洋葱皮乙醇提取物对冷却牛肉颜色、脂质和蛋白质氧化稳定性的影响

将牛肉切片在3种浓度（0.5 %、1.0%、2.0%）的洋葱皮乙醇提取物（Ethanol Extract of Onion Skin，EEOS）溶液中浸渍后在4 ℃条件下冷藏12 d，并与空白对照组和添加了抗坏血酸（ascorbic acid，V_C）的处理组进行比较，分析EEOS对牛肉在冷藏期间的颜色褐变、脂肪和蛋白质氧化以及腐败程度的影响。结果表明:EEOS总酚含量较高，具有很强的自由基清除活性；添加EEOS可延缓牛肉pH上升，提高颜色稳定性，减少高铁肌红蛋白的生成，同时延缓脂肪和蛋白的氧化进程。2% EEOS有效降低了牛肉样品硫代巴比妥酸反应物（Thiobarbituric acid reactive substances，TBARS）和蛋白质羰基含量，与空白对照组相比分别降低56.9%和17.6%。此外，2% EEOS还可显著降低挥发性盐基氮（Total Volatile Basic Nitrogen，TVB-N）的含量（P<0.05）。因此，添加2% EEOS可抑制牛肉冷藏期间的颜色褐变和脂肪、蛋白质的氧化，可在牛肉冷藏保鲜中作为天然抗氧化剂。

Effect of Ethanol Extract from Onion Skin on Color,Lipid and Protein Oxidative Stability of Fresh Beef

Beef slices were dipped in three concentrations(0.5%, 1.0%, 2.0%) of ethanol extract of onion peel(EEOS), and then refrigerated at 4 ℃ for 12 days. The inhibitory effects of EEOS on the color browning, lipid oxidation, protein oxidation and spoilage of beef during refrigerated storage were investigated and compared with control(without any antioxidant) and ascorbic acid(V_C). The results showed that EEOS displayed high phenolic content and strong radical scavenging activity. EEOS addition delayed the rise of pH values, enhanced the color stability, and reduced the metmyoglobin of beef. At the same time, it delayed the oxidation process of lipid and protein. Notably, 2% EEOS effectively reduced thiobarbituric acid reactive substances(TBARS) and protein carbonyl content of beef samples by 56.9% and 17.6% than the control group, respectively. In addition, EEOS could significantly reduce the content of total volatile basic nitrogen(TVB-N) of beef during refrigerated storage(P<0.05). Therefore, the addition of 2% EEOS could inhibit the color browning and the oxidation of fat and protein of beef, which could be used as a natural antioxidant in beef refrigerated storage.