Preparation of debranched starch with high thermal stability and crystallinity using a novel thermal cycling treatment.

Herein, the effects of temperature cycling (4 °C/50 °C/100 °C) on the recrystallization, physicochemical properties, and digestibility of debranched starch (DBS) were investigated. Temperature cycling involved heating DBS to 100 °C to dissociate weak heat-sensitive crystalline structures and cooling to 4 °C to induce the rapid growth of crystal nuclei, followed by maintaining the temperature at 50 °C to promote orderly crystalline growth. This procedure aimed to increase the degree of crystalline structure in recrystallized DBS, thereby resulting in DBS that was heat- and digestion-resistant. Temperature cycling increased the dissociation temperature of DBS, and temperatures of up to 114.8 °C were attained after five cycling times. With increasing cycles, the crystalline structure of DBS transitioned from B-type to the more robust and compact A-type, and the crystallinity increased to ∼81.9 % (after seven cycles). Raman and Fourier transform infrared (FTIR) spectra indicated that temperature cycling enhanced the short-range ordered structure of DBS. Moreover, in vitro digestion experiments demonstrated that the resistant starch content of DBS increased to ∼61.9 % after eight cycles. To summarize, this study demonstrated a green and effective method for preparing heat-and digestion-resistant recrystallized DBS, which can be used for developing dietary supplements and low gastrointestinal staples.