Quality attributes of set-style skimmed yoghurt affected by the addition of a cross-linked bovine gelatin

Abstract

Bovine gelatin was cross-linked using horseradish peroxidase, glucose oxidase, and glucose, and then used in the preparation of set-style skimmed yoghurt. Both bovine and cross-linked gelatins were added into yoghurt milk at 2 g/kg, whilst the yoghurt milk composed of table sugar of 60 g/kg was fermented by a commercial direct vat set starter at 42°C for 5 h. Yoghurt samples stored at 4°C for 1 and 7 d were assessed for their compositions and quality indices. In comparison with that contained bovine gelatin, the yoghurt contained cross-linked gelatin had similar chemical indices in terms of protein, reducing sugars, and total solids contents, but exhibited lower syneresis, larger hysteresis loop area, higher apparent viscosity, elastic and viscous moduli, and improved microstructure. Cross-linked gelatin could delay yoghurt post-acidification slightly. Cross-linked gelatin was thus proved to be a potential stabilizer better than bovine gelatin to improve the quality of set-style skimmed yoghurt.

Keywords

• Bovine gelatin
• enzymatic cross-linking
• skimmed milk
• set-style yoghurt
• quality