Lowry K R, Fly A D, Izquierdo O A, Baker D H
Department of Animal Sciences, University of Illinois, Urbana 61801.
JPEN J Parenter Enteral Nutr. 1990 Jan-Feb;14(1):68-73. doi: 10.1177/014860719001400168.
Several rat bioassays were conducted to evaluate protein quality and lysine (LYS) bioavailability (BIO) of Osmolite HN, a commercial enteral product, as affected by the severity of heat processing during sterilization and by storage of the products for 1 year. Without amino acid supplementation, the protein quality of Osmolite HN, as determined by protein efficiency ratio (PER), was lower than that of casein, regardless of heat treatment. With addition of the limiting amino acid, cystine, the PER of Osmolite HN was equivalent to that of cystine-fortified casein. Storage of the product for 1 year had no effect (p greater than 0.05) on PER, even though the products had darkened in color. Slope-ratio regression analysis (weight gain regressed on supplemental LYS intake) yielded a LYS BIO estimate of 94.4% for the Osmolite HN control relative to crystalline LYS. Partitioning weight gain into that resulting from LYS consumed in the basal diet and that resulting from the LYS supplement per se provided more accurate estimates of LYS BIO. This method estimated LYS BIO at 100% for the Osmolite HN products, regardless of heat treatment. With storage, LYS BIO decreased 11-12% in all of the Osmolite HN products. The decreased LYS BIO is of minimal nutritional significance in that overall protein quality of the products was not affected by storage. This is likely due to the fact that there is a plethora of lysine in Osmolite HN such that LYS is not a protein-quality limiting factor.
进行了多项大鼠生物测定，以评估市售肠内产品奥士莫莱特HN（Osmolite HN）的蛋白质质量和赖氨酸（LYS）生物利用率（BIO），该生物利用率受灭菌过程中热处理的严重程度以及产品储存1年的影响。在不添加氨基酸的情况下，无论热处理如何，通过蛋白质效率比（PER）测定的奥士莫莱特HN的蛋白质质量均低于酪蛋白。添加限制性氨基酸胱氨酸后，奥士莫莱特HN的PER与强化胱氨酸的酪蛋白相当。即使产品颜色变深，产品储存1年对PER也没有影响（p大于0.05）。斜率比回归分析（体重增加与补充LYS摄入量的回归）得出，相对于结晶LYS，奥士莫莱特HN对照组的LYS生物利用率估计为94.4%。将体重增加分为基础饮食中消耗的LYS导致的体重增加和补充LYS本身导致的体重增加，可以更准确地估计LYS生物利用率。无论热处理如何，该方法估计奥士莫莱特HN产品的LYS生物利用率为100%。储存后，所有奥士莫莱特HN产品的LYS生物利用率均下降了11 - 12%。LYS生物利用率的下降在营养方面意义不大，因为产品的总体蛋白质质量不受储存影响。这可能是由于奥士莫莱特HN中赖氨酸过多，以至于LYS不是蛋白质质量的限制因素。
