Enzymatic Synthesis and Antioxidant Activity of 1‐Caffeoylglycerol Prepared from Alkyl Caffeates and Glycerol

Caffeic acid (CA) as a strong antioxidant has lower solubility in nonpolar media, which limits its application in the food industry. To increase the lipophilicity of CA, 1‐caffeoylglycerol (1‐CG) was synthesized by lipase‐catalyzed transesterification of alkyl caffeates in solvent‐free system and its antioxidant capacity was investigated. Methyl caffeate was screened as the appropriate substrate from tested alkyl caffeates with a yield of 90.63%. Ethyl acetate was used for extracting 1‐CG from enzymatic reactants and could be easily recycled. The produced 1‐CG had 2.5‐ and 10‐fold lower values of half maximal inhibitory concentration (IC₅₀) (10.86 and 3.99 μM) than butylated hydroxyanisole by 1,1‐diphenyl‐2‐picrylhydrazyl radical scavenging and β‐carotene‐linoleic acid assays, respectively. Thus, 1‐CG is an excellent antioxidant for application in the functional food industry. Using alkyl caffeates and glycerol as substrates to produce 1‐CG catalyzed by immobilized lipase in a solvent‐free system is a simple, selective, and safe bioprocess that can readily be achieved in the food industry, and the product 1‐CG could be widely applied in food, nutraceutical, and biotechnological products.