Processing affects beta-casomorphin peptide formation during simulated gastrointestinal digestion in both A1 and A2 milk
Tim T. Lambers, Sjef Broeren, J.M.L. Heck, Marjolijn C. E. Bragt, Thom Huppertz
Abstract
Variation between bovine A1-or A2-type β-caseins are suggested to affect beta-casomorphin-7 (BCM-7) formation, which may affect health. Studies assessing BCM-7 formation often use raw milk, but processing of milk is known to affect digestion. Using in vitro digestion and stable-isotope assisted peptide quantification, we reveal that BCM-7 is formed under intestinal conditions from both A1-and A2-type milk. Moreover, formation of BCM-7 was affected by industrial relevant heating in both A1 and A2 milk. Further studies with a large number of single A1-and A2-type cows are needed to elaborate if amounts of BCM-7 formed are different between A1 and A2 milk. Both longer and shorter BCM peptide sequences that may display similar activities should be taking into account as a longer BCM-7 containing peptide (BCM-7 +2) could also be detected in A2 milk intestinal digesta.