Modification of Salt Using Spray Drying and Odor-Induced Saltiness Enhancement

Abstract

The goal of this research was to modify salt using spray drying and odor-induced saltiness enhancement (OISE). The identification of different types of odor potentially enhancing saltiness perception was examined by literature reviews and focus group interviewing. Result from six focus group interviews (n = 48 total) evidenced that most participants were aware of the sources of salty taste in foods and the adverse health effects of high salt intake and knew how to reduce salt in their diets. In addition, the participants identified sixty seven odor items based on their consumption experiences and behavior that were associated with salty perception. Only fifty seven food odor names available in the market were selected in a salty intensity rating test through self-administrated questionnaire. Four-hundred ten participants pointed out that fish sauce, fermented fish, salted fish, salted crab and soy sauce as Thai condiment items were mostly associated with salty taste perception. Only soy sauce odor was selected as representation to study effects of the OISE. In this research, we determined if tasteless soy sauce odor could be used to induce and enhance salty taste perception in water and salt solution models, respectively. The sensory threshold technique (ASTM E679-04, the ascending forced choice method of limits) was used to determine thresholds. Group best estimate threshold geometric means of soy sauce odor were expressed as parts-per-billion (ppb). Soy sauce odor could induce salty taste perception in water with the saltiness recognition threshold of soy sauce odor at 28.45 ppb. Furthermore, soy sauce odor enhanced salty taste perception in 0.02 M salt solution with the difference threshold of soy sauce odor at 122.71 ppb. Through the odor-taste interaction concept, this study demonstrated that the tasteless soy sauce odor could induce and enhance salty taste perception, which could be applied in development of low-sodium foods. Reduced sodium salt product developed by OISE using soy sauce odor powder in conjunction with process modification of salt production was investigated on its effect on perceived saltiness and consumer liking in roasted peanut. Result showed that the saltiness can be enhanced by using 50% soy sauce odor powder replacing commercial salt. Moreover, the reduced salt sample with 50% of soy sauce odor powder was not significantly preferred (P≥0.05) than the normal sample (100% salt). The level of soy sauce odor powder at 50% was used together with modified salt from spray drying process. The spray dried salt contained 0.03% moisture, 0.651 water activity and 0.74 g/mL bulk density. The spray dried salt in this research is typically small cubic shape, with the size in the range of 6.42-27.04 µm. The result from salty intensity rating and consumer testing of roasted peanut with salt from 2x2 factorial experiment designs showed that the type of salt and the concentration of soy sauce odor affected perceived saltiness, overall liking and liking of overall flavor and salty attributes. Investigation of consumer liking of roasted peanut containing spray dried salt with soy sauce odor powder at a ratio of 1:1 revealed that mean hedonic scores of all sensory attributes were between like moderately and like very much (72.9-75.0 scores).