Changes in the n-alkane composition of avocado pulp oil (Persea americana, Miller) during fruit ripening

Abstract

The n-alkane composition of Avocado pulp oil (cv. Hass) was investigated during fruit ripening. Three samples of fruit were harvested on March 3, 2003, March 18, 2003 and April 2, 2003. Glass gravity column chromatography was employed to separate n-alkanes from other minor components contained in the unsaponifiable fraction. Gas chromatography was used to analyze the eluate. Fourteen compounds were detected ranging from n-C21 to n-C 34; mainly n-C24, followed by n-C25 and then by n-C23. Quantities of n-C21, n-C22, n-C 23, n-C27 and n-C28 progressively increased during ripening, whereas n-C24, n-C25, n-C26, n-C29, n-C30 and n-C34 decreased from the first harvest date to the third harvest date. While odd-numbered carbon n-alkanes increased (52.38%, 52.85% and 53.06% for the three samples respectively), even-numbered carbon n-alkanes decreased as the fruit ripened (47.62%, 47.15% and 46.94%). The total n-alkane content decreased during ripening, from 25.20 mg/Kg (first harvest date) to 16.77 mg/Kg (third harvest date). In order to minimize the n-alkane content in avocado pulp oil it is necessary to delay the fruit harvest date.