Effect of Caseinophosphopeptides from αs- and ß-Casein on Iron Bioavailability in HuH7 Cells.

Two pools of caseinophosphopeptides (CPPs) obtained from αs- and ß-casein fractions (α-CPPs and ß-CPPs) were characterized. A total of 16 CPPs were identified in the α-CPPs pool, 9 of them derived from αs1-casein and 7 from αs2-casein. A total of 18 CPPs were identified in the ß-CPPs pool. Four of the identified CPPs contained the characteristic phosphoseryl-glutamic acid cluster SpSpSpEE. Calcein assay was used to compare the iron-binding capacity of the α- and ß-CPPs pools. At the concentration of 12.5 µM CPPs used in the iron bioavailability assays, ß-CPPs pools show greater iron-binding capacity than α-CPPs pools. HuH7 human hepatoma cells show many differentiated functions of liver cells in vivo and can be used to evaluate iron bioavailability (ferritin content and soluble transferrin receptor) from Fe-α-CPPs and Fe-ß-CPPs complexes. The α-CPPs and ß-CPPs pools did not improve ferritin content or soluble transferrin receptor in HuH7 cells.

Antioxidant activity and protective effects of peptide lunasin against oxidative stress in intestinal Caco-2 cells.

Oxidative stress is one of the most critical factors implicated in many disorders of the gastrointestinal tract, such as inflammatory bowel diseases and colon cancer. Lunasin is a seed peptide known by its properties against cancer and cardiovascular diseases. The present study investigated the in vitro antioxidant activity of this peptide that demonstrated to be a potent scavenger of peroxyl and superoxide radicals. In addition, the protective role of lunasin on cell viability and antioxidant defenses of human Caco-2 cells challenged by hydrogen peroxide and tert-butylhydroperoxide was evaluated. This peptide remained partially intact during incubation time with cells, preventing of the oxidative damage induced by both chemical agents. The direct antioxidant action of lunasin (within the physiological range of concentrations) on enterocytes exposed to oxidizing species makes this peptide a promising agent to preserve the integrity of intestinal mucosa against oxidative damage related diseases.

Iron and zinc bioavailability in Caco-2 cells: influence of caseinophosphopeptides.

A study has been made of the influence of two pools of caseinophosphopeptides (CPPs) obtained from α(s)- and ß-casein (CN) fractions, and of three specific CPPs (ß-CN(1-25)4P, α(s1)-CN(64-74)4P and α(s2)-CN(1-19)4P), on iron bioavailability (ferritin synthesis) and zinc bioavailability (retention, transport and uptake of zinc) in Caco-2 cells. α-CPP and ß-CPP pools did not improve ferritin synthesis, but the three specific CPPs showed an increase in ferritin synthesis in Caco-2 cells versus iron sulphate, ß-CN(1-25)4P being the most effective. In relation to zinc bioavailability, α-CPPs, ß-CPPs, α(s1)-CN(64-74)4P and ß-CN(1-25)4P increased zinc uptake. However, this increase was of the same order as the increase due to the presence of zinc sulphate.

Milk versus caseinophosphopeptides added to fruit beverage: resistance and release from simulated gastrointestinal digestion.

The influence of simulated gastrointestinal digestion on caseinophosphopeptides (CPPs) formation in milk-based fruit beverage was evaluated, together with resistance of a pool of CPPs added to fruit beverage. In milk-based fruit beverage, four CPPs were identified that can be justified by their presence in raw milk or due to processing. When it was subjected to simulated gastrointestinal digestion, 10 CPPs were identified, and only 1 presented the cluster (SpSpSpEE) (3 phosphoseryl group followed by 2 glutamic acid residues), which corresponded to alpha(s2)-CN(1-19)4P. CPPs added to fruit beverage are resistant to simulated gastrointestinal digestion, and 16 CPPs were identified originating from the fragmentation of added CPPs, and with a greater presence of the cluster compared with CPPs originating from milk-based fruit beverage. This could justify the use of CPPs as functional ingredients, and offer a good alternative to milk-based fruit beverage for improving mineral bioavailability.