Controlling the kinetics of phase separation in milk containing nutritionally significant beta-glucan concentrations

N Sharafbafi1, SM Tosh2, M Alexander1, and M Corredig1 

1Department of Food Science, University of Guelph, Guelph, Ontario, Canada
2Agriculture and Agri-Food Canada, Guelph Food Research Center, 93 Stone Road West, Guelph, Ontario, Canada

Bioactivity of beta-glucans (BG) isolated from cereal grains depends on their molecular weight, the ratio of cellotriosyl to cellotetrasoyl units, and concentration in final food product3. FDA requires about 0.75 g/serving of BG to allow labelling food products as having cholesterol-lowering effect1. At this concentration, BGs have shown thermodynamic incompatibility when mixed with milk proteins2. The main objective of this work was to control kinetics of phase separation using rennet gelation of milk proteins, and create novel structures and textures with nutritionally significant concentration of BG. The key strategy was to induce gelation before addition of BG to milk. Different concentrations of high molecular weight oat BGs (0.15-0.9% (w/w) were mixed with milk before and after addition of rennet. Rheological measurements clearly indicated that addition of BG after pre-renneting of milk could retard phase separating effect in mixtures containing ≥ 0.3% (w/w) BG, which is required for its health claims.

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