Fig. 3. Effects of spray dried and freeze dried on the contents of PC, SH, DT and MDA. (A) PC content in spray-dried WM, frozen-dried WM and frozen-dried SM; (B) SH content in spray-dried WM, frozen-dried WM and frozen-dried SM; (C) DT content in spray-dried WM, frozen-dried WM and frozen-dried SM; (D) MDA content in spray-dried WM, frozen-dried WM and frozen-dried SM. 130–180 °C, air inlet temperature of WM spray drying; freeze-dried WM, freeze-dried whole milk; spray-dried SM, 170 °C air inlet temperature spray-dried semi-skimmed milk; PC, protein carbonyl; SH, sulfhydryl; DT, dityrosine; MDA, malondialdehyde. Data are expressed as the mean ± SEM (n = 5 per group). Means among bars without a common letter differ, P < 0.05.