Effect of Cooking on the Content of Dietary Fiber in Vegetables, Method for Determination of Dietary Fiber in Vegetables, and Physiological Function of Dietary Fiber in Vegetables

用Prosky法和改进的Prosky法研究了烹饪对14种蔬菜中膳食纤维含量的影响，并对两种方法测定的膳食纤维含量进行了比较。在改进的Prosky方法中，不减去酶消化残留物中的粗蛋白(氮*6.25)来测定膳食纤维的值。此外，还对粗蛋白含量较高的6种蔬菜的酶解渣中的真蛋白含量进行了测定，除冬瓜和冬瓜外，酶解渣中的可溶性纤维粗蛋白含量为200~500 mg/g，不溶纤维中粗蛋白含量为50~260 mg/g。可溶性和不溶性膳食纤维含量随着煮沸和油炸的增加而增加、减少或不变。这些变化是不同的。可溶性纤维中真蛋白含量为粗蛋白的10%~19%，不溶性纤维中为31%~36%。这一结果表明，用Prosky法和改进的Prosky法测得的可溶性纤维含量相差极小，因为除牛膝外，鲜菜中的可溶性纤维含量均低于1g/100g鲜重。但两种方法测得的不溶纤维含量的差异对纤维含量影响较大，在蔬菜中含量最高，约为鲜重的10%，但因季节和品种的不同，纤维含量似乎有很大差异。饮食诱导的发热率，以含膳食的牛膝或竹笋为主，比无膳食的高2~4%。

The effects of cooking on the contents of dietary fiber in 14 kinds of vegetable were studied using Prosky method and the modified Prosky method, and the contents of dietary fiber measured by both methods were compared to each other. In the modified Prosky method, dietary fiber values were determined without subtraction of crude protein(nitrogen*6.25) in enzyme digested residue. In addition, the contents of true protein in enzyme digested residue were estimated in six kinds of vegetables which contained more crude protein.The contents of crude protein in enzyme digested residue were 200-500mg/g of enzyme digested residue in soluble fiber except bur-dock and cucumber, and 50-260mg/g in insoluble fiber. The contents of soluble and insoluble dietary fiber were increased, decreased or not changed with boiling or frying. The changes were different from each other. The amounts of true protein were lO-19% of crude protein in soluble fiber and 31-36% in insoluble fiber. This result suggests that in soluble fiber the difference of fiber contents measured by both Prosky method and the modified Prosky method was extremely small since the contents of soluble fiber in fresh vegetables were less than 1g/lOOg of fresh weight except bur-dock. But the difference of insoluble fiber contents measured by both methods influenced significantly the content of fiber in the kinds containing much amount of fiber.The fiber content of bur-dock was about 10 % of fresh weight, the largest value in those of vegetables, but the content seemed to vary with farming season and kinds very much.The diet induced thermogenesis in the women taking the bur-dock or bamboo shoots containing meal was 2-4% more than the bur-dock or bamboo shoots free meal.