干燥方式对油茶粉品质及挥发性风味物质的影响

目的：探究适合油茶粉的干燥方式，以便油茶食用和贮藏。方法：采用喷雾干燥、真空冷冻干燥、真空干燥3种干燥方式对油茶汤进行干燥处理，并对干燥后油茶粉的品质（水分含量、感官评价、色泽）及挥发性物质进行评价。结果：真空冷冻干燥油茶粉感官得分最高（93），含水量最低（3.78%），色泽较优（ΔE值49.74）。利用SPME-GC-MS技术从3种方式干燥油茶粉中共鉴定出104种挥发性物质，其中，影响油茶粉风味的有14种。冷冻干燥的特征风味物质（壬醛、癸醛、（Z）-2-癸醛、（Z）-2-壬烯醛、（E）-3,7-二甲基-2,6-辛二烯醛）呈现青香、油脂香，喷雾干燥和真空干燥的特有香气均为（Z）-3,7-二甲基-2,6-辛二烯醛、（E）-3,7-二甲基-2,6-辛二烯醛、癸醛，呈现青香、果香、蜡香。结论：真空冷冻干燥风味品质最佳。

Effects of drying methods on the quality and volatile flavor compounds of oil tea powder

Objective: This study aimed to explore suitable drying methods for oil tea powder, making it easier for oil tea consumption and storage. Methods: Spray drying, vacuum freeze drying and vacuum drying were used to dry oil tea soup, and the quality (moisture content, sensory evaluation and color) and volatile substances of dried oil tea powder were evaluated. Results: The sensory score of vacuum freeze-drying oil tea powder was the highest (93), the water content was the lowest (3.78%), and the color was better（ΔE value 49.74). 104 volatile substances were identified from three drying methods of oil tea powder using SPME-GC-MS technology, of which 14 affected the flavor of oil tea powder. The characteristic flavor substances (nonanal, decanal, (Z)-2-decanal, (Z)-2-nonenal, (E) -3,7-dimethyl-2,6-octadienal) of freeze-drying present green fragrance and fat fragrance. The special aromas of spray drying and vacuum drying are (Z)-3,7-dimethyl-2,6-octadienal, (E)-3,7-dimethyl-2,6-octadienal and decanal, presenting green fragrance, fruit fragrance, and wax fragrance. PCA and comprehensive evaluation indicate that vacuum freeze-drying has the best flavor quality, which is consistent with sensory evaluation results. Conclusion: The flavor quality of vacuum freeze-drying was the best.