Pullulanase hydrolysis behaviors and hydrogel properties of debranched starches from different sources

In the present study, debranched starches (DBS) from different sources were prepared by treatment with pullulanase with an aim to investigate the differences in pullulanase hydrolysis and the hydrogel properties of the resulting DBS. The results indicated that all DBS were V-type starches with hollow, single-helical structures. Debranched maize starch (DBMS) and wheat starch (DBWS) performed similarly. Pullulanase treatment resulted in an obvious reduction in viscosity for all tested starches except debranched pea starch (DBPeS). The average molecular weight of small fragments of debranched potato starch (DBPoS) was higher than that of the other samples, and longer lateral chains tended to be cleaved by pullulanase for DBPoS. The results of the solubility and water-holding capacity analyses indicated the DBS starches were capable of capturing water to form hydrogels. DBPoS was more easily digested by gastrointestinal amylase, whereas its pea-source counterpart showed the opposite trend. The results confirmed that generation of short linear glucan chains by pullulanase hydrolysis effectively improved solubility and water-holding capacity, which contributed to their hydrogel-forming properties.