Preparation, characterisation and in vitro digestibility of potato starch‐fatty acid complexes

Summary The starch‐fatty acid (FA) complex belongs to a new type of resistant starch (RS5) and has become a prevalent research topic because of its slow‐digestion and enzymatic resistance properties. In this study, the starch‐FA complexes were prepared from potato starch (PS) and FAs with various carbon chain lengths and unsaturation by hydrothermal treatment (HT), alcohothermal treatment (AT) or ultrasound treatment (UT), and their physicochemical properties and digestibility were interpreted. The PS‐8% lauric acid (Lau) with the highest complex index value (approximately 95%) and RS content (approximately 31%) was obtained by HT; meanwhile, it had a slow glucose diffusion rate and a low free fatty acid release rate in simulated gastrointestinal digestion compared to native PS. Besides, the V‐type crystalline structure was formed obviously after HT, but it was too weak for AT and UT samples to be detected. The gelatinisation viscosity was reduced due to the physical combination of PS and Lau. Therefore, HT was a relatively efficient and safe approach to prepare starch‐FA complex with high RS content, and the obtained starch‐FA complex has the potential to become an alternative functional food ingredient.