Enhancing the Benefits of Blueberry Polyphenols With Plant and Whey Proteins

Polyphenols are a structurally diverse class of secondary metabolites found in plants, with numerous documented benefits for human health including, but not limited to, anti-inflammatory, antioxidative and cardiovascular-protective effects. Dietary intake of polyphenols in the United States is low in comparison to other developed countries due to low intake of fruits and vegetables. Recent studies suggest fruit and vegetable intake should be increased by incorporating those foods into snacks and mixed meals as ingredients rather than standalone food items. Presently, berries comprise 10% of the total fruit intake and 7% of the total polyphenol intake of American adults. As a versatile food ingredient, berries can easily be added to foods like smoothies and yogurts as an ingredient to increase intake.

Low polyphenol intake is an issue exacerbated by poor bioavailability. Consumption does not necessarily mean that these beneficial compounds are delivered to body tissues, as evidenced by low levels of detection in blood and accumulation in the lower gastrointestinal tract after feeding. Bioavailability can be enhanced through the complexation of polyphenols with proteins, a phenomenon which occurs naturally in complex mixtures including both classes of nutrients. It has been shown that the complexation of polyphenols with proteins in cow's milk, known as a "matrix effect", enhances the polyphenol stability and uptake throughout digestion. The incorporation of berries into complex food mixtures may not only be an opportunity for improved health outcomes due to increased polyphenol intake, but also an effective strategy for ensuring that consumers receive the benefits of the nutrients they consume.

It is unknown whether the beneficial matrix effects observed when polyphenols interact with dairy proteins are exclusive to dairy proteins due to characteristics of high digestibility or structures which favor phenolic interaction, or if similar effects would be observed with proteins from other sources. Increasing consumer demand for alternative protein sources for reasons pertaining to human health and environmental sustainability has introduced a variety of novel plant-based proteins to the American diet, which may elicit similarly advantageous matrix effects on the bioavailability of polyphenols depending on their digestibility and structural characteristics. Understanding protein-polyphenol interactions in novel food matrices is necessary for the development of food products that promote polyphenol consumption and bioavailability with the aim to improve human health.