Life cycle assessment of environmental impacts of cold and hot break tomato paste packaged in steel drums and exported from Xinjiang, China

The purpose of this study was to conduct a life cycle assessment (LCA) of the environmental impact of highly concentrated tomato paste produced by cold break and hot break methods. We considered the environmental impact and environmental hot spots related to tomato cultivation, tomato paste processing, packaging, and transportation, and then identified potential improvements for each stage. The research site was in Xinjiang, China, which is the main production area of high-concentration tomato paste for export in China. Taking 240 kg tomato paste packed in 220-L steel drums as the functional unit, the main data were obtained from studies on production enterprises and agricultural statistics. Ten environmental impacts were calculated using eFootprint: primary energy demand (PED), resource depletion-water (WU), climate change (GWP), ozone depletion (ODP), acidification (AP), particulate matter (RI), photochemical ozone formation (POFP), eutrophication (EP), ecotoxicity-freshwater (ET), and human toxicity-cancer effects (HT-cancer); their respective values for cold break paste were 5947 MJ, 82400 kg, 490 kg CO2 eq, 4.07E-06 kg CFC-11 eq, 5.150 kg SO2 eq, 1.600 kg PM2.5 eq, 0.270 kg NMVOC eq, 1.000 kg PO43- eq, 4.230 CTUe, and 3.70E-07 CTUh. The results showed that the environmental impact of cold break paste was lower than that of hot break paste because of lower steam consumption. The cultivation phase was the main contributor to WU, AP, EP, ET, and HT-cancer. In the processing phase, mashed tomatoes are concentrated using a large amount of steam to obtain a concentrated paste product. The energy consumption in the processing phase contributed >50% of PED, GWP, and RI. Although the packaging and transportation phases had smaller environmental impacts, the use of steel drums for packaging cannot be ignored. We conducted sensitivity analyses to evaluate the overall benefits that could be achieved by different mitigation schemes. In the whole supply chain, improving irrigation and fertilization methods and replacing the primary energy for steam production are the best strategies to improve environmental sustainability.