Preparation and rheological properties of a dairy dessert based on whey protein/potato starch

Gels were prepared by heating different mixtures of whey protein concentrates (WPC) potatoes and ι-carrageenan. The influence of these ingredients on the strength of the obtained gels was investigated. The rheological properties of these gels were also measured during cooling from 90 to 10 °C at variable frequencies and strains. Analysis of variance showed a highly significant (P<0.0001) relationship between the concentrations of the different ingredients and the gel strength. The storage modulus (G′) was generally higher than the loss modulus (G″) at different temperatures. Generally, the log (G′) and log (G″) increased with the increase in the applied frequency, which suggested a weak gel entanglement network. Desserts were also prepared using 4% WPC and 3% potato starch (PS), 0.1% ι-carrageenan, 10% sucrose, 3% milk fat and 3% cocoa powder, by heating at 100, 110 or 120 °C for 30 min, packaged hot and stored for 28 days at room temperature (20 ± 5 °C). Samples of fresh and stored desserts were taken at 0, 7, 14, 21, 28 days of storage and their gel strengths were measured. Also, the effect of heat treatment during preparation on G′, G″ and phase angle (δ) of the different desserts was followed. The effects of the heating time and temperature on the gel strength and rheological properties were relatively small.