Life Cycle Assessment of a milk protein fractionation process: Contribution of the production and the cleaning stages at unit process level

Abstract

This paper aims at presenting a consistent Life Cycle assessment of the environmental impact of an industrial milk protein fractionation process at the level of unit processes (gate to gate approach), focusing on the effective contribution of both the production and the cleaning steps. The precise assessment of the impact of cleaning stages could indeed constitute key issues for the optimisation and management of food plants. The results show that the production phase accounts for approximately two-thirds of the environmental impact of the entire food manufacturing process, and the cleaning phase for more than 30% of the total impact. The latter is, however, underestimated due to methodological drawbacks and partly unavailable data. Among both the production and the cleaning stages the most impacting unit processes are the membrane and the thermal operations mainly due to the single-use of cleaning solutions and several temperature changes. Hence, for reduction of the overall environmental impact of the milk protein fractionation process it is advisable to primarily focus on improvement and optimisation of the microfiltration operation and secondly, on the thermal units.