Physicochemical evaluation of low-fat yoghurt produced with microbial transglutaminase

Currently consumers demand low-fat or non-fat yoghurt but their physical properties are less attractive than those of full-fat yoghurt. It was reported that microbial transglutaminase (TG) can be used in the production of low-fat yoghurt. The aim of this work was to evaluate the effect of TG on low-fat yoghurt to improve their physicochemical and textural properties to approach to those of full-fat yoghurt. Two TG application methods (addition before fermentation or simultaneous addition with the starter), three dose levels and TG origin were evaluated. Results were compared with commercial low-fat and full-fat yoghurts.

No significant differences between application methods were observed. Simultaneous addition of TG was preferred because additional time-consuming steps are not required. The best dose was 1 U TG g^-1 of protein that allowed a firmness higher (4.25 N) than that of commercial low-fat (3.05 N) and full-fat (4.43 N) yoghurts to be achieved. This implies that intermediate values of TG will permit the same firmness as commercial yoghurts to be obtained. It was observed some differences by the TG origin may be due to excipients.

TG may be used to replace stabilizers in the production of low-fat yoghurt as it improves texture and avoids initial syneresis. © 2018 Society of Chemical Industry.