Treatment of green table olive solutions with ozone. Effect on their polyphenol content and on Lactobacillus pentosus and Saccharomyces cerevisiae growth

103

Table olives are one of the oldest fermented foods and are considered as an important component of the Mediterranean diet, since their richness in monounsaturated fats (primarily oleic acid) and phenolic compounds may function as antioxidants in the human body; in the Western world they represent one of the most popular fermented vegetables but, despite its economic significance, table olive fermentation is still craft-based and empirical. In particular, such a type of fermentation results from the competitive activities among indigenous, contaminating microorganisms, the microbial balance depending on several intrinsic (pH, water activity, diffusion of nutrients from the drupe, and level of anti-microbial compounds) and extrinsic (temperature, oxygen availability, and salt concentration) factors. At present, to reduce the risk of spoilage and to achieve a more predictable process there is an increasing interest in developing starter cultures for table olives fermentation. Anyway, the application of starter cultures in the field of table olives is quite far from reaching the diffusion as it has in other sectors of food industry (e.g., dairy products and alcoholic beverages). This review focuses on experimental researches devoted to studying starter cultures for possible application to table olive fermentation both at artisan and industrial level.

Section: Starter Culturesmentioning

confidence: 99%

Application of starter cultures to table olive fermentation: an overview on the experimental studies

Corsetti¹,

Perpetuini²,

Schirone³

et al. 2012

103

“…(iv) It has been proven that yeasts could improve lactic acid bacteria growth and as well as the production of lactic acid (Tsapatsaris and Kotzekidou, 2004; Segovia Bravo et al, 2007). Yeasts appear to be active microorganisms synthesizing substances such as vitamins, amino acids and purines, or breakdown complex carbohydrates, which is essential for the growth of Lactobacillus species that need a more complex medium for optimal growth (Ruiz-Barba and Jiménez-Díaz, 1995; Viljoen, 2006).…”

Section: Use Of Yeast Starters With Technological Applications In Tabmentioning

confidence: 99%

Potential benefits of the application of yeast starters in table olive processing

Arroyo‐López¹,

Romero‐Gil²,

Bautista-Gallego³

et al. 2012

Yeasts play an important role in the food and beverage industry, especially in products such as bread, wine, and beer, among many others. However, their use as a starter in table olive processing has not yet been studied in detail. The candidate yeast strains should be able to dominate fermentation, together with lactic acid bacteria, but should also provide a number of beneficial advantages. Technologically, yeasts should resist low pH and high salt concentrations, produce desirable aromas, improve lactic acid bacteria growth, and inhibit spoilage microorganisms. Nowadays, they are being considered as probiotic agents because many species are able to resist the passage through the gastrointestinal tract and show favorable effects on the host. In this way, yeasts may improve the health of consumers by means of the degradation of non-assimilated compounds (such as phytate complexes), a decrease in cholesterol levels, the production of vitamins and antioxidants, the inhibition of pathogens, an adhesion to intestinal cell line Caco-2, and the maintenance of epithelial barrier integrity. Many yeast species, usually found in table olive processing (Wickerhamomyces anomalus, Saccharomyces cerevisiae, Pichia membranifaciens, and Kluyveromyces lactis, among others), have exhibited some of these properties. Thus, the selection of the most appropriate strains to be used as starters in this fermented vegetable, alone or in combination with lactic acid bacteria, is a promising research line to develop in the near future.

“…The inhibition of S. cerevisiae is probably due to the high lactic acid produced by LAB during this kind of fermentation. However, there is evidence that S. cerevisiae improves L.pentosus performances in green table olives (Segovia Bravo et al, 2007). I. orientalis is a common species that is found in fermented olives and its frequent occurrence is probably due to its multiple-stress-tolerant state, as it is acid, ethanol, salt and thermo tolerant (Muccilli et al, 2011).…”

Section: Yeasts In Table Olive Fermentationmentioning

confidence: 99%

“…The co-inoculation of yeasts and LAB strains has led to an improvement in the growth of the latter and consequently in the production of lactic acid due to the greater availability of the previously listed nutrients (Segovia Bravo et al, 2007; Aponte et al, 2012). …”

Section: Yeasts In Table Olive Fermentationmentioning

confidence: 99%

“…In this context, the unified qualitative standard applied to table olives pertaining to international trade, defines this product as: “the sound fruit of specific varieties of cultivated olive trees ( Olea europea sativa ) harvested at the proper stage of ripeness and [...] processed as specified in this standard [IOOC, 2008]. Such processing may include the addition of various products or spices of good quality” (Segovia Bravo et al, 2007; Aponte et al, 2010, 2012). …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microbial dynamics and biodiversity in table olive fermentation: culture-dependent and -independent approaches

Botta¹,

Cocolin²

2012

The microbial ecology of the table olive fermentation process is a complex set of dynamics in which the roles of the lactic acid bacteria (LAB) and yeast populations are closely related, and this synergism is of fundamental importance to obtain high quality products. Several studies on the ecology of table olives, both in spontaneous fermentations and in inoculated ones, have focused on the identification and characterization of yeasts, as they play a key role in the definition of the final organoleptic profiles through the production of volatile compounds. Moreover, these are able to promote the growth of LAB, which is responsible for the stabilization of the final product through the acidification activity and the inhibition of the growth of pathogenic bacteria. The current empirical production process of table olives could be improved through the development of mixed starter cultures. These can only be developed after a deep study of the population dynamics of yeasts and LAB by means of molecular methods. Until now, most studies have exploited culture-dependent approaches to define the natural microbiota of brine and olives. These approaches have identified two main species of LAB, namely Lactobacillus plantarum and L. pentosus, while, as far as yeasts are concerned, the most frequently isolated genera are Candida, Pichia, and Saccharomyces. However, there are a few studies in literature in which a culture-independent approach has been employed. This review summarizes the state of the art of the microbial ecology of table olive fermentations and it focuses on the different approaches and molecular methods that have been applied.