Lam-Sánchez A, Bressani R, Molina M R, Elías L G, González J M, Durigan J F
Arch Latinoam Nutr. 1985 Sep;35(3):447-57.
In the present study, three cone openings (0.133; 0.106, and 0.080 cm) and three initial moisture content values (9%, 15% and 21%) were used as treatments to evaluate their effects on the protein quality of full-fat soybean flour, extruded in the Brady Crop Cooker. The specific volume, protein and oil contents as well as available lysine content characteristic of the final product, were not affected by the treatments used. Processing temperatures, however, decreased when the initial moisture content of the material was increased. The nitrogen solubility index was affected by the cone opening but not by the moisture content of the material. With respect to the trypsin inhibitors content, the increase in the initial moisture content in soybeans gave conflicting results. At the 21% moisture treatment, the amounts of trypsin inhibitors were higher than those present in the raw material; a similar effect was also observed with urease activity. At the other two moisture contents (9 and 15%) the amounts of trypsin inhibitors and urease activity were decreased by heat treatment, mainly at the 9% moisture level, which were related to the cone opening of the extruder. PER values in rats were influenced by the moisture content and were not affected by the cone opening. Results obtained in the biological assays with chicks, both for weight gain and conversion efficiency, were favored by a decrease in cone opening. Nevertheless, the increase in the moisture content induced a decrease in weight gain at the 5- and 8-week periods, without affecting the conversion efficiency. The effect of consecutive passes of the material through the extruder was also studied. The product obtained with two extrusions presented a good biological value, probably as a consequence of the low values in the trypsin inhibitors and urease activities. When the material was extruded three times, results proved to be poor, due to a reduction to significant low levels of available lysine content--which becomes limiting--, and nitrogen solubility index of the full-fat soybean flour.
在本研究中，采用三种模孔直径（0.133厘米、0.106厘米和0.080厘米）和三种初始水分含量值（9%、15%和21%）作为处理因素，以评估它们对在布雷迪谷物蒸煮器中挤压的全脂大豆粉蛋白质质量的影响。所采用的处理因素对最终产品的比容、蛋白质和油脂含量以及有效赖氨酸含量特性没有影响。然而，当物料的初始水分含量增加时，加工温度会降低。氮溶解指数受模孔直径的影响，但不受物料水分含量的影响。关于胰蛋白酶抑制剂含量，大豆初始水分含量的增加产生了相互矛盾的结果。在21%水分处理下，胰蛋白酶抑制剂的含量高于原料中的含量；脲酶活性也观察到类似效果。在其他两种水分含量（9%和15%）下，热处理使胰蛋白酶抑制剂的含量和脲酶活性降低，主要是在9%水分水平，这与挤压机的模孔直径有关。大鼠的蛋白质效率比值（PER）受水分含量的影响，不受模孔直径的影响。在雏鸡的生物学试验中，无论是体重增加还是转化效率，模孔直径减小都有促进作用。然而，水分含量的增加导致5周和8周龄时体重增加减少，但不影响转化效率。还研究了物料连续通过挤压机的影响。经过两次挤压得到的产品具有良好的生物学价值，这可能是由于胰蛋白酶抑制剂和脲酶活性值较低的结果。当物料挤压三次时，结果很差，这是由于全脂大豆粉的有效赖氨酸含量显著降低（成为限制因素）以及氮溶解指数降低所致。
