Production of potential probiotic Spanish-style green table olives at pilot plant scale using multifunctional starters

Abstract

This work evaluates the use of two multifunctional starters of Lactobacillus pentosus species (TOMC LAB2 and TOMC LAB4) during elaboration of Manzanilla olive fruits processed according to the Spanish-style. Data show that the use of inocula at the onset of fermentation led to a proper acidification and sugar consumption of brines compared to the spontaneous process, obtaining in a shorter period of time the maximum population for lactic acid bacteria. Both inoculated L. pentosus strains were recovered at high frequencies at the end of fermentation on the olive surface, which was corroborated by RAPD-PCR analysis. In situ observation of olive epidermis slices by scanning electron microscopy revealed a strong aggregation and adhesion between microorganisms, which reached population levels of approximately 6 and 7 log10 cfu/cm(2) for yeasts and lactic acid bacteria, respectively. Enterobacteriaceae on the olive surface were also found at the onset of fermentation (∼9 log10 cfu/cm(2)), but they declined during the process and were below the detection limit at the end of fermentation. Results obtained in this study show the advantage of using multifunctional starters with the ability to adhere to the olive epidermis because, ultimately, the fruits are the food ingested by consumers.

Keywords: Biofilm; Fermentation; Functional olives; Lactobacillus pentosus; Probiotic; Starter culture.