Which protein in milk is most affected by acid?
                                
                                
                                •
                                
                                
                        
                                    
                                    4 min read                                
                            
                                Comprising about 80% of the total protein in cow's milk, casein is the milk protein most affected by acid, undergoing a crucial transformation during cheesemaking and digestion. When milk becomes acidic, the casein protein molecules lose their stability and clump together, causing the familiar curdling phenomenon. This reaction is a fundamental principle of dairy chemistry.