Real-time structural changes in the binding of polymerised whey protein–Ganoderma lucidum polysaccharide by simultaneous rheology and FTIR and exploring its application prospects in yoghurt

Abstract

Background, Context or Rationale

Protein–polysaccharide composite gels offer superior functionality for enhancing dairy products, yet real-time insights into their gelation are needed for targeted applications.

Aim(s)

This study aimed to elucidate the real-time structural changes in heat-induced polymerised whey protein (PWP) and Ganoderma lucidum polysaccharide (GLP) hydrogels and evaluate their efficacy in improving goat yoghurt.

Methods

To investigate the gelation mechanism, PWP-GLP hydrogels with GLP concentrations ranging from 0% to 4% were analysed. The analysis employed simultaneous rheology and Fourier transform infrared spectroscopy technology (SR-IR), a coupled technique that simultaneously monitors rheological responses and chemical structural changes, alongside fluorescence spectroscopy. Complementing these experimental approaches, molecular docking simulations were performed to predict the potential binding modes and interaction affinities between the components. Following the characterisation of their physicochemical, thermal, antioxidant and rheological properties, the optimal hydrogel was selected and incorporated into yoghurt for quality assessment.

Major Findings

The GLP enhanced hydrogel properties: increased particle size, thermal stability and antioxidant activity. The SR-IR and molecular docking revealed that hydrogen bonding and hydrophobic interactions drove gel formation, reducing gelation time and improving elasticity. Incorporating the 4% GLP hydrogel (1%) into yoghurt significantly improved its water-holding capacity, viscosity, texture (hardness and chewiness) and led to a denser microstructure.

Scientific or Industrial Implications

This work provides a mechanistic understanding of PWP-GLP gelation and demonstrates the hydrogel's potential as a natural, multifunctional additive for improving yoghurt texture and quality, supporting its application in the functional food industry.