| Title: | Survival of Kluyveromyces lactis and Torulaspora delbrueckii to simulated gastrointestinal conditions and their use as single and mixed inoculum for cheese production |
| Author(s): | Andrade RP; Oliveira DR; Lopes ACA; de Abreu LR; Duarte WF; |
| Address: | "Department of Biology. University of Lavras (UFLA), Lavras, MG, Brazil. Food Science Department, University of Lavras (UFLA), Lavras, MG, Brazil. Department of Biology. University of Lavras (UFLA), Lavras, MG, Brazil. Electronic address: whasleyduarte@dbi.ufla.br" |
| DOI: | 10.1016/j.foodres.2019.108620 |
| ISSN/ISBN: | 1873-7145 (Electronic) 0963-9969 (Linking) |
| Abstract: | "The demand for new probiotic products has shown recent increases alongside a growing interest in studying starter cultures of cheeses. This study thus aims to evaluate the ability to survive under simulated gastrointestinal conditions and impact of Torulaspora delbrueckii B14 and Kluyveromyces lactis B10 as single and mixed inocula for cheese production. These two yeast strains were subjected to simulated gastrointestinal tracts and tested for self-aggregation, hydrophobicity, pathogen inhibition, antibiotic resistance, and beta-galactosidase production. The yeast strains were also assessed for their ability to survive in different NaCl concentrations (2.5%, 5%, and 10% w/v), multiple temperatures (4?ª+ degrees C and 40?ª+ degrees C), and used as single and mixed starter cultures for cheese production. Yeasts population levels were monitored by YPD plating and MALDI-TOF and metabolites were analyzed by HPLC and GC-MS over the course of the 21?ª+days cheese maturation process. T. delbrueckii B14 and K. lactis B10 both showed >80% viability after the passage through the simulated gastrointestinal tract, had self-aggregation rates >90%, and displayed beta-galactosidase activities of 0.35?ª+U/g and 0.53?ª+U/g, respectively. Both yeasts survived at 2.5%, 5%, and 10% NaCl for 21?ª+days and showed growth at 4?ª+ degrees C. In cheese, the single inoculum of K. lactis B10 and mixed inoculum showed the highest levels of lactose consumption. HS-SPME GC-MS analysis of cheese samples allowed the identification of 38 volatile compounds. The highest concentrations of most of these compounds were observed after 21?ª+days of maturation for the cheese produced with mixed inoculum. The most abundant acids detected were hexanoic and decanoic acid; the most abundant alcohols were 2,3-butanediol, 2-phenylethanol and isoamyl alcohol, and the most prevalent ester compounds were isoamyl acetate and phenethyl acetate. Our results therefore show that T. delbrueckii B14 and K. lactis B10 are interesting yeasts for further studies in the context of probiotics and positively impact the composition of desirable volatile compounds in cheeses, particularly when used as mixed inoculum" |
| Keywords: | "Antibiosis Butylene Glycols Cheese/*microbiology Drug Resistance, Microbial *Food Microbiology Gastrointestinal Microbiome/*physiology Gastrointestinal Tract/*microbiology Hydrophobic and Hydrophilic Interactions Kluyveromyces/*physiology Lactose/metaboli;" |
| Notes: | "MedlineAndrade, Rafaela Pereira Oliveira, Daelen Resende Lopes, Ana Claudia Alencar de Abreu, Luiz Ronaldo Duarte, Whasley Ferreira eng Research Support, Non-U.S. Gov't Canada 2019/09/27 Food Res Int. 2019 Nov; 125:108620. doi: 10.1016/j.foodres.2019.108620. Epub 2019 Aug 18" |
