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The influence of enzymatic cross‐linking on the rennet coagulation of Berridge substrate was investigated in the rennet gel samples prepared by three different methods using a microbial Tgase. Protein cross‐linking was carried out at each of three stages: before the addition of rennet, simultaneously with rennet and after the addition of rennet. The results showed that the cross‐linking of milk proteins before the addition of rennet inhibited the primary enzymatic phase of rennet coagulation. It was observed that enzymatic cross‐linking affected both the primary and the secondary phases of rennet coagulation. The most suitable application method was the addition of transglutaminase at the 5th minute after the addition of rennet.

Several heat treatment norms are applied in the dairy industry during the manufacture of various products. The knowledge on the influence of temperature on the proteins-flavonoid binding is critical for optimization of process conditions. The aim of this study was to establish the effect of heat treatment on the interaction between milk proteins and flavonoids and also determine when to apply heat treatment. Reverse-phase high-performance liquid chromatography (RP-HPLC) analysis revealed that free flavonoids decreased in the presence of milk proteins and a binding ratio (%) was calculated based on this decrease. Three different heat treatment norms were selected (80, 85 and 90 °C  10 min). Analyses were carried out in both sodium caseinate and skimmed milk samples to observe the possible effect of milk serum proteins on the interaction. The binding ratio between flavonoids and proteins was found to be higher in the samples where green tea extract (GTE) was added before heat treatment than in the samples where GTE was added after heat treatment in both the skimmed milk and sodium caseinate systems. Results of protein surface hydrophobicity (PSH) index and protein partition also demonstrated that heat treatment must be applied after the addition of GTE to improve the amount of GTE binding to milk proteins.