Comparative assessment of innovative and conventional food preservation technologies: process energy performance and greenhouse gas emissions

This study aims to establish whether innovative food preservation technologies can offer significant reductions in energy consumption and corresponding greenhouse gas (GHG) emissions while delivering equivalent microbiological lethality, nutritional and organoleptic quality to conventional processes. The energy demand of high pressure processing, microwave, ohmic and conventional heating technologies, for achieving the same pasteurising effect in orange juice under commercially-representative processing conditions are measured and compared. The corresponding GHG emissions are evaluated using UK energy system emissions data, while the effect of equipment scale is explored empirically. The results show that for the same product quality, the innovative technologies are more energy- and non-renewable primary resource-efficient, with ohmic heating performing best, followed by high pressure processing at high fill-ratios. More significant improvements are expected in future, provided electricity grid decarbonisation is sustained. Energy performance improves with equipment scale for the microwave and high-pressure systems, but remains essentially constant for ohmic heating.

Industrial relevance: Using orange juice pasteurisation as case study, this work shows that for similar product quality, electrically-driven innovative food pasteurisation technologies like high pressure processing, ohmic and microwave heating are more beneficial than conventional techniques energy- and emission-wise, if a sufficient portion of the electricity is renewable. This is the case given the current decarbonisation level of the UK electricity grid and is expected to be more significant as more electricity is sourced renewably in the future as currently projected. The result should aid future industrial investment decisions.