2004 Volume 10 Issue 2 Pages 227-231
Poly-γ-glutamic acid (γ-PGA) from Bacillus subtilis (natto) with a high molecular weight (Av. M.W.=350,000) effectively inhibited the formation of insoluble calcium phosphate at Ca/P=0.5 (12.5 mM/25 mM) under the condition of 37°C and pH 7.4. Since decrease in inhibitory activity in γ-PGA was observed after the treatment by simulated gastric fluid (pH 1.2, 0.5% pepsin), γ-PGA was encapsulated by egg lecithin liposome to keep the inhibitory activity under gastric conditions. Encapsulation was done by dehydration-rehydration (DR) and reverse-phase-vesicle (REV) methods. Higher encapsulation efficiency (57.0%) was achieved by DR method. Turbidity measurement at 450 nm indicated the high stability of DR microcapsule, prepared with trehalose, against gastric juice. Encapsulated γ-PGA by DR method showed 93.3% residual inhibitory activity after the gastric juice treatment.
