Effect of deficit irrigation on fruit and oil quality of 'Konservolea' olives

• Published in: Acta horticulturae no. 924; pp. 445 - 451
• Main Authors: Rinaldi, R, Amodio, M.L, Colelli, G, Nanos, G.D, Pliakoni, E
• Format: Journal Article
• Language: English
• Published: International Society for Horticultural Science 01.01.2011
• Subjects: acidity; cell respiration; chlorophyll; color; deficit irrigation; fatty acid composition; firmness; fruit quality; growing season; irrigation rates; lipid content; oils; Olea europaea; oleic acid; olives; palmitic acid; peroxide value; polyphenols; polyunsaturated fatty acids; tocopherols; trees; water quality; water supply; Greece
• ISSN: 0567-7572
• DOI: 10.17660/ActaHortic.2011.924.57

The aim of this work was to evaluate the effects of deficit irrigation on quality of olives at harvest and on oil after processing. Olive trees (Olea europaea L. ‘Konservolea’) from Anchialos (central Greece) were subjected for 3 years (2006-2008) to 2 different irrigation regimes: fully irrigated (Ctrl) and deficit irrigation (deficit). Control trees received 4000-5000 m3/ha of good quality water (conductivity <700 µS/cm) per year; deficit-irrigated trees were irrigated as control during the growing season except during stone hardening and final flesh swelling, when water supplied per day was 20% of the control. The 2008 data are presented. At harvest, fruit respiration rate, firmness, color score (maturity index), size and shape, water and oil content were determined. On oil samples extracted at harvest, the following quality attributes were measured: color, acidity, peroxide value, extinction coefficients at 232 and 270 nm, oil stability, total polyphenols, tocopherols, carotenoids and chlorophyll content, and fatty acid composition. Oil content was significantly higher in deficit treated fruit, while no other differences were observed on fruit quality. Yield was 9.6 t/ha, with no difference related to irrigation treatments. Reduced water supply led to some improvement in oil quality, as indicated by a lower acidity and higher stability, polyphenols and chlorophyll contents compared to the control. Besides, oil from deficit irrigation had similar oleic acid, higher palmitic acid, and lower palmitoleic, linoleic, linolenic and arachidic acids contents than normally irrigated samples. As a consequence, MUFA/PUFA ratio was significantly higher in oils obtained from deficit irrigated plants. No difference between treatments was observed for the sensorial attributes of extracted oil.