Table 2.

List of the retrieved papers concerning physicochemical properties and protein functionality of A1 and A2 β-CN containing milk.

Review	Matrix	Investigated quality/ technological characteristic(s)	Main findings
Kamiński et al. (2)	Milk and dairy	Release BCM-7 during digestion	Release of BCM-7 following β-CN digestion requires a multi-enzyme system BCM precursors are detected in cheese; BCM-7 is largely detected in infant formulas A1 and A2 variants may present different physical properties in micelles
Raikos and Dassios (12)	Infant foods	Presence of BCM-7 in IF	BCM-7 and derivatives are released from commercial milk-based infant formulas following SGID
Nguyen et al. (9)	Milk and dairy	Presence of BCM-7 in dairy	BCM-7 is detected in raw milk and cheeses, but not in commercial yogurt, nor in pasteurized milk BCM precursors are detected in several cheeses BCM-7 in cheese does not originate from that originally present in milk, because peptides would be removed from the curd during the drainage of whey BCM-7 is higher in mold cheeses (Brie and Rokpol) than in semihard cheeses (Edamski, Gouda and Kasztelan) Proteolysis by enzymes from cheese starter cultures may reduce the amount of BCM-7
Pal et al. (13)	Milk and dairy	Presence of BCM-7 in dairy	BCM-7 is released from milk, yogurt and cheese following SGID Modest release of BCM-7 in cheese- and yogurt-making processes Certain yogurt bacteria may hydrolyze BCM-7
Brooke – Taylor et al. (5)	Milk	Release of BCM-7 during digestion	Release of BCM-7 following β-CN digestion requires a multi-enzyme system Presence of BCM-7 in fresh milk could be due to extended acidic hydrolysis In vivo studies indicate the release of BCM other than BCM-7
Gai et al. (8)	Milk and dairy	Effect of β-CN variants on milk yield, composition, protein structure, coagulation, foaming, emulsifying capacity	A2 variant has better chaperone capacity than A1, due to more proline helix formation Milk yield, protein yield, fat percentage and fat yield are significantly affected by β-CN variant, and the effect is enhanced by association with specific κ-CN variants A2 variant shows poorer coagulation properties than A1 (longer rennet coagulation time and looser curd), but may result in more easily digestible yogurt A2 variant shows a more acidic pI than A1, is more soluble, reaches the oil droplet surface more rapidly, but does not result in better emulsion stability. Results of the foaming properties of different β-CN variants are controversial
Summer et al. (26)	Milk and dairy	Presence of BCM-7 in dairy and effect on its release during digestion	Small amounts of BCM-7 could be released from A2 β-CN due to acidic hydrolysis in gastric environment BCM-7 is detected in a number of dairy products before and after SGID (pasteurized milk, cheese, laboratory-made yogurt, and other dairy products) Manufacturing and ripening in matured cheeses, and proteolysis by lactic acid bacteria and probiotics, exert a pivotal role in modulating the release BCM-7 before and after SGID The release of BCM-7 during SGID of sterilized infant formulas was hindered by protein glycation
Thiruvengadam et al. (21)	Milk and dairy	BCM-7 structure and metabolism	BCM-7 sequence is more hydrophobic, bitter to taste and its further digestion of is difficult because of the large percentage of proline BCM-7 and derivatives are released during the food processing (pasteurization, cheese- and yogurt-making, and other dairy products)

IF, Infant Formula; BCM, β-casomorphin; β/κ-CN, Casein β/κ; SGID, Simulated GastroIntestinal Digestion.