharide on preservation of cold fresh beef

以冷鲜牛肉为研究对象,采用不同质量浓度的壳寡糖（0、0.04、0.06、0.08 g/100 m L）对冷鲜牛肉处理后真空包装,在（0~4）℃的条件下贮藏30 d,每隔5 d取样测定牛肉的挥发性盐基氮（TVB-N）值、肉糜脂肪氧化程度（TBARS）值、高铁肌红蛋白值（met Mb%）、色差（L＊、a＊和b＊）、质构（硬度、弹性、黏性）的理化指标以及菌落总数、大肠杆菌的微生物指标。结果表明：冷鲜牛肉的TVB-N值、TBARS值、met Mb%、硬度以及菌落总数和大肠杆菌数都随贮藏时间延长而呈现增加的趋势,L＊、a＊和b＊值、弹性和黏度值一直降低。经壳寡糖处理过的实验组各项指标相对空白对照组变化较为缓慢,且当壳寡糖质量浓度为0.06 g/100 m L时,保鲜效果最佳。在第20天时,0.06 g/100 m L壳寡糖处理的冷鲜牛肉的挥发性盐基氮（TVB-N）值为17.47 mg/100 g、菌落总数的值为5.18 lg（CFU/g）、大肠杆菌的值为5.35 lg（CFU/g）,均未超出国家标准,货架期由原来的10 d延长至20 d,而且使牛肉的色泽与营养在更长的保存时间内保持不变。

The objective of the work was to investigate the effect of chitosan oligosacchar on the quality of cold fresh beef. Cold fresh beef was treated with different concentrations of chitosan oligosacchar（ 0,0. 04,0. 06 and0. 08 g /100 m L） and subsequently stored 0-4 ℃ for 30 days. Total volatile basic nitrogen（ TVB-N） value,meat fat oxidation degree（ TBARS） value,met Mb % value,color and texture characteristics,and the total viable count（ TVC） and Escherichia coli count of the microbiological index were tested on the treated and the control samples at five-day intervals during the storage. Results showed that TVB-N,TBARS,met Mb %,hardness,TVC and Escherichia coli count of cold fresh beef presented an increasing trend with the extension of storage time. At the same time,L＊,a＊and b＊value,elasticity and viscosity decreased gradually. All the tested parameters changed more slowly in the experimental groups than in the control group. Chitosan oligosacchar at 0. 06 g /100 m L was the most effective. At the 20 th days,TVB-N value was 17. 47 mg /100 g,the total viable count was 5. 18 lg（ CFU / g） and the value of Escherichia coli count was 5. 35 lg（ CFU / g）,all three indexes were met with the national standard. As a result,the shelf-life was extended from 10 d to 20 d,and the color and nutrients were remained unchanged.