Proximate composition of Karkadeh (Hibiscus sabdariffa) seeds and some functional properties of seed protein isolate as influenced by pH and NaCl.
Seeds of an inbred line (B-11-90) of Karkadeh (Hibiscus sabdariffa) were investigated for their proximate composition (AOAC methods), nitrogen solubility and protein isolate (Karkadeh seed protein isolates [KSPI]) functional properties (standard methods). The fat and protein contents of the seeds were 22.43% and 32.46%, respectively. Nitrogen solubility was good in both water and 1.0 M NaCl at alkaline pH rather than at acidic pH, with better solubility at higher pH levels in water than in 1.0 M NaCl. The functional properties of the KSPI were as follows: water absorption capacity, 181 ml/100 g; fat absorption capacity, 110 ml/100 g; bulk density, 0.77 g/ml; and apparent viscosity (at 20 degrees C), 13.42 cps. KSPI showed a maximum foaming capacity at pH 12 and 1.6 M NaCl, a maximum emulsification capacity at pH 11 and 1.8 M NaCl, and a weaker foam stability at neutral pH than at acidic or alkaline pH, with a better foam stability at alkaline pH. The foam stability was considerably improved by treatment with 1.6 M NaCl.
Salah
E O Mahgoub
EO
University of Botswana, Gaborone, Botswana. mahgoubs@mopipi.ub.bw
Hayat
Z E Elbashir
ZE
D000042:Absorption; D004041:Dietary Fats / Q000138:chemical synthesis* / Q000302:isolation & purification; D004044:Dietary Proteins / Q000032:analysis*; D005285:Fermentation; D031584:Hibiscus / Q000737:chemistry*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen / Q000737:chemistry*; D009753:Nutritive Value; D010940:Plant Proteins / Q000032:analysis / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry*; D012995:Solubility; D013397:Sudan; D014783:Viscosity
D004041:Dietary Fats; D004044:Dietary Proteins; D010940:Plant Proteins; D009584:Nitrogen