Modification of Phenolic Compounds and Volatile Profiles of Chemlali Variety Olive Oil in Response to Foliar Biofertilization

The main objective of this work was to studythe effects of foliar biofertilizers on individual volatile pro-files and phenolic compounds of olive oil (Olea europaeaL. cv. Chemlali). Three foliar biofertilizers were used intwo successive application seasons: T1 (rich in nitrogen,phosphorus and potassium); T2 (rich in calcium); and T3(application of both T1 and T2). Results showed that foliarfertilization with T2 increased the phenolic compound con-tents (e.g., oleuropein aglycone and decarboxymethyl lig-stroside aglycone) of Chemlali olive oil. It also enhancedthe levels of many volatile compounds responsible for thegoodflavor of olive oil such as hexanal. However,T1-tested fertilizer led to a significant decrease in the con-tent of phenolic compounds, although they seemed toimprove significantly the levels of the majority of volatilecompounds, especially hexanal. Based on these results, asignificant relationship between plant nutrition and qualityof oil was observed. Our results demonstrated a potentialpositive influence on the concentration of sensory qualitycompounds under T2 (Ca2+-based fertilizer). This resultshould be considered in the design of foliar nutrient appli-cation management strategies for olive trees.