Chemical and functional characterization of Gum karaya (Sterculia urens L.) seed meal

Chemical and functional characterization of the meal of Gum karaya (Sterculia urens) whole and dehulled–defatted seed were investigated. Dehulled–defatted seed meal (DDSM) contained 40.7% of protein as compared to 20.4% in the whole seed meal (WSM). Essential minerals of Ca 39.5, Fe 4.4, K 9.6 and P 995 mg/100 g were found in DDSM. A solid to solvent ratio 1:40 and extraction time of 60 min was optimum. The highest protein solubility (93.97%) was observed at pH 12 and the lowest (26.41%) protein solubility at pH 6. The solubility of protein was enhanced in the presence of 0.1 M and 0.5 M NaCl between pH rang of 2–12. The protein precipitation from an alkaline extract of pH 10 was maximum (81%) at pH 6. Polyacrylamide gel electrophoresis shows that 14 bands of SDS soluble protein subunits were observed in WSM and DDSM. A higher buffer capacity of the meal was observed in the acid medium than in alkaline medium. The DDSM had an initial moisture content (IMC) of 5.16%, which equilibrated at 32% RH and moisture content increased sharply at higher humidity (70%) which, indicated that the non-hygroscopic in nature. Water holding capacity and oil holding capacity were 111 and 81, 67 and 114 g/100 g of WSM and DDSM respectively. DDSM showed very good foam capacity (32%) and stability (75%) even after 90 min at room temperature. The emulsification capacity of DDSM was found to be 20 mL/g sample.

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