7种食用植物油中棉籽油掺假鉴别技术研究Identification technology of adulteration of seven kinds of edible vegetable oils with cottonseed oil

为选择更适宜的食用植物油中棉籽油掺假鉴别方法，分别采用3种方法（基于理化性质分析的哈尔芬试验、基于脂肪酸成分分析、基于特异性标志物苹婆酸测定）对新疆7种食用植物油中棉籽油掺假进行鉴别。结果表明：哈尔芬试验判断食用植物油中是否掺假棉籽油时，可能会存在假阴性情况，该试验仅能对棉籽油作简单的定性判定，不能通过显色的深浅判断棉籽油的掺假比例；基于脂肪酸成分分析法掺假鉴别，不同食用植物油存在区别，其中葵花籽油、菜籽油、红花籽油可通过棕榈酸含量变化，亚麻籽油可通过亚油酸含量变化，判定棉籽油掺假量在10%及以上油样，而大豆油、花生油通过特征脂肪酸含量变化判定棉籽油掺假量在20%以内的情况未能取得良好效果；基于特异性标志物苹婆酸的气相色谱-质谱联用（GC-MS）法测定的掺假方法准确可靠，可有效鉴别出食用植物油中掺假量在2%及以上的棉籽油。综上，相较于其他2种方法，基于特异性标志物苹婆酸的GC-MS法测定具有一定优势，更适宜食用植物油中棉籽油的掺假鉴别。 To select a more suitable method for identifying adulterated cottonseed oil in edible vegetable oils, three methods (Halphen test based on physicochemical property analysis, fatty acid composition analysis, and specific marker sterculic acid determination) were used to identify adulterated cottonseed oil in seven kinds of edible vegetable oils from Xinjiang. The results showed that the Halphen test might have false negatives when determining whether edible vegetable oils were adulterated with cottonseed oil,and the test could only provide a simple qualitative judgment of cottonseed oil and could not determine the adulteration proportion of cottonseed oil through color intensity. For fatty acid composition analysis, different edible vegetable oils exhibited differences. Sunflower seed oil, rapeseed oil, and safflower seed oil could be identified by measuring changes in palmitic acid content in the oil sample, while flaxseed oil could be identified by measuring changes in linoleic acid content when the adulteration level of cottonseed oil was 10% or more in the oil sample. However, soybean oil and peanut oil did not achieve good results when determining adulteration levels within 20% through fatty acid content changes. The GC-MS method based on specific marker sterculic acid was accurate and reliable, and could effectively identify cottonseed oil with adulteration levels of 2% or more in edible vegetable oils. In summary, compared to the other two methods, the GC-MS method based on specific marker sterculic acid has certain advantages and is more suitable for identifying adulterated cottonseed oil in edible vegetable oils.