Co-Fermentation of Dandelion Leaves (Taraxaci folium) as a Strategy for Increasing the Antioxidant Activity of Fermented Cosmetic Raw Materials—Current Progress and Prospects

In response to the growing interest in natural cosmetic raw materials with antioxidant and moisturising properties, this study focuses on the use of dandelion leaves (Taraxaci folium) in the co-fermentation process involving selected strains of Saccharomyces cerevisiae and Lactobacillus rhamnosus MI-0272. The aim of the study was to develop an innovative method of co-fermentation of dandelion leaves using waste beet molasses and organic cane biomolasses as substrates to produce lactic acid (LA), which is the main component of fermented cosmetic raw materials (FCRMs). The scope of the research included the determination of antioxidant activity using the DPPH (AA-DPPH) and ORAC (AA-ORAC) methods, determination of total polyphenol content (TPC) using the Folin–Ciocalteu method, assessment of lipophilicity by measuring the log P partition coefficient, assessment of wettability (contact angle), and statistical analysis. The key results indicated that the developed method allows for up to a fivefold reduction in fermentation time, enabling the production of FCRMs with the highest antioxidant activity (AA-DPPH = 3.0 ± 0.1 mmol Tx/L (Trolox equivalents per litre); AA-ORAC = 0.55 ± 0.02 mmol Tx/L) and the highest polyphenol content (TPC = 3589 ± 25 mg gallic acid equivalents per litre (GA/L)), with LA content (determined by GC-MS) up to 37 g/L. In addition, the analysis of the relationship between lipophilicity and membrane wettability showed that the hydrophilic antioxidants contained in FCRMs (log P = −0.9) can accumulate in the aqueous layers of the epidermis, suggesting their potential local protective and antioxidant effects. The results obtained confirm the potential of the developed technology in the production of modern cosmetic raw materials with antioxidant properties. Further research should include qualitative and quantitative analysis of phenolic acids contained in FCRMs and evaluation of the effectiveness of cosmetic preparations containing FCRMs in vivo.