电子束剂量率对牛肉蛋白结构和理化性质的影响  

Effect of Electron Beam Dose Rate on Myofibrillar Protein Structure and Physicochemical Characteristics of Chilled Beef

作　　者：程述震[1] 王晓拓[1] 张洁[1] 解新方 王志东[1] 

机构地区：[1]中国农业科学院农产品加工研究所,北京100193

出　　处：《食品科学》2018年第3期150-156,共7页Food Science

基　　金："十二五"国家科技支撑计划项目(2014BAA03B05);公益性行业(农业)科研专项(201103007)

摘　　要：为探究电子束剂量率对充氮包装冷鲜牛肉蛋白结构和理化性质的影响,用高能电子加速器辐照处理黄牛背最长肌,然后于4℃条件贮藏25 d,以2.5 k Gy辐照剂量,研究辐照组(辐照剂量率分别为30、150、300 k Gy/min)和对照组对肌原纤维蛋白二级结构、肌肉热稳定性和相关理化性质的影响。结果表明:辐照组和对照组相比,表面活性巯基质量摩尔浓度显著下降,在贮藏第0天,辐照组的活性巯基质量摩尔浓度分别下降了19.05%、22.00%和22.60%,差异显著(P<0.05);电子束处理使肌原纤维蛋白疏水性和溶解度下降,α-螺旋和β-折叠结构含量减少,无规卷曲和β-转角结构含量增加,蛋白质的无序程度增加;电子束处理组肌球蛋白氧化变性降解,对热稳定性下降。电子束处理改变了牛肉肌原纤维蛋白的结构,由此导致其某些理化性质发生变化,进而对其品质产生一定的影响,而150 k Gy/min剂量率的处理对牛肉蛋白结构和品质的影响相对较小。This study was performed to determine the effect of electron beam dose rate on myofibrillar protein structure and physicochemical properties of chilled nitrogen-packaged beef. Longissimus dorsi muscles from Chinese yellow cattle were irradiated by a high-energy electron accelerator at 2.5 k Gy at dose rates of 30, 150 and 300 k Gy/min and then stored at 4 ℃ for up to 25 days. Changes in the secondary structure and physicochemical properties of myofibrillar proteins and the thermal stability of muscles were examined at five-day intervals during storage. Compared with the control group, the sulfhydryl group content in the three irradiated groups declined significantly（P 0.05） by 19.05%, 22.00% and 22.60% at day 0 of storage, respectively. The surface hydrophobicity and solubility of myofibrillar proteins decreased in irradiated samples. In addition, the contents of α-helix and β-sheet decreased along with a simultaneous increase in β-turn and random coil; the protein structure became more disordered. Myosin was oxidized and degraded after electron beam treatment, and the thermal stability declined. To conclude, the irradiation treatment could result in changes in the structure and consequently some physicochemical properties of myofibrillar proteins in beef muscles, thereby affecting beef quality. However, the structure of myofibrillar proteins and meat quality were comparatively less affected at a dose rate of 150 k Gy/min.

关 键 词：电子束剂量率 肌原纤维蛋白 二级结构 热稳定性 理化性质 

分 类 号：TS251.1[轻工技术与工程—农产品加工及贮藏工程]