Calcium diglutamate improves taste characteristics of lower-salt soup

Objective: To ascertain (1) whether the taste characteristics of a conventionally-salted (150 mM NaCl) soup can be reproduced in soups of substantially lower NaCl level with the help of added glutamate, and (2) whether calcium diglutamate (CDG) is equivalent to monosodium glutamate (MSG) in its effect on the taste of soup. Design: Cross-sectional, with multiple measurements on each subject. Setting: Healthy university students. Subjects: A total of 107 volunteers, recruited by on-campus advertising. Methods: Subjects tasted 32 soups, with all possible combinations of four NaCl concentrations (0-150 mM), four glutamate levels (0-43 mM), and two glutamate types (MSG, CDG). Main outcome measures: Ratings of each soup on six scales (liking, flavour-intensity, familiarity, naturalness of taste, richness of taste, saltiness). Results: A 50 or 85 mM NaCl soup with added CDG or MSG is rated as high as, or higher than, a 150 mM NaCl soup free of added glutamate on five of the six scales (the exception being saltiness). CDG and MSG have equivalent effects. Conclusions: Addition of glutamate allows substantial reductions in Na content of soup, without significant deterioration of taste. CDG and MSG have equivalent effects, but use of CDG permits a greater reduction in Na intake.