| Starch is the main energy source for human life activities in food,and it’s changes during thermal processing have a very important impact on the sensory quality and nutritional function of starch-based foods.The structure of starch is destroyed after thermal processing,and the released amylose can combine with lipids to form starch-lipid complexes.Starchlipid complexes have received extensive attention due to their ability to delay starch retrogradation,reduce starch digestibility,and improve intestinal probiotic properties.In this study,a twin-screw extruder was used to prepare starch-lipid complexes.By changing the processing conditions(processing temperature,material moisture,screw speed),starch-lipid complexes with better formation number and crystal structure were prepared for real applications Studies have shown that with the increase of processing temperature,it is easier to form type II complexes with good crystal structure.At the same time,the increase of water content in starch is also beneficial to the formation of more type II complexes.When the water content is higher than 55%,the viscous texture produced by the high gelatinization of starch during processing will prevent the starch from contacting with fatty acids.Too high or too low screw speed is not easy to form starch-lipid complexes.On the one hand,lower screw speed leads to incomplete destruction of starch granules,amylose is not easily released and difficult to combine with fatty acids.The XRD and DSC results show that the type II complexes with ordered crystal structure are more likely to be formed under the processing conditions of higher temperature and higher water content,and the type I complexes with unstable structure are more likely to be formed under the conditions of lower temperature and lower water content.At the same time,different crystalline starch-lipid complexes prepared by twin-screw extruder were also used in noodles to observe their effects on real food systems.It was found that the prepared type I complex can improve the resilience of noodles,reduce the hardness and whiteness of noodles.Some functional properties can easily lead to a decrease in the resilience of the noodles and an increase in the hardness of the noodles.When the replacement amount of the complex is 50%,the noodles are not easy to form.However,the type II complex can reduce the digestibility of noodles due to its own ordered crystal structure,and can significantly increase the dietary fiber content in noodles.These studies can be better used to develop new foods and provide strong guidance for improving the quality and nutritional properties of starch-based foods during food processing. |
