Improving color and digestion resistibility of 3D-printed ready-to-eat starch gels using anthocyanins

Anthocyanins are natural pigments and dietary antioxidants, which have been widely applied to the production of functional foods. In this work, the anthocyanins extracted from sweet purple potato were added to the threedimensional (3D) printing of rice starch-based gels to improve the sensory acceptability and reduce the digestion rate of starch. The effects of anthocyanin content and pH on the gel rheological parameters, color, and printing effect were evaluated through steady flow test, small oscillation sweep, textural profile analysis, colorimetric measurement, and water distribution analysis. The optimal anthocyanins addition was 0.3%. The color of the 3Dprinted products changed from red to purple with pH increasing from 2.0 to 8.0. The starch hydrolysis rate of the 3D-printed products prepared at pH 6.0 was only 55.8%, and the estimated glycemic index (eGI) was 72.39, which is approximate to that of middle GI food. This work provides a new strategy for expanding the application of functional compounds in 3D-printed foods.