不同铜源对存储期间大豆油脂氧化酸败的影响

本试验旨在模拟实际生产中8%仔猪预混料中油脂与微量元素的添加量,分析不同形式的铜对大豆油油脂氧化指标的影响。将五水硫酸铜、碱式氯化铜和甘氨酸铜3种微量元素原料与大豆油的比例均设定在8.74:1000,与大豆油混合后在高温条件下储放0、10、20、30、40、50、60 d,检测各处理组的酸价、碘价、过氧化值和丙二醛含量。试验共设4个处理组,对照组的大豆油中不加铜,五水硫酸铜组在100 g大豆油中添加3.44 g五水硫酸铜,碱式氯化铜组在100 g大豆油中添加1.47 g碱式氯化铜,甘氨酸铜组在100 g大豆油中添加2.91 g甘氨酸铜。每个处理3个重复,试验期60 d。结果表明:与对照组相比,大豆油中添加不同形式的铜元素提高了大豆油的酸价、碘价、过氧化值和丙二醛含量(P<0.05);添加无机硫酸铜对大豆油的酸价、碘价、过氧化值和丙二醛含量的影响在3种铜元素形式中最为明显,甘氨酸铜组影响较小。因此,建议在使用油脂的大比例预混料中优先选择甘氨酸铜作为铜元素来源。

Effects of Different Copper Ions on Oxidation Rancidity of Soybean Oil during Storage

Three kinds of trace elements,copper sulfate pentahydrate,basic copper chloride and copper glycine were selected to be stored at higher temperature for 0,10,20,30,40,50 d and 60 d after mixing with soybean oil.The acid value,iodine value,peroxide value and malondialdehyde content of each treatment group were determined.A total of 4 treatment groups were set as:control groups,no copper ions were added to soybean oil;Copper sulfate group,100 g of soybean oil was added with 3.44 g of pentahydrate copper sulfate;Base copper chloride group,100 g soybean oil with 1.47 g base copper chloride;Copper glycine group,100 g soybean oil with 2.91 g copper glycine.Each treatment was repeated 3 times for a trial period of 60 days.The results showed that the values of acid,iodine,peroxide and malondialdehyde were significantly increased by adding copper ion in soybean oil compared with control group.Compared with the three kinds of copper ions,the inorganic copper sulfate group had the most obvious influence on acid value,iodine value,peroxide value and malondialdehyde content of soybean oil,while the copper glycine group had less influenc e.It was recommended that copper glycine should be preferred as a source of copper in a large proportion of premixes using grease.