Journal of Nutrition & Food Sciences
Open Access
ISSN: 2155-9600
ISSN: 2155-9600
Ikhlas Ibrahim Khalid and Sirelkhatim Balla Elharadallou
Chemical composition and functional properties of legume seed flours and protein isolates prepared by isoelectric precipitation procedure (A) and micellization procedure (B) were investigated. Cowpea (Vigna ungiculata L.) Protein Isolates (CPIA, CPIB) and Lupin (Lupinus termis) Protein Isolate (LPIA, LPIB) were prepared from dehulled defatted seeds. Proximate analysis gave 26.73-43.57% protein, 2.30%-9.75% fat, 3.87%-3.16% total ash, 1.02%-12.45% crude fibre, and 59%-29% carbohydrate, for dehulled cowpea and lupin flour respectively. The protein percentage of isolates was found to be 75%-76% in (CPIA and CPIB) while 91%-87% for LPIA and LPIB, respectively. The minimum protein solubility for CPIA was at pH 5.0 and for CPIB at pH 4.0. Protein solubility values of LPIB were higher than that of LPIA. Protein isolates showed good solubility in all pH ranges. For water and oil absorption capacity, Dehullued Cowpea Flour (DCF) gave 1.30 ml water/g sample and 1.04 ml oil/g sample respectively; while CPIA 2.10 ml water/g sample and 1.93 ml oil/g sample, CPIB 2.33 ml water/g sample and 2.37 ml oil/g sample. Dehullued Lupin Flour (DLF) gave 1.80 ml water/g sample and 1.80 ml oil/g sample. However, LPIB had higher oil absorption capacity than LPIA. The highest Emulsifying Capacity (EC) was observed at pH 12.0 for Dehullued Defatted Cowpea Flour (DDCF) (173 oil/g protein), for CPIA (160 oil/g protein) while CPIB showed highest EC (137 oil/g protein) at pH 2.0. The EC for both (CPIA and CPIB) was higher at pH 7.0 compared to value obtained from DDCF. In fact, LPIB had higher fat absorption and emulsification capacity than LPIA. The least gelation concentrations for studied legume flours and protein isolates were noted at 12.0% (w/v).