収穫時期におけるリンゴ‘ジョナゴールド’果皮の脂質の変化

Abstract

To determine the cause of a greasy phenomenon of the peel of apple cv. ‘Jonagold’, the main lipids of the peel were analyzed by gas chromatograph-mass spectrometer, particularly noting the unsaturated fatty acids which were fluid at normal temperature.As harvest was delayed, the number of components and the quantity of the lipids of the peel increased. The compositions of 17 aliphatic lipids were identified.In the stages before ripening, palmitic acid, stearic acid, oleic acid, linoleic acid and triacontane were scarcely detected, whereas in the stages after ripening, these lipids increased. Among them, lipids fluid at normal temperature were oleic acid and linoleic acid. Oleic acid was detected later than linoleic acid. The time of the increase in linoleic acid coincided with the appearance of greasiness of the peel.When commercial linoleic acid was painted on peel which had not shown the greasiness, the wax of the peel was melted and the greasy phenomenon similar to the natural appearance was produced.It was concluded that the natural greasiness of the ‘Jonagold’ peel was caused by linoleic acid and oleic acid.