Study the differences in vitamin B levels/contents of selected Sri Lankan traditional rice (Oryza sativa L.) varieties.

Abstract

Rice is one of the most widely consumed cereals in the world including Sri Lanka and the average annual per capita consumption of rice in Sri Lanka is approximately 107 kg. It is a good source of minerals (magnesium, phosphorous, manganese, selenium, iron) and vitamin B (folic acid, thiamin, pyridoxine and niacin) and is known to vary among rice varieties. To date, there are extremely limited studies on vitamin B contents of Sri Lankan traditional rice varieties. This study was evaluated vitamin B contents of ten traditional rice varieties of Sri Lanka (namely Herath Banda, Kalu Heenati, Kahawanu, Kurulu Thuda, Madathawalu, Murungakayan, Pachchaperumal, Pokkali, Rathel and Suwadel). Vitamin B was extracted from whole grain rice flour and simultaneously analyzed using High- Performance Liquid Chromatography coupled with a Diode- Array Detector (HPLC-DAD) set at operating wavelengths of 266, 270 and 275 nm. Results were expressed as mean ± standard deviation of triplicate (n = 3) analysis on dry weight basis for whole grain rice and data were statistically analyzed using SPSS version 20. One-way analysis of variance (ANOVA) and Tukey HSD post-hoc test was used for the multiple comparisons of mean differences among the rice varieties. Results clearly showed that vitamin B content significantly (p<0.05) varied between the studied rice varieties and B1, B2, B3, B5, B6 and B9 contents of were ranged from 4.1- 20.3, 0.7 - 7.7, 29.7 – 111.9, 7.7 – 93.9, 7.7 – 22.5 and 0.7 – 2.0 μg/g (on dry basis) of whole grain rice respectively. Vitamin B3 and B5 were abundantly present in studied rice varieties. Among the studied rice varieties, vitamin B1 was significantly highest (20.3 μg/g) in white rice variety, Rathel. The highest vitamin B2 (7.7 μg/g), B3 (111.9 μg/g) and B6 (22.5 μg/g) contents were found in white rice variety, Suwadel. Vitamin B5 was significantly highest (93.9 μg/g) in red rice variety, Pokkali whereas, the lowest (7.7 μg/g) was in Rathel. Almost all the studied rice varieties in their raw whole grain form contained vitamin B amounts higher than the Recommended Daily Intake (RDI) values. However, vitamin B is susceptible to losses during rice milling and cooking processes. Nevertheless, the knowledge of vitamin B contents and their variation among Sri Lankan traditional rice varieties may be important for achieving nutritional security or combatting vitamin B malnutrition in rice consumers through the development and distribution of new rice varieties rich in the vitamin B complex.