Influences of preparation process on the properties of high amylose corn starch-stearic acid complex

[Objective] This study aimed to establish a preparation process for starch-lipid complex with high resistant starch （RS） content and to explore the effects of process parameters on the anti-digestibility of the complex. [Methods] Using RS content as the indicator, one-way experimental and orthogonal designs were employed to study the effects of temperature and time parameters during the pretreatment of high amylose corn starch （HA） and its complexation with stearic acid （SA）. The physicochemical properties, anti-digestibility, and hydration characteristics of the HA-SA complex prepared by the optimal process were analyzed. [Results] Increasing pretreatment temperature in the gelatinization temperature range, prolonging the pre-treatment time, and complexing temperature above 75 ℃ all led to a significant decrease in RS content of HA-SA （P＜0.05）. The optimal process was as following: HA being pretreated at an annealing temperature of 85 ℃ for 12 h, and then complexed with SA at 75 ℃ for 90 min. The prepared HA-SA showed the V-type crystalline pattern and entire starch granules shape, and was characterized as the type I complex. It also presented the significantly enhanced thermal stability, bettered anti-digestibility, and lowered swelling power than HA （P＜0.05）. [Conclusion] Annealing temperature pretreatment and optimal complexation temperature favored to prepare the starch-lipid complex with higher anti-digestibility and entire granule structure. Excessive thermal strength during pretreatment causing excessive gelatinization could impede the formation of RS in the complexes. And a complexation temperature over 75 ℃ led to the disassociation of the complexation, decreasing the RS content. Annealing pretreatment preserved the entire starch granule of HA, which was one of the reasons for the higher digestibility of HA-SA.