中文摘要：

为探讨热处理对荔枝果汁品质的影响,将荔枝原果汁在60～100℃温度下进行热处理,测定果汁的褐变度、pH值、固形物含量、化学成分（糖分、抗坏血酸、5-羟甲基糠醛（5-HMF）、总酚）及挥发性风味成分等指标的变化。结果表明：荔枝果汁在0～60min内褐变度的变化符合零级反应动力学模型。热处理过程中抗坏血酸和总酚含量下降明显,而糖含量变化不大,因此抗坏血酸降解和多酚聚合可能是影响荔枝果汁褐变的主要因素。热处理后荔枝果汁风味出现明显变化,采用顶空固相微萃取-气相质谱对加热前后风味成分进行分析,发现低级醇和酯类含量明显下降,同时,产生了含硫化合物和高级醇等新物质。

英文摘要：

To explore the effect of thermal treatment on quality of litchi juice,the changes in browning index（A420,absorbance at 420 nm）,pH and the contents of soluble solid（SS）,ascorbic acid,5-hydroxy-ethylfurfural（5-HMF）,sugar,total phenols and volatile aromatic compounds of litchi juice during thermal treatment at 60-100 ℃ were measured.Results showed that the A420 of litchi juice was followed by zero order reaction kinetics within 0-60 minutes of thermal treatment.During the thermal treatment,the contents of ascorbic acid and total phenols were sharply declined,while the change of sugar content was not obvious.These results suggest that degradation of ascorbic acid and condensation of phenols are the major factors affecting non-enzymatic browning of litchi juice.Meanwhile,thermal treatment exhibited a negative effect on flavor components of litchi juice.Detected by headspace solid phase micro extraction combined with gas chromatography-mass（HS-SPME-GC/MS）,the contents of lower alcohols and esters exhibited a significant decrease,whereas some sulfur containing compounds and fatty alcohols were generated.