Copyright 2016 Accademia dei Georgofili
This study assessed the environmental impact of the industrial production of 1 kg of soft wheat bread, as packed in polyethylene pouches, in compliance with the Publicly Available Specification 2050 standard method. The sensitivity of the carbon footprint was analyzed with respect to the soft wheat, flour and bread chains, straw waste management, and uncertainty ranges of the emission factors for direct and indirect soil N2O emissions. The Life Cycle Inventory Analysis allowed the consumption of raw materials and energy resources, as well as the formation of solid wastes and by-products at the soft- wheat cultivation, bread manufacture, and consumer phases, to be estimated. By referring to the emission factors, as derived from the literature and databases of the SimaPro 7.2 software according to the method IPCC (1997), the CF was found to be about 750 g CO2e kg-1. The agricultural stage was identified as the primary hotspot, N2O emissions being the dominant ones (47.8% of total). The secondary hotspot was the transport phase, the 57.2% of total being associated to the transport of grains from the main soft wheat producing EU countries (i.e., France, Austria, Hungary and Germany). The third hotspot was bread processing. In addition, the waste management stage (i.e, landfilling of wheat milling wastes, use of bran, wheat germ, and bread making residues as feed, composting of wasted bread, and recycling of plastic residues) yielded a net reduction in the GHG emissions of about 270 g CO2e kg-1. A sensitivity analysis of the carbon footprint confirmed that the main hot spot in the life cycle of bread was soft wheat cultivation, that should be targeted for mitigating the carbon footprint of bread. Owing to the wide uncertainty range of the default emission factors for the direct and direct N2O emissions from managed soils, more research is thus needed to assess the effective values of such emissions.