Gastrointestinal In Vitro Digests of Infant Biscuits Formulated with Bovine Milk Proteins Positively Affect In Vitro Differentiation of Human Osteoblast-Like Cells.

Infant biscuits (IBs) are part of complementary feeding from weaning up to the age of five years. They normally contain bovine milk proteins, which can influence bone development. This potential effect was investigated using experimental baked IBs, which were prepared from doughs containing different type of dairy proteins: milk protein concentrate (IB1), whey protein isolate (IB2), and skimmed milk powder (IB3). Dairy protein-free (IB0) and gluten-free (IB4) biscuits were also formulated. The in vitro gastrointestinal digests of IBs (IBDs) were tested on a co-culture of Caco-2/HT-29 70/30 cells as an in vitro model of human small intestine. None of the IBDs influenced cell viability and monolayer integrity, while IBD0 and IBD4 increased Peptide-YY production. The basolateral contents of Transwell plates seeded with Caco-2/HT-29 70/30 co-culture, mimicking metabolized IBDs (MIBDs), were tested on Saos-2 cells, an in vitro model of human osteoblast-like cells. After incubation, MIBD0, lacking dairy proteins, decreased the cell viability, while MIBD2, containing whey protein isolate, increased both the viability and the number of cells. MIBD2 and MIBD4, the latter containing both casein and whey proteins, increased alkaline phosphatase activity, a bone differentiation marker. These results highlight that IBs containing dairy proteins positively affect bone development.

Terpenes and fatty acid profiles of milk fat and "Bitto" cheese as affected by transhumance of cows on different mountain pastures.

The evolution of fatty acid (FA) and terpenoid profiles was studied in milk (n=20) and "Bitto" (n=3), a protected designation of origin cheese produced in a restricted Italian alpine area. Milk came from 25 Italian Brown cows successively grazing pastures at 1400, 2100 and 2200m during transhumance in June-September 2006. The fat matter was analyzed for FAs and terpenes by means of gas chromatography and purge & trap/gas chromatography-mass spectrometry, respectively. FA composition of milk fat varied significantly (p<0.0001) in relation to contents of conjugated linoleic acid (CLA), stearic, linoleic and trans-vaccenic acids. Similar monoterpene profiles characterized milk fat from cows grazing the different pastures and the highest amount of terpenes was measured in milk coming from cows grazing at 1400m. High levels of δ3-carene in milk fat were likely related to the important presence of Ligusticum mutellina in the pasture. Only negligible amounts of sesquiterpenes were detected in milk fat whereas they were the most abundant class in fodder. Both FA and terpene profiles of ripened (70 days) cheeses resembled those of the original milks. Overall, results confirm the influence of the botanical composition of mountain pastures both in enhancing the ruminal synthesis of CLA and in modifying the FA and terpenoid profiles of milk and "Bitto" cheese. Nevertheless, neither the FA nor the terpenoid profiles revealed here can be considered as "unique" to "Bitto" cheese and, for this reason, they can hardly be assumed to be biomarkers for defining a specific relationship among grazing area, milk and "Bitto" cheese. They better represent the chemical fingerprint of the cow feeding, adopted in mountain areas.

Release of ß-casomorphins 5 and 7 during simulated gastro-intestinal digestion of bovine ß-casein variants and milk-based infant formulas.

The release of ß-casomorphin-5 (BCM5) and ß-casomorphin-7 (BCM7) was investigated during simulated gastro-intestinal digestion (SGID) of bovine ß-casein variants (n=3), commercial milk-based infant formulas (n=6) and experimental infant formulas (n=3). SGID included pepsin digestion at pH 2.0, 3.0 and 4.0 and further hydrolysis with Corolase PP™. ß-Casein (ß-CN) variants were extracted from raw milks coming from cows of Holstein-Friesian and Jersey breeds. Genomic DNA was isolated from milk and the ß-CN genotype was determined by a PCR-based method. Phenotype at protein level was determined by capillary zone electrophoresis in order to ascertain the level of gene expression. Recognition and quantification of BCMs involved HPLC coupled to tandem MS. Regardless of the pH, BCM7 generated from variants A1 and B of ß-CN (5-176mmol/mol casein) the highest amount being released during SGID of form B. As expected, the peptide was not released from variant A2 at any steps of SGID. BCM5 was not formed in hydrolysates irrespective of either the genetic variant or the pH value during SGID. Variants A1, A2 and B of ß-CN were present in all the commercial infant formulae (IFs) submitted to SGID. Accordingly, 16-297nmol BCM7 were released from 800ml IF, i.e. the daily recommended intake for infant. Industrial indirect-UHT treatments (156°C×6-9s) did not modify release of BCM7 and, during SGID, comparable peptide amounts formed in raw formulation and final heat-treated IFs.