Introducing vitexin in rice starch using ultrasound to enhance V-type resistant starch

V-type starch-polyphenol complexes demonstrate enhanced resistance to enzymatic digestion, despite their relatively rare occurrence in nature. This study utilizes various high-power ultrasound treatments to facilitate the formation of V-type complexes between vitexin, a flavonoid found in mung bean and native rice starch and subsequently investigates the digestive and physicochemical properties of the resulting complex. The findings revealed that high-power ultrasound treatment successfully formed a V-type starch-vitexin complex. The content of vitexin in the starch complex was the highest after 600 W ultrasound treatment (UT). Furthermore, adding vitexin during UT also altered the particle size distribution of the complex. The scanning electron microscope demonstrated that the particle size of starch increased after UT compared to native rice starch. Additionally, thermogravimetric analysis and infrared analysis confirmed that UT enhanced the thermal stability and disorder of the starch. The in vitro digestion experiments revealed that the starch-vitexin complex induced by ultrasound exhibited a decreased hydrolysis rate and increased content of resistant starch. In conclusion, both the UT of rice starch and the addition of vitexin together facilitated the formation of V-type starch, suggesting that vitexin could be utilized in the future production of functional foods with a sustainable processing method. • V-type complex was formed by rice starch and vitexin under ultrasound treatment. • The combination of vitexin increased the content of resistant starch in rice starch. • This approach can be applied in the production of functional foods.