OPTIMIZATION OF DEHYDRATION AND EXTRACTION OF PHENOLIC COMPOUNDS FROM MANGO PEEL

Mango peel, a by-product obtained from the industrialization of this fruit, is a promising and inexpensive source of phenolic compounds. In the present study, both the drying of the mango peel and the extraction of phenolic compounds were optimized using the response surface methodology. In this sense, temperature and charge/area ratio were selected as depend variables to drying process. Instead, for the ultrasonic assisted extraction (UAE) the temperature, ethanol-water concentration and time were optimized. For both processes, the total phenolic content (TPC) and mangiferin concentrations were the response variables. The TPC and the xanthone concentration were determined by the Folin-Ciocalteu method and HPLC-ESI-IT-MSn, respectively. The optimal conditions for the dehydration process were 54 °C and 2.3 kg m-2, reaching a TPC of 21.7 ± 1.6 mg GAE g-1 dw and a concentration of mangiferin of 1.94 ± 0.22 mg g-1 dw. Regarding to UAE, the optimum conditions were 51 °C, 50% ethanol and 71 min. Under these conditions, the TPC was 19.5 ± 0.8 mg GAE g-1 dw and the mangiferin concentration corresponded to 1.50 ± 0.13 mg g-1 dw. Additionally, 38 compounds were identified in the extract obtained under optimal conditions.芒果皮作为芒果工业化加工的副产物，是一类极具应用前景且成本低廉的酚类化合物来源。本研究采用响应面法（Response Surface Methodology），对芒果皮干燥工艺与酚类化合物提取工艺分别进行优化。其中，干燥过程选取温度与单位面积投料量作为自变量；超声辅助提取（Ultrasonic Assisted Extraction, UAE）工艺则以温度、乙醇-水溶剂体积分数与提取时间为优化参数。两项工艺均以总酚含量（Total Phenolic Content, TPC）与芒果苷浓度作为响应指标。总酚含量采用福林-酚法（Folin-Ciocalteu Method）测定，呫吨酮类化合物浓度则通过高效液相色谱-电喷雾离子阱多级质谱（HPLC-ESI-IT-MSn）分析。干燥工艺的最优条件为54 ℃、单位面积投料量2.3 kg·m⁻²，在此条件下总酚含量可达21.7 ± 1.6 mg GAE·g⁻¹ 干重，芒果苷浓度为1.94 ± 0.22 mg·g⁻¹ 干重。针对超声辅助提取工艺，最优条件为51 ℃、体积分数50%的乙醇溶液、提取时间71 min，该条件下总酚含量为19.5 ± 0.8 mg GAE·g⁻¹ 干重，芒果苷浓度为1.50 ± 0.13 mg·g⁻¹ 干重。此外，在上述最优工艺条件下得到的提取物中共鉴定出38种化合物。