Food Waste : Scientists in New Zealand find more sustainable way to treat apple waste

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Scientists in New Zealand have discovered a greener way to extract health-promoting molecules from organic waste materials.

In a study published in the journal Green Chemistry, researchers at the University of Adelaide tested extraction with a new type of green solvent.

They used the specific solvent to recover compounds found in apple pomace, that is, apple waste consisting of peels, pulp and seeds.

Apple pomace is known for its powerful antioxidant, antibacterial, anti-diabetes and anti-inflammatory properties. Molecules generated in this way are intended for repurposing in the skincare and pharmaceutical industry.

According to Dr. Long Yu, co-author of the study, apple waste is still underutilised by the manufacturing industry. She maintains that only 20% is recovered and used as animal feed, the remainder being destined for incineration, composting and landfill, the latter of which is responsible for the increased release of methane into the atmosphere.

“Extracting the ‘goodness’ from apple pomace is one way to make better use of this waste product and could help the apple processing industry become more sustainable.”

So far, the extraction of health-promoting compounds from apple waste was rendered difficult due to pomace’s low solubility in water-based solvents. This, in turn, led to a dependence on toxic organic solvents, which are known for their capacity for generating more pollutants.

University of Adelaide researchers sought to counteract this problem by attempting extraction via a next generation green solvent known as Deep Eutetic Solvent (DES).

Comprised of natural molecules, this solvent is not only more cost effective but also less environmentally hazardous than a conventional solvent. DES does not only trump volatile and toxic organic solvents when it comes to sustainability but also proves a better material extractor. The study proved that the DES solvent is able to pull a significantly larger proportion of bioactive compound from apple pomace than traditional solvents.

Professor Vincent Bulone from the University of Adelaide’s School of Agriculture, Food and Wine who supervised the research and co-wrote the paper, said: “We can conclude that DES is a green and tuneable alternative that not only efficiently collects powerful healthy molecules found in apple pomace, but also boosts the antioxidant activity of the extract. Not only do DES provide a more environmentally friendly way to make better use of what would otherwise go to waste, but the collection method may provide a way to improve skincare, biopharmaceuticals and nutraceutical”.

The scientists believe that the new extraction method using DES solvents may be used to collect and modify health-promoting molecules from other types of agricultural and food waste as well.