Biosynthesis, structural characteristics and anticariogenic properties of erythritol-based acceptor products

To obtain new anticariogenic sugars, erythritol derivatives (EG1-2) were synthesized through a Thermus sp. amylomaltase (AMase)-catalyzed reaction between tapioca starch and erythritol. The reaction parameters, including donor and acceptor substrate concentrations, enzyme unit, pH, reaction time and temperature, were optimized with a yield of 29.3 % as well as 6.7 mg/mL of EG1-2. The products were subsequently prepared on a large scale and purified by HPLC. Their structural characteristics were also investigated by mass spectrometry and NMR data analysis. The formed transferred products had molecular weights of 307.1 and 469.2 Da; these values were in accordance with glucosyl-erythritol (EG1) and maltosyl-erythritol (EG2), respectively. The possible structures of EG1 and EG2 were 1-O-/4-O-α-glucosyl-erythritol and.1-O-/4-O-α-maltosyl-erythritol. In addition, the EG1-2 showed greater water solubility than that of original erythritol. Their relative sweetness value, which depended on the glucosyl-chain length of EG1-2, displayed a higher level than that of erythitol. Interestingly, both EG1-2 demonstrated anticariogenic properties by inhibiting a dental plaque formation of the tooth decaying Streptococcus mutans. Thus, the EG1-2 have the potential to be used as anti-cariogenic sweeteners in tooth-friendly dental products and food.