The popularity of plant-based foods is steadily increasing due to growing concerns related to human health, animal welfare, and environmental sustainability. However, as plants do not synthesize vitamin B12 (cobalamin), fortification of plant-based products is strongly recommended to prevent cobalamin deficiency. At the same time, the food industry generates substantial quantities of organic by-products each year, among which fruit pomace – residues from juice and wine production – represents one of the most abundant fractions. Due to its high perishability and rich nutritional and bioactive composition, effective strategies for managing and valorizing fruit pomace are being actively explored.
The aim of this study was to investigate the feasibility of in situ cobalamin fortification of fruit pomace using safe, food-grade microorganisms: Propionibacterium freudenreichii DSM 20271 and lactic acid bacteria (LAB) – Lactiplantibacillus plantarum ATCC 10241. Propionic acid bacteria (PAB) are capable of synthesizing biologically active vitamin B12, while LAB were included due to their widespread use in the food industry and their positive impact on the sensory attributes of fermented products, such as flavor, aroma, and texture. Moreover, LAB produce lactic acid, which is the preferred carbon source for P. freudenreichii, potentially enhancing its metabolic activity in pomace-based matrices and thereby improving vitamin B12 production. Additionally, some LAB strains are capable of producing extracellular riboflavin, a key precursor in the biosynthesis of active cobalamin. A further objective of the study was to optimize the cobalamin fortification process in fruit pomace matrices in order to maximize production efficiency.
Fruit side-streams derived from blue honeysuckle berries, strawberries, and grapes were evaluated for nutritional properties relevant to the growth of PAB, including available carbon and nitrogen sources, amino acid profile, vitamins B2, B3, and B7, as well as cobalt content. Fruit pomace-based matrices were subsequently subjected to fermentation, and the effect of pomace type on the metabolism of bacteria was investigated. The results confirmed that fruit processing by-products can serve as effective substrates for both P. freudenreichii and L. plantarum, providing essential nutrients to support active microbial metabolism.
The findings demonstrated that fruit pomace can be successfully enriched with both vitamin B12 and propionic acid. Process optimization revealed that strawberry pomace was the most favorable substrate for propionic acid synthesis by PAB among the tested materials. In contrast, a combination of strawberry and grape pomace in appropriate proportions was found to promote cobalamin production most effectively. These results highlight the significant potential of fruit pomace valorization in accordance with zero-waste principles and sustainable development, aligned with the circular economy concept. Such an approach may deliver tangible environmental, social, and economic benefits by transforming food industry by-products into value-added functional food ingredients.
The experimental data include the following information:
- lactic acid bacteria screening towards co-culture with P. freudenreichii (files with annotation: screening),
- characteristics of pomace matrices (carbon sources, amino acid profiles, C/N molar and weight ratios, vitamins B2, B3, and B7, cobalt content) (files with annotation: matrices_0h),
- fermentation parameters: bacterial growth, carbon and nitrogen sources utlization, amino acid profiles, organic acid production (propionic acid, acetic acid, lactic acid), vitamin B12 production, ph changes (files with annotation: fermentation),
- standard curves used in research.
## File list:
*Readme.txt
*Bioscreen_BP_LAB_screening
*Bioscreen_SP_LAB_screening
*Bioscreen_GP_LAB_screening
*P_freudenreichii_Lb_screening
*P_freudenreichii_Lc_screening
*P_freudenreichii_Lp_screening
*P_freudenreichii_Lr_screening
*P_freudenreichii_Lre_screening
*P_freudenreichii_Lac_screening
*P_freudenreichii_control_screening
*Biotin_matrices_0h
*Cobalt_matrices_0h
*Niacin_matrices_0h
*Riboflavin_matrices_0h
*C_N_ratio_matrices_0h
*Nitrogen_content_matrices_0h
*Bacterial_growth_fermentation
*Carbon_sources_fermentation
*Amino_acid_profile_fermentation
*Lactic_acid_fermentation
*Propionic_acetic_acid_production_fermentation
*Correction_factors_acids_fermentation
*Propionic_acetic_acid_chromatograms_fermentation
*pH_fermentation
*LC_MS_MS_vitamin_B12_fermentation
*MBA_vitamin_B12_fermentation
*Standard_curves
