Researchers at Hochschule Geisenheim University, near Frankfurt, have found a way to maximise polyphenols in apple juice by using a novel squeezing method called a spiral filter press which actively takes out oxygen by vacuum-driven pressing. Moreover, they ensured that oxygen is excluded from all other processing steps, therefore reducing nutrient deterioration.
The study, published in Food Research International, found that this new method boosted polyphenol content by four times as much as regular apple juice.
Lead author of the paper, Professor Ralf Schweiggert, commented: “Apple juice is already a source of polyphenol compounds, but you would need to drink several glasses to reach the levels recommended by scientists for heart health effects. The new juicing method that we’ve investigated takes the polyphenol content to a new level by minimising the nutrient losses we typically see during juicing.”
Co-Researcher of the study, Stefan Dussling, said: “Nutrient losses are commonly due to the presence of oxygen which quickly degrades some of the nutrients in apple juice like flavan-3-ols or vitamin C. This would happen when we juice apples at home or buy a ready-made product. We hope that the new juicing method will be used more widely in the future to help people get more of these beneficial natural compounds simply by drinking one glass of juice”.