The French maritime pine bark extract Pycnogenol shows excellent stability against the harsh conditions of the stomach, and should be considered “a good source of phenolic compounds to be utilised for fruit juice enrichment”, says a new study.
Researchers from the National Research Institute for Food and Nutrition in Rome report that addition of Pycnogenol to fruit juices increased the polyphenol content before and after processing, following in vitro gastrointestinal digestion.
“In vitro digestion of both Pycnogenol-enriched pineapple and red fruit juices led to a significant increase in detectable chlorogenic and ferulic acids, indicating that hydrolysis of more complex molecules occurs,” stated the researchers in the Journal of the Science of Food and Agriculture.
The study appears to support the use of the pine bark extract to fortify fruit juices and enhance the polyphenol content of the product. Indeed, fruit juices undergo a processing step that may alter the polyphenol content of a beverage, and the new study shows “the stability of Pycnogenol after in vitro gastrointestinal digestion makes it a good choice for phenolic enrichment of fruit juices”, added the researchers, led by Carmen Frontela.
The study was welcomed by Frank Schonlau, PhD, director of scientific communication for Horphag Research, the company behind the Pycnogenol ingredient as "another example of Horphag Research' commitment for demonstrating Pycnogenol's compatibility, stability and functionality in food".
"This study was carried out in collaboration with the company Hero, famous for their jams and other fruit preparations, indicating that addition of Pycnogenol to fruit preparations will increase the amount of polyphenols bioavailable to the consumer," added Dr Schonlau.
Rising to the challenge
Polyphenols are receiving extensive research due to their potent antioxidant activity, their ability to mop-up harmful free radicals, and the associated health benefits. Many have also been implicated in possible protection against diseases such as cancer and cardiovascular disease, while some have been reported to potentially offer protection from Alzheimer's.
Despite this interest, Ming Hu from the University of Houston recently issued "a call to arms" for more relevant research into the bioavailability and utilization of the antioxidants, particularly polyphenols, in order to help "the successful development of polyphenols as chemopreventive agents in the future" (Molecular Pharmaceutics, Vol. 4, pp. 805-806).
Interest in polyphenol-rich beverages is also increasing, with Coca-Cola reporting recently that compounds from a range of sources, including green tea, apples, grapes, and citrus were absorbed in both the small and large intestine when consumed by human volunteers (Molecular Nutrition & Food Research, doi: 10.1002/mnfr.200900611).
The new study investigated the stability of Pycnogenol (supplied by Horphag Research) upon processing into a juice drink and the subsequent digestion in a model stomach system.
Frontela and her co-workers examined polyphenol contents in pineapple and red fruit juices alone or enriched with Pycnogenol. Results showed that exposure to the in vitro digestion model reduced polyphenol levels in the non-enriched juice. On the other hand, polyphenol levels increased in both Pycnogenol-enriched juices.
“Thus Pycnogenol, owing to its stability, could be considered a good source of phenolic compounds to be utilised for fruit juice enrichment,” wrote Frontela and her co-workers.
“However, for a better understanding of the interaction with fruit juice components, it would be worthwhile also to explore the effect of gastrointestinal digestion on Pycnogenol aqueous solution.
“Further work on the antioxidant activity of compounds released during gastrointestinal digestion must be carried out to confirm antioxidant effects in the gut,” they concluded.
Source: Journal of the Science of Food and Agriculture
Published online ahead of print, doi: 10.1002/jsfa.4183
“Stability of Pycnogenol as an ingredient in fruit juices subjected to in vitro gastrointestinal digestion”
Authors: C. Frontela, G. Ros, C. Martinez, L.M. Sanchez-Siles, R. Canali, F. Virgili