Effect of β-cyclodextrin Combined with Deranching on Digestibility and Structure of Recrystallized Rice Starch

To improve the contents of resistant starch(RS),explore the recrystallized rice starch(RRS),the digestibility and structural difference of β-cyclodextrin recrystallized rice starch(β-CD-RRS),recrystallized detached rice starch(DB-RRS),β-cyclodextrin recrystallized de-branched rice starch(DB-β-CD-RRS)were investigated. The digestibility was evaluated by simulated digestion in vitro. The structure,thermal stability,and morphology of starches were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),and scanning electron microscopy(SEM),differential scanning calorimetry(DSC). Digestion expetiment in vitro showed that:The RS contents of RRS,β-CD-RRS,DB-RRS and DB-β-CD-RRS were 16.45%,19.03%,43.83% and 52.34%,respectively. After cooking,the RS contents of RRS,β-CD-RRS,DB-RRS and DB-β-CD-RRS were 1.54%,5.73%,15.49% and 20.18%,respectively. XRD analysis indicated that recrystallized rice starch(RRS)and recrystallized rice starch with β-CD(β-CD-RRS)were amorphous. However,recrystallized debranched rice starch(DB-RRS)and recrystallized debranched rice starch with β-CD(DB-β-CD-RRS)contained B+V type crystalline and their crystallinity was 23.6% and 30.13%,respectively. Specially,a new diffraction peak at 5.2 ° appeared in the XRD spectrum of DB-β-CD-RRS,which might result from the starch-β-CD complex. SEM analysis showed that RRS and β-CD-RRS were flaky,while DB-RRS and DB-β-CD-RRS were compact spherical particles. These results indicated that the combination of debranching and β-CD could promote the recrystallization of starch and the formation of starch-β-CD complex,thus synergistically increasing the RS contents.