Tree Irrigation Levels for Optimum Chemical and Sensory Properties of Olive Oil
By M. Berenguer, P. Vossen, S. Grattan, J. Connell, V. Polito. 2006
158 citations recorded by the source corpus.
A comparative study was conducted to evaluate the infl uence of seven different levels of irrigation applied to 'Arbequina I-18' olive (Olea europaea L.) trees grown in a super-high-density orchard (1,656 trees/ha) in the Sacramento Valley of California. Wa- ter was applied differentially by drip irrigation at rates of 15%, 25%, 40%, 57%, 71%, 89%, and 107% evapotranspiration (ETc) in 2002, and 28%, 33%, 55%, 74%, 93%, 117%, and 140% ETc in 2003. Each treatment was replicated three times. Olives were harvested on two different dates each year from each of 21 plots. Three of four harvest dates showed a decrease in maturity index with increasing irrigation levels. Oils were made from olive samples collected from each plot and analyzed for oil quality parameters. Total polyphenol levels and oxidative stability decreased as the trees received more water, especially for the three lowest irrigation treatment levels in 2002, but few differences were noted between treatments in 2003 when all the trees were irrigated more heavily. Aver- age oxidative stability was correlated very closely with total polyphenol content with r 2 = 0.98 in 2002 and 0.94 in 2003. In 2002, free fatty acid levels increased and peroxide levels were unchanged, but in 2003, free fatty acid levels were unchanged and peroxide levels decreased in treatments receiving more water. Saturated fatty acids did not signifi cantly change in 2002, due to tree irrigation level. The mono-unsaturated fatty acid levels and oleic-linoleic relationship declined while poly-unsaturated fatty acid levels increased in 2002 with increased irrigation. In 2003, there was no notable difference in the ratio of mono to poly unsaturated fatty acid levels. The individual fatty acid most consistently affected by more irrigation water was stearic, which decreased in both years. Total sterol content (mg·kg -1 ), percentages of cholesterol and erythrodiol were signifi cantly infl uenced by tree irrigation levels, but increased in one year and either decreased or were unchanged the next. Oil sensory properties of fruitiness, bitterness, and pungency all declined in oils made from trees receiving more water. The lowest irrigation levels produced oils that were characterized by excessive bitterness, very high pungency, and woody, herbaceous fl avors. Intermediate irrigation levels (33% to 40% ETc) produced oils with balance, complexity, and characteristic artichoke, grass, green apple, and some ripe fruit fl avors. Higher irrigation levels lowered oil extractability and produced relatively bland oils with signifi cantly less fruitiness and almost no bitterness or pungency.
Subfields: Organic Chemistry, Plant Science, Soil Science
View Paper: https://www.semanticscholar.org/paper/8101377129634e97570950d2d543a63a37521bc0
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Citations in the corpus
- Productivity of olive trees with different water status and crop load (2007, background): “Irrigation delayed colour change and maturation in olive fruit, as in previous studies (Alegre et al., 2002; Faci et al., 2002; Berenguer et al., 2006.”
- Effects of different irrigation regimes on a super-high-density olive grove cv. “Arbequina”: vegetative growth, productivity and polyphenol content of the oil (2016, background): ““Arbequina” oil is known to have a polyphenol content that is already low, and excessive water application can cause a further reduction in the antioxidant component of the oil (Berenguer et al. 2006; Gucci et al. 2004; Gucci and Servili 2006; Patumi et al. 2002).”