Sensory and Functionality Differences of Whey Protein Isolate Bleached by Hydrogen or Benzoyl Peroxide

Area of Science:

• Food Science
• Protein Chemistry
• Sensory Analysis

Background:

• Whey protein isolate (WPI) is a functional food ingredient derived from cheese production.
• Annatto in Cheddar cheese whey necessitates bleaching of WPI for various applications.
• The impact of bleaching agents on WPI's sensory and functional properties is not fully understood.

Purpose of the Study:

• To compare the sensory and functional differences between WPI bleached with benzoyl peroxide (BP) and hydrogen peroxide (HP).
• To evaluate the effects of bleaching on WPI's flavor profile, protein solubility, heat stability, and gelation properties.

Main Methods:

• Manufacture of triplicate batches of HP-bleached, BP-bleached, and unbleached WPI.
• Descriptive sensory analysis and gas chromatography-mass spectrometry for flavor profiling.
• Functional property assessment including foam stability, protein solubility, SDS-PAGE, and gelation kinetics.

Main Results:

• HP-bleached WPI exhibited higher lipid oxidation and sulfur-containing volatile compounds, with characteristic cardboard, cabbage, and fatty flavors.
• BP-bleached WPI was distinguished by a low bitter taste.
• Both bleaching methods reduced soluble protein loss at pH 4.6 and affected heat stability, with SDS-PAGE indicating protein degradation.

Conclusions:

• Bleaching WPI with BP or HP significantly impacts its flavor profile and functional characteristics.
• The choice of bleaching agent influences the types and levels of volatile compounds and sensory attributes.
• Understanding these effects is crucial for optimizing WPI in food product applications.