Effect of Parboiling Technique on the Nutritional Quality of Rice

Rice (Oryza sativa) is among the seven crops of priorities in Rwanda that play a role in food security within household. Different varieties of rice both short and long are grown in Rwanda, among them Zong zeng, Yune Eritian and XY are grown and consumed in almost all parts of the country. The same for other crops, a huge amount of rice produced is lost during handling activities before reaching the consumer. The loss includes breakage, and loss of nutrients due to the removal of bran and husk. Different techniques are used for the reduction of such post-harvest losses of rice and rice parboiling is among the most useful techniques applied to reduce postharvest losses of rice and is now applied in different parts of the world. However, this technique has not yet been adopted by Rwandans for prevention of loss of rice after harvesting. Therefore, the objective of the present study was to assess the effects of parboiling technique on physico-chemical parameters of different rice varieties grown in Rwanda and to do its awareness for Rwandan population. Three new varieties: Zong Zeng, Yune Eritian, and XY were further prepared and analysed in comparing with the same rice varieties that is not parboiled. Paddy was weighed, cleaned 3 times, pre-steamed, soaked in water of 80 0C at ratio of 1: 2.5 in water bath set at 800C for 4 and 6 hours, and then the steaming was done for 10 min at 100 0C. Drying followed in order to reduce the moisture content using the dryer set at (20-25°C) and the the final moisture content was13%. Dried rice was then milled in a mortar by use of a pestle to remove husks. Nutritional analysis was done by measuring Ash, protein, fat and Vitamin B1. The findings of the present study show that parboiling resulted in increase of Fat, Vitamin B1, Protein and Ash content. 4 hours soaking time showed effect on the acceptability as the rice soaked for 4hours has been more accepted compared to the one soaked for 6 hours. 6 hours soaking time resulted in considerable increase of B1 compared to other used soaking times. Therefore, we can conclude that parboiling method is a good method for reduction of rice lost during rice processors and fighting against diseases such as beriberi caused by deficiency of Vitamin B1 due to its associated increase in B1.

Keywords: Zong Zeng; Yune Eritian; XY parboiling; Steaming; Vitamin B1.

Abbrevations: ANOVA: Analysis of Variance; CAVM: College of Agriculture, Animal Sciences and Veterinary Medicine; FAO: Food Agricultural Organization; G: Grams; MINAGRI: Ministry of Agriculture and Animal Resources; MINICOM: Ministry of Trade and Industry; MT: Metric Tones; NISR: National Institute of Statistics Rwanda; %: percentage; RCA: Rwanda Cooperative Agency; RDB: Rwanda Development Board; UR: University of Rwanda; YE: Yune Eritian; ZZ: Zong Zeng