# Application of Ultrasound Homogenization in Milk Ice Cream Mixes
## 3 Results and Discussion  
### The Stability of Milk Ice Cream Mixes  
The stability of emulsion is a crucial factor that refers to resisting undesirable changes during storage time. Therefore, the ice cream mixes are a multiphase product that also can be treated as an oil-water emulsion, and it is necessary to investigate this physical property. In the present paper, the stability of ice cream mixes was investigated by using the turbidimetric method [28]. The results were expressed as the TSI (Turbiscan Stability Index) value (Table 2) and as the backscattering (Figure 1a-c). Figure 1: _Cont._  
After 24 h of the maturation, the lowest value of TSI (Turbiscan Stability Index) was noted for the sample BU (after ultrasound treatment and with the addition of the enzymatic \(\beta\)-galactosidase hydrolyzates of iota carrageenanan), at level 1.3 (Tables 1 and 2). Simultaneously for these samples, this result presented the highest stability of the emulsion on the grounds that the lower TSI value is equal to better stability. Moreover, the lowest stability of ice cream mixes was indicated for the sample IH (after the mechanical homogenization and with the addition of iota carrageenanan). Taking into account the influence of the different sorts of homogenization, it could be noted that ultrasound homogenization improved the stability of milk ice cream mixes. In all samples, after the ultrasound treatment, the TSI values were lower in comparison to samples after the mechanical homogenization. The range of TSI values for samples after the ultrasound treatment was from 1.3 to 2.2 while for samples after the mechanical homogenization, it was from 2.5 to 7.3. Based on the statistical appraisal, the differences between samples were significant (\(p<0.05\)) (Tables 1 and 2). Additionally, it could have been concluded that the sort of homogenization  
Figure 1: (**a**) Variation in backscatter with time for control sample during maturation under refrigerated conditions. (**b**) Variation in backscatter with time for sample after mechanical homogenization treatment during maturation under refrigerated conditions. (**c**) Variation in backscatter with time for sample after ultrasound homogenization treatment during maturation under refrigerated conditions. Blue line presents measurements before maturation and red one presents measurements after maturation. during the process of manufacturing ice cream mixes significantly changed the stability of emulsion compared to the sort of used stabilizers. Due to the fact that the value of TSI was similar in the samples such as LU, AU, or BU (samples with the addition of the hydrolyzes of iota carrageenanan), the differences were noticed only in the case of homogenization, for instance, for samples LH and LU (Tables 1 and 2). Moreover, also in the control sample (CU), the effect of UV was seen on the grounds that the TSI value was at level 2.2 while in sample CH (after the mechanical homogenization and without stabilizers), it was at level 2.5 (Tables 1 and 2). In the previous research by [PERSON] et al. [29], the authors examined the addition of the same stabilizers, however, without any homogenization step in milk ice cream mixes. It was observed that the addition of stabilizers contributed to obtaining the TSI values from 1.9 to 2.8. Also, it proved the positive impact of using ultrasound homogenization in milk ice cream production. In 2018, [PERSON] and [PERSON] [30] published a paper in which ultrasound was used to improve the emulsification of a pectin mixture and concentrate of whey protein. Ultimately, the sonification also enhanced the stability, and ultrasound was successfully applied in low-fat systems. Similarly, [PERSON] et al. [31] found that higher energy input improved the stability of emulsion with the concentration of stabilizers at 0.5%. Additionally, such emulsion was more stable in terms of coalescence during the storage.