Dietary Fiber in Vegetables. - Some Physicochemical and Functional Properties of Pectic Substances -.

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The dietary fiber in vegetables (carrot, turnip, Japanese radish and cabbage) and some of its physico-chemical and functional properties of pectic substances were investigated.The results obtained were as follows:1. Quantitative analysis of dietary fiber: Quantitative analysis of dietary fiber were conducted. The author used Kainuma's method in this study, wherein the samples were extracted based on the classification of carbohydrate, except in the analysis of pectic substances. Likewise, Kainuma's method was used in the analysis of pectic substances and we obtained satisfactory results.2. Physico-chemical properties of pectic substances extracted under various pH: It was found that the methoxyl groups of galacturonic acid in carrots and turnips have higher values when extracted at low pH. The neutral sugar contents in pectic substances ranged from 3.0-7.5%. Among the neutral sugars detected, mannose was the highest content as compared to xylose, arabinose and fructose, in the order of diminishing content. The average molecular weight ( <M_w> ) was 16.2-18.9 X <10^4> for carrots, and 10.6 X <10^4> for carrots, and 10.6 X <10^4> for turnip. The radii of gyration ( <R_G> ) was 248-279 <Ang> for carrots and 214 <Ang> for turnip.3. Functional properties of pectic substances: Concentration dependence of various ions were recognized through ion exchange reaction in pectic substances.4. Future plans of study: 1) Quantitative analysis of dietary fiber and pectic substances in various kinds of vegetables. 2) Detailed investigations on the ion exchange reaction in the pectic substances.