为了解决冻干苹果片加工过程中的护色问题，设计了对照组（CK）、热烫组（BT）、护色液浸泡组（CP）、热烫-护色液浸泡复合护色组（BCP）四组，再采用真空冷冻干燥技术将苹果片制成即食脆片，对每组产品的含水率、维生素C含量、滴定酸度、复水比、质构、色差、感官评价、微观结构等品质进行比较分析。结果表明，四组冻干苹果片的含水率在5.13%~5.47%，维生素C含量在9.56~17.06 mg/100 g，滴定酸度在2.22~2.37 g/100 g，复水比在5.15~3.49，硬度在9715.67 g~9384.67 g，脆度在1762.50 g~1989.00 g，亮度在77.73~84.04，感官评分在5.82~8.02，其中CK组的维生素C含量显著高于其他三组（p<0.05）；BCP组的复水比显著高于CK组（p<0.05）；BCP组的护色效果最佳，产品亮度值L* 84.04，综合评分8.02。微观结构的结果表明，经预处理与真空冷冻干燥复合处理后细胞呈现杂乱排离，结构松散破碎。总体来说，四组冻干苹果片虽然在营养成分和感官评价上具有差异，但均保留了苹果的风味，BCP组具有更好的冻干片品质。本研究为冻干苹果片的工业化生产提供理论和技术指导。

In order to protect the color of apple during the processing of freeze-dried, four groups were designed according to different pretreatments: the control group, the blanching group, the color protection liquid soaking group, and the blanching-color protection liquid soaking composite color protection group. The vacuum freeze-drying was applied to produce freeze-dried apple slices, and then the water content, vitamin C content, titer acidity, rehydration ratio, texture, color difference, sensory evaluation, microstructure and other quality of each group of products were compared. The results showed that the moisture content, the vitamin C content, the titer, the rehydration ratio, the hardness, the brittleness, the brightness values and sensory evaluation in four freeze-dried apple slices ranged from 5.13% to 5.47%, 9.56 to 17.06 mg/100 g, 2.22 to 2.37 g/100 g, 5.15 to 3.49, 9715.67 to 9384.67 g, 1762.50 g to 1989.00 g, 77.73 to 84.04, 5.82 to 8.02, respectively. Vitamin C content of the CK group was significantly (p<0.05) higher than those of the other three groups. The rehydration ratio of the BCP group was significantly (p<0.05) higher than that of the CK group. The color protection effect of the BCP group was best, with the brightness value 84.04 and the overall score 8.02. The results of the microstructure showed that the cells were disorganized and the structure was loose and broken after the combined treatment of pretreatments and vacuum freeze-drying. In general, although the four groups of freeze-dried apple slices had differences in nutrient composition and sensory evaluation, they all retain the typical flavor of apples. The better freeze-dried slice quality was found in the BCP group. This study could provide the theoretical and technical guidance for the industrial production of freeze-dried apple slices.

国家重点研发计划项目（2017YFD0400902-2）；广东省级农业科技创新及推广项目（2019KJ101）；广东省重点领域研发计划项目（2018B020241003）