Profiling of amino acids in traditional and improved rice (Oryza sativa L.) varieties of Sri Lanka and their health promoting aspects

Abstract

Investigation made on the variation in amino acid compositions among selected traditional and newly improved rice varieties cultivated in Sri Lanka is presented. The free amino acid (FAA) composition including gamma-amino butyric acid (GABA) and protein bound total amino acids (TAAs) of eleven traditional and seven improved rice cultivars grown at Batalagoda across the two major cultivating seasons in the country were evaluated. Significant variations (p < 0.05) in GABA levels, individual and total amino acids in free and protein bound form were observed among the studied varieties. Both traditional and improved varieties reported comparable mean total FAAs and TAA levels. However, significantly higher levels of GABA, which has health promoting functional properties, were found in newly improved rice varieties in comparison to the traditional varieties. Significant impact of seasonal variation on total amino acid levels was observed in majority of the varieties with most of the varieties reporting higher amino acid levels when cultivated during the “Maha”, which is the major cultivation season in the country. The Behethheenati rice out of the traditional, while Bg 300 rice out of the newly improved, was found the most beneficial among the investigated varieties. The potential significant contribution obtainable with several local traditional and improved varieties in fulfilling the majority of the recommended essential amino acid nutrient requirement in the daily diet by the world health organization is highlighted.