1-Butanol-Hydrochloric Acid Hydrolysis of High-Amylose Maize Starch

The 1-butanol-hydrochloric acid (1-butanol-HCl) degradation mechanism of high-amylose maize starch, represented by amylomaize V, is investigated using different methods. More pores are formed in the amylomaize V granules during 1-butanol-HCl hydrolysis and these pores become larger and change into cracks. Correspondingly, the average granule size slightly decreases from 13.49 to 10.87 µm after 1-butanol-HCl hydrolysis for 7 d. The crystalline areas of amylomaize V are hydrolyzed by 1-butanol-HCl and the amylose-1-butanol complex might form. In addition, the weight-average molecular weight of amylomaize V dramatically decreases from 1.25 × 10 7 to 3.57 × 10 5 Da after hydrolysis for 4 h, then slowly decreases, and stabilizes at about 2.00 × 10 4 Da after hydrolysis for 4 d, which is in accordance with the result of iodine staining analysis. High-performance anion-exchange chromatography analysis indicates that 1-butanol-HCl can hydrolyze the starch like hydrolysis patterns of both the endo-enzyme and the exo-enzyme. These results suggests that HCl in 1-butanol quickly diffuses into the whole amylomazie V granule and simultaneously attacks the crystalline and disorder areas, while the compact periphery of amylomaize V keeps the granules from disintegrating.