Sustainable food packaging : food processing waste fibres for thermoformed moulded pulp food packaging : a thesis presented in partial fulfilment of the requirements for the degree of Master of Food Technology at Massey University, Manawatu, New Zealand

Abstract

There is growing demand for sustainable packaging alternatives that substitute non-recyclable plastic packaging. This thesis aimed to investigate the potential of New Zealand’s food industry waste fibres for manufacturing moulded pulp trays that can reduce overall plastic consumption in the food takeaway area. Two novel and promising fibres, apple pomace and corn husk, were pulped and formed into handsheets and trays to explore their potential enhancement in mechanical and barrier properties compared to conventional wood fibres. Handsheets were produced under standard and thermo-forming conditions, and their performance was assessed. Initially, standard sheets containing mechanically pulped apple pomace, hemp seed husk, and Bleached Chemi-Thermo-Mechanical Pulp (BCTMP) fibres were tested for mechanical performance, Cobb value (water barrier), and oil penetration to screen the best formulations. Formulation containing 50% and 25% of apple pomace and 50% corn husk were selected, standard and hot-pressed sheets composed and assessed using tensile, tearing, bursting, short-span compression, Gurley, Cobb, grease resistance testing, contact angle, as well as roughness (through OCT and fringe projection) measurements. Sheets produced with apple pomace and BCTMP exhibited promising mechanical and barrier properties, surpassing those made from BCTMP alone. Their improved performance was due to higher density and stronger fibrous bonding from the addition of shorter fibres, with better packing of fibres. When hot-pressed at 230°C for 30 seconds using pressure of 393 kPa, the sheets displayed even greater mechanical and barrier performance, owing to denser fibrous networks and lignin flow, though reduced flexibility likely due to hornification, partial components degradation, and lignin cross-link reactions. In contrast, sheets incorporating corn husks demonstrated inferior mechanical performance due to ineffective fibre bonding, uneven fibre distribution, and material loss during formation, but exhibited slightly improved water resistance from increased hydrophobicity and surface roughness from the material. Moulded fibre tray prototypes were also produced at pilot scale to demonstrate commercial feasibility. A commercialisation pathway was then explored, focusing on market availability, industrial feasibility, and cost analysis of necessary equipment and energy. New Zealand food contact compliance and the composition of materials that may pose potential risks were also evaluated, revealing the restriction of some chemicals and that the moulded pulp product should meet Good Manufacturing Practice (GMP) requirements.