## 3 Results and Discussion
### Stability Tests  
Formulation stability is an absolute prerequisite in cosmetics, especially in emulsion-type products. Centrifuge and temperature test results show that the stability of cosmetic formulations is not adversely affected by the addition of the plant powders evaluated in this study. No change in sample appearance and no layer separation were observed after the tests. [PERSON] et al. (2012) formulated stable emulsion-type facial masks, incorporating haskap berry (honeyberry) powder as one of the ingredients. The samples retained their stability after undergoing centrifugation (2000 rpm) and storage in a refrigerator and incubator at similar temperatures for a period of 30 days. [PERSON] et al. (2015) studied the effects of adding Zea Mays Starch and Zinc Oxide at different proportions to the formulations of cosmetic emulsions containing a sugar derivative as a rheology modifier. Centrifuge tests conducted at a set speed of 300 rpm for 30 min revealed a positive stability result for a sample containing only the additives at a 1:1 ratio. A Turbiscan device makes it possible to detect signs of emulsion instability already at a very early stage of storage. Furthermore, it allows for the identification of the type of instability (coalescence, flocculation, creaming, etc.). The visual evaluation of the formulated samples was verified on the basis of transmittance (T) and backscattering (BS) correlation profiles. The profiles obtained for the formulated hair conditioners are shown in Figure 2, Figures 3-4 (Appendix A). Based on the determined profiles (Figure 2, Appendix A: Figures 3-4), both the baseline emulsion and the hair conditioners formulated with the addition of black radish and burdock plant powders were found to be stable. Since the emulsions were very viscous, it was difficult to transfer them to the measuring vessels. During the transfer, the emulsions became aerated. Then, as a result of the temperature, they became deaerated during storage. Hence, there are slight deviations in graph slope, which, however, are not significant. In the studies conducted by [PERSON] et al. (2016), cosmetic emulsions were formulated with solid particles, including ground oat grain and ground orange peel. In general, the emulsion samples were characterized by a stable form (as determined by centrifuge and temperature tests). After a 60-day Turbiscan test, only minor signs of emulsion destabilization were seen, including sedimentation presumably caused by the settling of ground plant particles. The phenomenon was notable especially for the fragments of orange peel. [PERSON] and [PERSON] [47] conducted studies evaluating emulsion stabilization using a specific type of clay (montmorillonite) and applying different methodologies--visual and rheological--for stability assessment. The authors found that in a mixture of hydrophilic and hydrophobic clays, the emulsion exhibited synergistic stabilization due to the formation of an interfacial structure by the clay particles. [PERSON] et al. [48] evaluated the stability of emulsions stored at 25 \({}^{\circ}\)C during a 30-day test. The emulsions were formulated with the addition of watermelon seed oil and orange fibers. The authors identified a range of phenomena, including creaming, coalescence, and flocculation in the test samples at different stages of storage. The longest period of stability was recorded for the sample containing orange fibers (0.5 wt%) and watermelon seed oil (6.12 wt%). Another measure of emulsion stability is the Turbiscan Stability Index (TSI), which takes values from 0 to 100. The higher the TSI value, the greater the degree of emulsion destabilization. The TSI values obtained for the hair conditioner formulations are shown in Figure 3.  
The TSI values (Figure 3) determined for the formulated hair conditioners vary in the ranges of 0.95 to 2.4 and 1.25 to 3.2 at one and two weeks after preparation, respectively.