Contending with challenges
Achieving the right mouthfeel and texture is an important part of the challenge of developing a thermised yoghurt product that will appeal to consumers.
“Preferences vary from country to country when it comes to texture, but most want something smooth and glossy with a clean mouthfeel,” she adds. “The main quality issue, though, is always syneresis.”
Syneresis, or serum separation, refers to a shrinkage of the gel as a result of the instability of the gel network, with the structure of the yoghurt becoming so tight that the water is squeezed out.
“It’s very tricky,” she says. “If you use the wrong type of stabiliser or the dosage is too high, the water squeezes out because the structure becomes too tight. If you don’t use a stabiliser, you can’t bind the water so it will squeeze out from the curd.”
Thermised yoghurt also needs to undergo heat treatment and, as a result of the low pH levels, that process can denature the milk protein and cause the product to become curdled or grainy.
Another issue for manufacturers has been developing shelf-stable yoghurts with clean labels, with the commonly used stabilisers requiring E numbers.