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The effect of water stress on super‐high‐ density ‘Koroneiki’ olive oil quality
Author(s) -
Dag Ar,
Naor Amos,
BenGal Alon,
Harlev Guy,
Zipori Isaac,
Schneider Doron,
Birger Reuven,
Peres Moti,
Gal Yoni,
Kerem Zohar
Publication year - 2014
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.6913
Subject(s) - orchard , irrigation , olea , olive trees , fatty acid , horticulture , polyphenol , chemistry , environmental science , botany , biology , agronomy , antioxidant , organic chemistry , biochemistry
BACKGROUND Over the last two decades, the area of cultivated super‐high‐density olive orchards has increased rapidly. Water stress is an important tool in super‐high‐density orchards to reduce tree growth and promote suitability for overhead mechanical harvesters. Little is known regarding the effect of water stress in super‐high‐density orchards on oil quality parameters. In this study the effect of irrigation rate on oil quality parameters was evaluated in a six‐year‐old super‐high‐density ‘Koreneiki’ olive orchard for five consecutive seasons. Five water status levels, determined by irrigating in order to maintain various midday stem water potential threshold values (−1.5, −2, −2.5, −3 and −4 MPa ), were applied during the oil accumulation stage. RESULTS The MUFA / PUFA ratio and free fatty acid content generally decreased as a function of increasing tree water stress. In most seasons a reduction in polyphenols was found with decreasing irrigation level. Peroxide value was not affected by the water stress level. CONCLUSION The present study demonstrates that limiting irrigation and exposure of olive trees to water stress in a super‐high‐density orchard lowers free fatty acid content and therefore benefits oil quality. However, the decreased MUFA / PUFA ratio and the reduction in polyphenol content that were also found under increased water stress negatively influence oil quality. © 2014 Society of Chemical Industry