Sodium reduction in snack foods via optimized microstructural design of sodium delivery system

Excessive sodium consumption can result in hypertension, diabetes, heart diseases, stroke and kidney diseases. Chips, extruded snacks, and tortilla/corn chips accounted for almost 56% of snacks retail sales in 2010 and hence it is important to target sodium reduction in this area. Past studies had shown that modifying the rate-release mechanism of sodium is a promising strategy for sodium reduction in the food industry. Encapsulation or immobilization of salt can be a possible technique to control sodium release rate. The overall objective of this study was to develop effective immobilization methods to obtain different release profiles of sodium and saltiness perception. Two potential sodium carriers, porous corn starch (PCS) and lipoproteic matrix, were investigated to determine if sodium release profile could be controlled. The overall objective consisted of four specific objectives. The first specific objective was to examine PCS as a sodium carrier to modify sodium release profiles. The porous corn starch was produced by enzymatic treatment and characterized for its adsorption, morphology and porosity by gas multipycnometer. Salt was immobilized using PCS by spray-drying and their in vitro sodium release was measured by a conductivity meter. PCS was found to be unsuitable as a carrier as different enzymatic treatment time had no effect on its sodium release profile, and it could not effectively immobilize sodium inside its pores. The second specific objective is to immobilize salt in lipoproteic matrices and modify sodium release profiles. Lipoproteic matrix was developed by creating a gel from a homogenized emulsion, followed by freeze drying and grinding into fine powders. The powders were characterized for their morphology, porosity, sodium distribution and in vitro sodium release. The SEM images and CT-scan showed salt dispersed throughout the matrix. The lipoproteic matrices had different sodium release profiles compared to commercial salts, and protein content and fat content altered the release profiles. The lipoproteic matrices were selected as a sodium carrier and used for sensory analyses. The third specific objective was to evaluate the saltiness perception of the immobilized salt in lipoproteic matrix using Time-Intensity (TI). Saltiness perception of the 9 different immobilized salts in the lipoproteic matrices and 3 commercial salts were evaluated using TI with anchored structured line scale. Results from clustered panelists showed that some of the immobilized salts had higher maximum saltiness intensity, area under the TI curve, and maximum rate of saltiness incline compared to flour salt. The lipoproteic matrix was found to have potential as a sodium carrier. The fourth specific objective consisted of evaluating acceptance of a salty snack with regular sodium level and reduced sodium level of the immobilized salt in lipoproteic matrix, and a commercial salt. Acceptance test with 9-point hedonic scale was done with potato chips coated with regular sodium level and 25% reduced sodium level of flour salt and a single formulation of the immobilized salt. Potato chips coated with flour salt had higher acceptance scores in general compared to the immobilized salt. The findings of this study showed that the immobilized salts in the lipoproteic matrix were able to modify sodium release profiles and saltiness perception. Immobilized salts can be utilized in the food industry for topical applications on appropriate food systems