Giarraffa and Grossa di Spagna naturally fermented table olives: Effect of starter and probiotic cultures on chemical, microbiological and sensory traits

This work investigated on the effects of selected starters and of probiotic strains on the evolution of microbiota,on trend of volatile compounds and on the final sensorial traits of green table olives. The olives, belonging toGiarraffa and Grossa di Spagna cultivars, were processed according to Sicilian traditional method and the followingsamples were obtained: (1) un-inoculated spontaneous olives, control; (2) olives inoculated with probioticLactobacillus rhamnosus H25; (3) olives inoculated with commercial probiotic L. rhamnosus GG; (4) olives inoculatedwith Lactobacillus plantarum GC3 plus Lactobacillus paracasei BS21; and (5) olives inoculated withL. plantarum GC3 plus L. paracasei BS21 plus L. rhamnosus H25. Microbial growth, pH, lactic acid concentrationsand volatile compounds were monitored during the 120 days of fermentation, while sensory parameters wereevaluated in the final products. Results of microbiological and physico-chemical analyses did not reveal anysignificant difference between the cultivars, with fermentation being always carried out from both lactic acidbacteria (LAB) and yeasts, while results of volatile compounds and sensory analyses were significantlycultivar-dependent. Multiplex PCR assay of lactic acid bacteria (LAB) showed that L. casei was detected in allsamples, Lactobacillus pentosus was the dominant species in spontaneous samples and in probiotic inoculatedsamples. L. plantarum prevailed over native LAB population in inoculated samples. The presence ofL. rhamnosus species was revealed in samples where it was inoculated, demonstrating its survival in the olivebrine matrix.