Yeasts in foods and beverages: In vitro characterisation of probiotic traits

Abstract

Please cite this article as: Gil-Rodríguez, A.M., Carrascosa, A.V., Requena, T., Yeasts in foods and beverages: In vitro characterisation of probiotic traits, Abstract 23The possible beneficial properties of food and associated microorganisms for both 24 human and animal health are increasingly investigated. While many bacteria have been 25 characterised as probiotics, only one yeast variety, Saccharomyces cerevisiae var. 26 boulardii, has been recognised to be part of this group, regardless of the importance of 27 yeasts in the food industry. In this work, we have studied the probiotic or health-28 beneficial potential of 130 yeast strains isolated from food belonging to the collection of 29 the Institute of Food Science Research CIAL (CSIC-UAM). To that end, the response of 30 these yeasts to physiological conditions during consumption has been assessed through 31 measuring their capacity to grow at 37 °C and to survive the gastrointestinal transit 32 conditions. Almost 50% of the yeast analysed could thrive at the host intestine 33 temperature, and of these, almost 37% had growth kinetic parameters higher at 37 °C 34 than at 25 °C. In addition, about 95% of the strains could survive the exposition to 35 conditions simulating the gastrointestinal transit. The yeast strains were also analysed 36 for exhibiting auto-aggregation phenotype, antioxidant activity and the production of 37 killer peptides, this only found in 8.5% of the strains analysed. These properties could 38 be regarded as additional interesting features for selecting new probiotic strains.39 40

Probiotic potential of indigenous yeasts isolated during the fermentation of table olives from Northeast of Portugal

“…These results showed that this temperature was favorable for their growth and, therefore, these strains can easily adapt to the temperature of the host. Similar results were also obtained by Gil-Rodríguez et al (2015) for S. cerevisiae IFI-1145 and P. membranifaciens IFI-946, isolated from food and beverages. In contrast, isolates belonging to the genus Rhodotorula, R. graminis 20A and R. glutinis 27A, showed lower growth rates at 37°C (0.109 h − 1 and 0.186 h − 1 , respectively) than at 25°C, suggesting growing difficulties at human body temperature.…”

“…The highest antioxidant activities were obtained for S. cerevisiae 15A (16.47 ± 3.44%) and 15B (18.34 ± 2.24%), similar to the reference strain S. boulardii (16.22 ± 3.50%), while the lowest values were obtained for C. boidinii 32A (2.55 ± 3.45%) and 37A (3.52 ± 0.88%). Gil-Rodríguez et al (2015), in a study with yeasts isolated from different food and beverages, obtained higher values for different strains of S. cerevisiae, ranging from 19.74 ± 0.12% (IF-88) to 56.97 ± 0.30% (IFI-279), using a similar method to the present work. It is believed that the antioxidant activity of yeast is mainly due to the high content of (1,3)-β-D-glucan and other β-glucans found in the cell wall (Abbas, 2006;Jaehrig, Rohn, Kroh, Fleischer, & Kurz, 2007), to other cellular compounds and due to the presence of antioxidant enzymes such as superoxide dismutase, glutathione peroxidase and catalase (Chen et al, 2010).…”

“…After 4 h of incubation, the strains S. cerevisiae 15A and 15B, C. norvegica 7A, C. boidinii 37A and P. manshurica 2A, significantly increased their ability to form cellular aggregates, increasing continuously up to 24 h. The highest percentages of autoaggregation were determined after 24 h of incubation and ranged from 20.11 ± 4.20% (R. graminis 20A) to 93.94 ± 4.73% (C. tropicalis 1A). The variability in these results indicates that the autoaggregation ability is strongly strain dependent, as suggested by Gil-Rodríguez et al (2015). Our autoaggregation results obtained at 24 h for S. cerevisiae 15A and 15B (91.71 ± 5.58% and 74.33 ± 6.93%, respectively) were similar, under the same condition to those values reported by Gil-Rodríguez et al (2015) for S. cerevisiae IFI-87 (83.3 ± 0.1%) and IFI-244 (99.8 ± 5.74%), isolated from food and beverages.…”

“…The autoaggregation percentage of strains was performed using the method described by Gil-Rodríguez et al (2015). Sample (1.2 mL) of yeast culture in PDB broth was harvested by centrifugation (7200g, 5 min, 4°C) and washed twice with a sterile solution 0.9% NaCl (w/v).…”

“…The assessment of the ability of yeast growth at 37°C is an important parameter when it is desired to select promising probiotic microorganisms (Gil-Rodríguez et al, 2015). To exert their beneficial effects, microorganisms need to multiply within the host.…”