Practical determination of oil content in avocado (Persea americana Miller) pulp in correlation with water content

Abstract

As the usual process used to determine oil content of avocado pulp (Soshlet's extrator) is expensive and very slow, it becames important the knowledge of an quick and practical method of avaliation of the oil content of the pulp. In this paper we tried to find a possible correlation between the quantities of water and oil in the avocado pulp. The determination of water percentage in the pulp is easy and no expensive, and through of it probably we could determined the oil content. Whit this objective it was conducted an experiment in three ecologically different regions of São Paulo State - Brazil. In each region it was utilized three orchards and in each orchard it was selected five trees of 'Wagner', Trince' and 'Collinson' cultivars, picking up two fruits per tree and the set (ten fruits) was the sample per cultivar to be analysed. Harvestings were done in pre-determined time, aiming at the analysis of oil and water content of pulp of fruit, from it setting to maturation time. It was also accomplished analysis of samples of fruits kept to ripe till consumption point (soft pulp). It was observed that the evolution of pulp oil content of avocado processes slowly at begining, accentuating in the final of fruit development and inverse for water content. It was verified a correlation between increase of oil content and decrease of water pulp content. Relating such a fact, it was met a general regression equation, Y = 86,626 - 0,727 X, where Y = percentage of water and X = percentage of oil, with good adaptation to linear regression, as it proves its determination coeficient of 91.50%.