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

采用Prosky法和改良Prosky法研究了烹调对14种蔬菜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。在改良的Prosky法中，在不减去酶消化残渣中的粗蛋白（氮 *6.25）的情况下测定膳食纤维值。此外，对粗蛋白含量较高的6种蔬菜的酶解残渣中真蛋白含量进行了测定，结果表明：除牛蒡和黄瓜外，可溶性纤维酶解残渣中的粗蛋白含量为200- 500 mg/g，不溶性纤维酶解残渣中的粗蛋白含量为50- 260 mg/g。水溶性和不溶性膳食纤维的含量随煮制或油炸而增加、减少或不变。变化各不相同。可溶性纤维中真蛋白含量占粗蛋白的10 -19%，不溶性纤维中真蛋白含量占31-36%。这一结果表明，在可溶性纤维中，Prosky法和改良Prosky法测定的纤维含量差异很小，因为除牛蒡外，新鲜蔬菜的可溶性纤维含量均小于1g/100 g鲜重。但两种方法测定的不溶性纤维含量的差异对纤维含量高的品种的纤维含量有显著影响，牛蒡的纤维含量约为鲜重的10%，是蔬菜中最高的，但其含量因农时、农事种类而异，且差异很大。含牛蒡粉或竹笋粉比不含牛蒡粉或竹笋粉高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.