The structural, functional and digestive characteristics of acorn starch after combined debranching and heat–moisture treatment and their relationships

Abstract

SummaryIn this work, acorn (Quercus suber) starch was first modified by debranching, and then subjected to heat–moisture treatment (HMT) at different temperatures (90 °C, 100 °C and 110 °C). Debranching and HMT could facilitate the aggregation of starch samples. The short‐range order and crystallinity were improved after debranching and HMT. The onset temperature (53.24 °C), peak temperature (63.41 °C), conclusion temperature (75.47 °C) and enthalpy change (11.38 J g−1) of native acorn starch increased after debranching and HMT. The solubility of native acorn starch increased after debranching, whereas the swelling power and freeze–thaw stability decreased. Compared with debranched starch, the freeze–thaw stability increased after HMT, while the swelling power and solubility decreased. Compared with native acorn starch, the water absorption capacity (WAC) was reduced after debranching, while the oil absorption capacity (OAC) was enhanced, and WAC and OAC of the debranched samples decreased after subsequent HMT. The total amount (72.98%, dry basis) of slowly digestible starch and resistant starch of native acorn starch after debranching and HMT increased significantly up to a maximum (80.36%, dry basis). These results indicated that the combination of debranching and HMT could be used as an effective strategy to improve the physicochemical properties of acorn starch.