Nutritional Content of Rice
Rice is a nutritional staple food which provides instant energy as its most important component is carbohydrate (starch). On the other hand, rice is poor in nitrogenous substances with average composition of these substances being only 8% and fat content or lipids only negligible, i.e., 1% and due to this reason it is considered as a complete food for eating. Rice flour is rich in starch and is used for making various food materials and is also used in some instances by brewers to make alcoholic malt. Likewise, rice straw mixed with other materials is used to produce porcelain, glass, and pottery. Rice is also used in manufacturing of paper pulp and livestock bedding.
The variability of composition and characteristics of rice is really broad and depends on variety and environmental conditions under which the crop is made. In husked rice, protein content ranges between 7% to 12%, which can vary up to 6 to 7 percentage points for the same variety depending on environmental conditions of cultivation. Also, the increase of nitrogen fertilization increases the percentage content of some amino acids, while decreasing or unchanged for others.
The comparative table in the picture below shows the nutritional content of major cereals for human consumption. You can view the difference in nutritional content of bran rice and raw rice.
As for the vitamins and minerals, there are significant differences between different kinds of rice. For example, brown rice is rich in some vitamins, especially B1 or thiamine (0.34 mg), B2 or riboflavin (0.05 mg), niacin or nicotinic acid (4.7 mg) and PP. In contrast, the white rice is poor in vitamins (0.09 mg of vitamin B1, vitamin B2 0.03 mg and 1.4 mg of niacin) and minerals as they are found mostly in the outer layers of the grain, which are removed by polishing process, or "bleaching" whereas parboiled rice is rich in these vitamins as a result of their particular process, although fewer than brown rice.
Cooking procedures can reduce the richness of vitamins and minerals in rice, and in fact, cooking is usually done with water which is then neglected and much of these nutrients dissolve in water and get wasted. Also it is interesting to note that since ancient times, the digestibility of rice is very popular. Yes, it is an easily digestible food therefore it has been strongly recommended in preparing specific diets against stomach and intestinal disease processes as well as feeding the infants and old people.