People eating a plant-based diet are recommended supplements, including B12, in order to fill some key nutritional gaps.
B12 is naturally found in animal products including milk, cheese and eggs. Although some fortified breakfast cereals are good sources of B12, it is not found naturally in foods such as fruit, vegetables and grains. Meanwhile, the most common supplemental form of B12 is synthetic, possibly a concern among consumers. Discoveries of potential plant-based sources of B12 are therefore potentially hugely significant.
The study suggests that with the help of the fermentation process, vegans can be guaranteed a sufficient and safe B12 intake directly from grain-based food, without pills.
In his doctoral dissertation, Chong Xie from the Faculty of Agriculture and Forestry, University of Helsinki, used 11 different grain-based materials including cereals, pseudocereals and legumes and fermented them with Propionibacterium freudenreichii -- the only B12-producing micro-organism accepted for food products.
Propionibacterium freudenreichii, the essential microbe in Emmental cheese, produced nutritionally significant amounts of vitamin B12 in most of the fermented grain materials. During the three-day fermentation process, rice bran and buckwheat bran had the highest B12 production.
The addition of Lactobacillus brevis - a type of lactic acid bacteria found in milk products and in some plants as they decompose - was able to dominate indigenous microbes during fermentation and therefore greatly improve microbial safety during the fermentation process. In general, brans and legume flours demonstrated a higher production of vitamin B12 than did cereal and pseudocereal flours.
Xie said that the addition of fermented brans in food products can be a promising way to provide vitamin B12 to consumers. For instance, by replacing 15% of wheat flour with fermented oat bran, 2 slices of bread (40-60 g) per day can provide a sufficient amount of vitamin B12. However, he stressed that the stability of synthesized vitamin B12 in different processes, and its bioavailability to the human body, should also be studied.
He also added that fermentation was potentially more cost-effective than fortification.
“Since its chemical synthesis is overly complicated and expensive, the commercial vitamin B12 used for food fortification is exclusively produced via a biotechnological process. As compared to fortification with this commercial form of vitamin B12, in situ fortification via fermentation can be a more cost-effective alternative. As a commonly consumed staple food, grains are excellent vehicles for enrichment with micronutrients,” said Xie.
“Overall, this thesis demonstrates that the fermentation of grain materials with P. freudenreichii and an appropriate co-culture, such as L. brevis, is a promising way to provide vitamin B12 in non-sterilized grain-based materials, without compromising microbial safety. Meanwhile, selecting raw materials that provide optimal conditions for P. freudenreichii can significantly improve the efficacy of vitamin B12 synthesis.”
He added that the fermentation of grains offered a potential solution for people unable to get enough Vitamin B12 from animal sources.
“Animal-origin food products are the main dietary source of vitamin B12. Thus, developing plant-origin food products that are fortified with vitamin B12 can provide not just a way to increase dietary intake of the vitamin in people with limited access to animal products, but also help meet growing nutritional needs, caused by the current trend of replacing animal food products with plant-based alternatives.
“To fully exploit the potential of the proposed co-fermentation technology for in situ fortification of vitamin B12, different strains of P. freudenreichii should be studied with a wide variety of most potential raw materials.”
In situ fortification of vitamin B12 in grain materials by fermentation with Propionibacterium freudenreichii
Doctoral dissertation: https://helda.helsinki.fi/handle/10138/317682