de Oliveira J E, de Souza N, Jordão Júnior A A, Marchin J S
University of São Paulo, Brasil.
Arch Latinoam Nutr. 1998 Mar;48(1):35-40.
Soybean protein is one of the best quality foods available. Contribution of soy to human nutrition increases because of its overall positive nutritional profile, low cost, high protein and excellent functional properties. Addition of methionine to rat soybean diets improve biological value of soy protein. Few studies on methionine fortification of soya protein were carried in infants, but fortification of baby formulas with this amino acid is usually found. This study was carried out to demonstrate in malnourished children that the effect of methionine supplementation of soya milk and soy isolated protein, as well as to compare with their results to cows' milk. A total of 30 malnourished children, 1 to 3 years old, admitted to our metabolic unit and distributed in groups of 6 children were studied. They were fed experimental formulas with cows' milk, soya milk, soya milk plus methionine, soya isolated and soya isolated plus methionine. Nutrient compositions of formulas were calculated to be similar to mothers' milk. DL-methionine, 1.5 g per 100 g protein content was added to soya milk and soya isolated formulas. Two nitrogen balances, 3 days each, were carried out. Fecal and urinary nitrogen, serum proteins, creatinine and urea in serum and urine were followed during the study. Results showed differences of intake and retention of nitrogen between some of the groups, but there were no statistically significant differences on protein absorption in the groups. No differences were demonstrated in serum proteins, total nitrogen and other serum and urine parameters analyzed. Cows' milk fed children presented the highest nitrogen retention in both balance studies. The addition of methionine to the soya milk formula increased the nitrogen retention, not reaching the cows' milk levels and did not have the same effect when added to the isolate soy protein.
大豆蛋白是现有优质食物之一。由于大豆具有全面积极的营养特性、低成本、高蛋白以及出色的功能特性，其对人类营养的贡献不断增加。在大鼠的大豆饮食中添加蛋氨酸可提高大豆蛋白的生物学价值。针对婴儿进行的大豆蛋白蛋氨酸强化研究较少，但通常会在婴儿配方奶粉中添加这种氨基酸。本研究旨在证明在营养不良儿童中补充蛋氨酸的豆浆和大豆分离蛋白的效果，并将其结果与牛奶进行比较。共有30名1至3岁的营养不良儿童入住我们的代谢科，按每组6名儿童进行分组研究。他们分别喂食含牛奶、豆浆、加蛋氨酸的豆浆、大豆分离蛋白以及加蛋氨酸的大豆分离蛋白的实验配方奶粉。配方奶粉的营养成分经计算与母乳相似。在豆浆和大豆分离蛋白配方奶粉中每100克蛋白质添加1.5克DL-蛋氨酸。进行了两次为期3天的氮平衡研究。在研究过程中监测粪便和尿液中的氮、血清蛋白、血清和尿液中的肌酐及尿素。结果显示部分组之间在氮的摄入量和潴留量上存在差异，但各小组在蛋白质吸收方面无统计学显著差异。在分析的血清蛋白、总氮及其他血清和尿液参数方面未显示出差异。在两项平衡研究中，喂食牛奶的儿童氮潴留量最高。在豆浆配方奶粉中添加蛋氨酸可增加氮潴留量，但未达到牛奶的水平，且添加到大豆分离蛋白中时效果不同。
