饲料中粗脂肪超声提取快速测定方法的研究

Study on Ultrasonic Extraction Assisted Rapid Determination Method for Crude Fat in Feed

[目的]优化饲料中粗脂肪超声提取工艺参数。[方法]以草鱼膨化配合饲料为试验材料,设计单因素试验,考查分析4个因素(液料比、浸泡时间、超声时间和超声次数)不同水平对饲料粗脂肪含量测定的影响。在单因素试验基础上,设计4因素3水平L9(34)正交试验,优化饲料粗脂肪超声提取工艺参数。采用优化后的超声提取工艺测定草鱼膨化配合饲料的粗脂肪含量,并与索氏提取法测定结果进行比较,重复6次,以此验证最佳超声提取工艺参数。超声提取工艺参数确定后,分别采用超声提取法和索氏提取法测定13种不同饲料样品的粗脂肪含量,重复6次,分析比较两种方法在测定饲料原料和常见动物性饲料产品粗脂肪含量的差异。[结果]影响饲料粗脂肪含量测定各因素的排序为超声次数>液料比>超声时间>浸泡时间;最佳超声提取工艺为液料比37.5 mL/g,浸泡0 min,超声时间30 min,超声提取2次;最佳超声提取工艺下,草鱼膨化配合饲料的粗脂肪含量为4.76%(n=6),而索氏提取法粗脂肪含量为4.77%(n=6),试验证明超声提取工艺稳定且可行;分别采用超声提取法和索氏提取法测定13种不同饲料样品的粗脂肪含量,两种方法测定结果差异不显著(P>0.05)。[结论]该试验确定的饲料中粗脂肪超声提取最佳工艺参数稳定且可行。

[Objective]The aim of this study was to optimize the ultrasonic extraction process parameters of crude fat in feed.[Method]Using the grass carp expanded compound feed as experimental material,a single factor experiment design was adopted to investigate and analyze the effects of 4 factors(liquid to material ratio,soaking time,ultrasonic duration and ultrasonic frequency)at different levels on the determination of crude fat content in feed.In addition to the single factor experiments,a 4-factor and 3-level L9(34)orthogonal experiment was conducted to optimize the ultrasonic extraction process parameters of crude fat in feed.The crude fat content of grass carp expanded compound feed was measured using the optimized ultrasonic extraction process,and the results were compared to those obtained using the Soxhlet extraction method.The process was repeated 6 times to verify the optimal ultrasonic extraction process parameters.Following the determination of the ultrasonic extraction process parameters,the crude fat contents of 13 different feed samples were measured using both the ultrasonic extraction method and the Soxhlet extraction method with 6 repeated tests.The differences in crude fat content of the feed raw materials and common animal feed products between the two extraction methods were then analyzed and compared.[Result]The factors affecting the determination of crude fat content in feed was in the order of ultrasonic frequency>liquid to material ratio>ultrasonic duration>soaking time.The optimal ultrasonic extraction process parameters were liquid to material ratio of 37.5 mL/g,soaking for 0 min,ultrasonic duration for 30 min,and ultrasonic extraction twice.The crude fat content of grass carp expanded compound feed determined by the optimal ultrasonic extraction process was 4.76%(n=6),whereas that determined by the Soxhlet extraction method was 4.77%(n=6),proving that the ultrasonic extraction process was stable and feasible.The differences in crude fat content determination results of 13 different feed samples between the ultrasonic extraction method and the Soxhlet extraction method were not significant(P>0.05).[Conclusion]The optimal process parameters for ultrasonic extraction of crude fat in feed determined in this study were stable and feasible.