Olive (Olea europaea L.) tree nitrogen status is a key factor for olive oil quality.
The influence of macronutrient status on olive oil properties was studied for three years. Data were analyzed by a multivariate model considering N, P, K, and fruiting year as explanatory factors. Oil quality parameters were primarily associated with N concentration in leaves and fruits which increased with N in irrigation solution. The effect of P on oil quality was mainly indirect since increased P availability increased N accumulation. The potassium level had negligible effects. The oil phenolic content decreased linearly as a function of increased leaf N, indicating protein-phenol competition in leaves. The overall saturation level of the fatty acids decreased with fruit N, resulting in increased polyunsaturated fatty acids. Free fatty acids increased with increased levels of fruit N. High fruit load tended to reduce fruit N and subsequently improve oil quality. The effect of N on oil properties depended solely on its concentration in leaves or fruits, regardless of the cause.
Institute of Soil, Water and Environmental Sciences and ‡Institute of Plant Sciences, Gilat Research Center, Agricultural Research Organization , Mobile Post Negev 2, 85280, Israel.
Ran
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Erel
Zohar
Z
Kerem
Alon
A
Ben-Gal
Arnon
A
Dag
Amnon
A
Schwartz
Isaac
I
Zipori
Loai
L
Basheer
Uri
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Yermiyahu
D057914:Agricultural Irrigation; D005231:Fatty Acids, Unsaturated / Q000032:analysis / Q000378:metabolism; D063427:Food Quality; D005638:Fruit / Q000737:chemistry / Q000378:metabolism; D015999:Multivariate Analysis; D009584:Nitrogen / Q000378:metabolism*; D031658:Olea / Q000737:chemistry / Q000502:physiology*; D000069463:Olive Oil; D010636:Phenols / Q000032:analysis; D010758:Phosphorus / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism; D010938:Plant Oils / Q000737:chemistry*; D011188:Potassium / Q000378:metabolism
D005231:Fatty Acids, Unsaturated; D000069463:Olive Oil; D010636:Phenols; D010938:Plant Oils; D010758:Phosphorus; D009584:Nitrogen; D011188:Potassium