Characteristic aroma components of rennet casein

Area of Science:

• Food chemistry
• Dairy science
• Analytical chemistry

Background:

• Rennet casein is widely used in food and industrial applications.
• A common issue with rennet casein powder is an undesirable odor, often described as 'wet dog'.

Purpose of the Study:

• To identify the specific volatile compounds responsible for the characteristic odor of rennet casein powder.
• To understand the chemical basis of rennet casein's off-flavor.

Main Methods:

• Aroma extracts were prepared using high-vacuum distillation of solvent extracts.
• Analysis involved gas chromatography-olfactometry (GCO), aroma extract dilution analysis (AEDA), and GC-mass spectrometry (MS).
• Sensory descriptive analysis was used to confirm the impact of identified compounds.

Main Results:

• Gas chromatography-olfactometry detected volatile acids, phenolic compounds, lactones, and furanones.
• Aroma extract dilution analysis identified o-aminoacetophenone as a potent odorant.
• Sensory analysis revealed hexanoic acid, indole, guaiacol, and p-cresol as the primary contributors to the typical rennet casein odor.

Conclusions:

• The characteristic odor of rennet casein is primarily attributed to specific volatile compounds, including hexanoic acid, indole, guaiacol, and p-cresol.
• Understanding these odorants allows for potential strategies to improve rennet casein quality and flavor profiles.