Changes in the n-alkane composition of avocado pulp oil ( &lt;i&gt;Persea americana&lt;/i&gt;, Mill.) during fruit ripening

A M Giuffrè

doi:10.3989/gya.2005.v56.i1.137

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 -C 21 to n -C 34 ; mainly n -C 24 , followed by n -C 25 and then by n -C 23 . Quantities of n -C 21 , n -C 22 , n -C 23 , n -C 27 and n -C 28 progressively increased during ripening, whereas n -C 24 , n -C 25 , n -C 26 , n -C 29 , n -C 30 and n -C 34 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.

Highlights

Climatic conditions characterizing the province of Reggio Calabria (Southern Italy) permit the cultivation of a large number of subtropical species
In order to improve the studies on avocado pulp oil, new attention has been focused on the minor components of this vegetable oil
The glass gravity column chromatography used in this study has been proven able to separate n-alkanes from the other components of the unsaponifiable fraction

Summary

Introduction

Climatic conditions characterizing the province of Reggio Calabria (Southern Italy) permit the cultivation of a large number of subtropical species. Avocado fruit contains a large quantity of oil. In order to improve the studies on avocado pulp oil, new attention has been focused on the minor components of this vegetable oil. A high content of hydrocarbons with chain length > C29, reduces the quality of vegetable oil. This happens because the short chain hydrocarbons are well absorbed by the mammalian small intestine. N-Alkanes of carbon number > C29 are not significantly absorbed In this perspective, as avocado fruit is largely employed for human consumption, it becomes very important to know the hydrocarbon content in the avocado pulp oil as well as the hydrocarbon chain length. Little attention has been focused on n-alkanes of edible vegetable oils. Neukom, (Neukom et al 2002), have found that in edible vegetable oils more than 50 mg/Kg of mineral paraffins could be found, originating from extraction plants or from air pollution

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