Effect of saline irrigation water on olive oil composition

Abstract

Virgin olive oils were obtained in Egypt from fruits of olive trees irrigated with waters of different salinity concentration (control, 1800, 3600 and 6000 ppm) during the 1992 season. The effect of water salinity on olive oil fatty acid, fatty acid location in triacylglycerol moiety, triacylglycerol, sterol and tocopherol composition was determined. Oleic acid slightly increased and linoleic decreased in the total fatty acid composition, as well as on glycerol carbon‐2 and‐1(3), with increased water salinity. Trioleoyl, stearoyldioleoyl and palmitoyldioleoyl glycerols are slightly increased with increased water salinity. Total tocopherol was 87.7 mg/kg in the control and increased to 147.0 mg/kg for water with 1800 ppm salinity. At higher salinity concentration, total tocopherol decreased to 107.2 and to 89.1 mg/kg for water salinities of 3600 and 6000 ppm, respectively. The same trend was observed for α, β and γ‐tocopherols. Campesterol and β‐sitosterol were increased with water salinity of 1800 ppm and decreased when water salinity increased further. Stigmasterol increased at water salinity of 3600 ppm and decreased sharply when the salinity was increased to 6000 ppm. These olive oil composition studies showed that although water salinity may have some compositional effects, there was no major adverse effect on fatty acid, triacylglycerol, triacylglycerol fatty acid location, sterol and tocopherol composition for oil from olives of trees grown with water with a salt composition of up to 6000 ppm.

A multivariate study of the correlation between tocopherol content and fatty acid composition in vegetable oils

“…Data used in this study were collected from previous references (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) with the prerequisite that analyses for both fatty acid profiles and tocopherol levels were performed on the same oil sample. The data set included 14 vegetable oils: cashew nut (Anacardium occidentale, Anacardiaceae), cottonseed (Gossypium hirsutum, Malvaceae), groundnut (Arachis hypogea, Leguminosae), linseed (Linum usitatissimum, Linaceae), maize (Zea mays, Graminae), olive (Olea europea, Oleaceae), nigella seed (Nigella sativa, Ranunculaceae), niger seed (Guizotia abyssinica, Compositae), palm (Elaes spp., Palmae), perilla seed (Perilla frutescens, Labiatae), rapeseed (Brassica napus, Cruciferae), sesame (Sesamum spp., Pedaliaceae), soybean (Glycine max, Leguminosae), and sunflower (Helianthus annuus, Compositae).…”

Irrigation‐induced salinity affects olive oil quality and health‐promoting properties

“…14,15 These changes, however, differed greatly among the studies, to an extent where no general statement can be made concerning characteristic tendencies. With respect to nutritional and health-related quality, levels of tocopherols (vitamin E isomers) 16,17 and phytosterols 18 were reported to increase significantly with increased salinity but to then decrease with very high salinity, whereas total polyphenol concentrations were reported to rise with increasing water salinity, and continued to increase even for high EC values. 17,19,20 Chlorophyll levels of oil consistently declined when irrigation water EC values increased 15,16 while carotenoid levels were not consistently affected by salinity, and were alternatively found to either rise, 16 decline, 15 or not change.…”

Effects of reclaimed wastewater irrigation and fertigation level on olive oil composition and quality

“…Elevation in the levels of N and P was correlated with a reduction of oleic acid (C18:1) and increase of linolenic acid (C18:3), and free fatty acids (FFAs) increased in response to high fertilization levels . Despite the shortage of freshwater and the increasing needs for the use of marginal water for irrigation, only a few studies regarding the effect of water source on olive oil quality have been published . Irrigation‐induced salinity was found to differentially affect a number of important quality parameters of olive oil .…”

“…Irrigation‐induced salinity was found to differentially affect a number of important quality parameters of olive oil . As salinity of the irrigation water increased, a desirable rise in polyphenol and tocopherol levels were measured in olive oil, but undesirable alteration in fatty acids composition was also detected . Previously, Cresti et al .…”

“…In Israel, the majority of irrigated olive orchards are irrigated with non‐potable, marginal to low‐quality water, mainly RWW, and similar trends are nowadays seen in additional regions in the Mediterranean basin . Several studies have focused on effects of irrigation with either fresh or saline water on the composition and quality of olive oils . The rising use of RWW for olive irrigation in the Mediterranean calls for intensive study .…”