The Effects of Thermal Treatment on Lipid Oxidation, Protein Changes, and Storage Stabilization of Rice Bran

Abstract

Rice bran is a nutrient-rich and resource-dense byproduct of rice milling. The primary cause of rice bran utilization limitation is oxidative deterioration and inadequate storage facilities. Improving stability to extend the shelf-life of rice bran has thus become an utmost necessity. This study aimed to stabilize raw fresh rice bran (RB) by using dry heat methods at 120 °C (233, 143, and 88 min) and 130 °C (86, 66, and 50 min). The results indicated that after dry heat pretreatment, peroxidase levels were at 90%, and the storage stability of dry-heat-stabilized RB was better. However, with an increase in treatment temperature and time, the peroxidase activity improved while the lipase activity decreased to a certain extent without significant changes. The total saturated and unsaturated fatty acids were significantly unchanged during storage, while oleic/linoleic acid increased substantially by 1% at 120 °C for 88 min. The increase in treatment time and temperature was beneficial in controlling the fatty acid values. However, extended treatment time caused an increase in the peroxide value and MDA. The essential and non-essential amino acid ratios, which evaluate a protein’s nutritional value, remained relatively stable. The essential subunit of rice bran protein was not affected by the temperature and time of dry heat treatment and storage time.