A Simple Approach to Determine Diffusion Coefficient of Salt in Various Foods

Abstract

This study presents a simple, low-cost methodology to experimentally determine salt diffusion coefficients in food matrices, demonstrated using five food types: potato, sweet potato, pumpkin, taro, and radish. Each sample was manually shaped into a sphere of known diameter and immersed in pre-mixed salt solutions. The salt concentration at the center of each sample was measured using a compact salt meter (LAQUAtwin-salt-11 by Horiba), and the data were fitted to a theoretical diffusion model to extract diffusion coefficients. The coefficients ranged from 6.0 × 10⁻¹⁰ m²/s in taro to 1.3 × 10⁻⁹ m²/s in pumpkin. The method was validated through simulation and titration, both showing strong agreement with experimental data and deviations under 10%. This approach stresses the simplicity, speed, and cost-effectiveness of the method in contrast to traditional techniques such as NMR and titration. Additionally, temperature effects were investigated, with experiments at 100°C yielding an activation energy of approximately 74 meV (7.13 kJ/mol). By successfully applying this method across diverse food types, this work offers a scalable and practical alternative for food processing, quality control, and educational purposes.