Sorbitol Enhances The Physicochemical Stability Of B-12 Vitamers

The stability of B-1(2) vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitot. The degradation losses of cyanocobalam in in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitot significantly prevented the Loss of cyanocobalamin (p < 0.05). Hydroxocobalamin and methylcobalamin exhibited degradation tosses ranging from 24%-26% and 48%-76%, respectively: added sorbitot significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitot (p < 0.05). Heat exposure (100 degrees C, 60 minutes) caused a greater toss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (similar to 15%) were prevented by adding sorbitot. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.