The effect of transglutaminase on physicochemical, microstructural, and organoleptic properties of low fat karish cheese

Karish cheese is considered to be one of the most traditional Egyptian cheeses. It is manufactured from low-fat milk. It can be a key part of a healthy diet, especially for the elderly and those suffering from obesity-related illnesses. Low-fat cheese such as karish cheese has the problem of crumbly texture characteristics, which is the main problem for cheesemakers. This research aimed to improve the texture of karish cheese using transglutaminase (TGase), and to study the effects on cheese physical, microstructural, and organoleptic properties at different TGase levels of 1.0, 1.5, and 2.0 U g−¹ protein. TGase increased the structure of karish cheese at a rate of 1.5–2.0 U g−¹ protein, compared to the control sample. Scanning electron microscopy images showed that the protein matrices in karish cheese samples that had been treated with TGase were relatively more compact than those in the untreated sample. Proteins in karish cheese samples treated with TGase showed crosslinking in SDS-PAGE scans. Casein fractions corresponding to bands became less intense as the concentration of TGase increased. To conclude, TGase improved the characteristics of karish cheese at the rate of 1.5–2.0 U g−¹ protein TGase, and it is recommended to enhance the structure of this type of traditional cheese in order to meet consumer demand.