2.3.2. Acid and lime treated soy hulls (ALSH) and soy hull pectin (SHP)
CSH were mixed with 0.1 N HCl solutions (1:10 ratio) and stirred at 90 C for 1 h. The acid treated slurries were allowed to cool to room temperature, and centrifuged at 4500 rpm for 20 min. The supernatants were collected, and dispersed in equal volume of 2 propanol for 30 min. SHP was precipitated by adjusting the pH 3.5 with 0.1 N HCl and allowed to stand for 6 h. The precipitate was collected, centrifuged (4500 rpm for 20 min), dispersed in 2 propanol, stirred for 1 h, and centrifuged. The precipitate was washed with 70% 2-propanol, centrifuged, and dehydrated in a 55 C air dryer for 72 h. At the above first centrifugation step, the wet cakes were washed with deionized water after collecting supernatant. After centrifugation (4500 rpm for 20 min), the wet cake was treated equally by following the procedure for LSH.