Baglieri A, Mahé S, Benamouzig R, Savoie L, Tomé D
Institut National de la Recherche Agronomique, Unité de Nutrition Humaine et de Physiologie Intestinale, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, France.
J Nutr. 1995 Jul;125(7):1894-903. doi: 10.1093/jn/125.7.1894.
The purpose of this work was to determine if endogenous luminal proteins are stimulated differently by various dietary proteins and if their digestibility differs from that of dietary proteins. Intestinal effluents were collected from the jejunum of four volunteers who had previously fasted or ingested either casein or soybean proteins. After separating the jejunal digested fraction (nonprotein nitrogen) by dialysis, the protein nitrogen fractions of the effluents and of the protein sources were further hydrolyzed in vitro in a digestion cell with simultaneous dialysis of the digestion by-products. The results indicated a higher (P < 0.05) gastrojejunal absorption of casein (64.5 +/- 2.5%) compared with soybean protein (49.9 +/- 4.1%) in humans. Compared with fasting conditions, protein ingestion increased both the total nitrogen and protein nitrogen of the endogenous nitrogen fraction slightly (P < 0.05) but had no effect on the nonprotein nitrogen fraction. The amino acid profiles of the nonprotein nitrogen in the effluents differed from those of both the protein sources and their mixtures with endogenous secretions. This was attributed to the specific release of amino acids by pancreatic enzymes as measured in vitro. The hydrolysis patterns of amino acids were determined by the structure of food proteins and their interaction with endogenous proteins. Soybean and endogenous nitrogen had equivalent digestibilities when measured in vitro.
这项工作的目的是确定不同膳食蛋白质对肠腔内源性蛋白质的刺激是否存在差异，以及它们的消化率是否与膳食蛋白质不同。从四名志愿者的空肠收集肠流出物，这些志愿者之前禁食或摄入了酪蛋白或大豆蛋白。通过透析分离空肠消化部分（非蛋白氮）后，将流出物和蛋白质来源的蛋白氮部分在消化池中进行体外进一步水解，同时对消化副产物进行透析。结果表明，与大豆蛋白（49.9±4.1%）相比，人类对酪蛋白的胃空肠吸收率更高（P<0.05）（64.5±2.5%）。与禁食状态相比，摄入蛋白质使内源性氮部分的总氮和蛋白氮均略有增加（P<0.05），但对非蛋白氮部分没有影响。流出物中非蛋白氮的氨基酸谱与蛋白质来源及其与内源性分泌物混合物的氨基酸谱不同。这归因于体外测量的胰腺酶对氨基酸的特异性释放。氨基酸的水解模式由食物蛋白质的结构及其与内源性蛋白质的相互作用决定。在体外测量时，大豆氮和内源性氮具有相同的消化率。
