Volatile compounds in medlar fruit (Mespilus germanica L.) at two ripening stages

摘要

Medlar is the fruit of Mespilus germanica L. in the family of Rosaceae. The fruit can be eaten only if ‘bletted’ (softened by frost or longer storage). The effect of the maturation stages on the volatile compounds of the medlar fruit was investigated during two different stages. Volatile flavour substances were isolated from the minced pulp of unripe and full ripe medlar fruits by simultaneous steam distillation extraction (SDE) with methilen chloride as the extracting solvent. The concentrate was analysed by GC-FID-MS. Hexanoic and hexadecanoic acids were the predominant acids, hexanal and (E)-2-hexenal were the predominant aldehydes, (Z)-3-hexenol and hexanol were the predominant alcohols, with p-cymene, terpinen-4-ol, and γ-terpiene (the terpenes responsible for the characteristic medlar flavour) being also present. The C6 aliphatic compounds, such as hexanal and (E)-2-hexenal, were observed as the major volatile constituents in the green stage. In contrast, hexanol and (Z)-3-hexenol were the main volatiles in ripe fruits.