Massey Documents by Type

Permanent URI for this communityhttps://mro.massey.ac.nz/handle/10179/294

Browse

Filters

2003 - 200912010 - 20182

Settings

Has files: YesSubject: search.filters.subject.Extrusion process

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Design and development of a small-scale pellet extrusion system for 3D printing biopolymer materials and composites : submittted to the School of Engineering and Advanced Technology in partial fulfillment of the requirements for the degree of Master of Engineering, Mechatronics at Massey University, Auckland, New Zealand
    (Massey University, 2018) Whyman, Sean Matthew
    The aim of this research project is to develop a pellet-based 3D printing system that will accept biopolymer pellets to experiment with composite additives. Currently a majority of easily accessible or hobbyist 3D printers use filament as the input material for extrusion. With the goal in mind of printing using biopolymer materials and additive mixes, using filament remains achievable, but it would not provide as much freedom and exploration into unexplored areas. This can be an issue on the research side and a restriction on the hobbyist or consumer side where the material variety and printing capabilities such as recycling are much harder to achieve if not out of reach. This research report presents the process of designing and developing a pellet-based extrusion system to accept a range of biopolymer pellets for 3D printing. The system has been designed from first principles and therefore can be extended to other materials with slight parameter adjustments or hardware modifications. A robust mechatronic design has been developed using an unconventional yet simplistic approach to achieve the desired operating characteristics. The extrusion system uses a series of control factors to generate a consistent output of material over the course of a print. The platform and surrounding processes are setup so that software can be used to define the printing parameters, thus allowing for easy and simple adaption to dissimilar materials. The utility of the extruder is demonstrated through extensive printing and testing of the printed parts. Using Polylactic Acid (PLA) as the base material to test and develop the extruder system, the results of the print quality evolved as the extruders design became more robust. Several factors of the extruder contributed to large improvements such as; the hoppers rigidity, the internal geometries, the cooling efficiency and the software parameters. As these features progressed it enabled a much finer print quality and dimensional accuracy similar to what is seen in current Fused Deposition Modelling (FDM) extruders today. The print comparison tests were carried out against FDM PLA samples to reveal a high similarity in mechanical strength and improvements to some areas of surface quality. Further testing revealed success in testing other materials such as PETG, as well as successfully mixing and extruding Harakeke flax fiber composite additives. The major limiting factor of the current design is its ability to withstand heat propagation up through the extrusion system. As higher temperatures are required to melt different polymers, the thermal tolerance of the drive motor will quickly reduce causing inconsistencies earlier on during printing. The water cooling block added into the design only prevent heat from travelling through the wall of the extruder and not the screw. A further limitation is that the extruder is made using aluminium as the material. This allows for quick start-up times, but it also wears at a fast rate and the shaved off aluminium ends up contaminating the processed material. Because this extruder accepts pellets, the range of possibilities for future applications is vast. With further improvements to better refine the process, the material range could expand to more unconventional materials that otherwise could not be printed using popular extrusion methods. As for a business sense, there are few well known methods of pellet printing and especially affordable systems. Therefore, an opportunity could be present to develop a commercially affordable desktop system or spin-off to enter a niche market.
  • Thumbnail Image
    Item
    Development of a functional food ingredient using extrusion processing technology : a thesis presented in partial fulfillment of the requirements for the degree of Master of Technology in Food Technology at Massey University
    (Massey University, 2003) Gibbs, Briar
    This project aimed to develop a puffed "functional food" cereal ingredient that could subsequently be used in muesli bar products and potentially be on sold to breakfast cereal manufacturers. This ingredient was to contain nutrients that provided heart health benefits and also to possess good textural properties and to have an acceptable taste. Extrusion processing was used to produce the ingredient; extrusion processing transformed the raw materials used into a more palatable and texturally acceptable form and changed the nutritional quality. The decision as to which nutrients to include in the ingredient required consideration of efficacy, regulatory and consumer and market factors. A literature review was undertaken to identify potential nutrients that would have heart health efficacy, meet regulatory guidelines and still be acceptable to consumers. A qualitative consumer study was conducted to gauge consumer awareness of the nutrients investigated and the desirability for these ingredients to be included in a bar benefiting heart health. The main heart health nutrient selected for use in the puffed muesli ingredient, based on the results of screening, was soluble fibre. The source of soluble fibre selected was oat. The total, soluble and β-glucan (a particular form of soluble fibre) dietary fibre contents and the physical properties were of interest due to their influence on heart health benefits, product claims and sensory characteristics. The effect of formulation (starch level, starch type), enzyme treatment and extruder processing settings on the fibre content and physical properties of the puffed ingredient was investigated. It was found that soluble fibre increased during the extrusion process, partially at the expense of insoluble dietary fibre. However, β-glucan was found to decrease during processing. The level of starch in the formulation was found to have the most significant effect on both the physical and nutritional properties. Increasing the level of starch had a positive effect on the physical properties, but decreased dietary fibre levels. The puffed extrusion product contained a low level of β-glucan and a moderate level of total and soluble dietary fibre. A number of recommendations are presented concerning the feasibility of commercialisation, ingredient supplementation requirements and further research associated with the optimisation of the formulation and extrusion processing conditions.
  • Thumbnail Image
    Item
    Development of expanded snack foods containing pumpkin flour and corn grits using extrusion technology : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University, Palmerston North, New Zealand
    (Massey University, 2013) Md Nor, Norfezah
    The production of expanded snack foods using vegetable powder as an ingredient in ready-to-eat food is rare. In view of its natural desirable colour, flavour, sweetness and health benefits, pumpkin was chosen as an additive to the traditional corn grits or rice used as the basis of an extrusion expanded snack or breakfast food concept. Pumpkins also have a large range of uses as a potentially valuable food for humans and animals. However, they are an underutilised product. This study was undertaken to demonstrate the potential of pumpkin products as additives in expanded snack food products. Processing the fresh pumpkin into flour dramatically extends the shelf life and makes the ingredient available throughout the year. The flour is more convenient for extrusion as it is stored and handled as a dry powder. Research was conducted to produce and characterise pumpkin flour made by convection oven and freeze drying of a pumpkin fractions such as peel, pulp (rind), flesh and seed. The flour was combined with corn grits in various proportions up to a maximum of 20% w/w. After determining suitable processing conditions and the maximum acceptable concentration of pumpkin flour for an edible product, the effect of process parameters on product quality were determined. Finally the product was optimised using response surface methodology (RSM). The proximate compositions of pumpkin flour from convection oven and freeze drying were as expected identical to commercial pumpkin flour. The carbohydrate content ranged between 69.8 and 89%, protein ranged between 1.3 and 21%, and fat between 0.03 - 0.53%. Pumpkin flour produced by freeze drying revealed L, a and b values higher than in commercial pumpkin flour, indicating that the flour was lighter in colour and appeared more orange than that oven dried. The effect of varying pumpkin flour proportion at two mass flow rates of 7.5kg/hr and 8.5kg/hr revealed that mass flow rate did not have any significant correlation to the extrusion parameters and the final quality of the expanded snack product. However, a high quality final product can be achieved at all mass flow rates with less than 20% pumpkin flour incorporated into the blend. Varying the proportion of pumpkin flour between 5% and 20% in combination with corn grits using screw speeds of 250rpm and 350rpm showed that, increasing the proportion of pumpkin flour to 20% significantly (P<0.05) decreased specific mechanical energy (SME) and torque. The extruded pellets using a 20% blend of pumpkin with corn grits were harder, more denser and less expanded than those made with higher proportions of corn grits. The crispiness and hardness of the final product was not closely related to the number or area of bubbles present in the structure. Screw speed did not significantly (P>0.05) affect the specific mechanical energy (SME) or the physical characteristics of the final product. Hardness seemed to be due to bubble wall stiffness i.e. effectively the thickness and rigidity of the set starchy matrix. Response surface methodology (RSM) was predicted four solutions for optimum conditions which can be achieved at barrel temperature ranging from 165°C to 167°C at a constant feed rate of 10.50kg/hr and pumpkin flour percentage ranged from 16% to 17%. With these conditions, the optimum SME of 0.15 was achieved and this product had a maximum radial expansion of 11.00%, hardness less than 142.0N with a total carotenoid content of 2.07ppm to 2.13ppm. Sensory analysis revealed most consumers preferred expanded snack products containing 5% pumpkin flour and produced by extruding at a barrel temperature of 170°C and mass flow rate of 12.0kg/hr. The panellists indicated that they would buy this product due to its acceptable taste, texture, odour and overall product characteristics. However, the expanded snack with 15% pumpkin flour was found to have highest total carotenoid content (5.78ppm) and protein content (28.8%) after processing and may have been, in nutritional terms, the best product. The slowly digestible starch (SDS) value and carbohydrate content of this product was found at 97.03mg/g and 59.29% respectively. From this work useful information regarding pumpkin flour and its application in extruded expanded snack production was obtained. This work has the potential to diversify the application of pumpkin flour and offer new uses for pumpkin in the food industry.