Effect of milk kind and storage on the biochemical, textural and biofunctional characteristics of set-type yoghurt

Set-type yoghurts were manufactured from skimmed sheep (SF0), semi-skimmed sheep (SF2), semi-skimmed cow (CF2) and goat (GF4) milk. In all yoghurts, approximately 109 cfu g−1 cocci were detected throughout storage, while bacilli were <104 cfu g−1. Small-size nitrogen compounds ranged from 4.3 to 4.8% of total nitrogen and storage caused no significant proteolysis in all yoghurts. GF4 yoghurt had the highest water holding capacity and SF2 had the highest firmness and viscosity. SF0 and SF2 exhibited the highest DPPH⋅ scavenging activity (69-81%), goat GF4 the lowest. All yoghurts had >68% Fe2+-chelating activity throughout storage; superoxide scavenging activity was constant, the lowest being observed in GF4 (44-45%). ACE-inhibition was moderate with GF4 exhibiting the lowest activity (9.1-12.9%). Treatment of ovine monocytes and neutrophils with water soluble extracts of sheep and cow milk yoghurts resulted in down-regulation of pro-inflammatory IL1B and IL12B and up-regulation of anti-inflammatory IL10 in neutrophils.