LAUSR

BACKGROUND 3D printing is an emerging technology finding numerous applications in the development of novel foods to meet personalized and special dietary needs. Using 3D printing, foods with modified texture and consistency can be conveniently prepared. In this work, an indigenous rice-black gram batter was fortified with pearl millet flour and 3D printed in the in-house developed extrusion-based food printer CARKTM . The impact of material supply composition was investigated along with optimization of different printing parameters and in-depth analysis of post-printing fermentation kinetics. Further, the shape changes in the 3D printed constructs during fermentation were analyzed using a pixel count-based image processing technique that correlates with the change in surface area. RESULTS The addition of millet flour resulted in accelerated fermentation. At 20% w/w level, better printability with higher precision and layer definition was obtained at 800 mm/min of printing speed, 360 rpm extrusion motor speed, and 1.22 mm nozzle diameter with an extrusion rate of 15.57 mm3 /s. The constructs of PMF fortified idli batter have shown good structural stability and creep recovery. Fermentation-assisted shape change was found to be significantly influenced by infill levels. Both raw and steamed constructs with 40% infill showed around 37% lower hardness than 100% infill constructs owing to porous inner structure with reduced expansion in surface area/volume during fermentation. CONCLUSION The results of the study provide insights into the scope of printing fermented foods through the food-to-food fortification approach and textural modification of foods using 3D printing by varying the infill levels. This article is protected by copyright. All rights reserved.