Age Gelation, Sedimentation, and Creaming in UHT Milk: A Review

Area of Science:

• Food Science
• Dairy Technology
• Materials Science

Background:

• Growing demand for ultra-high-temperature (UHT) milk and protein beverages.
• UHT milk exhibits microbiological stability but undergoes chemical and physical changes during storage, impacting quality and shelf life.
• Key storage defects include age gelation, sedimentation, and creaming, which can limit consumer acceptance.

Purpose of the Study:

• To review the current knowledge on age gelation, sedimentation, and creaming in UHT milk during storage.
• To critically evaluate existing literature on these storage-induced defects.
• To propose mechanisms for age gelation and sedimentation based on the literature review.

Main Methods:

• Comprehensive literature review of scientific publications on UHT milk storage.
• Critical analysis of factors influencing age gelation, sedimentation, and creaming.
• Synthesis of information to propose underlying mechanisms for observed defects.

Main Results:

• Age gelation occurs via proteolytic enzyme activity or physico-chemical changes influenced by protein concentration and heat processing.
• Sedimentation is affected by factors similar to those influencing age gelation.
• Creaming is less studied, suggesting it is a less frequent or detrimental defect compared to gelation and sedimentation.

Conclusions:

• Understanding the mechanisms of age gelation and sedimentation is crucial for improving UHT milk stability.
• Further research is needed, particularly on the creaming phenomenon in UHT milk.
• Optimizing UHT processing and milk composition can mitigate storage-related quality degradation.