# From Forest Berry Leaf Waste to Micellar Extracts with Cosmetic Applications
## 3 Results and Discussion
### Evaluation of Selected Functional Properties of Bath Washes
#### 3.3.3 Foam Stability Index (FSI)  
High stability in foams is a highly desirable feature, especially for bath cosmetics. Foam enhances the aesthetic appeal of bathing and is associated with both cleansing and relaxing effects. During the washing process, bath water may contain various types of impurities, including sebum, which is often referred to as the skin's lipid layer. Sebum is a mixture of various components, including waxes, squalene, cholesterol, and free fatty acids [30;31]. Consequently, the FSI was experimentally assessed both in the presence of model sebum (lanolin) and without it, with the results shown in Figure 3.  
An analysis of the data (Figure 3) shows that the highest FSI value was obtained for bath wash B, formulated without micellar extracts (FSI = 97.6%). The bath cosmetics containing micellar leaf extracts exhibited a relative decrease in the FSI value compared to the baseline (formula B). The results of the tests conducted without the model sebum can be presented in the following ranking order:  
\[\text{FSI}_{\text{B}}\ (97.6\%)>\text{FSI}_{\text{\leavevmode\
obreak\ \small{ RFL}}}\ (95.6\%)>\text{FSI}_{\text{\leavevmode\
obreak\ \small{ FVL}}}\ (94.7\%)>\text{FSI}_{\text{\leavevmode\
obreak\ \small{ VML}}}\ (91.8\%)\]  
When the tests were conducted in the presence of the model sebum, the ranking order for the tested cosmetics remained consistent; however, the FSI values obtained were relatively lower:  
\[\text{FSI}_{\text{B}}\ (95.2\%)>\text{FSI}_{\text{\leavevmode\
obreak\ \small{ RFL}}}\ (91.6\%)>\text{FSI}_{\text{\leavevmode\
obreak\ \small{ FVL}}}\ (91.5\%)>\text{FSI}_{\text{\leavevmode\
obreak\ \small{ VML}}}\ (90.0\%)\]  
Figure 3: Foam stability index values of analyzed bath washes. Overall, a trend for reduced values of the measured parameter was observed in the formulation with the added micellar extract compared to the baseline formulation. Additionally, a decrease in the FSI value was noted following the application of a model stain (lanolin) during the test. Shampoos formulated with micellar extracts of dock, ash, and bistort were the focus of the study conducted by [PERSON] et al. [29]. The tested extracts were used in cleansing formulations at a concentration of 50 wt%. The FSI values for shampoos containing micellar extracts were found to range from 94% to 97%. For the shampoo without the added micellar extract, the measured parameter reached 97%. [PERSON] et al. [64] studied the effects of hydrophilic extracts (water and water/glycerin) of dogwood on the properties of body wash cosmetics, using these extracts in formulations at a concentration of 10 wt%. The results of their experiments demonstrated that the extracts used in the formulations were highly polar, enabling the production of body wash cosmetics with a high foam stability index (FSI = 92%), surpassing that of the reference shower gel (FSI = 87%). The team also used extracts with lower polarity (water/betaine and water/propenediol). In these cases, the FSI values were comparable to those of the baseline gel. A methodology for assessing the effect of model setbm on the FSI values of facial cleansing gels containing polyvinylpyrrolidone (PVP) of different molecular weights (MW = 10,000; 50,000; 1,500,000) was employed by [PERSON] et al. [38]. Based on the study results, it can be concluded that an increase in the molecular weight of the PVP led to a rise in the FSI values, reaching approximately 95% compared to the formulation without PVP (FSI = 83%). It was also observed that the presence of lanolin as a model sebum led to a decrease in the measured value by up to one-third compared to the results obtained in the absence of lanolin. Based on the research findings and literature data [38], it can be concluded that the presence of lanolin as a model sebum reduces the foaming properties of cleansing cosmetics. A similar trend is observed when plant extracts are added to the formulation of cleansing cosmetics, although the measured values are likely influenced by the polarity of the extract.