Decalcification strongly affects in vitro gastrointestinal digestion of bovine casein micelles under infant, adult and elderly conditions

Abstract

Effects of 0–90% decalcification on the coagulation behavior and gastrointestinal digestibility of bovine casein micelles were studied in vitro under infant, adult and elderly conditions. Gastric coagula became looser with increasing level of decalcification, especially up to 40% under the infant condition and up to 69% under the adult and elderly conditions. Casein degradation showed a similarly increasing trend with increasing level of decalcification under the three age conditions. Casein degradation was fastest under the adult condition, but slowest under the elderly and infant conditions at 0–40 and 69–90% decalcification, respectively. Formation of free amino groups and small peptides increased with increasing level of decalcification and in order of infant, elderly and adult conditions. In intestinal phase, the remaining caseins were very rapidly degraded. Formation of free amino groups and smaller peptides showed minor differences with increasing level of decalcification, but increased in order of infant, elderly and adult conditions. This study highlighted the different level of decalcification suitable for diverse age populations to improve the gastrointestinal digestibility of bovine casein micelles.