Life-cycle assessment of fresh and frozen chestnut

Life-cycle assessment (LCA) has been applied to calculate the environmental impacts of various nuts; however, no studies were found for chestnut. This article presents a LCA of fresh and frozen chestnut produced in Portugal, intended both for export and domestic consumption. A “cradle-to-plate” life-cycle model was implemented considering cultivation, two types of processing (fresh and frozen chestnut), domestic and international distribution, retail, home storage, and cooking. Different markets (consumer locations) and alternative transport modes were assessed. Variability in cultivation and two alternative household storage times for frozen chestnut (45 days or six months) were also analyzed. Cultivation contributed most to the life-cycle impacts of both fresh and frozen chestnut (from 34% to 98%), mainly due to diesel and fertilizer use. Frozen chestnut presented higher impacts than fresh due to higher energy requirements for frozen storage (factory, retail and household) and processing losses. Post-harvest stages, particularly home storage and cooking, contribute significantly to life-cycle impacts. Important differences between the locations of final consumption were found due to differences in the electricity mix of the various countries. Furthermore, increasing storage time in the home freezer from 45 days to six months can lead to considerably higher life-cycle impacts. The consumption of products out of season can present significantly higher impacts than fresh; however, chestnut (fresh or frozen) shipped by air showed higher impacts than off-season. To mitigate the environmental impacts of chestnut, it is important to improve fertilizer and fuel use, as well as to reduce energy use in storage and cooking.