Studies on the enzymatic synthesis and free radical scavenging ability
of phenolic acid glycerols
Abstract
The potentially wide application of Phenolic acids (PAs) in industries
was severely limited by their inadequate solubility and stability in
polar/non-polar media. To overcome these limits, studies on the
enzymatic esterification of PAs with glycerol were carried out to reach
a yield of 95% of phenolic acid glycerols (PAGs) under the following
reaction conditions: 1:150 molar ratio of caffeic acid (CA) to glycerol;
25% of Lipozyme 435 relative to the weight of total substrates;
temperature 80 oC, 500 rpm; 86.7 kPa and reaction time
10 h. Three resulting PAGs including caffeoyl glycerol (CG), feruloyl
glycerol (FG) and p-hydroxycinnamoyl glycerol ( p-HCG)
were confirmed by MS, 1H NMR and 13C
NMR. Among them, CG showed a comparative free radical scavenging ability
to CA, indicating its potential use as a water-soluble antioxidant
alternative to CA for food and cosmetic applications. Moreover, the
direct esterification of PAs with glycerol decrease the product cost and
increase the feasibility of industrial production compared with the
previous transesterification sythesis methods of PAGs.