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

Abstract

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 methylene 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 gamma-terpinene (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.

Mušmula (Mespilus germanica L) je voće iz porodice ruža (Rosaceae). Zeleni plodovi mušmule nisu jestivi već treba da ugnile (omekšaju usled mraza ili tokom čuvanja) pre nego što se koriste u ishrani. Efekat procesa sazrevanja na isparljive komponente ploda mušmule ispitivan je u dve različite faze njegove zrelosti. Isparljiva jedinjenja su izolovana iz izmrvljene pulpe nezrelih i zrelih plodova mušmule pomoću simultane destilacije vodenom parom i ekstrakcije metilen-hloridom. Koncentrovani uzorak je analiziran kombinacijom metoda GC-FID-MS. Heksanska i palmitinska kiselina su najzastupljenije kiseline, heksanal i (E)-2-heksenal su najzastupljeniji aldehidi, (Z)-3-heksenol i heksanol su najzastupljeniji alkoholi i p-cimen, terpinen-4-ol i γ-terpinen, terpeni odgovorni za karakterističnu aromu ploda mušmule, takođe su prisutni. C6 alifatična jedinjenja, kao što su heksanal i (E)-2-heksenal su nađeni kao glavne isparljive komponente zelenih mušmula. Za razliku od njih, heksanol, (Z)-3-heksenol su glavne komponente zrelih plodova mušmule.