Predicting coagulation and syneresis parameters of milk gels when inulin is added as fat substitute using infrared light backscatter

• Models to predict coagulation and syneresis parameters in milk gels with added inulin were developed.
• It was necessary to include independent variables for prediction of syneresis.
• Inulin addition decreased syneresis and increased curd yield.
• Gelation time was predicted with an R2 of 0.98 and SEP of 1 min.
• Application of prediction models could improve manufacturing of reduced fat cheeses.

Production of reduced fat cheeses often requires modification of the manufacturing procedure using fat substitutes such as inulin, in order to achieve acceptable sensory properties. Nowadays the use of optical sensors in cheese making justify developing prediction algorithms for coagulation and syneresis parameters in milk gels with inulin with the goal of improve cheese yield, quality and homogeneity. A randomized factorial design was used to test the effect of inulin concentration (0%, 3%, and 6% w/w), temperature (27, 32, and 37 °C), and fat (<0.2%, and 1.5% w/w) on light backscatter parameters typically used for predicting significant coagulation and syneresis indexes. The coagulation process was monitored using near infrared spectrometry, small amplitude oscillatory rheometry and visual coagulation indexes. The extent and kinetics of syneresis was evaluated by volumetric methods. Prediction models with one, two and three-parameter were determined for the whey drainage kinetic rate constant (k), curd yield (cy), clotting time (tclot), visual cutting time (tcut), as well as the rheologically-determined gelation (tG′1) and cutting times (tG′30). The results demonstrated that it is possible to obtain models for the prediction of coagulation and syneresis parameters in milk gels when inulin is added as a fat substitute using a fiber optic light backscatter sensor.