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Controlling the kinetics of phase separation in milk
containing
nutritionally
significant
beta-glucan
concentrations
N Sharafbafi1, SM Tosh2, M Alexander1, and M Corredig1
1
Department of Food Science, University of Guelph, Guelph, Ontario, Canada
Agriculture and Agri-Food Canada, Guelph Food Research Center, 93 Stone Road
West, Guelph, Ontario, Canada
2
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.
References
1. Jenkins,D.J.A., Kendall,C.W.C., Vuksan,V., Vidgen,E., Parker,T., Faulkner,D.,
Mehling,C.C., Garsetti,M., Testolin,G., Cunnane,S.C., Ryan,M.A., & Corey,P.N. (2002)
Soluble fiber intake at a dose approved by the US Food and Drug Administration for a claim
of health benefits: serum lipid risk factors for cardiovascular disease assessed in a
randomized controlled crossover trial. American Journal of Clinical Nutrition 75, 834-839.
2. Kontogiorgos,V., Tosh,S.M., & Wood,P.J. (2009) Phase behaviour of high molecular weight
oat beta-glucan/whey protein isolate binary mixtures. Food Hydrocolloids 23, 949-956.
3. Tosh,S.M., Wood,P.J., Wang,Q., & Weisz,J. (2004) Structural characteristics and
rheological properties of partially hydrolyzed oat beta-glucan: the effects of molecular
weight and hydrolysis method. Carbohydrate Polymers 55, 425-436.