Abstract

The aim of this study is to up-cycle mushroom production waste by incorporating macerated mushroom caps and stalks into moulded Kraft pulp packaging material and to compare the properties of this new material with existing food packaging materials, namely moulded pulp packaging (MPP) and polypropylene (PP) punnets. Corrugated cardboard fibre (CCF) was blended with 30% waste mushroom caps and stalks (MW) with and without addition of alkyl ketene dimer (AKD). Microbiological assessment of the packaging material from selected production stages and the finished punnets was conducted the determine levels of aerobic colony count, Pseudomonas spp., and yeasts and moulds. Also, finished punnets were characterized for their physical properties (moisture, density, surface hydrophobicity, mechanical properties, microstructure) and used for cold storage trials using fresh mushrooms comparing performance to MPP and PP punnets in terms of change in colour (CIE L*, a*, b*) and microbial load of the packed mushrooms. During seven days of cold storage of fresh mushrooms, both mushrooms and packaging materials were analysed for their total aerobic bacteria, Pseudomonas spp., and yeasts and moulds. Results showed that at the end of the storage, MW/CCF and MW/CCF + AKD punnets showed similar performance with PP punnet on the microbial quality of fresh mushroom. The fresh mushrooms had better colour compared with those stored in MPP. The paper-based punnets had higher microbial growth in the packaging material than PP punnet. Incorporation MW improved the mechanical properties of CCF. The MW/CCF and MW/CCF + AKD punnets had a higher Young’s modulus than MPP. Results indicated that, moulded pulp punnets prepared using 30% mushroom waste used for fresh mushroom packaging provide the similar microbial quality with better product colour compared with commercial counterparts while allowing agri-waste up-cycling.