Submicronization of sodium chloride and its effect on the physico-chemical and microbiological characteristics of surface salted cheese crackers
Reducing particle size of salt to submicron range increases its surface area. The objective of this study was to develop submicro salt (sodium chloride) by using a nanospray drying method and using the developed submicro salt in surface salted cheese crackers and evaluating their physico-chemical, and microbiological characteristics. The sodium chloride solution (3% w/w) was sprayed through the nozzle size of 4 μm with air flow of 125 l/min, pressure of 3800 Pa, head temperature of 95°C and spray percentage of 90%. The processing parameters were optimized to ensure formation of the smallest size submicrosalt, as measured by Scanning Electron Microscopy and Dynamic Light Scattering. The cheese cracker treatments consisted of 3 different salt sizes (regular, microsalt and submicrosalt) and 3 different concentrations (2, 1.5 and 1%). The 9 (3 sizes x 3 concentrations) different cheese cracker treatments were tested for salt concentration and sodium content at week 1. Water activity (Aw), yeast and mold counts, texture-fracturability, and color were determined at week 1 and 4 months of storage. Completely Randomized Design (CRD) was used for salt and sodium content and CRD with repeated measures was used for Aw, yeast and mold counts, texture-fracturability, and color. The 80% of the submicro particles produced by the nanospray dryer B-90 was between 500 nm to 1900 nm. Yeast counts and Aw in all treatments increased from 1 week to 4 months. Submicrosalt treatments (2, 1.5 and 1%) had positive effect in yeast reduction at 4 months compared to regular salt (2, 1.5 and 1%). There was no mold growth in all treatments at all times. The L*, b*, C* and h* values in all treatments increased significantly (P<0.05) from 1 week to 4 months. The sodium chloride micro and submicro particles maintained low counts in yeasts, no counts in molds and did not adversely influence quality attributes.
Keywords: Submicro, salt, cheese cracker