【摘要】 本试验研究了粉状谷类食品,经过一般的烹调过程后营养成分的变化。结果证明一般营养素如蛋白质、脂肪、粗纤维、无机盐、钙及磷,经过烹调后,变化不大。在进行膳食调查时,可以用生谷类食品来计算这些营养成分,其中某些营养成分的含量如蛋白质却因来源不同而有一定的差别。 调制窝窝头时,每公斤加4克小苏打,对硫胺素、核黄素及尼克酸都没有影响。在制馒头的发酵及加碱过程中,硫胺素及核黄素都有些损失,一般介于15一20％之间。在一般蒸熟过程中,如蒸窝窝头及蒸馒头,硫胺素、核黄素及尼克酸均无甚损失。烙饼时,核黄素损失约为20％;烤烧饼使硫胺素损失约30％。炸油桧时,全部硫胺素破坏,而核黄素及尼克酸亦仅保留其原料含量的一半。在煮面条过程中,乙种维生素复合体损失约30—40％。更多还原

【Abstract】 Standard wheat flour (about 85% extraction) and mixed maize-soybean flour are consumed as staple foods in North China. They ate usually used to prepare steamed bread. The wheat flour dough is leavened by natural fermentation and the acid produced is neutralized with soda. In the preparation of maize-soybean bread, a small amount of sodium bicarbonate is added for leavening purpose; The other products prepared from wheat flour are noodles, unleavened pancake (烙饼), roast cake (烧饼) and Chinese doughnut (油条).Since the above products provide an important source of calories, proteins, and vitamin-B complex, any significant loss in the cooking process might well affect the nutritive value of the diet. Except the preparation of noodles in which case the cooking water is discarded, there is practically no effect of the cooking process on the proximate composition of either cereal flour product. The loss of protein in noodles as a resultof preparation is about 2-5% of the original protein content.In most cases, the loss of thiamin in the fermentation process of the wheat flouris about 0.04 mg% on the basis of the weight of the flour. The amount lost seems to be independent on the original content of this vitamin in the flour. In this process, the loss of riboflavin is about 20% (18-38%) while that of nicotinic acid is insignificant.Steaming does not reduce the thiamin, riboflavin, or nicotinic acid content.When 6 gms. of sodium bicarbonate are added to 1.5kg. maize-soybean flour before, steaming, there is no loss of thiamin in the finished product.The riboflavin content is slightly lowered in baked unleavened pancake, but there seems to be no effect on thiamin or nicotinic acid. However, in baking theroast cake, the retention of thiamin is only 70% of the original content of the raw material., This is probably due to the high temperature employed in the cooking procedure.The thiamin ox wheat flour is completely destroyed during preparation of the fried Chinese doughnut, and the retention of riboflavin and nicotinic acid is only about 50%.Retention of the vitamin-B complex is about 60-70% after noodles have been cooked.更多还原