[Tracking casein phosphopeptides during fermentation by high performance liquid chromatography-tandem mass...

Area of Science:

• Food Science
• Biochemistry
• Microbiology

Background:

• Casein phosphopeptides (CPPs) are bioactive peptides derived from casein.
• CPPs possess health benefits, including enhanced mineral absorption, antioxidation, and dental caries prevention.
• Endogenous proteases in milk contribute to basal CPP levels.

Purpose of the Study:

• To investigate the release and identification of CPPs in milk and yogurt.
• To analyze the impact of fermentation by *Lactobacillus debrueckii subsp. bulgaricus* and *Streptococcus thermophilus* on CPPs.
• To characterize specific CPP structures formed during fermentation.

Main Methods:

• High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed for CPP analysis.
• Comparative analysis of CPPs in raw milk versus fermented yogurt.
• Investigation of casein structure's role in CPP release during fermentation.

Main Results:

• Milk naturally contains CPPs, primarily from αs1-CN and β-CN.
• Fermentation significantly increased CPPs and phosphorylation sites due to lactic acid bacteria proteases.
• Specific CPPs, including those with SpSpSpEE sequences, were identified in yogurt.
• Casein structure was found to be crucial for CPP release during fermentation.

Conclusions:

• Lactic acid bacteria fermentation effectively releases bioactive CPPs from milk.
• Yogurt produced by *Lb. bulgaricus* and *S. thermophilus* contains CPPs that promote mineral absorption.
• The study highlights fermentation as a method to enhance the functional properties of milk-derived peptides.