Manufacture and Characterization of 3D-Printed Sugar-Reduced Layered Chocolates and their Sensory Perception

  • Author / Creator
    Khemacheevakul, Khemiga
  • High global sugar consumption exceeding recommendations and an increased awareness of health concerns associated with excess sugar consumption have promoted the development of sugar-reduced foods by manufacturers, and consumption of sugar-reduced foods by consumers. As confectionary items are a major contributor to total sugars intake, sugar-reduction strategies should focus on this group of foods. 3D food printing (3DFP) is an emerging area of research, and previous studies have investigated single-extruder 3D printers, with a focus on optimizing material formulation and 3D printing parameters. However, few have addressed sensory perception of the printed foods, and none have utilized 3DFP for sugar-reduction. Furthermore, novel methods to optimize 3DFP can be developed as there are several ways to define a ‘good’ print. Therefore, this research comprises two studies that aimed to demonstrate the capability of a dual-extruder 3D food printer as an innovative tool to manufacture sugar-reduced 3D printed chocolates with desirable sensory qualities. A novel optimization procedure that compiles several previously proposed concepts for 3D printing parameters was also developed.

    In the first study, six variations of a three-layered hollow cylinder (diameter 28.00 mm, height 10.80 mm, wall thickness 4.37 mm) was designed in CAD software. Each variation had different layering orders of H or L chocolate to create sugar-reduced and non-sugar-reduced chocolates with different total % sugar concentrations. A semi-quantitative procedure for optimizing 3D printing parameters was developed, and this four-step approach was used to optimize printing parameters for a dual-extruder 3D printer with L and H chocolate. 3D printer speed and flow rate settings were first quantified. Then, chocolate lines that were 3D printed at varying print speed and flow rate were assessed by qualitative criteria (non-linearity, localized bulging, localized thinning, and breakage) to determine optimal print settings. Then, printed product accuracy and precision was validated by comparing measured mass and dimensions (height, wall thickness and diameter) of 3D chocolate prints to digital designs. Finally, 3D printed chocolate quality was evaluated by determining chocolate melting properties prior to and after 3D printing. The optimal print setting for both extruders was identified as print speed 35 (2.92-2.94 mm/s) and flow rate 100 (6.11-6.55 mm3/s) as it manufactured 3D printed chocolates with no qualitative defects and with similar mass and dimensions compared to the digital designs. The six designs had mean total % sugar (g sugar/g chocolate) of 51.5%, 41.6%, 41.6%, 34.9%, 34.0%, and 26.7%. Melting properties suggested that a printing temperature between 28-30℃ was suitable for both chocolates, as the chocolates remained tempered after 3D printing at these temperatures.

    In the second study, the temporal sensory profile, perceived sweetness intensity, and acceptance of the six manufactured sugar-reduced and non-sugar reduced 3D printed chocolates were investigated. The chocolate with 51.5% total sugar (printed with only H chocolate) was used as a high sugar control. A consumer panel (n=72) completed a temporal dominance of sensations (TDS) evaluation, rated overall sweetness intensity on a 5-point scale (1=not at all sweet, 5=extremely sweet), and rated liking on a 9-point hedonic scale (1=dislike extremely, 9=like extremely). 3D printed chocolates with 19% sugar reduction were perceived as similarly sweet compared to the high sugar control, while samples with 32% sugar reduction were perceived as less sweet. Layering order of H and L chocolates changed the temporal sensory attribute profile of the 3D printed chocolates, which influenced perceived overall sweetness. A sugar concentration gradient between layers improved the sweetness enhancement effect. All the manufactured 3D printed chocolates were similarly well-liked.

    This research presented an alternative sugar-reduction method that utilized dual-extrusion 3DFP to create sugar-reduced 3D printed chocolates. The spatial distribution of sugar concentration in layers to reduce sugar in foods has not previously been demonstrated for chocolate, and not with 3DFP. A novel, semi-quantitative printing parameter optimization procedure was proposed and demonstrated for a dual-extruder 3D food printer with two types of chocolate. Manufactured sugar-reduced 3D printed chocolates were also evaluated for their temporal sensory perceptions. Although this research focused on chocolate, the printing parameter optimization procedure, and the sensory perception results can be used to guide the development of improved 3D food printing processes for further sugar-reduction and customization of a variety of 3D printed foods.

  • Subjects / Keywords
  • Graduation date
    Fall 2021
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.