The digestion of major whey proteins/peptides, transforming growth factor-beta2 (TGF-β2) and insulin-like growth factor-I (IGF-I) in a bovine whey protein extract (BWPE) was investigated in vitro using a dynamic gastrointestinal digestion system (TIM-1). β-lactoglobulin and glycomacropeptide were the whey components most resistant to 3 h of gastric digestion (pepsin) and were also the last to be cleared from the gastric compartment. All of the major proteins were hydrolyzed rapidly upon reaching the intestinal compartments. At the end of the 5-h digestion, most (73%) of the nitrogenous portion of BWPE was found in the jejunal and ileal dialysis fluids as peptides smaller than 5.8 kDa, while about 25% was discharged in the effluent destined for the colon. TGF-β2 seemed resistant to gastrointestinal enzymes since more than 95% of it was found intact in the effluent after the 5-h digestion. In contrast, IGF-I was totally hydrolyzed when it reached the intestinal compartment, suggesting its high susceptibility to pancreatic enzymes. These results support the view that TGF-β2 in a complex protein extract resists digestion and could therefore exert its biological activity when taken orally.

Background: Frozen yoghurt is a suitable vehicle to deliver bioactive compounds and beneficial microorganisms, and to develop new functional dairy products. Methods: Bifidobacterium bifidum was used in the manufacture of frozen yoghurt, whereas skim milk powder was substituted by Nanoparticles Coconut Flour (NCF) and Coconut Flour (CF). The physicochemical, microbiological and sensory properties were assessed for frozen yoghurt from different treatments. Results: The prepared NCF by ball-milling had sizes that range between 81.96nm to 83.53nm. The addition of NCF affected variably the pH values, moisture content, the overrun, fiber content, freezing points and viscosity of the prepared frozen yoghurt depending on the ratio of substituted skim milk. Also, the addition of NCF improved the viability of Bifidobacterium bifidum, Bifidobacterium breve, Streptococci, and Lactobacilli and total bacterial count of frozen yoghurt during frozen storage. The addition of NCF improved the sensory properties of frozen yoghurt. Conclusion: The use of Nanoparticles Coconut Flour (NCF) and Bifidobacterium sp., in the preparation of frozen yoghurt improved its physicochemical, microbiological and sensory properties.