Easter eggsperts: chemical engineers have chocolate eco-ratings licked

Article by Adam Duckett

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AS we peel the foil off our Easter eggs this Sunday, chemical engineers are urging us to consider the environmental impact of chocolate and how it can be made more planet-friendly.

The study from The University of Manchester evaluates the impacts of chocolate production and consumption in the UK and points out which forms of chocolate are the worst for the environment. The team found that the biggest sinner per kilogramme of chocolate are sharing bags, such as bags of Maltesers, due to their ingredients and bigger packaging.

Sharing bags came out worst on a number of points including highest primary energy demand, global warming potential, water footprint, ozone depletion and mineral depletion.

National impacts

However, looking at the impacts on a national level, the researchers found that the most popular forms of chocolate, as might be expected, contribute the most environmental impact. Scaling up their per-kilogramme-findings, the team reports that the 635,000 t of chocolate eaten in the UK each year consumes 21 TJ of primary energy and emits 2.1m t of CO2.

Popular so-called ‘countlines’, which include the likes of KitKat, have the highest contribution to the total impacts at UK level, providing 37–43%. Second is sharing bags at 28–33%, while moulded chocolate, such as Dairy Milk,  and seasonal chocolate including Easter eggs make up the rest.

Study author Adisa Azapagic, head of sustainable industrial systems at Manchester, and an IChemE Fellow, says: “Most of us love chocolate, but don’t often think of what it takes to get from cocoa beans to the chocolate products we buy in the shop.

“Cocoa is cultivated around the equator in humid climate conditions, mainly in West Africa and Central and South America so it has to travel some distance before it makes it into the chocolate products we produce and consume in the UK.”

Cocoa and cows

The team analysed the environmental impacts of chocolate from the raw materials, including production of sugar and cocoa powder; the manufacture including power, water consumption and cleaning activities; packaging, distribution, consumption and management of industrial and consumer waste.

Production of milk powder and cocoa derivatives, along with the manufacturing process are the main contributors to the environmental impacts so should be targeted for improvement. For example, composting the dairy manure, reducing energy consumption in the milk parlour by 20% and supplementing cows' feed with linseeds could together reduce the GWP of chocolates by 14–19%, the team reports.

Chocolate by numbers:

4.25m t - Annual production of cocoa beans in 2016
US$101bn - worldwide sales of chocolate in 2015
45% - Europe accounts for almost half of global chocolate consumption
7.9 kg – the weight in chocolate that each person in the UK eats on average, equivalent to around 157 Mars bars
2.4% - the proportion of greenhouse gas that chocolate contributes to the UK food and drink sector

Azapagic added: It is true that our love of chocolate has environmental consequences for the planet. But let’s be clear, we aren’t saying people should stop eating it.

“The point of this study is to raise consumers’ awareness and enable more informed choices. Also, we hope this work will help the chocolates industry to target the environmental hotspots in the supply chains and make chocolate products as sustainable as possible.”

Food Research International: http://doi.org/cmv9

Article by Adam Duckett

Editor, The Chemical Engineer

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