Natural products are becoming a trend in the cosmetic market, due to a growing awareness and concern with the origin of these products. The certification of natural products, especially organic ones under the COSMOS signature preserves the integrity of the constituents, in an environmentally appropriate and safe for human health, expanding the concept of "green chemistry”, guaranteeing the origin, and processing of the products, storage, manufacturing, packaging, etc. The objective of this study was to develop a moisturizing cosmetic emulsion in the solid format according to COSMOS certification, with guarantee the quality of the product in a new concept of solid cosmetic. 59 tests were carried out to optimise this emulsion, with the best possible hydration level. The different tests included variations in components and their amounts, following be evaluation of sensory aspects for each formulation. The final cosmetic emulsion formulation (Figure 1) contains components of Portuguese origin such as grape seeds oil from Douro Valley, olive oil and extract of by-products of acorn (Quercus Ilex L.) and essential oils of mandarin, geranium, coriander and cinnamon. The formulation has undergone accelerated stability tests with temperatures (40 ºC /-12 ºC). The pH, density and organoleptic characteristics were evaluate. The phenolic profile of acorn by-product (Quercus ilex L.) was performe by UHPLC-DAD-ESI-MS2. A questionnaire was applying to evaluate the acceptance after use of the moisturizing cosmetic emulsion. In stability tests, overall the formulation showed small color variations and less aroma intensity, maintaining hydration and solid state. The pH changes were from 4.68 ± 0.006 to 4.78 ± 0.05 and the density was maintaining at 0.73 kg/m3 . The polar extract of acorn by-product have as major compounds trigalloyl-HHDP-glucose, valoneic acid dilactone and gallic acid, known as antioxidants compounds. The essential oils bring beneficial properties to the skin and the aroma. In the post use of solid emulsion survey applied shown that “aroma” was the second point most valorised (47.6%), after “hydration” (90.5%). The results shown that the majority of participants (81.0%) were “very satisfied” or “satisfied” with the solid emulsion indicating the intention to use it if it is on the market (76.2%). This study highlights the research in reformulations from liquid to solid products, and the potential of using Portuguese raw materials such as acorn.Thanks to FCT (Portugal) and the ERDF under the PT2020 Program for financial support to CIMO (UIDB/00690/2020) and LAQVREQUIMTE (UIDB/50006/2020). SMC acknowledges the research contract (project AgroForWealth, CENTRO-01-0145- FEDER000001).info:eu-repo/semantics/publishedVersio
