Greenhouse Gas Emissions Generated by Tofu Production: A Case Study

Abstract

The objective of this study was to evaluate the greenhouse gas emissions (GHGEs) generated by the production of tofu. A partial life cycle assessment (LCA) was performed using SimaPro 8 software with a functional unit of 1 kg of packaged tofu and a farm to factory gate boundary. Original production data for the period of 1 year were obtained from a tofu manufacturer based in the United States and used with soybean production data from SimaPro 8 Ecoinvent 3.1 and U.S. Life Cycle Inventory databases to calculate the associated GHGEs as carbon dioxide equivalents (CO2e). The LCA calculations included resource inputs required to produce and package tofu: soybeans, water, electricity, natural gas, transportation, and packaging materials. The LCA boundary was from the cradle (i.e., soybean farm) to the factory exit gate (i.e., postpackaging). Uncertainty analyses were performed using Monte Carlo simulations. Total CO2e from packaged tofu were 982 g/kg, 9820 g/kg of protein, 1150 g/1000 calories, and 336 g/retail packet of 396 g. For 1 kg of packaged tofu, 16% of CO2e resulted from soybean production, 52% from tofu manufacturing, 23% from packaging, and 9% from transportation. Tofu, a protein-rich plant food, generates relatively low GHGEs.