Enzyme‐Catalyzed Starch Esterification in Deep Eutectic Solvent. Issue 2 (14th January 2019)

• Record Type: Journal Article
• Authors: Deng, Xiaonan; Han, Xiaozhao; Hu, Xianguo; Zheng, Shufeng; Liu, Kun
• Is Part Of: ChemistrySelect. Volume 4:Issue 2(2019)
• Page Start: 565
• Page End: 569
• Publication Date: 2019-01-14
• Subjects: Starch -- Esterification -- Deep eutectic solvent -- Enzyme -- Phase transfer agent; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.201803981
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: For the first time the enzymatic esterification of starch in deep eutectic solvent (DES) was reported using DES of choline chloride (ChCl)‐ethylene glycol (EG) as reaction solvent/medium, Novozyme 435 as catalyst, and PEG 400 as phase transfer agent to synthesize starch decanoate, starch laurate, and starch palmitate. The product samples of esterified starches were characterized by FTIR, 1 H NMR, GPC, SEM, XRD, and DSC tests. The results showed that, the degrees of substitution were in the range of 0.07‐0.19 and the addition of PEG 400 was helpful to increase the DS. The optimal esterification temperature for DS was 338 K in the range studied. The degradation of starch was found to be minor due to the use of long‐chain fatty acid and relatively low reaction temperatures. The dissolution, gelatinization, esterification, and recrystallization of starch in DES broke the particles into smaller ones and altered the crystal structure of native starch while the aggregation between particles was increased and the degree of crystallinity was decreased for the esterified starch with the length of carbon‐chain in the fatty acids. Abstract : The starch esterification was successfully synthesized via the Novozyme 435‐catalyzed esterification of starch in DES of ChCl‐EG. The degrees of substitution of the product starches were in the range of 0.07‐0.19 depending on the esterification condition. The addition of PEG 400 could raise the DS pronouncedly and the optimal esterification temperature was 338 K.