# From Forest Berry Leaf Waste to Micellar Extracts with Cosmetic Applications
## 3 Results and Discussion
### Evaluation of Selected Functional Properties of Bath Washes  
#### 3.3.1 Dynamic Viscosity  
The viscosity of a cosmetic is a vital parameter that affects the ease of dispensing the product from its packaging. For bath washes, this parameter is crucial as it aids in the dissolution of the cosmetic in the washing bath. If the viscosity is too high, it prolongs the dissolution time. Conversely, if the viscosity is too low, it may cause excessive spillage of the product from the bottle. The results of the viscosity measurements performed for the prototype bath washes are presented in Figure 1. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Sample** & **Time of** & \multicolumn{4}{c}{**Parameter**} \\ \cline{3-6}
**Symbol** & **Storage [Days]** & **Color** & **Odor** & **Sediment** & **Mold** \\ \hline \multicolumn{6}{c}{**Micellar extracts**} \\ \hline \multirow{2}{*}{FVL\_ME} & 0 & dark brown & distinct tea odor & not observed & not observed \\  & 30 & dark brown & distinct tea odor & not observed & not observed \\ \hline \multirow{2}{*}{RFL\_ME} & 0 & dark brown & distinct tea odor & not observed & not observed \\  & 30 & dark brown & distinct tea odor & not observed & not observed \\ \hline \multicolumn{6}{c}{**VML\_ME**} & 0 & dark brown & distinct tea odor & not observed & not observed \\  & 30 & dark brown & distinct tea odor & not observed & not observed \\ \hline \multicolumn{6}{c}{**Model bath washes**} \\ \hline \multirow{2}{*}{B} & 0 & opalescent white & neutral odor & not observed & not observed \\  & 30 & opalescent white & neutral odor & not observed & not observed \\ \hline \multirow{2}{*}{FVL} & 0 & dark brown & delicate tea odor & not observed & not observed \\  & 30 & dark brown & delicate tea odor & not observed & not observed \\ \hline \multirow{2}{*}{RFL} & 0 & dark brown & delicate tea odor & not observed & not observed \\  & 30 & dark brown & delicate tea odor & not observed & not observed \\ \hline \multirow{2}{*}{VML} & 0 & dark brown & delicate tea odor & not observed & not observed \\  & 30 & dark brown & delicate tea odor & not observed & not observed \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Results of micellar extracts and model bath wash stability evaluation. The values of dynamic viscosity (\(\eta\)) of the formulated bath washes ranged from 3490 mPa\(\cdot\)s to 4270 mPa\(\cdot\)s (Figure 1). The cosmetic without the extract (formulation B) exhibited the highest viscosity (\(\eta\) = 4270 mPa\(\cdot\)s), while the bath wash containing the micellar extract of the wild strawberry leaves (FVL) had the lowest viscosity (\(\eta\) = 3490 mPa\(\cdot\)s). For the RFL and VML formulations, the obtained \(\eta\) value was consistently 3670 mPa\(\cdot\)s. Overall, the use of the proposed micellar extracts derived from the leaves of berry plants resulted in a reduction in the measured value by up to 20% compared to the extract-free formulation. A similar tendency to reduce the dynamic viscosity after the incorporation of micellar extracts into shampoos was reported by [PERSON] et al. [29]. The team formulated cosmetics with micellar extracts obtained from Bistortae rhizoma, Frazimus excelsior, and Romex crispus. The researchers examined how different extracts affected the properties of the developed shampoos, including the viscosity and color. The results of their study showed that the plant raw materials decreased the viscosity of the prototype cosmetics by up to half compared to the baseline formulation (\(\eta\) = 1520 mPa\(\cdot\)s). Micellar extracts were also incorporated as an ingredient in shower gels by [PERSON] et al. [58]. The team developed extracts using grape pomace, repurposing it from waste material. The extract contained 10 wt% and 20 wt% of pomace, with its concentration in the shower gel formulation reaching up to 65 wt%. The team measured the viscosity of the cosmetics as a function of the shear rate.