# Application of Ultrasound Homogenization in Milk Ice Cream Mixes
## 3 Results and Discussion
### The Analysis of Rheological Properties of Milk Ice cream Mixes
Only sample IU, after ultrasound treatment and with the addition of iota carrageenanan, was characterized by a flow behavior index at level 1.168, which means that this sample can be classified with shear-thickening (dilatant) behavior. The increase in viscosity with the simultaneous increase in the shear rate may be related to the increasing alignment of constituent molecules of the tested system. The higher values of n are connected with the higher stability of the product during processing. Moreover, the combination of iota carrageenanan with the ultrasound treatment in accordance with the value of TSI had the lowest stability in comparison to other samples with the addition of stabilizers (Table 2) [42]. In research by [PERSON] et al. [39], ice cream with different amounts of homogenized hazelnut milk was examined. By using the Ostwald de Waele model, such parameters as the apparent viscosity, consistency index, and flow behavior index were measured. It was noted that the consistency value ranged from 0.89 to 4.13 Pas\({}^{n}\) and the flow behavior index was assessed from 0.61 to 0.76. Overall, it was concluded that with the increasing amount of homogenized milk in ice cream, the consistency index was higher while the flow behavior index was lowered [37]. A smaller \(n\) value contributes to a higher shear-thinning attitude and is more pseudoplastic [43]. Therefore, the better/higher shear-thinning behavior can bring advantages such as decreasing the energy input during the ice cream production process, pumping, or mixing. Moreover, such properties as texture and mouthfeel can also be improved by a higher shear-thinning attitude [39]. Having discussed the influence of the acoustic intensity (11.2 \(\pm\) 0.3 \(W\)/cm\({}^{2}\); 14.4 \(\pm\) 0.5 \(W\)/cm\({}^{2}\); and 18.4 \(\pm\) 0.8 \(W\)/cm\({}^{2}\)) of ice cream, [PERSON] and [PERSON] [32] reported that the flow behavior index (\(n\)) was also increased with the increase in acoustic intensity. In the case of the consistency index (\(K\)), it was increasing also with the higher intensity of ultrasound but not gradually. It means that in the intensity 18.4 \(\pm\) 0.8 \(W\)/cm\({}^{2}\), there was significant growth of the consistency index. Turning now to the experiment results after maturation, a slight increase was noted in all samples, and the consistency index (\(K\)) ranged from 0.007 to 0.040. Moreover, the same tendency was observed as it was before maturation that samples after the ultrasound treatment had a lower consistency index (\(K\)) than samples after the mechanical homogenization. For instance, the consistency index for sample BH was at the level of 0.033 while for sample BU, it was 0.018 (Tables 1 and 3). The \(n\) value decreased in comparison to results before maturation. Only samples IU and BU had a value of more than 1 while for other samples, it was less than 1. Based on that observation, sample IU was changing to achieve more pseudoplastic behavior (from 1.168 to 1.02) and for sample BU, the increase was noted from 0.957 to 1.019. Nonetheless, based on the statistical results, there were no significant differences between samples; therefore, the obtained results were not taken into further consideration. The detailed examination of the rheological characterization of ice cream with different food hydrocolloids by [PERSON] et al. [42] showed that with the increasing amount of gum concentrations in ice cream, the decrease in the flow behavior index was also visible. Notwithstanding, the differences in the value of \(n\) could have been connected with the different concentrations and molecular sizes. Therefore, stabilizers with low n values are advisable for ice cream mixes on the grounds that they can positively influence the desirable mouthfeel characteristic of ice cream [42]. The maturation in ice cream production has been identified as a major contributing factor to the overall quality of ice cream. Thus, the relationship between maturation and rheological properties of ice cream was also presented in research by [PERSON] et al. [44].