中文摘要：

为了研究龙眼果皮酶促褐变产物的最佳提取工艺、稳定性和抗氧化活性,以样品中总蒽醌含量为指标,通过单因素和正交试验法,考察乙醇的浓度、料液比、提取时间、提取温度4个因素对应用回流法提取褐变产物的影响,探讨提取龙眼果皮中酶促褐变产物的最佳工艺条件。采用分光光度法对褐变产物的稳定性和体外抗氧化活性进行了测定。结果表明,回流法提取酶促褐变产物最佳工艺条件为：乙醇浓度为70%,提取时间为8h,料液比为1：2,提取温度为40℃。在试验温度范围内,酶促褐变产物比较稳定;但对光照比较敏感,尤其是在紫外光下稳定性较差;在酸性条件下的稳定性比在碱性和中性条件下好;在4种不同种类添加剂影响下,其稳定性均变差。体外抗氧化试验结果表明,龙眼果皮总蒽醌浓度为9.55μg/mL时,对1,1-二苯基-2-三硝基苯肼自由基（DPPH.）清除率为74.1%;浓度为4.55μg/mL时,羟基自由基（.OH）清除率达81.6%;浓度为6.70μg/mL时,超氧阴离子自由基（.O2-）清除率达86.1%。回流法可提取龙眼果皮中酶促褐变产物。温度对酶促褐变产物稳定性影响不明显,光照、pH、食品添加剂因素影响其稳定性。酶促褐变产物具有一定的清除DPPH.、.OH和.O2-自由基的能力。

英文摘要：

In order to study the extraction, stability and antioxidational effects of the enzymatic browning product in Dimocarpus longan pericarp, with the total anthraquinones content as evaluation indicator, single factor exploration was performed to find out ethanol concentration, the suitable temperature, ratio material to liquid, extraction time and extracting temperature, and then L9（34） orthogonal design was adopted to select out the best extracting conditions of bath reflux. The stability and antioxidational effects of the enzymatic browning product were investigated, the content as evaluation indicator was determined by spectrophotometry. The results showed that the best extracting conditions of the bath reflux were that 70% of ethanol concentration, 8 h of extraction time, 1：2 of ratio material to liquid, 40℃ of extracting temperature of the enzymatic browning product was good in temperature, but poor under light expecially under ultraviolet radiation, better in a acidic condition than in alkalic and neutral condition, poor respectively in four kinds of food additive. The scavenging activities of the enzymatic browning product were 74.1% for the 1,1-diphenyl-2-picrylhydrazyl radicals （DPPH·） in vitro, when the concentration of the extracts was 9.55 μg/mL. The scavenging activities of the enzymatic browning product were 81.6% for hydroxyl radical （·OH）, when the concentration was 4.55 μg/mL. The scavenging activities were 86.1% for superoxide anion radicals （·O2-）, when the concentration was 6.70 μg/mL. The enzymatic browning product could be extracted by the bath reflux. The factor of temperature didn＇ t affect the stability of the enzymatic browning product, but other factors of light, pH, food additive affected the stability of the enzymatic browning product. The enzymatic browning product had the scavenging activities for DPPH-, ·OH and ·O2-.