Characterisation of the Volatile Compounds and Key Odourants in Japanese Mandarins by Gas Chromatography–Mass Spectrometry and Gas Chromatography–Olfactometry

Abstract

Japanese mandarins are becoming increasingly popular due to their pleasant aroma. The volatiles in four varieties of Japanese mandarins (Iyokan, Ponkan, Shiranui, and Unshiu mikan) were extracted by headspace solid-phase microextraction (HS-SPME) and solvent extraction, then analysed by gas chromatography–mass spectrometry (GC-MS). Principal component analysis (PCA) of the GC-MS data demonstrated distinct segregation of all four Japanese mandarin varieties. Esters, such as neryl acetate, distinguished Iyokan. Methylthymol uniquely characterised Ponkan, valencene was exclusive to Shiranui, and acids like hexanoic acid and heptanoic acid differentiated Unshiu mikan from the other three varieties. Aroma extract dilution analysis (AEDA) revealed 131 key odourants across four Japanese mandarins, including myrcene (peppery, terpenic), perillyl alcohol (green, spicy, floral), trans-nerolidol (sweet, floral), and trans-farnesol (woody, floral, green). Finally, sensory evaluation was conducted on the four Japanese mandarin peel extracts to describe the distinct aroma profile of each variety of Japanese mandarin: Iyokan had higher floral and juicy notes, Ponkan showed higher sulphury notes, Shiranui was perceived to have more albedo notes, and Unshiu mikan exhibited higher peely, green, and woody notes.