Release of β-casomorphin-7 in A1/A1 and A2/A2 dairy systems: Insights from simulated semi-dynamic gastrointestinal digestion

The study aimed to determine the amount of β-casomorphin-7 released during semi-dynamic in vitro gastrointestinal digestion of A1/A1 and A2/A2 milk, yogurt, and Cheddar cheese. Samples were collected at 10 and 120 min during the intestinal phase for each of the four gastric emptying points, following the INFOGEST digestion model. β-Casomorphin-7 was quantified using liquid chromatography coupled to triple quadrupole mass spectrometry. The levels of β-casomorphin-7 were similar in A1/A1 (8.65-11.72 μg/100 g protein) and A2/A2 (9.64-15.29 μg/100 g protein) milk digests, higher in A1/A1 yogurt, while A1/A1 cheese digest exhibited the highest levels among all samples (36.19-62.73 μg/100 g protein), nearly ten times higher than A2/A2 cheese digest. After in vitro gastrointestinal digestion of a serving size of the studied dairy products the released amounts may not align with levels required for in vivo opioid activity. However, further human clinical trials are warranted.