三种有机酸对红豆越橘花青素的热稳定性研究

Effects of three organic acids on thermal stability of lingonberry anthocynanins

研究分析了红豆越橘花青素在光照和不同pH条件下花青素稳定性的变化;以及添加抗坏血酸、草酸和苹果酸后对花青素稳定性的影响。通过测定吸光值、颜色、ABTS和DPPH自由基清除能力等指标来反映花青素的稳定性。研究结果表明:红豆越橘花青素在可见光谱520 nm处有典型吸收峰;随着光照时间延长,吸光值也逐渐降低,最初2 d下降较明显,约下降30%;pH值为4～6的弱酸性条件下,吸光值无显著变化,随着pH增加,吸光值明显降低,pH值为7时吸光值变化最显著(p<0.05);草酸和苹果酸对红豆越橘花青素加热时吸光值和抗氧化性的改变均起稳定性作用;抗坏血酸会促进红豆越橘花青素吸光值的降低。

The stability of lingonberry anthocynanins （LA） was assessed under sun light, at different pH, and in the presence of ascorbic acid, oxalic acid, malic acid. The absorbance （Abs）, color, ABTS- and DPPH-scavenging activity were measured to reflect stability changes of LA. LA Abs decreased under sun light, especially during the first two days with 30% decrease. There was no obvious Abs change at 520 nm when LA was heated at pH4-6, while the significant change was observed at pH7. Oxalic acid and malic acid could protect LA from the thermal change in both Abs and antioxidant activity. LA Abs was decreased significantly in the presence of ascorbic acid.