微囊型脂肪粉中粗脂肪的快速测定

为了解决新型油脂产品——微囊型脂肪粉因缺乏粗脂肪检验方法造成的贸易困惑,建立了微囊型脂肪粉中粗脂肪含量的快速测定方法。以包埋率较高的微囊型脂肪粉样品为主要试材,通过对酸水解条件和萃取方法的研究而建立方法;并确定了方法的适用范围;对5个不同包埋率微囊型脂肪粉代表性样品依据GB/T 6379.2—2004《测量方法与结果的准确度》进行实验室间验证比对以考察方法的精密度和准确度。建立的方法为：样品(1~2 g)用4 mol/L盐酸在85℃±5℃下水解1 h,而后用20 mL石油醚连续萃取2次(20 mL×2);萃取液蒸馏除去溶剂后于103℃±2℃烘干15 min,重量法测定。验证数据经过柯克伦(Cochran)检验和格拉布斯(Grubbs)检验,结果无离群值,一致准确。该方法的平均重复性误差和再现性误差(RSD)分别为0.34%~0.58%和0.38%~1.33%,完全符合GB/T 27404—2008《实验室质量控制规范》对精密度的要求。本方法适用于不含磷脂的微囊型脂肪粉中粗脂肪的测定。和现行标准GB/T 6433—2006相比,本方法更为准确、快速、经济,已经被相关企业采用。

Crude Fat in Micro-encapsulated Fat Powders: Rapid Determination

To deal with the trade problems of new type products of fat powders caused by lacking suitable determination method of crude fat, a rapid and reliable determination method of crude fat in the products of micro-encapsulated fat powders was developed by selecting the micro-encapsulated fat powders with higher embedding rates as main testing samples and establishing the hydrolysis method and the extraction method. The testing scopes of this method were also studied. According to the requirements of the national standard GB/T 6379.2—2004 Accuracy of Measurement Methods and Results, the accuracy and precision of this method were then determined by testing the crude fat contents of five micro-encapsulated fat powder samples with different embedding rates in 3 independent labs. In this method, the sample (1-2 g) was hydrolyzed by 4 mol/L hydrochloric acid at 85℃ ± 5℃ for 1 h, and then the solution was extracted twice by petroleum ether (20 mL×2). After removing the petroleum solvent by distilling, the residue was dried at 103℃±2℃ for 15 min, then the residue was determined by Gravimetric method. After examined by Cochran test and Grubbs test, the results were found to be consistent and accurate without outliers. The average repeatability errors and reproducibility errors (RSD) of the method were 0.34%-0.58% and 0.38%-1.33%, respectively, indicating that this method could fully meet the precision requirements of the national standard GB/T 27404—2008 Specification for Laboratory Quality Control. This newly developed method is suitable for determination of crude fat in micro-encapsulated fat powder products without phospholipids, and is more accurate, fast and cost-effective, and more reliable when compared with the current standard GB/T 6433—2006.