Evolution of Yeast Consortia during the Fermentation of Kalamata Natural Black Olives upon Two Initial Acidification Treatments

Bonatsou, Stamatoula; Paramithiotis, Spiros; Panagou, Efstathios Ζ.

doi:10.3389/fmicb.2017.02673

Cited by 35 publications

(30 citation statements)

References 47 publications

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“…On the other hand, yeasts are the main organisms driving the fermentation of naturally processing olives [33], although there are studies that have reported the presence of LAB [34]. In the current study, LAB growth in AL7 might have been hampered by salt-tolerant yeast species, resulting in a less acidic product, which was in accordance with the literature [29,35]. 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].…”

Section: Physicochemical Analysessupporting

confidence: 90%

“…Yeast growth had an initial lag phase in all cases, occurring across treatments and reaching the maximum level approximately at circa 8 days (7 log cfu/mL), which was in agreement with the literature [2,29,30]. Following, a major decrease in AL8 and AL9 was observed, reaching a value of 3.7 log cfu/mL and 3.5 log cfu/mL at day 60, respectively ( Figure 1B).…”

Section: Physicochemical Analysessupporting

confidence: 90%

“…Samples were analyzed at regular time intervals (Days 0, 8,15,22,29,45,60,90,120,150,210,281,365) throughout fermentation. They were determined for the total viable count (TVC), Enterobacteriaceae, LAB, yeasts, Coliforms, Staphylococci, using the standard pour and spread plate methods after serial dilutions in 0.85% w/v saline water ( Table 1).…”

Section: Microbiological Analysismentioning

confidence: 99%

“…Finally, in order to detect the presence of the starter culture, rep-PCR genomic fingerprinting was performed on 17 random strains isolated from MRS agar, from brines AL7, AL8, and AL9 at 120 days of fermentation, using the (GTG) 5 -primer (5 -GTG GTG GTG GTG GTG-3 ). DNA from each strain was obtained according to Bautista-Gallego [28] and stored at −80 • C. PCR reaction and amplification conditions were applied following a method previously described [29].…”

Section: Isolation Of the Predominant Microfloramentioning

confidence: 99%

“…Concerning ethanol, it is mainly related to yeast production activity, having a crucial impact on the sensory properties of naturally fermented olives [29]. Its concentration in AL7 increased gradually until day 90 of fermentation, reaching values 250 mM, followed by a minor decrease thereafter until Sugars diffused from fruits into the brine are the main nutritional elements for microbial growth and fermentation.…”

Section: Physicochemical Analysesmentioning

confidence: 99%

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

Anagnostopoulos

Goulas

Xenofontos

et al. 2019

Foods

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Table olives are one of the most established Mediterranean vegetables, having an exponential increase consumption year by year. In the natural-style processing, olives are produced by spontaneous fermentation, without any chemical debittering. This natural fermentation process remains empirical and variable since it is strongly influenced by physicochemical parameters and microorganism presence in olive drupes. In the present work, Cypriot green cracked table olives were processed directly in brine (natural olives), using three distinct methods: spontaneous fermentation, inoculation with lactic acid bacteria at a 7% or a 10% NaCl concentration. Sensory, physicochemical, and microbiological alterations were monitored at intervals, and major differences were detected across treatments. Results indicated that the predominant microorganisms in the inoculated treatments were lactic acid bacteria, while yeasts predominated in control. As a consequence, starter culture contributed to a crucial effect on olives fermentation, leading to faster acidification and lower pH. This was attributed to a successful lactic acid fermentation, contrasting the acetic and alcoholic fermentation observed in control. Furthermore, it was established that inhibition of enterobacteria growth was achieved in a shorter period and at a significantly lower salt concentration, compared to the spontaneous fermentation. Even though no significant variances were detected in terms of the total phenolic content and antioxidant capacity, the degradation of oleuropein was achieved faster in inoculated treatments, thus, producing higher levels of hydroxytyrosol. Notably, the reduction of salt concentration, in combination with the use of starter, accented novel organoleptic characteristics in the final product, as confirmed from a sensory panel; hence, it becomes obvious that the production of Cypriot table olives at reduced NaCl levels is feasible.

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