Abstract Mulberry red pigments are safe, nontoxic and are one of the 48 natural pigments officially approved in China. Cyanidin-3-O-glucoside accounts for about 20 % of the total mulberry red pigments and has high physiological activity. Therefore, a novel microfluidic aqueous two-phase system with immobilized enzyme was constructed to enhance the cyanidin-3-O-glucoside content in red pigments under parallel-laminar flow condition for the first time. The effects of two-phase flow rates, temperature, pH and substrate concentration on cyanidin-3-O-rutinoside conversion and cyanidin-3-O-glucoside purity were investigated. The cyanidin-3-O-rutinoside conversion was 75.66 % within 8.59 s, and the purity of cyanidin-3-O-glucoside in the product was 88.78 % with an increase of 68 %. The immobilized enzyme could be reused seven times, maintaining a relative activity over 60 %. Compared with aqueous two-phase system, the overall reaction efficiency of mulberry red pigments in microfluidic aqueous two-phase system was higher. Cyanidin-3-O-rutinoside and cyanidin-3-O-glucoside were identified by HPLC-PDA-ESI-MS/MS. Overall, a new kind of high-quality red mulberry pigments with a cyanidin-3-O-glucoside purity close to 90 % was prepared using the innovative system quickly and effectively. This is of great significance for resource utilization.

中文翻译：

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一种新型的固定化酶微流体水性两相系统提高桑果红色素中花青素-3-O-葡萄糖苷含量

摘要 桑红素安全、无毒，是我国正式批准的48种天然色素之一。Cyanidin-3-O-葡萄糖苷约占桑树红色素总量的20%，具有较高的生理活性。因此，首次构建了一种新型的固定化酶微流体水性两相体系，以提高平行层流条件下红色颜料中的花青素-3-O-葡萄糖苷含量。研究了两相流速、温度、pH 和底物浓度对 cyanidin-3-O-rutinoside 转化率和 cyanidin-3-O-glucoside 纯度的影响。8.59 s内花青素-3-O-芸香苷的转化率为75.66%，产品中花青素-3-O-糖苷的纯度为88.78%，提高了68%。固定化酶可重复使用七次，保持相对活性超过 60%。与水性两相体系相比，桑红素在微流控水性两相体系中的整体反应效率更高。Cyanidin-3-O-rutinoside 和 cyanidin-3-O-glucoside 通过 HPLC-PDA-ESI-MS/MS 进行鉴定。总体而言，使用该创新系统快速有效地制备了一种新的高品质红桑色素，其 cyanidin-3-O-glucoside 纯度接近 90%。这对资源利用具有重要意义。使用该创新系统快速有效地制备了一种新的高品质红桑色素，其 cyanidin-3-O-glucoside 纯度接近 90%。这对资源利用具有重要意义。使用该创新系统快速有效地制备了一种新的高品质红桑色素，其 cyanidin-3-O-glucoside 纯度接近 90%。这对资源利用具有重要意义。