Cloudy apple juice may be richer in nutrients than clear apple juice, a new study reports.
Researchers from the Agricultural University of Wroclaw and the Medical University of Warsaw found that the polyphenol content of cloudy apple juice is four times greater than clear juice. Polyphenols have antioxidant activity and contain flavonoids with disease fighting properties.
In the study, clear and cloudy apple juices from Idared and Champion varieties were studied for their radical-scavenging effects. The polyphenolic content and composition of the juices before and after thiolysis were determined by high-performance liquid chromatography with diode array detection.
It was found that cloudy juices, especially those prepared from Champion variety, had a higher content of procyanidins than clear juices.
According to the report, the production of clear apple juice involves addition of enzyme to remove the pectin and starch content of the cloudy juice. Researchers suggested that this process may also affect the polyphenol content of the resulting juice.
The study reported that clear juice made from the Idared apple variety contained 250 milligrams of polyphenols per liter, while cloudy juice made from the Champion apple variety contained 1,044 milligrams per liter.
The radical-scavenging activity of the juices was measured with electron paramagnetic resonance (EPR) spectroscopy using the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical, with the cloudy Champion apple variety juice reported to scavenge 93 percent of the radicals after three minutes, compared to only 24 percent for the clear Idared variety juice.
The study concluded that apple juices, especially cloudy ones, are a rich source of natural antioxidants that may be used in the pharmaceutical or food industry.