Influence of different harvest dates and ripening periods on fruit quality and oil characteristics of Fuerte avocados

Abstract

Ripening and procedures of highly enriched and specialized oil in Fuerte avocado (persea americana Mill.) during storage at 20 o C were investigated. Three different harvest dates (early, middle and late) of avocado fruits were evaluated. Fruits were collected in first November, December and January of the season 2007 - 2008 at one-month intervals. Samples were kept for 7 days under controlled temperature (20 o C) to ripe. Fruit quality, ripening properties, oil characteristics, fatty acid composition of avocado fruit as well as a comparison between avocado and olive (cv. Coratina) oils were investigated with respect to the harvesting and postharvest (ripening) period. The dry matter (DM) of Fuerte avocado fruits were increased gradually, while, fruit firmness (FF), soluble solid concentration (SSC) and titratable acidity (TA) showed a gradual and significant decrease during the various dates of harvest and ripening period at 20 o C, respectively. Skin fruit color had a slight significant differences between color parameters L*, a*, b* and Chroma (C*) and Hue angle ( h*) values. Respiration rate had a significant increase at the different harvest dates reaching its peak value at 1 st Dec. and finally decreased. Oil characteristics (oil content (OC), acid value (AV), peroxide value (PV), iodine value (IV), color index (CI), refractive index (RI) and fatty acid composition (FA)) of avocado oils at different harvest dates and ripening at 20 o C were discussed. Oil content of Fuerte avocado fruit was increased to the 1 st Dec. then decreased at the 1 st Jan., Meanwhile, the oil content of Coratina olive was increased from the 1 st Nov. to the 1 st Jan. The AV of Fuerte and Coratina cultivars decreased, meanwhile PV increased. There was a change in the unsaturation character (IV) for Fuerte and Coratina varieties. RI had no noticeable change occur during all of the months for both varieties. Oleic and linolenic acids showed increase values in avocado oil in comparison with olive oil. Moreover, Palmitic and linoleic acids, showed high value in olive oil than avocado oil.