Abstract:

Using immobilized malate dehydrogenase as the catalyst, L-ascorbyl malate was synthesized in an acetone system, and the product content was determined by HPLC. The results showed that when the catalyst amount was 4 g/L, the molar ratio of L-ascorbic acid to malic acid was 1:3, and the reaction temperature was 55 ℃, the highest L-ascorbyl malate yield of 69.30% could be obtained. In addition, when the addition of L-ascorbyl malate to soybean oil was 0.05%, the POV value on the 7th day was only 8.41 meq/kg, indicating that L-ascorbyl malate has significant antioxidant activity. When the addition of L-ascorbic malate was 0.18%, its inhibitory rates against Escherichia coli, Staphyloccus aureus, and Bacillius subitills were 92.13%, 90.84% and 84.63%, respectively. It was concluded that L-ascorbyl malate is a potential antioxidant and bacteriostat.

Key words: immobilized enzyme, catalyst, L- ascorbyl malate, antioxidation, antibacterial activity