Short communication: Volatiles in microfluidized raw and heat-treated milk

Area of Science:

• Food Science
• Dairy Processing Technology

Background:

• Milk aroma is crucial for consumer acceptance.
• Innovative processing equipment requires assessment for its impact on milk volatile compounds.
• Microfluidization causes high-pressure homogenization, potentially affecting aroma, but its immediate effects on volatile compounds are unknown.

Purpose of the Study:

• To investigate the effect of microfluidization on volatile compounds in milk.
• To compare microfluidization with conventional 2-stage homogenization.
• To determine if microfluidization alters milk aroma profiles.

Main Methods:

• Analyzed 11 selected volatile compounds in raw, thermized, pasteurized, and UHT milk before and after processing.
• Applied microfluidization at 170 MPa and 2-stage homogenization at 15 MPa.
• Compared volatile compound concentrations across different milk types and processing methods.

Main Results:

• Microfluidization generally had minimal impact on volatile compound levels compared to starting milk.
• Heptanal increased in thermized and UHT milk post-microfluidization.
• Nonanoic acid and acetone decreased in raw, thermized, and pasteurized milks; octanoic acid decreased in thermized and UHT milks.
• 2-stage homogenized milk exhibited the highest levels of most volatile compounds.

Conclusions:

• Microfluidization appears to have a limited effect on the volatile compound profile of milk.
• Conventional 2-stage homogenization significantly impacts volatile compounds more than microfluidization.
• Sensory evaluation is recommended to correlate volatile compound changes with actual aroma and flavor perception.