Abstract:The immobilization of liquid lipase CALB was investigated, which was used to catalyze the esterification of L-ascorbic acid with stearic acid to prepare L-ascorbic acid stearate(AS). The macroporous adsorbent resin was used as the immobilized carrier for liquid lipase CALB, and the immobilization loading rate was up to 72%. The effect of different reaction variables (reaction solvent, temperature, enzyme loading amount, molar ratio of substrate, substrate concentration and molecular sieve addition amount) on the esterification was investigated and the reaction conditions were optimized. The optimal conditions were 72 ℃, 1∶12 molar ratio of L-ascorbic acid and stearic acid, 22.49% enzyme loading amount (mass fraction), and 24 h of reaction. Under the optimal reaction conditions, the maximum yield of AS was (41.33±1.81) %. The product was separated and purified, and the product was identified as AS by mass spectra. The results of Rancimat showed that AS had good antioxidant activity, and the oxidation induction period of corn oil with 100 mg/kg AS was similar to that with 50 mg/kg of TBHQ.
