Cluster Analysis of GC Data on Oxygenated Terpenes of Young Leaf and Green Fruit Samples of Japanese Pepper (Xanthoxyum piperitum DC.)

Cluster analysis was applied to the GC data on oxygenated terpenes of various samples of young leaves and green fruits of Japanese pepper ( Xanthoxyum piperitum DC.) to select superior cultivars rich in flavoring potency. Of 74 leaf samples, six samples were rich in citronellal, linalool, isopulegol, piperitone, geranyl acetate, citronellol, and geraniol. Of 71 fruit samples, three samples were rich in isopulegol, piperitone, geranyl acetate, methoxycitronellal, and geraniol, and nine samples were rich in citronellal, linalool, citronellyl acetate, γ-terpineol, and citronellol. Similarity in the clusterings of the leaf and fruit samples were not observed. Of 78 plants, only one plant gave young leaves and green fruits rich in citronellal, linalool, isopulegol, geranyl acetate, and citronellol. Keywords: Japanese pepper; volatile compounds; cluster analysis