Abstract: The effects of autoclaving treatment and retrogradation on the structure and in vitro enzymatic digestibility of complex (HA7-SA) formed between stearic acid (SA) and debranched high amylose starch were investigated. The long-range and short-range molecular orderliness and phase transition temperature of HA7-SA before and after treatment were determined by X-ray diffraction (XRD), laser confocal microscopy-Raman spectroscopy and differential scanning calorimetry. The in vitro enzymatic digestibility was evaluated by in vitro digestion experiments. It was found that autoclaving treatment could significantly decrease the crystallinity of V-type crystal, and increased the crystallinity of B-type crystal, phase transition temperature and short-range molecular orderliness of HA7-SA (P < 0.05). The in vitro enzymatic digestibility and estimated glycemic index (eGI) were significantly decreased after autoclaving treatment. Storage at 4, 25 and 50 ℃ for 24 h after the processing had no significant effect on the structure or in vitro enzymatic digestibility of HA7-SA complex.

Key words: starch-lipid complexes; in vitro digestibility; autoclaving treatment; structure; estimated glycemic index