## 3 Results and Discussion
### Viscoelastic Properties  
Our research conducted in 2020 confirmed that the structure of high-protein fat-free dairy desserts exhibits gel-like properties. The value of storage modulus (G\({}^{\prime}\)) for dessert with 9% WPC80 was 867.07 Pa and for loss modulus (G\({}^{\prime\prime}\)) was 342.99 Pa [22]. G\({}^{\prime}\) and G\({}^{\prime\prime}\) described, respectively, the energy that is stored by the system as a consequence of elastic deformation and the ratio of energy during the deformation process dissipated as heat [40]. In tested samples, the G\({}^{\prime}\) values increased in dairy desserts with carrot, beetroot, and onion powder, along with the higher amount of powders (1, 3, or 5%) (\(p<0.05\)). It confirms the strengthening of the gel structure of dairy products. Only in samples with champignon, a decrease in the value of the G\({}^{\prime}\) modulus of the samples was observed (Table 3). In all tested products, the number values of G\({}^{\prime}\) were higher compared to the G\({}^{\prime\prime}\). It indicates that the desserts exhibited elastic (gel) properties.  
Figure 1: Effect of different dried vegetable powders and amounts (1, 3, 5%) on the viscosity of fat-free dairy desserts. Letters (**a**–**d**) describe different desserts: (**a**) with beetroot powder (Be); (**b**) with onion powder (O); (**c**) with champignon powder (Ch); and (**d**) with carrot powder (C).  
The correlation between G\({}^{\prime}\) and G\({}^{\prime\prime}\) with hardness can be observed. The structure in the samples with the addition of champignon powder becomes less elastic along with the amount of additive. Compared to the results of desserts without vegetable powders, the value of tested features increased. The same trend was noted by [PERSON] et al. (2010). They incorporated different amounts of organ fiber into yogurt. Researchers observed that elastic (G\({}^{\prime}\)) and viscous moduli (G\({}^{\prime\prime}\)) were higher in products with bigger particles compared to yogurts with smaller size of dietary fibers [44]. On the other hand, the phase angle can estimate whether the final product exhibits gel-like properties (\(\delta<45^{\circ}\)). Only in the sample with 1% onion powder addition the value of \(\delta\) was much higher than \(45^{\circ}\). When \(\delta=45^{\circ}\), it is considered a gel point. A value higher than \(45^{\circ}\) characterizes a product with viscous-like properties [45]. Additionally, obtained results may be connected with adding WPC80 and eliminating fat from the formula. Researchers confirmed that the amount of protein impacted the values of loss and storage moduli [46]. The decrease in the value of G\({}^{\prime}\) in desserts with champignon powder could be related to the foamability of the whey proteins. The molecules' structure is the forces between them influencing the gelling process [47]. The composition of ingredients that create dessert described as the weak gel can be influenced by tested powder, which can interact with other particles and weaken the final product's texture. For example, dessert with 5% mushroom powder significantly decreased compared to the product with the addition of 3%.