Christopher J. Chuck

The environmental impact of petroplastics that do not readily biodegrade has intensified the search for sustainable packaging materials. Polysaccharides derived from plant and marine sources are biodegradable and renewable, but their hydrophilicity and weak mechanical and barrier properties limit their use in high-performance packaging. Chemical modification offers an effective solution by introducing hydrophobic or functional groups that enhance physicochemical performance, making modified polysaccharides strong candidates for sustainable packaging applications. This review provides a comprehensive overview of recent advances in the chemical modification and development of plant-based polysaccharides (starch, cellulose and its derivatives, and pectin) and marine-based polysaccharides (agar, carrageenan, alginate, and chitosan) for food packaging applications. Emphasis on how chemical modifications influence key functional properties relevant to sustainable packaging, including barrier performance, biological activities, and freshness-monitoring capabilities. Film fabrication techniques such as solution casting, extrusion, coating, and electrospraying are also discussed regarding their impact on material performance. Overall, the reviewed studies demonstrate that chemical modification can substantially enhance the functional properties of polysaccharides and enable active and intelligent packaging functionalities. While challenges related to food safety, scalable production, environmental impact, and real-world performance remain, chemically modified polysaccharides show strong potential as sustainable and functional materials for the next generation of food packaging.

In this work we aimed to increase the food potential of UK pasture by coupling targeted mechanochemical processing and novel biotechnology to convert silage into edible protein and lipid fractions. To this end, the water-soluble protein and vitamins were extracted from silage using a twin-screw extruder at room temperature. The extrusion of the silage was optimized in water with no additional chemicals. Under optimal conditions, 22 wt% of the silage was solubilized, with this fraction containing 52% of the protein present from the original material. The protein contained key essential amino acids with a profile similar to soy protein. Vitamins B ₁ , B ₂ , B ₃ (nicotinamide and nicotinic acid) and B ₆ (pyridoxine, pyridoxal and pyridoxamine) were also extracted. The resulting solids from the extruder, which contained further insoluble protein and the carbohydrates from the silage, were then depolymerized and used to culture the oleaginous yeast Metschnikowia pulcherrima producing further mycoprotein and lipid from the system. The mycoprotein contained a balanced amount of vital amino acids, while the yeast lipid had a fatty acid profile containing high levels of monounsaturated lipids. The silage was also found to contain high value lipids, rich in omega-6 linolenic acid. The work presented here represents a preliminary study but highlights the possibility of extracting edible nutrients from grass feasibly, with the potential to make UK agriculture far more resilient and sustainable. This article is part of the theme issue ‘Transforming terrestrial food systems for human and planetary health’.

Seaweeds contain many varied and commercially valuable components, from individual pigments and metabolites through to whole biomass, and yet they remain an under cultivated and underutilised commodity. Currently, commercial exploitation of seaweeds is predominantly limited to whole biomass consumption or single product extracts for the food industry. The development of a seaweed biorefinery, based around multiple products and services, could provide an important opportunity to exploit new and currently underexplored markets. Here, we assessed the native and invasive seaweeds on the South West coast of the UK to determine their characteristics and potential for exploitation through a biorefinery pipeline, looking at multiple components including pigments, carbohydrates, lipids, proteins and other metabolites.