Proteinpolyphenol

Proteinpolyphenol refers to complexes or conjugates formed between proteins and polyphenolic compounds. These interactions can be non-covalent, such as hydrogen bonding, hydrophobic interactions, and electrostatic attractions, or covalent, resulting from oxidation of polyphenols to o-quinones that react with amino groups or thiol groups on proteins. Proteinpolyphenol associations are common in foods and biological systems where polyphenol-rich plant materials meet protein matrices.

In food systems, polyphenols such as tannins, catechins, and gallic acid interact with milk, soy, or cereal proteins, as well as with tea polyphenols. Factors like pH, temperature, metal ions, and oxygen influence the extent and type of binding. Covalent conjugates can form under oxidative conditions and may be relatively stable to processing, whereas non-covalent complexes may be sensitive to ionic strength and pH.

Effects on properties and functions include altered digestibility, as binding can mask protease access, and potential changes in allergenicity and bioavailability of polyphenols. Binding can also modify functional properties, improving or hindering emulsification, foaming, and clarification. In beverages and foods, polyphenol–protein interactions can cause haze or sediment but can also be exploited to stabilize emulsions or to deliver polyphenols via protein-based carriers in functional foods.

Measurement and applications: Researchers study these interactions with UV-Vis spectroscopy, fluorescence, isothermal titration calorimetry, mass spectrometry, FTIR, and chromatography. Applications span functional foods, nutraceutical delivery, and edible coatings, while challenges include heterogeneity, processing sensitivity, and variable bioavailability. The term proteinpolyphenol thus encompasses the spectrum of protein–polyphenol complexes with relevance to nutrition, food quality, and health.