Article

Yeasts in table olive processing: desirable or spoilage microorganisms. Int J Food Microbiol

Food Biotechnology Department, Instituto de la Grasa (CSIC), Avda. Padre García Tejero 4, 41012 Seville, Spain. Electronic address: .
International journal of food microbiology (Impact Factor: 3.08). 11/2012; 160(1):42-9. DOI: 10.1016/j.ijfoodmicro.2012.08.003
Source: PubMed

ABSTRACT

Yeasts are unicellular eukaryotic microorganisms isolated from many foods, and are commonly found in table olive processing where they can play a double role. On one hand, these microorganisms can produce spoilage of fruits due to the production of bad odours and flavours, the accumulation of CO(2) leading to swollen containers, the clouding of brines, the softening of fruits and the degradation of lactic acid, which is especially harmful during table olive storage and packaging. But on the other hand, fortunately, yeasts also possess desirable biochemical activities (lipase, esterase, β-glucosidase, catalase, production of killer factors, etc.) with important technological applications in this fermented vegetable. Recently, the probiotic potential of olive yeasts has begun to be evaluated because many species are able to resist the passage through the gastrointestinal tract and show beneficial effects on the host. In this way, yeasts may improve consumers' health by decreasing cholesterol levels, inhibiting pathogens, degrading non assimilated compounds, producing antioxidants and vitamins, adhering to intestinal cells or by maintaining epithelial barrier integrity. Many yeast species, usually also found in table olive processing, such as Wicherhamomyces anomalus, Saccharomyces cerevisiae, Pichia membranifaciens and Kluyveromyces lactis, have been reported to exhibit some of these properties. Thus, the selection of the most appropriate strains to be used as starters, alone or in combination with lactic acid bacteria, is a promising research line to develop in a near future which might improve the added value of the commercialized product.

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Available from: Francisco Noe Arroyo-López, Jan 22, 2014
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    • "Furthermore, yeasts are able to enhance the growth of Lactic Acid Bacteria (LAB) (Tsapatsaris and Kotzekidou, 2004; Segovia Bravo et al., 2007) and to biodegrade phenolic compounds (Ettayebi et al., 2003). Indeed, a possible role of yeasts as starters have been recently proposed for production of table olive (Arroyo-López et al., 2008, 2012a,b; Bevilacqua et al., 2013; Bonatsou et al., 2015). We previously reported that in several cultivars of black table olives yeasts were present during the fermentation, whereas LAB resulted associated only to the last stage of the process produced (Bleve et al., 2014, 2015a). "
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    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.
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    • "The production of green Spanish-style table olive is a traditional process which is usually achieved by spontaneous fermentation at ambient temperature. The main group of microorganism involved in the fermentation process is LAB (lactic acid bacteria), but yeasts are always present throughout processing (Garrido-Fernández et al. 1997; Arroyo-López et al. 2012a). In general, the genus Lactobacillus is recognized as the most characteristic of the indigenous LAB involved in green Spanish-style fermentation (Hurtado et al. 2012; Doulgeraki et al. 2013). "
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    ABSTRACT: This work focuses on the persistence of the putative probiotic bacteria Lactobacillus pentosus TOMC-LAB2 on green Spanish-style Manzanilla olives according to different packaging conditions and storage temperatures. The lactic acid bacteria population decreased with time but the highest survival counts (and lowest yeasts) at the end of storage (8 months) were observed in plastic pouches under nitrogen atmosphere and glass jars with brine stored at 20°C. Molecular techniques showed a 100% presence of the putative probiotic bacteria in biofilms adhered to olive epidermis, while it was absent in PPB (plastic pouches with brine) and in olives stored at 7°C. No changes in NaCl, pH or combined acidity were observed during the storage except for a slight increase in titratable acidity at 20°C. The color of the fruits was stable but degraded at 20°C for olives in plastic pouches with brine.
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    • "The growth of LAB in naturally fermented olives depends largely on the processing conditions (Abriouel, Benomar, Lucas, & G alvez, 2010). Yeasts can exert both positive or negative role, depending on the species involved (Arroyo-L opez et al., 2012). One of the major drawbacks of spontaneous fermentation is the slow processing time, linked to the debittering process that, as "
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    ABSTRACT: The processing of natural table olives is still empirical and far to be controlled. Taking natural fermentation (NF) as control, the performances of a single strain LAB starter culture (SSL) and a selected inoculum enrichment (SIE) were compared. The results showed that the SIE was more efficient in controlling spoiling microflora (Enterobacteriaceae spp.) compared to SSL and NF. Indeed, Enterobacteriaceae in SIE samples were not detectable starting from 10 days, while in SSL and NF samples starting from 30 days. Both starters rapidly acidified the brine, lowering the pH to safety levels (<4.0) after 12 days, while NF samples reached pH 4.3 after 45 days, and these values were kept constant up to 150 days. Moreover, both starters showed debittering activity, as stated through sensory analyses and HPLC analysis of phenols. Compared to NF samples, SIE and SSL extracts retained more hydroxytyrosol at the end of the process, and this could partially account for their higher scavenging activity. Texture profile analysis (TPA) showed that olives processed with SIE inoculum were firmer and more elastic, compared to SSL inoculated olives, thus resulting more similar to NF samples.
    No preview · Article · Jun 2015 · Lebensmittel-Wissenschaft und-Technologie
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