That’s according to Italian academics Miichele Manfredi and Guiseppi Vignali from the Department of Engineering at the University of Parma, who assessed the impact of two ‘typical’ systems in regard to effluent emissions, releases into the environment and resource consumption.
Orange juice in PET bottles
Writing in the Journal of Food Engineering, the academics analyzed the environmental performance of hot filling and aseptic cold filling systems to package a high acid, extended shelf life beverage – in this case orange juice in 500ml one-way PET bottles.
Using a Life Cycle Assessment methodology (LCA), they only included materials and processes that differ between the two technologies – i.e. heat treatment, filling operations and packaging materials.
Manfredi and Vignali discounted beverage production and transport of raw food materials from their central analysis – since there are no differences between the two systems analyzed, in these two phases.
They presumed a fill speed of 36,000 bottles/hour and a 120-hour continuous work cycle for both systems – in other words a medium-speed line.
Energy savings
Hot filling and aseptic packaging systems differ in terms of the filling system used and connection between the pasteurizer and the filler.
Aseptic systems achieve considerable energy savings by using heat from a heated beverage flow to heat the cold prepared beverage flowing into the system, while this cold liquid reciprocates by cooling the heat-treated drink prior to filling.
This heat recovery system allows a reduction in natural gas consumption for steam production – used in continuous heat exchangers to pasteurize the product in both systems.
However, since aseptic cold filling occurs at room temperature the heat of the product does not decontaminate the PET bottles, which must be sterilized separately using (usually) a solution of paracetic acid hydrogen peroxide, while filling must take place in a separate, sterile zone that uses more energy to maintain.
Hot filling requires heavier PET bottles
Concluding, Manfredi and Vignali said that their results indicated that – considering the processing stage – aseptic systems had a higher environmental impact in terms terrestrial acidification, freshwater eutrophication, marine eutrophication, particulate matter formation, ionising radiation and metal depletion.
However, hot filling systems were more impactful across nine of the fifteen impact categories in total – human toxicity, climate change and fossil depletion, to name but three.
Moreover, the academics say their conclusions change once packaging materials are included in the analysis – since hot filling requires heavier PET bottles to withstand high temperatures of 92C during filling.
“When the product is hot filled a heavier PET bottle is required. In this analysis 24g and 16g PET bottles were taken into consideration for hot filling and aseptic packaging systems respectively – thereby reproducing the contemporary market situation,” they wrote.
“An 8g weight difference changes the environmental profile of the two technologies completely – lowering the environmental impact of aseptic packaging systems by over 20% on average for the categories analyzed,” the academics added.
That said, and while it didn’t form part of their central analysis, they used data compiled by Doublet et al. 2013 to analyze the orange juice production phase – calculating that this accounted for over 60% of the environmental impact of both aseptic and hot filling systems.
Title: ‘Comparative Life Cycle Assessment of Hot Filling and Aseptic Packaging Systems Used for Beverages’
Authors: Manfredi, M., Vignali, G.
Source: Journal of Food Engineering 147 (2015) 39-48.http://dx.doi.org/10.1016/j.jfoodeng.2014.09.018
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