Evaluation of the Soaking Conditions (Temperature and Time) on the Physicochemical Properties of Parboiled Rice: A Review

Soaking is a temperature-dependent process, which determines the rate of water diffusion into the rice kernel. Similarly, soaking also leaches the fiber, fat, and mineral composition of the rice kernel, thereby changing their composition in rice grain. This review aims to evaluate the effect of soaking conditions (temperature and time) on the physicochemical properties of selected parboiled rice varieties. As a result of the NERICA-4 rice variety, soaking at 65°C for 6 hours was the ideal temperature and time. Under these conditions, the ideal response variables for hardness, cooking time, moisture, ash, protein, fat, carbohydrate, energy, magnesium, potassium, and phosphorous content were 375.37 N, 52 min, 12.3%, 1.24%, 13.86%, 2.17%, 3.2942%, 67.1171%, 343.5 kcal/100 g, 274.72 mg/100 g, and 268.31 mg/100 g, respectively. The soaking temperatures and time is an essential operation in the process and affects the quality characteristics of the rice, including its physical characteristics, chemical composition, starch characteristics, cooking characteristics, etc. The functional characteristics are conducted to identify and possibly better determine how new proteins, fats, fibers, and carbohydrates can perform in specific systems and demonstrate whether or not such proteins can be used to stimulate or replace conventional proteins. Finally, the results demonstrated that the research environment's optimal parboiling settings were used to process rice types, in particular NARICA 4 rice variety, for enhanced physical qualities, proximate composition, and mineral content.