Pedro Alessandra Cristina, Granato Daniel, Rosso Neiva Deliberali
Graduate Program in Food Science and Technology, State University of Ponta Grossa, Av. Carlos Cavalcanti, 4748, CEP 84030-900 Ponta Grossa, PR, Brazil.
Graduate Program in Food Science and Technology, State University of Ponta Grossa, Av. Carlos Cavalcanti, 4748, CEP 84030-900 Ponta Grossa, PR, Brazil.
Food Chem. 2016 Jan 15;191:12-20. doi: 10.1016/j.foodchem.2015.02.045. Epub 2015 Feb 16.
This study was aimed the extraction of total flavonoids, anthocyanins and phenolics, as well as the antioxidant activity of black rice (Oryza sativa) and to study the stability in relation to pH, light and copigmentation. Variations in temperature (10-50°C), time (20-80min), and solid-solvent ratio (1:15-1:45) were studied using a Box-Behnken design. The regression models were significant (P<0.001) and determination coefficients ⩾0.900. Extraction at 34.7°C for 80min using a solid:solvent ratio of 1:30 rendered an extract with 51.26mg 100g(-1) of flavonoids, 116.58mg 100g(-1) of anthocyanins, 520.17mg 100g(-1) of phenolics and 46.50% inhibition of the DPPH radical. A decrease in the color intensity was observed when pH values were changed while anthocyanins were reversible in the process of protonation/deprotonation. The addition of glucose, phytic and gallic acids in the optimized extract exposed to light displayed an intermolecular copigmentation. The main anthocyanin identified in black rice was cyanidin-3-glucoside.
本研究旨在提取黑米（水稻）中的总黄酮、花青素和酚类物质，以及其抗氧化活性，并研究其在pH值、光照和共色作用方面的稳定性。采用Box-Behnken设计研究了温度（10 - 50°C）、时间（20 - 80分钟）和固液比（1:15 - 1:45）的变化。回归模型具有显著性（P<0.001），决定系数⩾0.900。在34.7°C下以1:30的固液比提取80分钟，得到的提取物中含有51.26mg/100g的黄酮类化合物、116.58mg/100g的花青素、520.17mg/100g的酚类物质，对DPPH自由基的抑制率为46.50%。当改变pH值时，颜色强度降低，而花青素在质子化/去质子化过程中是可逆的。在优化提取物中添加葡萄糖、植酸和没食子酸后，光照下显示出分子间共色作用。黑米中鉴定出的主要花青素是矢车菊素-3-葡萄糖苷。
