选用红柠檬作为研究对象，以透光率为指标来研究果胶酶、复合酶、壳聚糖、膨润土和硅藻土这5种澄清剂对红柠檬汁的澄清效果，并探讨其中澄清效果较好的澄清剂对澄清后果汁品质的影响。通过单因素试验和Box-Behnken试验设计对红柠檬汁澄清工艺进行优化。结果表明，膨润土和硅藻土对红柠檬汁几乎没有澄清作用，果胶酶、复合酶和壳聚糖澄清效果都比较好。综合经济、方便和澄清后红柠檬汁品质3个方面考虑，最后选择果胶酶作为红柠檬汁的澄清剂。利用响应面优化试验得到了澄清型红柠檬汁的最优工艺，其条件为果胶酶用量0.22 g/100mL、处理温度50.3 ℃、pH 4.3和时间62 min，在此条件下，红柠檬汁透光率为93.8%。

In this paper, red lemons were used as the main material, the clarification effects of pectinase, complex enzyme, chitosan, bentonite and diatomite on the red lemon juice were studied with light transmittance as the index. The best clarifying agent for the fruit juice was selected. According to single-factor experiments and Box-Behnken experimental design, the optimized clarification process of red lemon juice was obtained. The results showed enzyme and chitosan were better in the clarifying process of the juice. In contrast, bentonite and diatomaceous earth had little effects. Considering the economy, convenience and clarification of the quality of red lemon juice, pectinase was selected a clarifying agent for red lemon juice. The optimum conditions of clarified red lemon juice were: 0.22 g/100mL pectinase, at 50.3 ℃ with pH 4.3 for 62 min, the red lemon juice transmittance was as high as 93.8%.