Quality characteristics of Arbequina and koroneiki cultivar olive oils produced from defected drupes cultivated under various farming practices: focusing on the effect of planting density

Abstract

In this work, the influence of different farming management treatments on the yield and quality attributes of ‘Koroneiki” and “Arbequina” cultivar olive oils was investigated. Samples were collected from trees grown in the same orchard (American Farm School) under different agronomical practices, i.e. planting density (super-high, high and medium/conventional), irrigation (high, low) and fertilization (soil: high, low and foliar: presence or not). The focus of the present study is on the evaluation of the “planting density” effect. 23 Arbequina and 24 Koroneiki olive oils were produced from defected drupes and examined for their acidity, peroxide and K values, colour, pigments (chlorophylls and carotenoids), and antioxidant activity (DPPH radical scavenging capacity). Results revealed that unfavourable weather conditions, olive fruit fly and Gleosporium infestation reduced the quality of the examined olive oils. Still, some oils maintained the extra virgin or virgin olive oil category according to market quality parameters. Medium/Conventional planting density presented statistically significant inferior performance in comparison to high and super-high density systems for both cultivars. This could be probably attributed to the higher competitiveness of the fly with the lower amount of drupes available from medium density trees.