Determining sequential difference thresholds for sodium chloride reduction

In response to the Institute of Medicine's suggestion for an industry-wide mandate on salt reduction via gradual stepwise decline of salt in foods, the objective of this study was to determine a set of sequential difference thresholds for sodium chloride reduction in plain water, and in water with added taste stimuli (sucrose, citric acid, caffeine, monosodium glutamate, disodium 5′- inosinate and disodium 5′- guanylate) to simulate a more complex-flavored broth. Ten subjects were recruited from a trained descriptive analysis panel of 6-n-propylthiouracil tasters and supertasters. Using paired-comparison tests, difference thresholds were established for each of the two described solutions starting at a salt concentration comparable with that of commercially available soup, and ending at a concentration required to meet the Food and Drug Administration's low-sodium guidelines. From these thresholds, two series of concentrations were established: a 26-step reduction for salt in water, and a 12-step reduction for salt in water with added stimuli. The difference in the number of steps illustrates the importance of product complexity in determining sensitivity to sodium reduction and provides basic information for manufacturers interested in gradually decreasing salt content of foods without being noticed by consumers.