Effect of temperature and pH on stability of anthocyanin obtained from blueberry

Abstract

Temperature and pH are the key factors which affect the stability of blueberry anthocyanin and blueberry deep processed products, but the effect of temperature and pH on individual anthocyanin (IAC) in blueberries is lack of the further discussion. Blueberry extract containing a variety of anthocyanins was used as research material and modern analytical instrument was combined to investigate the effect of temperature and pH on the stability of blueberry total anthocyanin (TAC) and IAC. The half-life of blueberry TAC began to decrease rapidly from 60 °C with a final half-life of only one-third of 50 °C, or even the original quarter. The initial content blueberry TAC significantly reduced and the half-life t1/2 was only about 4 h at pH 8.0, 9.0. Ten kinds of anthocyanins carrying malvidin, delphinidin, petunidin, cyanidin four common aglycones from blueberry extract were identified. Malvidin-3-O-galactose and malvidin-3-O-arabinose were found to have the alkali resistance. The content of malvidin-3-O-arabinose increased after heated which was different from that of other blueberry anthocyanins under the condition of pH 5.0–6.0. The effect of pH and temperature on all IAC and TAC content were consistent. The results showed that low temperature and low pH were beneficial to the maximum stability of blueberry anthocyanins. What’s more, the data obtained from the research provided important guiding significance for the rational utilization of the abundant resources of blueberry fruit.