Spiral filter pressing and nutrient retention of apple juice
Research findings on polyphenol content
Researchers at Oxford Brookes University in the UK have introduced a new apple pressing method that increases polyphenol content fourfold compared to conventional apple juice.
Polyphenols, natural plant compounds found in fruits, red wine, and cocoa, are antioxidants that offer numerous health benefits for the heart and brain while helping to prevent diseases. Therefore, when this new juicing method is widely adopted in the future, it could help people absorb more of these beneficial natural compounds.
How to eliminate oxygen during juicing
The new method is called spiral filter pressing, which actively removes oxygen using vacuum pressing. According to experts, oxygen is eliminated from all other processing steps, thereby minimizing nutrient degradation.
Results from previous studies show that a group of polyphenols, known as flavan-3-ols, can help improve blood pressure, cholesterol levels, and blood sugar levels. Stefan Dussling, co-author of the study, said: “Nutrient loss is often caused by oxygen rapidly degrading certain nutrients in apple juice, such as flavan-3-ols or vitamin C. This occurs whether we juice apples at home or buy pre-packaged juice.”.
Notes on sugar and juice intake
Dr. Ana Rodriguez-Mateos at King's College London, who was not involved in the study, said that finding a method to retain more flavan-3-ols and vitamin C in apple juice during industrial processing is of great value. Thanks to this, people would choose to consume a healthier fruit juice than those commercially available. However, Dr. Ana also cautioned that while apple juice contains high amounts of sugar, conventional apple juice processing produces juice with similar sugar levels but fewer phytochemicals. Therefore, if someone still wants to drink apple juice, it is best to opt for one richer in phytochemicals rather than regular juice.
The National Health Service (NHS), UK recommends that individuals consume no more than 150ml of drinks from fruit juice, vegetable juice, and smoothies per day.
According to Dr. Aisling Daly, co-author of the study, the new method produces apple juice that is richer in flavanols compared to other apple juicing methods. However, the research team suggests that people should consume fruits and their related nutrients in whole fruit form.