Transglutaminase treatment of thermally and high pressure processed milk: Effects on the properties and storage stability of set yoghurt

The objectives of this work were to study the effect on the quality parameters of set yoghurt made from high pressure (HP) and transglutaminase (TGase) treated milk (separately or in combination), and to determine the shelf life of this product. Yoghurt samples made from HP— in combination with TGase-treated milk exhibited the highest values of firmness, lowest values of whey separation and similar values of acidity with the other samples. All yoghurt samples made from HP-treated milk, (with or without subsequent TGase treatment), exhibited a creamier perception than the ones from thermally-treated milk. Yoghurt samples prepared by the conventional procedure were judged as unacceptable after the fifth week of storage due to an intense syneresis and separation of the coagulum from the cup. Overall, HP and TGase treatment of milk can be a useful tool for the dairy industry to achieve products of improved structure and desirable sensorial characteristics.Industrial relevanceIn order to achieve a tight and compact structure of yoghurt, solid fortification and/or addition of stabilizers is needed. Transglutaminase and high pressure treatment of milk (when applied individually or in combination) can be alternative treatments of milk to produce yoghurt with improved textural and sensorial characteristics, without dependence on costly solid fortification.

► HP and TGase treatments have a synergistic effect on the quality indices of yoghurt.
► HP and TGase treatments of milk resulted in gels with improved protein network.
► The quality of HP- and/or TGase-treated samples remained stable during storage.
► HP and TGase treatment can replace the costly addition of protein source in yoghurt.