Optimization of ultrasound-assisted extraction of phenolic compounds from jussara (Euterpe edulis M.) and blueberry (Vaccinium myrtillus) fruits

Abstract This study was aimed at optimizing the ultrasound-assisted extraction (UAE) of phenolic compounds from jussara and blueberry fruits using the response surface methodology (RSM). UAE was found to be more efficient to extract phenolic compounds from both fruits than the conventional extraction. The optimum extraction conditions for the jussara fruits were: extraction time between 30 and 62 min for total anthocyanins and total phenolics, fruit:solvent ratio of 10% and 6% (w/v) for total anthocyanins and total phenolics, respectively. The ethanol concentration was non-significant (p> 0.05). Acidified water was found to be an extracting solvent as efficient as ethanol in the extraction of phenolic compounds from jussara fruits. The optimum extraction conditions for blueberry anthocyanins were: ethanol concentration between 20-70% vol, and fruit: solvent ratio greater than 20% (w/v) within the range studied. The extraction time was not significant (p> 0.05). For total phenolic content: the concentration of ethanol was between 40-80%, and fruit: solvent ratio greater than 20% (w/v) and extraction time over 50 minutes. It was possible to adjust the mathematical model for the coordinates a* (verde vs vermelho) and C* (color saturation) of the jussara extracts.

摘要 本研究旨在采用响应面法（response surface methodology, RSM）优化超声辅助提取（ultrasound-assisted extraction, UAE）尤萨果（jussara）与蓝莓果实中酚类化合物的工艺。结果表明，相较于传统提取方式，超声辅助提取对两种果实中酚类化合物的提取效率均更为优异。
尤萨果的最优提取条件如下：总花青素与总酚类的提取时间区间为30~62 min；果实与溶剂的质量体积比（weight/volume, w/v）分别为10%与6%，适配总花青素与总酚类的提取需求；乙醇浓度对提取结果无显著影响（p>0.05）。此外，研究证实酸化水作为提取溶剂，其提取尤萨果中酚类化合物的效果与乙醇相当。
蓝莓花青素的最优提取条件为：乙醇体积浓度介于20%~70%，在所考察的参数范围内，果实与溶剂的质量体积比需大于20%（w/v）；提取时间对提取结果无显著影响（p>0.05）。针对总酚类含量的优化条件则为：乙醇浓度介于40%~80%，果实与溶剂的质量体积比大于20%（w/v），且提取时长需超过50 min。
本研究可针对尤萨果提取物的a*（绿色-红色轴）与C*（色彩饱和度）坐标参数拟合适配的数学模型。