Characterising the techno- and bio-functional properties of milk protein-polyphenol complexes for application in performance nutrition

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van de Langerijt, Tessa M.
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University College Cork
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There is increased consumer interest in performance nutrition, focusing especially on enhancing muscle strength and recovery. Dairy-plant hybrid beverages, rich in milk proteins and polyphenols, have considerable potential in this area, because both proteins and polyphenols have been positively linked to muscle strength and recovery. However, there is limited knowledge of the effects of protein-polyphenol interactions on the techno- and bio-functional properties (e.g., physical stability of casein micelles, heat stability, bioaccessibility and bioavailability) of liquid dairy systems. In these studies, the addition of polyphenols to systems containing casein micelles increased the attractive forces within the casein micelles, due to complex formation, preventing casein micelle dissociation. When milk protein systems contained blackberry polyphenols, their heat stability increased in the pH range 6.2-6.4. In this pH range, blackberry polyphenols bound calcium, which prevented protein aggregation and increased heat stability. Co-concentration of milk proteins and polyphenols was achieved by ultrafiltration, enabled by milk protein-polyphenol complex formation, allowing the complexes to be retained. Milk fat in mixed milk protein-blackberry systems positively influenced the bioaccessibility of polyphenols but had a negative effect on their bioavailability after in vitro digestion. Increasing the leucine content in these systems did not impact the bioaccessibility or bioavailability of polyphenols. In contrast, proteins increased the bioaccessibility of polyphenols and reduced the hydrolysis of polyphenols during in vitro digestion, which resulted in an increased polyphenol bioavailability. In conclusion, protein-polyphenol complexes showed considerable promise for preventing casein micelle dissociation, improving heat stability, facilitating co-concentration by ultrafiltration and improving the bioaccessibility and bioavailability of blackberry polyphenols. This new knowledge may help support the successful development of protein-polyphenol rich beverages for performance nutrition.
Milk proteins , Blackberries , Polyphenols , Heat stability , Casein micelle stability , Bioaccessibility , Bioavailability , Ultrafiltration , Dairy
van de Langerijt, T. M. 2023. Characterising the techno- and bio-functional properties of milk protein-polyphenol complexes for application in performance nutrition. PhD Thesis, University College Cork.
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