Structure-function guided design of sequential whey protein-polyphenol-pectin conjugates for enhanced lutein...

Area of Science:

• Food Science and Technology
• Biomaterials Engineering
• Nutritional Biochemistry

Background:

• Developing effective delivery systems for lipophilic bioactives like lutein is crucial for enhancing their stability and bioavailability.
• Whey protein (WP), pectin (PE), and polyphenols (gallic acid, GA; tannic acid, TA) are promising components for creating functional food matrices.
• Understanding the structure-function relationships of protein-polysaccharide-polyphenol conjugates is key to optimizing their performance.

Purpose of the Study:

• To engineer novel binary and ternary conjugates of whey protein with pectin and polyphenols for improved lutein delivery.
• To investigate the impact of different conjugation strategies (Maillard reaction, alkaline-driven) on conjugate structure and properties.
• To evaluate the emulsification, stability, digestibility, and antioxidant capacity of the developed lutein carriers.

Main Methods:

• Synthesis of WP-PE, WP-GA, WP-TA, and sequential dual-covalent WP-GA/TA-PE conjugates.
• Characterization using SDS-PAGE, FTIR, and fluorescence spectroscopy to confirm covalent bonding.
• Assessment of emulsification performance, UV, thermal, and storage stability of lutein-loaded conjugates.
• In vitro digestibility studies to determine lutein bioaccessibility and free fatty acid release.

Main Results:

• Sequential dual-covalent conjugation (WP-GA/TA-PE) resulted in significant modification of protein functional groups.
• WP-TA-PE conjugates demonstrated superior emulsification (~94% increase in Emulsion Stability Index) due to synergistic cross-linking and coating.
• Conjugates provided enhanced UV, thermal, and storage stability for lutein.
• A trade-off was observed: polyphenol conjugates (WP-GA/TA) excelled as antioxidants, while dual-covalent conjugates (WP-GA/TA-PE) were superior emulsifiers and protectants, with reduced bioaccessibility.

Conclusions:

• Rational design of whey protein-based conjugates using pectin and polyphenols enables creation of multi-functional lutein delivery systems.
• Conjugation pathway dictates structure-function relationships, allowing tailoring for specific applications (e.g., antioxidant vs. emulsifier/stabilizer).
• These engineered colloidal systems offer tunable properties for enhanced lutein delivery in fortified foods and supplements.