Effects of physical and chemical properties on the dissolution of sea salt

Abstract

Salt plays a crucial role in human health. However, excess use of NaCl in food products can be harmful to health. One suggestion for this problem is optimization salt dissolution to increase the content of salt ions in the mouth. For this purpose, it is important to understand the solubility properties of salt crystals in saliva. The dissolving process is not only affected by the physical properties but also by the chemical composition of the salt. This study compared the solubility of four commercial grain salts in four regions in Vietnam (Bac Lieu, Thanh Hoa, Sa Huynh, Vung Tau), one flower salt in Sa Huynh and a control sample with two particle sizes 1 - 2 mm and 2 - 3 mm in a Saliva Artificial Gal – Fovet solution (SAGF). Dissolution was determined by analyzing microscopic images taken by the time and analysis by Bayesian and Partial Least Squared methods. The research evaluated the influence of physical properties (area, Feret's diameter, circularity, aspect ratio and solidity) and chemical compositions (sodium, potassium, magnesium, calcium and moisture content) on the dissolving process. Salt samples showed significant differences in physical and chemical properties by region. Morphological parameters are affected by conditions of salt crystallization that indicated through region of origin. Dissolution is evaluated through solubility coefficient, Sa Huynh flower salt and control salt have the highest solubility coefficient, simultaneously, it is also the smallest value of roundness and surface index. The projected area, magnesium and sodium content are the factors which strongly affecting on dissolution of salt samples. These results demonstrated the possibility to exploit these factors to adjust the solubility of salt as well as the perceived salinity over time.