Tovar L R, Carpenter K J
Arch Latinoam Nutr. 1982 Dec;32(4):961-72.
Corn, made into tortillas (flat cakes baked from lime-treated corn) is the staple food of Mexico. The amino acid deficiencies of tortillas (TT) and boiled corn (BC), and the supplementary value of amaranth seed (PA), another traditional Mexican food, roasted to the point of "popping", were studied. The feeding tests were 14-day PER trials using weanling rats; each diet contained 8.95% crude protein, all from corn, or with PA providing 3.6% protein and corn the remainder, with vitamin and mineral supplements. In addition each diet was supplemented with lysine (lys) so that tryptophan (trp) would be the first limiting amino acid or vice versa. In no comparison did TT give a significantly different value from BC. With trp limiting, the mean PER for the two corn preparations alone was 1.55, and with PA, 2.22. The amaranth had shown a high trp value (1.55 g/16g N). g N). With lys limiting, the mean PER for corn was 1.15; adding PA failed to improve this. Popping amaranth also reduced its reactive lysine value (by dye-binding) from 5.9 to 4.0 g/16g N. It appears that making tortillas has no adverse effect on protein value, but that 'popping' can reduce the value of amaranth seeds. The higher PER for corn with trp as the limiting amino acid (rather than lys) was due to lower ad libitum food intake with the same weight gain.
玉米制成的玉米饼（由经过石灰处理的玉米烤制而成的薄饼）是墨西哥的主食。研究了玉米饼（TT）和煮玉米（BC）的氨基酸缺乏情况，以及另一种传统墨西哥食物——烤至“爆花”程度的苋菜籽（PA）的补充价值。喂养试验采用断奶大鼠进行了为期14天的蛋白质效率比值（PER）试验；每种日粮含有8.95%的粗蛋白，全部来自玉米，或者PA提供3.6%的蛋白质，其余由玉米提供，并添加维生素和矿物质补充剂。此外，每种日粮还补充了赖氨酸（lys），以使色氨酸（trp）成为第一限制氨基酸，反之亦然。在任何比较中，TT的值与BC均无显著差异。当trp为限制氨基酸时，仅两种玉米制品的平均PER为1.55，添加PA后为2.22。苋菜籽显示出较高的trp值（1.55 g/16g N）。当lys为限制氨基酸时，玉米的平均PER为1.15；添加PA未能改善这一情况。将苋菜籽爆花还使其反应性赖氨酸值（通过染料结合法测定）从5.9降至4.0 g/16g N。看来制作玉米饼对蛋白质价值没有不利影响，但“爆花”会降低苋菜籽的价值。以trp作为限制氨基酸（而非lys）时玉米的PER较高，是因为在体重增加相同的情况下，随意采食量较低。
