Skimmilk Solids as Substrate for the Preparation of Casein Enzymatic Hydrolysates

The time‐course hydrolysis curves of low‐heat (LH) and high‐heat (HH) skimmilk powders (SMP) by trypsin or chymotrypsin were compared to that of sodium caseinate (SC). Rates of hydrolysis, shown to be different (P < 0.05), were SC > LH‐SMP > HH‐SMP. A two‐step ultrafiltration process was applied to hydrolyzed LH‐SMP and to hydrolyzed SC, and results were compared. Protein and lactose composition differences between LH‐SMP and SC were accentuated by ultrafiltration. The hydrolysis profile (molecular weight distribution of peptides, amino acid content) of LH‐SMP tryptic hydrolysate showed a greater proportion of short peptides (<2000 Daltons) and a lower content in GLU, PRO, VAL and TYR, compared to that of SC.