烹调对蔬菜中硝态氮及V_c含量影响的研究

Effects of Different Cooking Methods on the Contents of Nitric Nitrogen and Vitamin C in Vegetables

以菠菜、黄瓜、豇豆、胡萝卜4种有代表性的蔬菜为实验材料,研究了炒、炖、微波、蒸、焯、炸6种不同烹调方法对亚硝酸盐、硝酸盐及VC含量的影响。结果表明,不同烹调方法对4种蔬菜的亚硝酸盐含量影响显著,炒、炖、微波、蒸、焯制蔬菜亚硝酸盐下降率分别为44%～63%,58%～72%,46%～78%,31%～53%,65%～87%;而炸制却使菠菜和豇豆有所增加,其增长率分别为9.7%,23.1%。蔬菜中硝酸盐含量经烹调加工后都有不同程度的降低,焯、微波、炖制下降率明显,炸、炒、蒸制作用不明显。其中焯制硝酸盐的下降率最高,炸制下降率最低。大部分蔬菜中V_C含量经烹调加工后都有不同程度的降低,特别是炸制V_C损失率最高,为35%～79%,微波对蔬菜维生素损失率最低,为4%～18%,唯有焯制,使得叶菜菠菜V_C反而增加4%。炒、炖、蒸制蔬菜V_C损失率分别为11%～52%,10%～55%,12%～44%。综合蔬菜食用安全性和营养素保留率,可尽可能多的考虑微波、焯、炒制烹调蔬菜,少用炸、炖、蒸制法。

With Spinach,cucumber, bean, carrot to be main raw materials,this paper studied the effects of 6 kinds of different cooking methods,including stir-frying,stewing,microwave,steaming,scalding and frying on the contents of nitrite, nitrate and vitamin C in vegetables. The results showed that the effects of various cooking methods on nitrite content were remarkable. Stir-frying, stewing, microwave, steaming, scalding reduced nitrie content by 44 %-63 % ,58 %-72% ,46%-78 % ,31%-53% and 65%-87% respectively,whereas frying would increase the nitrite contents in spinach and bean,whose growth rates were 9.7% and 23.1%respectively. The nitrate contents in vegetables were degreased in different degrees after cooking, which reduced remarkably when scalding, microwave and stewing but which has no obvious effect when frying, stir-frying and steaming. The loss rate of nitrate content was highest when scalding and lowest when frying.The vitamin C contents in most vegetables were degreased in different degrees after cooking. The loss rate of vitamin C content was highest when frying and lowest through microwaveBut scalding would increase vitamin C contents in Spinach by 4 %. Stirfrying, stewing, steaming reduced vitamin C content by 11%-52 %, 10 %-55 % and 12 %-44 % respectively. Concidering food safety of fresh vegetables and retention of nutrient, microwave, scalding and stir-frying should be used to cook vegetables much more than frying, stewing and steaming.