Energy flows and greenhouses gases of EU (European Union) national breads using an LCA (Life Cycle Assessment) approach

Bread represents a staple food in many parts of the world including Europe. Depending on the region of origin and the respective cultural heritage bread is made with different ingredients and is consumed in various forms. This work consists of an environmental sustainability assessment of 21 different types of bread, representing a wide spectrum of typologies of such food consumed across the European Union, via a Life Cycle Assessment approach. The embedded energy and equivalent greenhouse gas emissions of each type of bread were estimated, from cradle to bakery gate, by considering a mass, a nutritional value and a price based functional unit. Overall, the results have highlighted the variability of the embedded energy and the equivalent GHG (greenhouse gas) emissions associated to the consumption of the 21 kinds of bread rooted in the cultural environment of 21 EU countries. When considering a functional unit of 1 kg of bread, the Cumulative Energy Demand results range from 9 MJ/kg to 32.9 MJ/kg. The Global Warming Potential indicator has a minimum value of 0.5 kgCO2eq/kg and a maximum of 6.6 kgCO2eq/kg. For a functional unit amounting to a 100 kcal provided by the consumption of bread, the Cumulative Energy Demand results vary from 0.33 MJ/100 kcal to 0.93 MJ/100 kcal whilst the Global Warming Potential indicator varies from 0.019 kgCO2eq/100 kcal to 0.135 kgCO2eq/100 kcal. For a functional unit amounting to the quantity of bread purchased with 1V (weighted according to the purchasing price of each nation in the European Union), the Cumulative Energy Demand results vary from 1.197 MJ/V to 3.708 MJ/V whilst the Global Warming Potential indicator varies from 0.15 kgCO2eq/V to 0.376 kgCO2eq/ V. The study has pinpointed the importance of evaluating food, in terms of environmental sustainability, with more than one type of functional unit in order to account not only for the bread's nutritional purposes but also the need to satisfy social, cultural, hedonistic and other qualitative functions. Specifically, when using a mass based functional unit, the less impactful results involve bread types with simple recipes, based essentially on flour, yeast and water. By assessing the breads with an energy based functional unit, bread types which also contain vegetable oils and small amounts of animal based ingredients result as more carbon and energy friendly. The use of a price based functional unit indicates that the higher priced bread types, manufactured with more expensive ingredients that are produced in an environmentally efficient manner, are the more sustainable ones. Overall, for many types of bread, the energy consumption during the production phase, in particular the baking process, represents a hot spot and is dependent on the size and shape of the bread. Furthermore, the efficiency of ingredient production (in terms of material and energy use and in terms of the respective yields of each nation in the European Union), such as that of milk and flour, also influences the sustainability of the bread types