Production of folate in oat bran fermentation by yeasts isolated from barley and diverse foods
Article first published online: 1 JUL 2014
© 2014 The Society for Applied Microbiology
Journal of Applied Microbiology
Volume 117, Issue 3, pages 679–689, September 2014
How to Cite
Korhola, M., Hakonen, R., Juuti, K., Edelmann, M., Kariluoto, S., Nyström, L., Sontag-Strohm, T. and Piironen, V. (2014), Production of folate in oat bran fermentation by yeasts isolated from barley and diverse foods. Journal of Applied Microbiology, 117: 679–689. doi: 10.1111/jam.12564
- Issue published online: 18 AUG 2014
- Article first published online: 1 JUL 2014
- Accepted manuscript online: 10 JUN 2014 07:36AM EST
- Manuscript Accepted: 3 JUN 2014
- Manuscript Revised: 29 MAY 2014
- Manuscript Received: 3 DEC 2013
- Academy of Finland
- lactic acid bacteria;
- oat bran;
The focus of the research was to identify yeasts from barley kernels in order to study their folate production capability while maintaining high viscosity caused by soluble fibres in oat bran fermentation.
Methods and Results
The 65 isolated yeasts were characterized by API carbohydrate utilization tests, and assays for extracellular enzyme activities were the following: amylase, beta-glucanase, cellulase or CMCase, lipase, protease and xylanase. Yeasts were identified by partial DNA sequencing of the 25S D1/D2 and ITS1-5.8S-ITS2 regions. They belonged to the genera Aureobasidium, Cryptococcus, Pseudozyma and Rhodotorula. Folate production was determined from supernatant and cells grown in a rich laboratory medium or directly from oat bran solution inoculated with the appropriate yeast. Food yeasts, Saccharomyces cerevisiae, Candida milleri, Kluyveromyces marxianus and Galactomyces geotrichum, were used for comparison. Most of the yeasts isolated from barley destroyed the solid, viscous structure of the oat bran solution, indicating that they degraded the viscosity-generating soluble fibres, considered to be nutritionally advantageous. The best folate producers were S. cerevisiae, followed by Pseudozyma sp., Rhodotorula glutinis and K. marxianus. The yeasts maintaining high viscosity were used together with lactic acid bacteria (LAB) Streptococcus thermophilus or Lactobacillus rhamnosus to ferment oat bran solution. None of the yeasts isolated from barley, contrary to S. cerevisiae and C. milleri, produced together with LAB significant amounts of folate.
Fermentative yeasts together with LAB are potential for use in developing novel high folate content healthy foods and snacks from oat bran.
Significance and Impact of the Study
High soluble fibre content and high natural folate content but low energy content food and snack products with pleasant fermentation aroma provide possibilities for new developments in the food industry.