Printability Of Purple Sweet Potato Puree For Extrusion-Based 3D Printing

3D food printing is an innovative technology with potential benefits for the future,capable of revolutionizing food production.Extrusion-based printing,because of its wide applicability,has great prospects,which could propel its industrial relevance sooner than expected.However,there are still hurdles to overcome,before it could be channeled towards the manufacture of real foods.A great aspect of this challenge is related to material formulation and adaptability to suit current functionalities of available 3D food printers.This study investigated the printability of purple sweet potato puree,as a fundamental base for other related food materials,using an extrusion-based Cartesian 3D food printer.The influence of three starch materials(sweet potato,potato and corn starches)at varying concentrations(2%,4%,6%,8% and 10%)on the printability of sweet potato puree samples,was investigated.Printability assessment involved the evaluation of the printing process and the final object quality.The printing process assessment involved monitoring of the printing process through visual observation,and with the aid of a digital camera,while objective data was extracted from the video recordings using Tracker software to determine the nozzle movement speed and diameter of the material deposited per second.Image J software was employed to measure the area,height,perimeter and angles of the final object,which were further analyzed to determine the consistency and deviations from the target model.The puree samples were successfully printed,and quality of final print improved with increased starch concentration,especially at 8% and 10%.At 8% starch concentration,purple sweet potato puree yielded good mechanical strength and compact network suitable for printing.Uniform flow and consistent diameter(0.88mm)was achieved at 10mm/s for sweet potato puree at 8% starch concentration.The printing time was 9.20 minutes,longer than the 8 minutes in the slicer code.An accurate geometry was achieved with no discontinuous lines and angle overlap at 8% starch concentration.Although the model was supposed to be printed within 8 minutes,based on the slicer code,however,the printing time was longer,which confirmed that other variability exists during 3D printing process.From this study,the important phases during the printing process were deduced to be;the beginning,retraction during non-printing moments and towards the final phase.Both velocity and diameter profiles confirmed that although nonprinting moments involved continuous nozzle movement from A to B,material deposition does not occur.Inability of the nozzle to effectively retract during this moment could affect the final geometry of the print object.The work presented in this thesis has provided information on the printability of sweet potato puree.Thus,the printability of a food material depends on its material composition,properties(such as viscosity)& structure,for it to perform well under printing conditions and result into accurate,high-quality product.