Rice Products and Their Nutritional Status. Research Bulletin No. 23.

Abstract

Rice (Oryza sativa L.), the most popular cereal crop, is consumed as a staple food in the form of various processed product. Rice grain is harvested as rough rice after attaining maturity. The grain is generally stored at 12 to13% of moisture content for obtaining higher head rice recovery and better cooking quality. Rice grain is dehusked and milled by hulling and milling machine to get brown rice and milled rice respectively. Milling of brown rice is generally performed to increase the storability. Some varieties in which the kernel fused with some bran layers after milling are reported to contain higher phenolic compounds (hydroxybenzoic acids and hydroxycinnamic acids), flavonoids, minerals (iron and zinc), proteins, vitamin-E, γ-oryzanols and different proximate compounds as compared to white rice. In India, the rice grain have been utilised for making several products. The processing is mainly based on hydrothermal treatments of different forms of the grain. For every instance, the reorientation of starch granules is occurred. Amongst all the products, puffed rice is very popular in many countries as a breakfast component due to its lightness and crispiness. It is prepared from treated (hydro-heated i.e double parboiling) milled rice by heating in hot sand (200 -300⁰C), or also from raw milled rice in microwave oven or by the puffing gun. Puffed rice provides less calories compared to cooked rice, making it a better option for those who are considering losing weight that is low in calorie and as well as nutritious. Popped rice is a popular snack food in the south East Asian countries. It is prepared by putting moisture-adjusted paddy to high temperature, short-time treatment in sand medium, when the inner grain expands and is forced out through the opened husk like a flower. However, popping percent depends upon the genotypes. It is highly nutritious having more antioxidative compounds as compared to others. Flaked rice is obtained after hydrothermal processing of paddy and its further processing in a machine yields flaked rice of very low thickness with relatively lower weight. Flaked rice generally consumed as breakfast item and snacks, is specific to particular regions in India, Bangladesh and a few Asian countries. Flaked rice is rich source of carbohydrates, protein, vitamin-E, minerals (Fe), phytochemicals, and essential amino acids. Finally, cooked rice in different forms is very popular throughout the world though it is less nutritious than other products. It is most popular due to easy preparation technology and better sensory quality. There are two ordinarily home-cooked products found in Asian countries: rice porridge and cooked rice. A negative correlation between thermal processing and the content of antioxidative compounds, such as phenolic, flavonoids, vitamins etc has been proved. Therefore, information regarding nutritional profiling of various rice products is necessary for understanding our daily intake of nutritional compounds through rice.