Fried, sliced potato crisps were flavored with sodium chloride of varying size fractions to investigate the impact of salt crystal size on the delivery rate of sodium to the tongue and resultant saltiness, measured over 65 s with a defined chew protocol (three chews, then holding the bolus in the mouth without swallowing). Salt crystal size impacted upon the delivery rate and perceived saltiness. The smallest crystal size fraction dissolved and diffused throughout the mouth to the tongue saliva faster than the medium and the largest ones; the smallest crystal size fraction also had the highest maximum concentration and greatest total sodium. These results correlated well with the sensory perceived saltiness, where the smallest crystal size fraction resulted in the fastest Tmax, highest maximum saltiness intensity and maximum total saltiness. The different delivery rates can be explained by differential dissolution kinetics and enhanced mass transfer of sodium across the saliva.
Sodium reduction is a major challenge for the global food industry. The results of this work illustrate how modification of salt crystal size fraction might impact sensory perceived saltiness, and that a smaller crystal size fraction can achieve a greater maximum saltiness per unit of sodium consumed. There are a number of technical hurdles to be overcome before implementation of this approach, both practical (limitations in processability) and sensorial (changes in the time–intensity profile), but the results do demonstrate that enhanced dissolution and diffusion kinetics can be achieved through modification of salt crystal size, which should be seriously considered by snack food manufacturers when approaching product reformulation.