Sustainability by Reduced Energy Consumption during Manufacturing: The Case of Cosmetic Emulsions

Abstract

Energy input in emulsion manufacturing comprises thermal and mechanical energy, with thermal energy being predominant. In terms of raw material selection, there is a widely accepted belief that natural formulations are more “eco-friendly” than their standard (not natural) counterparts. The aim of this study was to compare the energy consumption and subsequent carbon footprint resulting from the production of two main emulsion types, each represented by its standard and natural variant and made by using different manufacturing processes (hot, hot-cold and cold). This resulted in six samples of oil-in-water (O/W) and water-in-oil (W/O) emulsion types, respectively. Scale-down calculations were used to establish the required homogenisation time and speed of the laboratory homogeniser, necessary to achieve the same shear rates as the chosen industrial vessel. The resulting emulsions were characterised using rheological and textural analysis. The six emulsions within each emulsion type have exhibited sufficiently similar characteristics for the purpose of carbon footprint comparisons. Calculations were conducted to quantify the energy input of hot and hot-cold procedures, followed by cradle-to-gate life cycle analysis (LCA). Energy calculations demonstrated that the hot-cold manufacturing process saved approximately 82% (for O/W) and 86% (for W/O) of thermal energy in comparison to the hot process. LCA has shown that the effects of using natural instead of standard ingredients were negative, i.e., it led to a higher carbon footprint. However, it was dwarfed by the effect of the energy used, specifically thermal energy during manufacturing. This strongly indicates that the most efficient way for companies to reduce their carbon footprint is to use the hot-cold emulsification process.