Encapsulant-bioactives interactions impact on physico-chemical properties of concentrated dispersions

Occasionally, bioactive ingredients desired for encapsulation (such as polyphenols) naturally interact with the structure-forming food components intended for their protection and delivery. Non-covalent protein-polyphenol conjugation interactions have been reported to occur naturally under mild pH and temperature conditions, causing changes to protein structures and consequent functionality. Highly concentrated liquid dispersions of varied solids contents, ratios of whey protein isolate (WPI) to sucrose contents, and Aronia berry polyphenols contents were formulated and analyzed to determine potential effects of protein-polyphenol conjugation in the system on the physical properties of dispersions. Dispersions were characterized by rheological measurements, flow testing, particle size analysis, centrifuge separation, and drop sizes produced, and microstructures were visualized with optical light microscopy. Addition of polyphenols was found to alter dispersions physical characteristics including increased viscosity and surface tension and reduced particle size of dispersions, with changes being attributed to conjugation interactions between proteins and polyphenols.