Assessing the Challenges in the Application of Potential Probiotic Lactic Acid Bacteria in the Large-Scale Fermentation of Spanish-Style Table Olives.

Francisco Rodríguez-Gómez,Joaquín Bautista-Gallego,Verónica Romero-Gil,Antonio Garrido-Fernández,Pedro García-García,Juan C Roldán-Reyes,Francisco N Arroyo-López,Rosa Torres-Gallardo

doi:10.3389/fmicb.2017.00915

Francisco Rodríguez-Gómez, Joaquín Bautista-Gallego + Show 6 more

Open Access

https://doi.org/10.3389/fmicb.2017.00915

Copy DOI

Abstract

This work studies the inoculation conditions for allowing the survival/predominance of a potential probiotic strain (Lactobacillus pentosus TOMC-LAB2) when used as a starter culture in large-scale fermentations of green Spanish-style olives. The study was performed in two successive seasons (2011/2012 and 2012/2013), using about 150 tons of olives. Inoculation immediately after brining (to prevent wild initial microbiota growth) followed by re-inoculation 24 h later (to improve competitiveness) was essential for inoculum predominance. Processing early in the season (September) showed a favorable effect on fermentation and strain predominance on olives (particularly when using acidified brines containing 25 L HCl/vessel) but caused the disappearance of the target strain from both brines and olives during the storage phase. On the contrary, processing in October slightly reduced the target strain predominance on olives (70–90%) but allowed longer survival. The type of inoculum used (laboratory vs. industry pre-adapted) never had significant effects. Thus, this investigation discloses key issues for the survival and predominance of starter cultures in large-scale industrial fermentations of green Spanish-style olives. Results can be of interest for producing probiotic table olives and open new research challenges on the causes of inoculum vanishing during the storage phase.

Highlights

Table olives are a fermented vegetable of the Mediterranean basin with many centuries of history
Ruiz-Barba and Jiménez-Díaz (2012) have presented a novel L. pentosus paired starter culture that was tested in several industrial 10-ton vessels
The actual processing conditions prevailing in the current fermentation yards together with the industrial high volume vessels with considerable brine surface exposed to air makes difficult the survival of any starter culture over the environmental microbiota by just controlling the physicochemical conditions

Summary

Introduction

Table olives are a fermented vegetable of the Mediterranean basin with many centuries of history. The adhesion of lactobacilli and bifidobacteria on the epidermis of the processed olives (Lavermicocca et al, 2005) and the formation of true biofilms on green Spanish-style table olives (Arroyo-López et al, 2012a; Domínguez-Manzano et al, 2012) have been reported recently Such discoveries have encouraged researchers to investigate the use of multifunctional starter cultures for producing potential probiotic olives at laboratory and pilot plant scales. Blana et al (2014) used single and combined cultures of L. pentosus and Lactobacillus plantarum, isolated from industrially fermented olives, for processing Halkidiki olives in 14 L capacity plastic vessels Both potential probiotic strains successfully colonized the olive surface, L. pentosus B281 presented the most desirable characteristics for predominance. Bevilacqua et al (2015) made a review of the most relevant biotechnological innovations in table olives, based on both traditional and innovative starter cultures

Objectives

Methods

Results

Conclusion