Crystallization of amylose—fatty acid complexes prepared with different amylose chain lengths

V-amylose Structural Characteristics, Methods of Preparation, Significance, and Potential Applications

“…The minimum amylose size for complexing with fatty acids is around [30][31][32][33][34][35][36][37][38][39][40] glucosyl residues to complex palmitic acid and 20-30 glucosyl residues for lauric and caprylic acids, which is about the chain length to accommodate two fatty acids per chain. (105) It was also illustrated that, irrespective of the complexation temperature, the critical minimum DP for complex formation and precipitation was 35 and 40 for complexes with glycerol monostearate (GMS) and docosanoic acid (C22), respectively, which also corresponded to the length needed to accommodate two of each of the ligand molecules. (33) The minimum required DP for complexation and precipitation therefore apparently depends on the acyl chain length.…”

“…V-amylose yield is more sensitive to amylose molecular weight than the number of carbons of the fatty acids. (105) The complex yield and crystallinity increases with the degree of amylose polymerization below DP 400, but decreases at higher DP of 950. (33) The increase in crystallization yields with amylose chain length could be explained by a combination of increased amylose solubility and the ability to form complexes that can precipitate in the crystallization medium.…”

“…The excess amylose chain length then contributes to the amorphous V-amylose component, (5,74) which would lead to an increase in the proportion of amorphous lamellae in the V-amylose suprastructure. (9,105) The optimum DP for V-amylose formation is still not clear given the 400-950 range was not investigated. However, the optimum DP probably depends on the structure of the included ligand since Kubik and Wulff (34) showed that the enthalpy of complex formation reaches a maximum at DP 400 and DP 250 for 4-tertbutylphenol and sodium dodecyl-sulphate, respectively.…”

“…(33) The increase in crystallization yields with amylose chain length could be explained by a combination of increased amylose solubility and the ability to form complexes that can precipitate in the crystallization medium. (105) The decrease in 24 crystallization yield at higher DP probably results from the presence of more amylose chain than that required for complexing the ligand (fatty acid). The excess amylose chain length then contributes to the amorphous V-amylose component, (5,74) which would lead to an increase in the proportion of amorphous lamellae in the V-amylose suprastructure.…”

“…(79) I t w a s postulated that the general minimum DP is 30, suggesting that amylopectin, which has short side chains (DP = 20), cannot form inclusion compounds. (105) 25…”