辐照剂量率对牛肉脂肪和蛋白氧化及蛋白特性的影响

为研究电子束辐照剂量率对冷却牛肉脂肪和蛋白氧化及蛋白理化特性的影响,试验分析了电子束辐照处理不同剂量率对脂肪和蛋白氧化程度及其蛋白溶解性、疏水性与持水力等特征指标的影响。结果表明:2 k Gy电子束辐照后牛肉脂肪及蛋白氧化程度显著加剧,蛋白溶解性及持水力显著降低,疏水性显著增加(p0.05);在0~2500 Gy/s剂量率范围内,随着剂量率的增大,牛肉的TBARS、酸价、过氧化值、羰基和二硫键含量降低,巯基含量上升,脂肪及蛋白氧化程度减弱;剂量率与蛋白溶解性和持水性呈显著正相关,而与疏水性呈显著负相关(p0.05)。试验结果进一步证明了电子束辐照剂量率会显著影响牛肉脂肪及蛋白氧化。辐照氧化导致蛋白结构的破坏,引起蛋白理化特性的显著变化(p0.05),这为电子束辐照过程中冷却牛肉的氧化控制提供理论参考。

Effect of Dose Rate on Lipid and Protein Oxidation and the Properties of Beef Proteins

The Chilled beef meat was irradiated with electron beams and the effect of irradiation dose rate on the degree of lipid and protein oxidation was examined. Additionally, physicochemical properties of beef proteins such as the solubility, surface hydrophobicity, and water-holding capacity (WHC) were evaluated. The results demonstrated that after irradiation with 2 kGy electron beam, the degree of lipid and protein oxidation increased, and the surface hydrophobicity of beef proteins increased significantly (p < 0.05). In contrast, the solubility and water-holding capacity of the proteins decreased. On increasing the irradiation dose rate from 0 to 2500 Gy/s, the thiobarbituric acid reactive substances (TBARS), acid value, peroxide value (POV), and carbonyl and disulfide (SS) content decreased; thiol group (SH) content of beet meat increased; and the degree of beef protein oxidation decreased. The dose rate, showed significant positive correlation with protein solubility and water-holding capacity (WHC), whereas a significant negative correlation with surface hydrophobicity of beef proteins (p < 0.05). The results revealed that the dose rate of electron beam irradiation could significantly affect the oxidation of lipid and protein. Radiation oxidation could result in damage to the protein structure and significant changes in the physicochemical properties of proteins. These results provide a theoretical reference to control chilled beef oxidation during electron beam irradiation.