Vitamin B12 production in solubilized protein extract of bioprocessed wheat bran with Propionibacterium freudenreichii
Bhawani Chamlagain, Minnamari Edelmann, Kati Katina, Pekka Varmanen, Vieno Piironen
Abstract
Wheat bran, a nutrient-rich byproduct of wheat milling, has the potential to be used for the production of vitamin B12 (B12) in order to fortify plant-based foods that are lacking in this vitamin. This study aimed to investigate B12 production in the soluble extract of bioprocessed wheat bran using Propionibacterium freudenreichii. The optimal conditions for B12 production were found to be a bioprocessing time of 24 hours, along with the use of a commercial starter culture of lactic acid bacteria and yeast, with pH adjusted from 4.0 to 6.4. The highest B12 production (55 ng/mL) was achieved within three days of fermentation. Cobalt supplementation (as CoCl2 or food-grade yeast extract) resulted in up to four-fold increase in B12 production. Similar results (50–70 ng/mL) were obtained when the processes were scaled up, with bioprocessing involving up to 15 kg and B12 fermentation involving up to 5 L, demonstrating the robustness of the procedure. Microbiological safety was ensured with the absence of Enterobacteriaceae in the extracts after bioprocessing and B12 fermentation. Overall, this study highlights the potential of under-utilized wheat bran as a raw material for producing B12-enriched bran extract, which can be used to fortify plant-based products in various food applications.