饮料体系中玫瑰茄花青素的稳定性

Stability of Roselle Anthocyanins in Beverages

摘要:

玫瑰茄花青素（Roselle Anthocyanins, RA）是一种天然功能性着色剂。为了研究RA在酸性饮料体系中的稳定性，该文通过pH示差法评估了pH、温度、金属离子、氨基酸、多酚和糖等常见物化因素对RA含量的影响。结果表明：RA仅在pH值≤3时呈现鲜艳的红色；RA的热降解规律符合一级动力学，半衰期在40、60、80、100 ℃下分别为5.89、2.28、1.52、0.97 h；金属离子Mg2+、Na+、K+、Ca2+对RA稳定性无显著影响，Al3+可使RA稳定性提高10.59%，而Cu2+、Fe3+和Fe2+则破坏RA的稳定性；4种多酚改善RA稳定性的能力为槲皮素（14.11%）>芸香叶苷（10.48%）>没食子酸（4.84%）≈阿魏酸（1.21%）；7种氨基酸中苏氨酸、甘氨酸和酪氨酸对RA的稳定效果最好，分别提高了15.99%、11.92%和11.89%；蔗糖、葡萄糖、果糖和木糖醇对RA稳定性无显著影响，而维生素C会引起RA的降解，质量浓度为2.0 mg/mL时可使RA稳定性降低23.74%。该研究可为RA作为功能性着色剂在酸性饮料的应用提供理论基础。

Abstract:

Roselle anthocyanins (RAs) are natural functional colorants. To study the stability of RAs in acidic beverages, the common physiochemical factors (pH, temperature, metal ions, amino acids, sugars, and polyphenols) influencing RA levels were evaluated using the pH differential method. The results showed that RA appeared bright red only at pH≤3. The thermal degradation pattern of RA followed first-order kinetics, with half-lives of 5.89, 2.28, 1.52, and 0.97 h at 40, 60, 80, and 100 ℃, respectively. Metal ions Mg2+, Na+, K+, and Ca2+ did not significantly influence the stability of RA, while Al3+ enhanced RA stability by 10.59%, and Cu2+, Fe3+, and Fe2+ reduced the stability of RA. The abilities of the four polyphenols to stabilize RA followed the order: quercetin (14.11%)>rutin (10.48%)>gallic acid (4.84%) ≈ ferulic acid (1.21%). Among the seven amino acids, threonine, glycine, and tyrosine had the most significant stabilizing effect on RA, increasing by 15.99%, 11.92%, and 11.89%, respectively. Sucrose, glucose, fructose, and xylitol had no significant effect on RA stability, whereas vitamin C induced the degradation of RA, reducing RA stability by 23.74% at a mass concentration of 2.0 mg/mL. This study provides a theoretical basis for the application of RA as a functional colorant in acidic beverages.