A Comparative Study on Carbon Footprints between Wheat Flour and Potato in China Considering the Nutrition Function of Foods

Abstract The food production is a significant contributor to global greenhouse gas (GHG) emissions, and it has attracted many researchers’ attention. In the present study, carbon footprints (CFs) of wheat-based foods and potato during cultivation, transportation, storage, and processing phases were investigated according to the LCA (life cycle assessment) principle. The results showed that wheat-based products were associated with much higher carbon emissions than potato per kilogram of edible portion. Cultivation phase is the most important stage, and carbon emissions per kg food increased with more machining process. For different carbon emission sources, fertilization, electricity use, and N2O emissions are the top three contributors. On the other hand, CFs of foods were evaluated based on carbohydrate based-, protein based-, fat based-, dietary fiber based-, and nutrient density based functional units. CF values of product per functional unit varied depending on the functional unit used. When the macro-nutrients were considered, the low-carbon emissions competitiveness of potato over wheat flour was reduced significantly. In this research, nutrient density used as the basis of functional unit could be more appropriate than individual nutrient alone to illustrate the environmental impacts of different foods. In summary, consumption of more standard grade flour and potato instead of tailared flour (grade one) could cut a considerable amount of GHG emissions in China.