Denaturation kinetics and storage stability of Osteopontin in reconstituted infant milk formula

Osteopontin (OPN) is a multifunctional whey protein with numerous health benefits and is recommended to supplement Infant Milk Formula (IMF) with it. For the first time, the denaturation kinetics and storage stability of bovine OPN were studied in reconstituted IMF. The effect of thermal treatments (63-90 °C) and High Pressure Processing (HPP) were investigated. OPN showed higher retention (around 90%) after both LTLT (Low Temperature Long Time) and HTST (High Temperature Short Time) treatments, however higher temperature and longer treatment induced substantial denaturation indicating UHT may not suit OPN-added items. Significant denaturation occurred at higher pressure (>400 MPa), and more pronounced OPN denaturation was observed after HPP at elevated temperature. OPN remained stable during4 °Cstorage for 14 days. This investigation deduced thermal stability of OPN as α-Lac > OPN > LF, whereas the pressure resistance observed as α-Lac > LF > OPN > β-Lg.