Better Soy-Milk Calcium Fortification

WHITEKNIGHTS,UKSoymilk has a healthful mix of nutrients but, compared to cows milk, it comes up short in the calcium department unless it is fortified. Natural soy milk contains only 200 mg calcium per liter, about 1/6 that of cows milk. Fortification can be problematic because of the tendency of the calcium to precipitate out or coagulate in the soymilk matrix. To mitigate the problem, researchers at he University of Reading, Whiteknights, investigated the effects of different chelating agents on some of the physicochemical properties of soymilk and their ability to prevent coagulation. The soymilks underwent pasteurization to look at changes in these properties and the effect of heat on stability.

The researchers found that decreasing ionic calcium and increasing pH reduced sediment formation and susceptibility to coagulation, with trisodium citrate and sodium dihydrogen phosphate, the most effective chelating agents. These compounds also reduced viscosity and particle size. Sodium hexametaphosphate was less effective, reducing ionic calcium but not greatly affecting pH. The disodium salt of ethylenediamine tetraacetic decreased the pH of soy milk, so it did not have a positive effect.