黑豆皮花色苷的酶法酰化制备及其稳定性分析

Preparation of enzymatically acylated anthocyanin from black soybean hull and its stability evaluation

摘要:

以黑豆皮花色苷矢车菊素-3-O-葡萄糖苷（cyanidin-3-O-glucoside，C3G）为原料，采用月桂酸为酰基供体，经酶法酰化制备具有亲脂性能的花色苷脂肪酸酰化产物。分别以黑豆皮粗提物（C3G含量35.8%）、纯化C3G样品（纯度>80%）、C3G标准品（纯度>98%）为底物进行酰化，通过改进反应溶剂体系，实现了黑豆皮粗提物中花色苷的高效酰化，酰化率达66.59%，产率达到C3G标准品酰化的75%，但工艺更为简单，底物无需纯化；酰化产物矢车菊素-3-O-葡萄糖苷月桂酸酰化物（cyanidin-3-O-glucoside-lauric acid，C3G-La）经液液萃取，纯度可达82.39%；经进一步正相硅胶分离纯化后，产物纯度达97.58%。稳定性试验发现，在pH为中性和酸性环境中，C3G-La的稳定性优于C3G，但二者在碱性和光照条件下稳定性均较差。

Abstract:

Cyanidin-3-O-glucoside (C3G) from black soybean hull was enzymatically acylated with lauric acid to achieve an anthocyanin derivative with improved lipophilic property. Various reaction solvent systems were tested and compared for the efficient acylation of anthocyanin by using crude black soybean hull extract (C3G content 35.8%), purified C3G sample (purity>80%), and C3G standard (purity>98%), respectively, as substrate. With the method developed, the acylation rate of the anthocyanin from crude black soybean hull extract reached 66.59%, which reached 75% of that from purified C3G; the acylated product, cyanidin-3-O-glucoside-lauric acid (C3G-La), reached a purity of 82.39% after simple liquid-liquid extraction, and further to a purity of 97.58% after separation and purification by normal phase silica gel. The stability test showed that C3G-La is more stable than C3G in either neutral or acidic pH environment, while both of them are labile under alkaline and light conditions.