Effects of acid hydrolysis on the physicochemical properties of pea starch and its film forming capacity

The effects of acid hydrolysis treatment on the properties of pea starch (PS) and PS-based films by solution casting were investigated. Native pea starch granules were partially hydrolyzed with 2% hydrochloric acid for 0.5, 1.0, 1.5, 2.0, and 2.5 h. Acid hydrolysis treatment lowered the molecular weight of amylopectin from 27.94 × 107 g/mol for native PS to 9.16 × 107 g/mol for the sample of 2.5 h hydrolysis, but had no obvious effect on the molecular weight of amylose. Micrographs of the hydrolysis starch granules exhibited surface erosion and fragmentation. The relative crystallinity slightly increased, whereas the peak, trough, final and setback viscosities decreased during acid hydrolysis. After acid hydrolysis treatment, the tensile strength of the pea starch film significantly increased and reached a maximum of 21.21 MPa with 2.0 h of acid hydrolysis.