Alvita Mathias | ALES Graduate Seminar

Date(s) - 21/01/2021
1:00 pm - 2:00 pm

A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Alvita Mathias. This seminar is open to the general public to attend.

Join Zoom Meeting
Meeting ID: 966 7362 5393
Passcode: 929288

Thesis Topic: Development of 3D printed foods and their drying and decontamination using light emitting diodes

MSc with Dr. Roopesh Syamaladevi.

Seminar Abstract:

3D printing has gained a lot of popularity in the recent years. 3D food printing is a layer-by-layer deposition technique in a 3-dimensional space, but with food materials. 3D printing can be used to develop personalized food products for athletes, elderly, and children. Most of the 3D food printing research focused on the selection of suitable raw materials, optimization of printing parameters, and the development of post-processing techniques. The overall objective of this study was to develop 3D printed foods with selected ingredients and explore the use of ultraviolet light (UV) produced from light emitting diodes (LED) for rapid drying and decontamination of these 3D printed foods.

The first part of this research focused on the use of UV LEDs for the inactivation of Escherichia coli AW 1.7 (model microorganism) in 3D printed foods made of miso, a traditional Japanese paste. The 3D printed food samples were treated by UV light pulses with 395 nm wavelength, emitted from LEDs for different periods of time. The miso samples were printed in single, 2 layers and 5 layers, and each sample was subjected to LED treatments. For single layer 3D printed foods, 60 min of LED treatment resulted in 2.66 log reductions in E. coli. For 3D printed foods with 2 layers, 10 min LED treatment of individual layers resulted in 1.23 log reductions, while 20 min treatment of the whole sample resulted in 1.24 log reductions in E. coli. The water activity (aw) values of 3D printed products were decreased during LED treatment, for instance, the aw was decreased from 0.81 to 0.56 after 60 min LED treatment.

The second part of this research focused on the development and drying of a 3D printed high protein fruit-based snack. Selected ingredients, including pea protein, strawberries, bananas and xanthan gum (thickening agent) were used to develop the 3D printed snack. Various combinations of printing conditions, including print speed and flow rate were tested. Based on visual observation, print speed of 70 mm/s produced the best results. The moisture contents (dry basis) of samples printed at 23 oC were decreased by 32.5 % and 37.8 %, while those printed at 50 oC were decreased by 21.9 % and 42.7 % after 10 and 20 min LED treatments, respectively. This research shows that LED treatment could be used to dry and decontaminate 3D printed foods. Further research on the integration of LEDs to 3D printers and optimization of printing and LED treatment parameters is required.