Electronic Theses and Dissertation

Umbi gadung ungu (Dioscorea alata) merupakan bahan pangan tinggi karbohidrat dengan nilai indeks glikemik rendah. Indeks glikemik merupakan indikator kemampuan bahan pangan meningkatkan kadar gula darah setelah dikonsumsi. Indeks glikemik bahan pangan dipengaruhi oleh beberapa faktor seperti komposisi karbohidrat dan kandungan zat antinutrien. Penelitian ini bertujuan untuk mengevaluasi komposisi karbohidrat dan kandungan zat antinutrien umbi gadung ungu. Komposisi karbohidrat umbi gadung ungu (gula pereduksi, pati, amilosa, amilopektin, serat kasar, dan serat pangan) dan kandungan zat antinutrien (tanin, oksalat, asam fitat dan saponin) dianalisis dengan metode titrimetri, gravimetri dan spektrofotometri, sedangkan komposisi gula (glukosa, fruktosa, sukrosa, dan maltosa) dianalisis dengan instrumen HPLC. Hasil penelitian menunjukkan komposisi karbohidrat umbi gadung ungu meliputi kadar gula pereduksi, pati, amilosa, amilopektin, serat kasar dan serat pangan berturut-turut adalah 0,14%; 56,56%, 37,93%; 62,07% 3,02%; dan 21,33% berat kering (bk). Komposisi gula umbi gadung ungu meliputi glukosa, fruktosa, sukrosa dan maltosa berturut-turut adalah 0,94%; 0,16%; 2,26% dan

Purple water yam (Dioscorea alata) is a high carbohydrate food with low glycemic index value. The glycemic index is an indicator of the ability of food to increase blood sugar levels after consumption. The glycemic index of foods is influenced by several factors such as carbohydrate composition and antinutrient content. This study aims to evaluate the carbohydrate compositions and antinutrien content of purple water yam tuber. The carbohydrate compositions (reducing sugars, starch, amylose, amylopectin, crude fiber, and dietary fiber) and antinutrient content (tannin, oxalate, phytic acid, and saponins) were analyzed titrimetric, gravimetric and spectrophotometric methods, while sugar content (glucose, fructose, sucrose, and maltose) were analyzed using HPLC instrument. The result showed that the carbohydrate composition of purple water yam tuber including reducing sugars, starch, amylose, amylopectin, crude fiber, and dietary fiber were: 0,14%, 56,56%, 37,93%, 62,07%, 3,02%, and 21,33% dry weight (dw), respectively. The sugar content including glucose, fructose, sucrose and maltose were: 0,94%; 0,16%; 2,26% and