Effect of enhanced solar UV radiation on almond (Prunus dulcis) tocopherols and fatty acids

Y. Zhu, K. Wilkinson, K. King, J. Javorniczky, M.G. Wirthensohn
This study investigated the effects of increased solar ultraviolet (UV) radiation on almond (Prunus dulcis LSQUONonpareilRSQUO) lipids and tocopherols (Vitamin E), as well as fatty acid composition. Placing white weed mat in almond orchards, from fruit set till harvest, beneficially enhanced, by an average of 14%, almond tree exposure to solar UV radiation. Under these conditions, almond α-tocopherol concentrations increased by 30%, but other tocol homologues, γ-tocopherol, β-tocopherol and α-tocotrienol for example, were not significantly changed. Almond kernel lipid content was not affected, but fatty acid composition was slightly altered; i.e., linoleic acid concentrations decreased by 2%, oleic acid increased by 0.8% and myristic acid increased by 10.7%, while other fatty acids remained the same. The influence of almond position within the tree canopy was also studied. Canopy positioning had no impact on α-tocopherol, γ-tocopherol or α-tocotrienol concentrations, but β-tocopherol was slightly higher in almonds harvested from the inner canopy. Lipid concentration was not different in almonds harvested from the inner vs. outer canopy, but almonds harvested from the inner canopy comprised 2% less linoleic acid, 1.4% less oleic acid and 9.5% less myristic acid. Results from this study suggest white weed mats could be used in almond orchards as a cost-effective technique for increasing almond Vitamin E content, to improve almond kernel quality.
Zhu, Y., Wilkinson, K., King, K., Javorniczky, J. and Wirthensohn, M.G. (2018). Effect of enhanced solar UV radiation on almond (Prunus dulcis) tocopherols and fatty acids. Acta Hortic. 1219, 143-150
DOI: 10.17660/ActaHortic.2018.1219.24
α-tocopherol, γ-tocopherol, β-tocopherol, α-tocotrienol, lipids, oleic acid, ultra violet

Acta Horticulturae