McDonough F E, Sarwar G, Steinke F H, Slump P, Garcia S, Boisen S
U.S. Department of Agriculture, Beltsville Human Nutrition Research Center, Beltsville, MD 20705.
J Assoc Off Anal Chem. 1990 Jul-Aug;73(4):622-5.
True protein digestibilities of 17 protein sources were estimated by 6 laboratories using an in vitro, 3-enzyme digestion system in a pH stat. Samples from animal, vegetable, and mixed food sources were freeze-dried (if not already dried), ground, mixed, and shipped to each collaborator along with a sodium caseinate standard and trypsin, chymotrypsin, and peptidase. The uptake of titrant during enzymatic digestion was used to calculate estimates of digestibility. Digestibilities ranged from 100% for casein to 89.9% for whole wheat cereal. Mean relative standard deviations for repeatability were 1.4% for rolled oats and less than 1% for the remaining 16 samples. Mean relative standard deviations for reproducibility ranged from 5.0 to 0.8%; values were less than 2.5% for 13 of the 17 samples.
6个实验室使用pH计中的体外三酶消化系统，对17种蛋白质来源的真实蛋白质消化率进行了估算。来自动物、植物和混合食物来源的样品经过冷冻干燥（如果尚未干燥）、研磨、混合后，与酪蛋白酸钠标准品、胰蛋白酶、糜蛋白酶和肽酶一起运送给每位合作者。酶促消化过程中滴定剂的吸收量用于计算消化率估算值。消化率范围从酪蛋白的100%到全麦谷物的89.9%。燕麦片重复性的平均相对标准偏差为1.4%，其余16个样品的平均相对标准偏差小于1%。再现性的平均相对标准偏差范围为5.0%至0.8%；17个样品中有13个的值小于2.5%。
