干燥方式对油茶粉品质及挥发性风味物质的影响

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

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。

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.