Skimmed milk structural dynamics during high hydrostatic pressure processing from in situ SAXS

Understanding the changes in milk at a nanostructural level during high-pressure (HP) treatment can provide new insights to improve safety and functionality of dairy products. In this study, modifications nanostructure HP were studied situ by small-angle X-ray scattering (SAXS). Skimmed was pressurized 200 or 400 MPa 25, 40 60 °C held for 5 10 min, effect single- double-HP also investigated. most cases, SAXS patterns skimmed are well fitted with three-population model: low-q micellar feature reflecting overall micelle size (~0.002 Å?1), small casein cluster contribution intermediate-q (around 0.01 Å?1) high-q (0.08–0.1 population protein inhomogeneities. However, colloidal calcium phosphate (CCP) which is normally only seen neutron scattering, observed 0.035 Å?1. By varying pressure, temperature, holding depressurization times, as performing cycled pressure treatment, we followed dynamic structural structure different length scales, depending on processing conditions, irreversible reversible within timescales Pressure temperature process have major effects, not micelles, but “protein inhomogeneities” their internal structure. Under HP, increasing time induced re-association however, more pressure-dependent than dependent.