Effects of irrigation treatments on the quality of table olives produced with the Greek-style process

The irrigation of olive orchards is commonly applied to produce table olives with optimal size. No data have been published on the microbiological quality of drupes from irrigated olive groves during fermentation. The trials T100 and T50 (receiving a water amount equivalent to 100 % and 50 % of the required, respectively) and the control T0 (rainfed trial) were monitored during two consecutive years. Results showed significant increase of equatorial diameter and flesh:pit ratio of irrigated drupes. The decrease of pH and the numbers of lactic acid bacteria (LAB) registered for the irrigated trials during the fermentation were more consistent than those displayed by control T0. Lactobacillus pentosus, Lactobacillus plantarum, Lactobacillus coryniformis and Pediococcus pentosaceous for LAB, and Candida boidinii, Candida diddensiae and Wickerhamomyces anomalus for yeasts were isolated at highest concentrations. The global sensory acceptance was better for irrigated trials rather than control T0. The statistical multivariate analysis showed that the effect of irrigation was independent from the seasonal variability and it clearly distinguished the T100 and T50 trials from rainfed control. The irrigation improve significantly the quality of table olives. Interestingly, all explorative multivariate analyses showed low dissimilarity between irrigated trials; thus the thesis T50 represents an effective approach to save water in olive orchards without compromising the quality of table olives.