New process for production of fermented black table olives using selected autochthonous microbial resources

Abstract

Table olives represent one important fermented product in Europe and, in the world, their demand is constantly increasing. At the present time, no systems are available to control black table olives spontaneous fermentation by the Greek method. During this study, a new protocol for the production of black table olives belonging to two Italian (Cellina di Nardò and Leccino) and two Greek (Kalamàta and Conservolea) cultivars has been developed: for each table olive cultivar, starter-driven fermentations were performed inoculating, firstly, one selected autochthonous yeast starter and, subsequently, one selected autochthonous LAB starter. All starters formulation were able to dominate fermentation process. The olive fermentation was monitored using specific chemical descriptors able to identify a first stage (30 days) mainly characterized by aldehydes; a second period (60 days) mainly characterized by higher alcohols, styrene and terpenes; a third fermentation stage represented by acetate esters, esters and acids. A significant decrease of fermentation time (from 8 to 12 months to a maximum of 3 months) and an significant improvement in organoleptic characteristics of the final product were obtained. This study, for the first time, describes the employment of selected autochthonous microbial resources optimized to mimic the microbial evolution already recorded during spontaneous fermentations.

Benefits of the Use of Lactic Acid Bacteria Starter in Green Cracked Cypriot Table Olives Fermentation

“…Nevertheless, yeast growth is not considered to present any consumption risk during the fermentation of green olives; On the contrary, yeast can metabolize ingredients that enrich the sensory palette and determine the quality of the final product [36]. It is worth noticing that the presence of yeasts, especially in the first days of the process, might have led to the enhancement of the starter culture in inoculated treatments due to their potential production of vitamins and other nutrients, which are mandatory for LAB growth [37].…”

Effects of Exogenous Yeast and Bacteria on the Microbial Population Dynamics and Outcomes of Olive Fermentations

“…The proportions of these two genera then diminished to background levels within the first 70 days of the experiment. Thus far, few published reports have investigated the effects of exogenous yeast cultures on the population microbial dynamics and diversity in olive fermentations (5, 7, 16). According to culture-dependent methods applied in those reports, levels of the inoculated yeast cells were either maintained (5) or significantly reduced (16) as the fermentations progressed.…”

“…Thus far, few published reports have investigated the effects of exogenous yeast cultures on the population microbial dynamics and diversity in olive fermentations (5, 7, 16). According to culture-dependent methods applied in those reports, levels of the inoculated yeast cells were either maintained (5) or significantly reduced (16) as the fermentations progressed. Such variation might be the result of the processing method applied or yeast strain- or species-dependent differences in the capacity to successfully invade and colonize olive drupes in the presence of the indigenous fermentation-associated microbiota.…”

“…Although starter cultures are not yet used for the production of Sicilian-style olives in the United States, numerous studies have investigated strains of Lactobacillus and Leuconostoc as starter cultures for other olive fermentation methods (5–10). In those studies, strains of Lactobacillus plantarum and Lactobacillus pentosus were shown to be effective at increasing rates of brine acidification and improving the organoleptic qualities of the final product.…”

Table Olive Fermentation Using Starter Cultures with Multifunctional Potential

“…The most studied species for their potential use as starters in table olive production are LAB and yeasts. According to a recent study [31], the use of autochthonous yeasts and LAB has shown to shorten the time of fermentation, standardize the process, and improve their organoleptic and nutritional properties. Specifically, the role of microbial starters, selected for specific biotechnological and safety traits is considered to be the [31]:

improvement of table olives sensory attributes;

control of the fermentation process;

monitoring of the correct evolution of the process;

maintenance and/or improvement of nutritional and healthy features of the product;

protection from undesirable spoilage and pathogenic microorganisms;

fortification of table olives with microorganisms exhibiting probiotic potential;

enhancement of product stability and extension of shelf life.

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