超声辅助低共熔溶剂制备咖啡果皮可溶性膳食纤维

Preparation of Soluble Dietary Fiber from Coffee Peel by Ultrasonic-Assisted Deep Eutectic Solvent

为进一步探索制备咖啡果皮中可溶性膳食纤维的绿色新方法。本研究建立了一种省时、高效、环保的超声辅助低共熔溶剂(UAE-DESs)制备咖啡果皮可溶性膳食纤维(SDF)的方法,并通过单因素试验和响应面试验优化了其工艺参数。采用加热法制备了8种氯化胆碱基的DESs作为提取溶剂,并与传统水提法作对比。结果表明:氯化胆碱与尿素摩尔比为1∶2的DES体系制备的咖啡果皮SDF得率最高,为10.10%±0.11%,显著高于传统水提法(6.50%±0.22%)。通过单因素实验,探讨了DES组成(摩尔比、含水量、液固比)和超声波处理(超声功率、超声时间)对咖啡果皮SDF得率的影响。在此基础上,采用响应面法(RSM)结合Box-Behnken设计(BBD)对SDF得率进行优化,考察DES含水量、液固比、超声功率和超声时间对SDF得率的影响。根据RSM的优化结果,确定最佳制备条件为:DES含水量为39.91%,液固比为32.37 mL/g,超声功率为305.20 W,超声时间为33.80 min,在此条件下,咖啡果皮SDF得率最大,为10.74%±0.14%,与其预测值10.80%接近。因此,DES作为一种高效、无污染的绿色溶剂,可用于咖啡果皮SDF的制备。本研究结果将为咖啡果皮可溶性膳食纤维的制备提供新思路和理论参考,并在咖啡副产物的增值利用、生产新型高附加值产品以及开发天然功能性食品等方面具有潜在的应用前景。

A time-saving,efficient and environmentally friendly method for the preparation of soluble dietary fiber(SDF)from coffee peel with ultrasound-assisted low eutectic solvents(UAE-DESs)was established for the first time,and its process parameters were optimized by single-factor test and response surface test to further explore a new green method for the preparation of soluble dietary fiber from coffee peel.Eight choline chloride-based deep eutectic solvents were prepared as extraction solvents by the heating method and compared with the conventional water extraction method.The results showed that the deep eutectic solvent system with a 1∶2 molar ratio of choline chloride to urea prepared the highest yield of soluble dietary fiber from coffee peel at 10.10%±0.11%,which was significantly higher than that of the conventional water extraction method at 6.50%±0.22%.The effects of DES composition(molar ratio,water content,liquid-to-solid ratio)and ultrasonic treatment(ultrasonic power,ultrasonic time)on the yield of soluble dietary fiber from coffee peel were investigated by single-factor experiments.The response surface methodology(RSM)combined with Box-Behnken design(BBD)was used to optimize the soluble dietary fiber yield and investigate the effects of deep eutectic solvent water content,liquid-solid ratio,ultrasonic power and ultrasonic time on the yield of soluble dietary fiber.Based on the optimization results of RSM,the optimal preparation conditions were determined as follows:water content of deep eutectic solvent 39.91%,liquid-solid ratio 32.37 mL/g,ultrasonic power 305.20 W,and ultrasonic time 33.80 min.Under this condition,the maximum soluble dietary fiber yield of coffee peel was 10.74%±0.14%,which was close to the predicted soluble dietary fiber value of 10.80%.Therefore,as an efficient and non-polluting green solvent,deep eutectic solvent can be used for the preparation of soluble dietary fiber from coffee peel.The results of this study would provide new ideas and theoretical references for the preparation of soluble dietary fiber from coffee peel,and have potential applications in the value-added utilization of coffee by-products,the production of new high value-added products and the development of natural functional foods.