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Production of folate in oat bran fermentation by yeasts isolated from barley and diverse foods
Author(s) -
Korhola M.,
Hakonen R.,
Juuti K.,
Edelmann M.,
Kariluoto S.,
Nyström L.,
SontagStrohm T.,
Piironen V.
Publication year - 2014
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.12564
Subject(s) - food science , bran , biology , rhodotorula , geotrichum , fermentation , yeast , cellulase , xylanase , kluyveromyces marxianus , microbiology and biotechnology , biochemistry , saccharomyces cerevisiae , hydrolysis , enzyme , raw material , ecology
Aims 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 CMC ase, lipase, protease and xylanase. Yeasts were identified by partial DNA sequencing of the 25 S D 1/ D 2 and ITS 1‐5.8 S ‐ ITS 2 regions. They belonged to the genera A ureobasidium , C ryptococcus , P seudozyma and R hodotorula . 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, S accharomyces cerevisiae , C andida milleri , K luyveromyces marxianus and G alactomyces 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 P seudozyma sp., R hodotorula glutinis and K . marxianus . The yeasts maintaining high viscosity were used together with lactic acid bacteria ( LAB ) S treptococcus thermophilus or L actobacillus 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. Conclusions 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.