Determination of powder flow properties of skim milk powder produced from high-pressure homogenization treated milk concentrates during storage

The aim of this study was to determine effects of high-pressure homogenization (HPH) treatment to milk concentrates on powder flow properties of skim milk powders (SMP). For this purpose, SMP samples were produced from skim milk concentrates which were HPH treated at 0 (control), 50, 100 and 150 MPa. SMP samples were stored 180 days at 20 and 40 °C and caking, cohesion and powder flow speed dependency test (PFSD) were performed using a Powder Flow Analyzer. HPH treatment decreased cohesion and caking properties of SMPs. At the 0. day, cake strength of SMPs from HPH treated concentrates varied from 0.43-2.70 mN.m, whereas cake strength of SMP-0 (control) was 8.20 mN.m. Cohesion index (CI) of samples ranged from 6.80-15.74 mm during storage. Based on CI, SMPs from HPH treated concentrates showed free and easy flowing flow behavior during storage at 20 and 40 °C. In addition, cohesion index at four speeds indicated that SMP from HPH treated concentrates were more flowable at even lower flow speeds then SMP-0. PFSD test verified that all SMP samples showed more free-flowing characteristics with increasing flow speeds. Flow stability of samples ranged from 0.95-1.15 and also flow stability of SMP-0 increased during storage at both 20 and 40 °C. The results revealed that HPH treatment to milk concentrates could improve powder flow properties of skim milk powders.