Deep eutectic solvent-inspired solid alkali carbonate for highly efficient interesterification of lard

Abstract

A novel and efficient strategy based on deep eutectic solvent (DES)-inspired potassium carbonate (K2CO3, K) for the interesterification of lard was investigated. K2CO3 was pretreated with glycerol (G) in a DES synthesis method. Compared with K2CO3 and glycerol in non-DES form (K+G), their DES form (KG-DES) exhibited excellent activity for the interesterification of lard. When the amount of KG-DES3 was 3 g·100 g−1, the interesterification degree (ID) of lard reached 100% at 120 °C for 1 h, and the corresponding triglyceride content was 71.01 mol·100 mol−1. The analysis of FTIR and 1H NMR showed that hydrogen bond interaction existed between K2CO3 and glycerol in KG-DES. The enhanced interesterification degree is mainly due to that the hydroxyl oxygen activated by carbonate ion is more favorable to attack the positive carbon of carbonyl group coordinated with K+. The crystal structure, glycerides and fatty acid composition, microscopic morphology and melting characteristics showed that the crystalline of interesterified lard was mainly β′, moreover, the sanding of lard was significantly suppressed. This strategy for pretreating solid alkali carbonates following the concept of DES will provide an efficient method for the application of solid catalysts in the modification of oils and fats.