Biotechnology of olive fermentation of 'Galega' Portuguese variety

‘Galega' is the main Portuguese olive variety providing the greatest percentage of table olive production from homemade and industrial methods. In this work a better understanding of the fermentation involved in both methods is intended. Yeasts and lactic acid bacteria (LAB) constitute the microflora acting in olive fermentation, with Pichia membranaefaciens being the dominant yeast specie present throughout the process. LAB develop their activity mainly along the second fermentation stage where Lactobacillus plantarum and Lactobacillus pentosus were isolated and identified, as well as Leuconostoc mesenteroides and Pediococcus pentosaceus . Results of a chemical analysis have shown the effectiveness of both homemade and industrial fermentation methods. Nevertheless, the chemical composition of the brines from homemade samples was more similar than those from the industrial ones. Remarkable differences were found in the phenolic compound profile mainly on the final fermentation stage. The amount of volatile compounds has enhanced on the same phase in both methods and some differences were found between them. Sensorial analysis has shown the best results obtained through the homemade method.