This work examined the influence of crop season, extraction system and production site on the composition of fresh olive mill wastewater collected from northern Morocco. ANOVA analysis showed that most of traits were largely affected by extraction system (≥ 60% of total variance). Comparison among extraction systems showed significant differences for all traits, except for chlorides. Three phase centrifugation system (C3) displayed the highest value of total phenols, while all the remaining traits were higher in two phase centrifugation system (C2). Concerning crop seasons, we noticed a general decrease in values of total solids, chemical oxygen demand, chlorides, C/N ratio and total aerobic mesophilic flora, from 2014 to 2016 season; in contrast, an increase in suspended solids, total kjeldahl nitrogen and proteins was detected. OMW with highest total phenols content and then more acidic were collected during 2015 season. Between production sites, Bni Frassen produced OMW with the highest values for salt and total phenols, but the lowest ones were obtained for microbiological traits. OMW from Taza were rich in total kjeldahl nitrogen and proteins. An increase in organic load indicators was observed in Bouchfaa. Principal component analysis (PCA) explained about 82% of total variability: 58, 16 and 8% for principal component 1 (PC1), PC2 and PC3, respectively. Extraction system fitted the variability of PC1. PC2 was mainly explained by production sites, while PC3 separated crop seasons. Correlation studies showed significant relationships especially among the traits expressing organic load, while microbiological counts were largely associated to total phenols and pH.

The purpose of this work is to evidence the effects of ripening index and water regime on the quantity and quality indices of “Moroccan Picholine” virgin olive oil (VOO) produced in northern Morocco. Olive trees were subjected to full irrigation and rainfed conditions, and olive fruits were collected at different ripening times. Results showed that the extracted volume of VOO increased during ripening, and decreased when full irrigation was applied. In regard to VOO quality, the statistical analysis revealed the predominant effect of ripening index on the majority of the considered parameters, except total phenols content that was strongly influenced by water regime. At more advanced stages of maturity, lower values of peroxide value, K232, carotenoids, chlorophylls and total phenols were registered while more free fatty acids were accumulated. Moreover, full irrigation reduced total phenols and increased free fatty acids, even if a great amount of pigment content was scored. Correlation studies showed significant relationships between pigments content and oxidation indices (peroxide value and K232).