Proteolytic Activity in Ultra-Pasteurized, Aseptically Packaged Whipping Cream ¹

Area of Science:

• Food Science
• Microbiology
• Enzymology

Background:

• Ultra-pasteurized, aseptically packaged cream can develop bitter flavors.
• Microbial proteolytic activity is a potential cause of bitterness in dairy products.

Purpose of the Study:

• To investigate the proteolytic activity in commercial cream samples exhibiting bitterness.
• To determine the influence of temperature and pH on the rate of proteolysis.

Main Methods:

• Analysis of microorganisms in cream samples.
• Measurement of proteolytic activity at varying temperatures (20-50°C) and pH levels (7.0-9.0).
• Monitoring proteolysis rates over incubation time.

Main Results:

• Optimum proteolytic activity occurred at 37°C for two samples (A & B) and between 30-37°C for sample C.
• Specific pH optima varied: pH 7.0-7.5 for A, pH 7.0-9.0 for B, and pH 8.0 for C.
• The rate of proteolysis consistently increased with extended incubation periods.

Conclusions:

• Microbial proteolytic enzymes contribute to bitter flavor development in ultra-pasteurized cream.
• Temperature and pH significantly influence the activity of these enzymes.
• Understanding these factors is crucial for controlling bitterness in dairy products.