Total and free amino acid contents of popular rice varieties (Oryza sativa L.) consumed in the capital city of Sri Lanka

Abstract

This study investigated the amino acid composition of eight local and three imported rice varieties frequently consumed by consumers in the capital of Sri Lanka. Investigation included twenty free amino acids (FAAs) analysed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and sixteen protein bound amino acids analysed using high performance liquid chromatography with diode array detection (HPLC-DAD). The mean total amino acid (TAA) in rice ranged between 64.5 ± 1.9 g/kg and 96.0 ± 5.1 g/kg on dry basis (db). Ponni, Basmathi, Rathu Nadu and Fragrant rice which were parboiled varieties, reported the overall highest mean TAA contents while imported Ponni and Basmathi exhibited the highest mean essential amino acid (EAA) contents depicting high quality protein. Red rice varieties of Nadu, Kekulu and Kekulu Samba reported signifi cantly (p < 0.05) higher mean TAA contents than their white counterpart varieties. The parboiled varieties; Rathu Nadu, Sudu Nadu, Keeri Samba and Samba reported the overall highest gamma amino butyric acid (GABA) contents (0.9 ± 0.3-5.0 ± 1.7 mg/100g). Completely polished Sudu Kekulu reported the overall lowest mean TAA, EAA and GABA contents. Except for unanalysed tryptophan, fi ndings revealed that disregarding the nutritional loss encountered during cooking irrespective of variety, consumption of approximately 100 g of raw rice (after cooking) three times a day will provide an average adult (of 50 kg body weight) more than 50 % of the daily intake of essential individual amino acids recommended by the Food and Agricultural Organization (FAO).

Variation in amino acid composition of rice ( Oryza sativa L.) as affected by the cooking technique

“…This method was validated (Liyanaarachchi et al, 2020a), and the performance characteristics of the method as indicated in Table 1 were found in compliance with the requirements specified in the international method guidelines for method validation.…”

“…The column was operated at 40°C. The detection of FAAs was performed using an Eksigent Expert Ultra LC 100 XL (Eksigent, Netherlands) UPLC system, coupled to an ABSciex (QTrap) 4500 series triple quadrupole linear ion trap mass spectrometer (Sciex, USA) in electro spray ionization (ESI) with multiple reaction monitoring (MRM) transitions (Supplementary Table S1) for the detection of FAAs including GABA as specified by Liyanaarachchi et al (2020a). The ion spray voltage was set at 5500 V, while the source temperature was maintained at 500°C.…”

Pre‐gelatinization and cellulase addition improve fermentation performance and antioxidant activity of black rice wine

“…FAAs were analyzed using an automatic amino acid analyzer (S‐4330D, Sykam, Munich, Germany) according to the method of Liyanaarachchi et al 17 …”

“…FAAs were analyzed using an automatic amino acid analyzer (S-4330D, Sykam, Munich, Germany) according to the method of Liyanaarachchi et al 17 Volatile flavor substances analysis Gas chromatography-mass spectrometry (GC-MS) was applied to determine the content of volatile flavor substances and 2-octanol was used as the internal standard according to our previous publication. 18 Each rice wine sample was diluted with deionized water to a final concentration of 6% (v/v) ethanol.…”

Mapping Productivity-related Spatial Characteristics in Rice-based Cropping Systems in Sri Lanka

“…Apart from dietary carbohydrates, rice also contains proteins, lipids, minerals, and vitamins (Fageria 2015 ). The annual per capita consumption of rice in Sri Lanka is 105 kg indicating the major contribution of rice to the Sri Lankan diet (Jayatissa et al 2014 ; Liyanaarachchi et al 2020 ). Moreover, the daily rice consumption is 300.6 g/capita/day in Sri Lanka, ranking at the 9th highest in the world.…”