Aroma Profiling of Young Yuzu Leaves by GC/MS and Sensory Evaluation

Yuzu (Citrus junos Sieb. ex Tanaka) is a traditional Japanese citrus fruit valued for its characteristic aroma, and extensive studies have focused on volatile compounds in fruit peels. In contrast, young yuzu leaves that emerge before fruiting are typically discarded as an underutilized resource, despite their citrus-like fragrance and reduced grassy notes compared with mature leaves. This paper characterized the aroma profile of young yuzu leaves (YL) by gas chromatography-mass spectrometry (GC/MS) and sensory evaluation, and compared it with that of mature leaves (ML), green yuzu peel (GP), and yellow yuzu peel (YP). Samples were dried by freeze drying or hot air drying at 40 °C and 60 °C, then powdered for analysis. GC/MS analysis identified characteristic differences in the volatile aroma compounds among the materials. YL contained relatively high levels of linalool and thymol. These compounds exhibited larger peak areas than those in the ML, indicating chemical features specific to the YL. In addition, β-phellandrene was detected in the leaf samples but not in the peel samples. Sensory evaluation by seven fragrance experts using the Semantic Differential method showed that GP and YP were rated significantly higher than leaf samples in terms of intensity and citrus-related impressions. However, no statistically significant differences were observed between YL and ML in terms of sensory attributes, despite the clear chemical differences. These results suggest that YL possesses a distinctive chemical aroma profile compared to of that ML. This work supports the potential utilization of YL as a novel aroma material.