Comparative analysis of nutritional and functional components of different colored rice varieties in Guangxi

【Objective】To compare the differences in nutritional and functional components of different types of colored rice varieties in Guangxi,and provide theoretical basis for the development and utilization of colored rice in Guangxi.【Method】Six main locally grown colored rice varieties(4 red rice varieties and 2 black rice varieties)from Bama County, Guangxi were selected as experimental materials,with white rice as the control. Using national food safety standard methods and reagent kit detection methods,19 nutritional components and 6 functional components of brown rice,a local variety of colored rice,were determined. Statistical analysis,color difference analysis,and correlation analysis were conducted to clarify the differences and dominant components of different varieties of colored rice.【Result】The contents of protein,dietary fiber,vitamin B₂(V_B2),vitamin E(V_E),anthocyanin and flavonoid of colored rice in Bama County were significantly higher than those of white rice(_P<0.05,the same below),which were 18.9%-44.6%,27.0%-90.4%,9.1% -134.0%,29.2%-109.1%,197.7%-565.8%,10.8%-42.1% higher respectively. Other components varied depending on the variety type. Among the nutrients,the amino acid composition of Nayi short straw black glutinous rice,Nayi long straw black glutinous rice and Pobang red rice was balanced and reasonable,and the essential amino acids/non-essential amino acids value was 54.40%-55.75%,which was close to the Food and Agriculture Organization of the United Nations/World Health Organization(FAO/WHO)model (60.00%). The fat content of Nayi short straw black glutinous rice and Nayi long straw black glutinous rice were 22.6% and 17.0% higher than that of white rice,respectively. The amylose content of four red rice varieties was 18.8%-82.0% higher than that of white rice. The mineral elements in Longwei red rice and Nayi long straw black glutinous rice were rich,and contents of copper(Cu),manganese(Mn),zinc(Zn)and selenium(Se)were significantly higher than white rice. Nayi long straw black glutinous rice was rich in vitamins,the contents of vitamin B₁ (V_B1),V_B2,vitamin C(V_C)and VE were significantly higher than those of white rice. Among the functional components, two black rice varieties,Longwei red rice and Longwei red japonica rice were abundant,but the most dominant components were different among different varieties. The anthocyanins content of Nanyi short straw black glutinous rice were 565.8% higher than that of white rice,the proanthocyanidins and β-carotene contents were 26.8 and 20.5 times as that of white rice,and the sterols content of Nanyi long straw black glutinous rice were 10.5% higher than that of white rice. The γ -aminobutyric acid(GABA)content of Longwei red japonica rice was 25.6% higher than that of white rice,and the flavonoid content of Longwei red rice was 42.1% higher than that of white rice. The greater the color difference between colored rice and white rice,the greater the total chromaticity value of the color difference(△E). Red rice △E ranged from 18.63 to 27.37,while black rice △E ranged from 32.62 to 33.52,which was consistent with the visual perception of rice grains. Correlations among total color difference,nutrition and functional components were analyzed,and 21 of 325 correlations among 25 indexes were found to reach significant level.【Conclusion】Colored rice contains common advantageous components,and although they have the same origin,there are differences due to different types of varieties,manifested as containing other advantageous components with different characteristics. In production,targeted processing,utilization, and industrial development can be carried out based on product positioning. It is concluded that Nayi short straw black glutinous rice and Longwei red rice have higher development and utilization value.