Protein binding assays for an accurate differentiation of vitamin B12 from its inactive analogue. A study on edible cricket powder

Authors: FEDOSOV, SERGEY - Aarhus University; NEXO, EBBA - Aarhuis University; HEEGAARD, CHRISTIAN - Aarhuis University; GOLDIN, JARROD - Entomo Farms; MASON, JOEL - Jean Mayer Human Nutrition Research Center On Aging At Tufts University

Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/2/2023
Publication Date: 8/9/2023
Citation: Fedosov, S.N., Nexo, E., Heegaard, C.W., Goldin, J., Mason, J.B. 2023. Protein binding assays for an accurate differentiation of vitamin B12 from its inactive analogue. A study on edible cricket powder. Food Chemistry. https://doi.org/10.1016/j.fochx.2023.100824.
DOI: https://doi.org/10.1016/j.fochx.2023.100824

Interpretive Summary: Due to emerging issues of agricultural sustainability, there is increasing interest in alternative sources of animal-derived sources of dietary protein, including insect-based foods. Assays based on older methodologies demonstrate that insect-based 'flours' contain substantial quantities of vitamin B12. However, the food industry commonly uses methods to determine B12 content that cannot distinguish between true B12 and other analogues of B12 that are not bioavailable to the human, resulting in misleadingly high values for true B12 content. We utilized a novel methodological approach to analyze the B12 content of two commercially available cricket powders that accurately distinguishes the two. We found that the true B12 content of both preparations of cricket powder was only 3-5% of total B12-like compounds that were reported on the nutrient composition listed on the package. These observations suggest that the food industry needs to switch to methodologies that accurately measure the B12 content of insect-based foods that is bioavailable to humans.

Technical Abstract: Inactive analogues of vitamin B12 (cobalamin, Cbl) can mimic the active Cbl in food if using the traditional microbiological measurements. Thus, overestimated Cbl was recently revealed in edible insects employing immunoaffinity adsorption, HPLC-separation and mass spectrometry (https://doi.org/10.1016/j.foodchem. 2021.129048). Here we demonstrate the utility of a convenient binding assay to evaluate Cbl in edible cricket powders. The assay employed the Cbl-specific protein intrinsic factor (IF) and the analogue-detecting protein haptocorrin. The excessive analogues had a weak affinity for IF, resulting in a modest overestimate of Cbl. This overestimate was corrected by a novel mathematical procedure, based on the ratio of analogue/Cbl in the sample and their relative affinities for IF. We found that 100 g of cricket powders contained 40-60 micro-g of analogues and 0.75-2.2 micro-g of Cbl. This result was confirmed by HPLC. A correct approach to Cbl-measurements is essential for nutritional assessment of any analogue-containing food.