Stabilization of emulsions and foams using barley beta-glucan

Barley beta-glucan (BBG) is receiving increasing attention as a food hydrocolloid. Stability of foams and emulsions was assessed using whey protein concentrate (WPC) as an emulsifier and foaming agent, and BEG gum extracted at pilot plant or laboratory scale as a stabilizer. WPC had a significant lowering effect (P less than or equal to 0.05) on surface tension of water and water-oil interfacial tension, while the effect of beta-glucan was time dependent. Differential scanning calorimetry (DSC) showed that BBG formed a gelled network, responsible for stabilizing, that melts at 58-62 degrees C. Reversible gels of BBG melt around 63 degrees C. Emulsion (50% o/w) droplet size decreased several fold when prepared with BBC gum and phase separation was substantially decreased. Foam volume and 50% drainage were significantly (P less than or equal to 0.05) improved upon addition of beta-glucan. Sugar significantly enhanced foam stability only when used together with beta-glucan. BBG shows potential as a stabilizer in foam- and emulsion-type food products. (C) 2000 Elsevier Science Ltd. All rights reserved.