Identification and Maillard reaction activities of dilauryl mannose isomers formed during lipase-catalyzed condensation

Abstract

Lauryl mannoses were synthesized by lipase-catalyzed condensation using d-mannose and lauric acid in acetone in the presence of molecular sieves at 50 °C. 6- O-Lauryl mannose, 1,6-di- O-lauryl mannose, 3,6-di- O-lauryl mannose, and 4,6-di- O-lauryl mannose were isolated and identified by FT-IR, MS, and NMR. Maillard reaction activities of mannose with l-cysteine and lauryl mannoses with l-cysteine were evaluated by headspace solid phase microextraction (HS-SPME) method combined with GC/MS. 1,6-Di- O-lauryl mannose exhibited the lowest Maillard reaction activity, compared with 6- O-lauryl mannose, 3,6-di- O-lauryl mannose and 4,6-di- O-lauryl mannose. Low activity of Maillard reaction by lauryl mannoses compared to that by mannose was due to the structures of mannose and lauryl mannoses determined by NMR analysis.