离子液体辅助双水相系统提取茶渣中茶多酚工艺优化

为发展一种绿色、高效及温和的茶多酚提取方法,采用离子液体(IL)辅助乙醇/硫酸铵双水相系统(ATPS)提取茶渣中的茶多酚,考察了离子液体结构和用量对茶多酚得率和抗氧化性的影响,对提取工艺进行了正交试验优化。结果显示,少量IL添加可提高乙醇/硫酸铵ATPS的分相能力及其对茶多酚的得率,但对提取液的抗氧化活性没有明显影响;咪唑型离子液体对提取茶多酚具有更好的促进作用,咪唑环上侧链越长,其茶多酚得率越高;[C₄mim]Cl辅助乙醇/硫酸铵ATPS对茶渣中茶多酚得率明显高于其他体系,且其提取液中儿茶素类组分含量更高。茶渣多酚最佳提取工艺为[C₄mim]Cl质量分数10%、硫酸铵质量分数30%、乙醇体积分数60%,料液比1∶40 g/mL及超声功率540 W,在此条件下,茶渣中茶多酚得率为85.31±1.25 mg·g^-1。IL辅助双水相系统是一种有前景的茶多酚提取工艺,在保持茶多酚活性的同时,能获得较高的茶多酚得率和儿茶素类组分含量。

Optimization of the Extraction Technology of Tea Polyphenols from Tea Waste by Aqueous Two-phase Systems with Ionic Liquids as Additives

In order to propose a green, efficient and gentle method for extraction of tea polyphenols, ionic liquids (ILs) assisted ethanol/ammonium sulphate aqueous two phase system (C₂H₅OH/(NH₄) ₂SO₄ ATPS) was used as a alternative technique for extraction of the tea polyphenols in tea biomass, the effects of ionic liquids structures and amounts on the yield and antioxidant activity of tea polyphenols were studied, the optimal extraction was explored by orthogonal test. The results showed that the C₂H₅OH/(NH₄) ₂SO₄ ATPS added with ILs as adjuvants in small amounts displayed a better phase separation and a higher yield, but no notable influence on the antioxidant activity of the extracts. The ILs with imidazolium cation showed a better improvement in extraction of tea polyphenols, and higher yield of tea polyphenols was obtained when the imidazolium ionic liquids with a longer side chain. The[C₄mim]Cl assisted C₂H₅OH/(NH₄) ₂SO₄ ATPS showed a higher yield of polyphenols and a higher content of catechin than other extraction systems. The optimal extraction conditions of tea polyphenols concluded by the corresponding surface optimization method was that:[C₄mim]Cl and (NH₄) ₂SO₄ mass fraction was 10% and 30%, ethanol volume fraction was 60%, liquid to solid ratio was 1:40 g/mL, ultrasonic power was 540 W, thus the yield of tea polyphenols obtained was 85.31±1.25 mg·g-1 at the conditions. Ionic liquids assisted ATPS showed an promising extraction of polyphenols, while the biological activities of the tea polyphenols were remained and a higher yield of polyphenols and content of catechin components were obtained.