Angiotensin l-converting enzyme-inhibitory activity of the Norwegian autochthonous cheeses Gamalost and Norvegia after in vitro human gastrointestinal digestion

摘要

The angiotensin I-converting enzyme (ACE) inhibitory activity of Gamalost cheese, its pH 4.6-soluble fraction, and Norvegia cheese was monitored before and after digestion with human gastric and duodenal juices. Both Gamalost and Norvegia cheeses showed an increased ACE-inhibitory activity during gastrointestinal digestion. However, only Norvegia showed pronounced increased activity after duodenal digestion. More pep-tides were detected in digested Gamalost compared with digested Norvegia. Most of the peptides in Gamalost were derived from β-casein (CN), some originated from α_s1-CN, and only a very few originated from α_s2-CN and k-CN. In general, the number of peptides increased during gastrointestinal digestion, whereas some peptides were further degraded and disappeared; however, surprisingly, a few peptides remained stable. The aromatic amino acids, such as Tyr, Phe, and Trp; the positively charged amino acids (Arg and Lys); and Leu increased after simulated gastrointestinal digestion of Gamalost and Norvegia. After in vitro gastrointestinal digestion, both Gamalost and Norvegia showed high ACE-inhibitory activity, which may contribute in lowering of mild hypertension.