天然防腐剂柠檬烯在橙汁保鲜中的应用

对柠檬烯乳化及其在橙汁保鲜中的应用进行研究。乳化实验结果表明，添加20g/L 的蔗糖酯SE-15，乳化效果最好，离心前后吸光变化率为26.70%。橙汁保鲜实验结果表明，添加0.25g/L 的柠檬烯保鲜效果较差，贮存期间细菌总数变化，只有第4 天明显低于空白对照，pH 值和感官品质与空白对照相比，始终无明显差异；而添加大于等于0.50g/L 的柠檬烯，保鲜效果明显，在整个检测过程中，细菌总数、pH 值变化和感官品质都明显优于空白对照。

Fresh-keeping Effect of Limonene as a Natural Preservative on Orange Juice

To evaluate the fresh-keeping effect of limonene as a natural preservative, the emulsification of limonene with various emulsifers and the changes in physicochemical and microbiological and sensory attributes of freshly squeezed sweet orange juice added with emulsified limonene during storage at (36 ± 1) ℃ were investigated. The attendance of sucrose ester SE-15 at the concentration of 20 g/L in the aqueous solution gave the best emulsification of limonene, with an absorbance difference at 420 nm of the emulsion before and after centrifugation. The addition of SE-15 emulsified limonene at the level of 0.25 g/L had no obvious fresh-keeping effect on sweet orange juice. However, the treated sweet orange juice exhibited a much lower total number of bacteria than the control without the addition of SE-15 emulsified limonene after 3 days of storage. There were no obvious differences in pH and sensory attributes between the treated and untreated sweet orange juices throughout the 8-day storage period. When the amount of added emulsified limonene was no less than 0.50 g/L, an obvious fresh-keeping effect on sweet orange juice was observed. Moreover, the treated sweet orange juice was better than the control in terms of total number of bacteria, pH and sensory attributes.