Enrichment of rice with natural thiamine using high-pressure processing (HPP)

Abstract

Rice, one of the most widely consumed foods across the world, is a cereal grain which forms the staple diet of many people. The process of obtaining white rice involves the husking of paddy/rough rice, followed by polishing to remove the bran layer. When brown rice is polished, rice loses many vitamins and minerals through the bran. An important nutrient of these is thiamine (Vitamin B1), an essential vitamin, deficiency of which is known to cause beriberi. Brown rice does not have a long shelf-life because it is prone to oxidation due to the presence of unsaturated fatty acids in the bran layers. It also possesses a nutty flavour which is not very palatable. This research outlines the treatment of paddy rice with High-Pressure Processing (HPP), thereby obtaining rice that possesses higher amounts of natural thiamine. HPP is known to produce gelatinizing effects in rice starch. Differential Scanning Calorimetry and X-Ray Diffraction were conducted to find the degree of gelatinization and crystallinity, respectively, of samples subjected to different treatment temperatures (50 and 70 °C), pressures (450 and 600 MPa) and times (15 and 30 min) during HPP. The rice samples were checked for thiamine using the fluorometric method. It was observed that HPP produced some gelatinization in rice and significantly increased thiamine content of it with higher temperature and pressure. This method of treatment was found to be shorter and showed good potential in thiamine enhancement of white rice with higher organoleptic attributes.