Characterization and potential valorization of industrial food processing wastes

Valorization and utilization of industrial food processing waste as value added products, platform chemicals and biofuels, are needed to improve sustainability and reduce waste management costs. Various industrial food waste stream samples were characterized with respect to their physico-chemical characteristics and elemental composition. A subset of starchy food wastes and milk dust powder were evaluated in batch fermentation to acetone, a useful platform chemical. Production levels were similar to acetone produced from glucose but were achieved more quickly. Lactose concentration negatively affected fermentation and led to 50 % lower acetone concentration from milk dust powder than from starchy wastes. Uncooked starch waste can produce 20 % more acetone than cooked and modified starch waste. Fatty waste and mineral waste can be digested anaerobically generating biogas. Calorific value of soybean waste was 40 MJ/kg sufficiently high for biodiesel production. Low C/N ratios of wastewater and solids from food processing waste makes them unsuitable for anaerobic digestion but these waste types can be converted thermochemically to hydrochar and used as soil amendments. Low calorific content (10-15 MJ/kg) vegetable wastes also are not ideal for energy production, but are rich in flavonoids, antioxidants and pigments which can be extracted as valuable products. A model mapping food waste characteristics to best valorization pathway was developed to guide waste management and future cost and environmental impact analyses. These findings will help advance food industry knowledge and improve sustainable food production through valorized processing waste management.