Li B W
U.S. Department of Agriculture, Agricultural Research Service, Food Composition Laboratory, Beltsville, MD 20705, USA.
J AOAC Int. 1995 Nov-Dec;78(6):1440-4.
A simplified enzymatic-gravimetric method for total dietary fiber (TDF) determination has been published and used in the Food Composition Laboratory of the U.S. Department of Agriculture since 1988. THis method gives comparable results to AOAC Official Methods 985.29 and 991.43 but the AOAC methods use 100 degrees C (water bath) to gelatinize the sample and a combination of alpha-amylase and an amyloglucosidase to hydrolyze starches, whereas the simplified method incorporates an autoclaving step (121 degrees C) for gelatinization followed by incubation with only amyloglucosidase. The simplified method omits protease hydrolysis and does not require any pH adjustment. Overall, the simplified method cuts cost and is less labor intensive. An interlaboratory study was conducted to validate this method. Blind duplicates of six sample (baked beans, corn bran, roasted peanuts, cooked potatoes, white bread with reduced calories, and cooked white rice) were sent to 11 laboratories. The reproducibility relative standard deviations of the TDF values (without outliers) ranged from 3.46 to 27.6%. The repeatability standard deviations ranged from 0.91 to 14.6%.
一种用于测定总膳食纤维（TDF）的简化酶重量法自1988年起已发表并在美国农业部食品成分实验室使用。该方法给出的结果与AOAC官方方法985.29和991.43相当，但AOAC方法使用100摄氏度（水浴）使样品糊化，并使用α-淀粉酶和淀粉葡糖苷酶的组合来水解淀粉，而简化方法采用高压灭菌步骤（121摄氏度）进行糊化，随后仅与淀粉葡糖苷酶一起孵育。简化方法省略了蛋白酶水解，并且不需要任何pH调节。总体而言，简化方法降低了成本且劳动强度较小。进行了一项实验室间研究以验证该方法。将六个样品（烤豆、玉米麸、烤花生、煮土豆、低热量白面包和煮白米）的盲法双份样品发送至11个实验室。TDF值（不包括异常值）的再现性相对标准偏差范围为3.46%至27.6%。重复性标准偏差范围为0.91%至14.6%。
