Call Prefix : PR-T

Call Suffix : 1988

Call Cutter : T - FoSc 12

Location : SEARCA Library

Format : TD

Publisher : University of the Philippines Los Banos,

Publication Date : January 1988

Publication Place : Los Banos, Laguna, the Philippines :

Summary : Mungbean (KS1, KS2, Autong 1), rice bean (native variety from Thailnd and Philippines); and lablab bean (EG Green Podded, EG Light Green Podded, Tein Roong, and Manmuyao) were analyzed for tannin content using three methods: modified vanillin, Prussian blue assay, and protein precipitation. The tannin analysis invariably yields different results since they detect tannin on different bases. Several treatments reduced the chemically assayable tannis in three legumes. Soaking seeds for 6-36 hours in water reduced tannin contents in mungbean (Autong 1), rice bean (Philippine variety), and lablab bean (Manmuyao) by 31.30 - 67.18 percent, 39.07 - 71.29 percent, and 24.69 - 53.62 percent, respectively. Use of NH (subscript 4), KOH, and CaO solutions reduced tannin content by 27-77 percent in mungbean, 29 - 9.27 percent in rice bean (Philippine vareity), and 43 - 85 percent in Manmuyao. The amount of tannin removed depended on soaking time, seed morphology, and nature of alkali used. Low concentration of alkali removed tannins more effectively than higher concentrations. Boiling removed 70.93 percent of tannin in mungbean, 74.62 percent in rice bean, and 58.73 percent in lablab bean. In vitro protein digestibility (IVPD) of seeds treated with alkali and/or heat increased with decrease in tannin content. Reduction in tannin content of treated seeds did not increase in vitro protein digestibility. During germination, chemically assayable tannins were reduced by 45, 37, and 44 percent in mungbean, rice bean, and lablab bean, respectively. Condensed tannins were isolated and purified from the crude methanolic hull extracts from KS (subscript 2), rice bean (Thai variety), and Manmuyao by absorption chromatography on Sephadex LH-20. The purified condensed tannin exhibited extract. Patial characterization of each purified tannin showed differences in their reactivity toward the phenol reagents Folin-Denis, leucoanthoacyanin test, and vanillin test. UV-spectrophotometry revealed the presence of free 70H group in th...