Environmental assessment of drying methods for the production of apple powders

The aim of this work is to analyse and minimise, using a life cycle approach, the environmental performances of apple powders' production. Fruit powders, with respect to fresh fruits' juices, are easier to handle and used as an ingredient for the production of baby foods, snacks, and other items. A detailed life cycle assessment (LCA) analysis was made to compare and optimise the two production processes, based on two drying techniques (drum or multistage drying), made by an Italian firm. All the quantities related to materials, energy consumption and emissions to air, soil and water were reported to the chosen functional unit (one apple powders' package). Data were analysed using SimaPro 8.0.4 software, whereas the Ecoinvent 3.1 database was used for the life cycle inventory, according to the reference standard for LCA (i.e. ISO 14040-14044). The system boundaries were set from apples' transportation to the company up to apple powders' distribution; in this way, a from gate to gate approach was followed. The IMPACT 2002+ method was used to select the impact categories. The ones that are mainly influenced by the industrial stages of apple powders' production are carcinogens, non-carcinogens, respiratory inorganics, aquatic acidification, global warming potential and mineral extraction. Among the two processes under study (a drum drying-based process and a multistage drying one), the first one (that is also the simpler and cheaper one) generated the higher emissions on all the impact categories. An in-depth analysis regarding all the industrial stages was made, in order to select the industrial steps whose impacts have to be minimised. For the process based on drum drying, the midpoint considered categories are mainly affected by the drying operation, whereas for the multistage drying-based process, some categories are mainly affected by drying, some others by storage. Different improvement scenarios were proposed to minimise the emissions related to both the apple powders' productions. Global emissions related to the apple powders' production were lowered using improved industrial scenarios. In order just to compare different scenarios characterised by not summable parameters, a global index (calculated as the sum of normalised values) was used. For the drum drying-based process, the global saving was equal to 31 %, whereas for the multistage drying-based process, it is equal to 27 %. Also in the case of improved scenarios, the drum drying-based process generated higher emissions on all the impact categories with respect to the multistage drying-based process.