• apple seeds
• cosmeceutical compounds

Food waste is becoming an increasingly critical issue from both an economic and environmental perspective. Any portion of food that is lost or spoiled further exacerbates this problem. To mitigate this challenge, the concept of recovering and valorizing by-products is gaining traction an approach that has now become essential. This necessity arises primarily from the benefits these by-products offer, as they are rich in polysaccharides, proteins, organic acids, and other valuable compounds, such as polyphenols, making them a promising alternative for the food and cosmeceutical industries. The processing of fruit and vegetables originates the majority of this type of waste.
This study aimed to valorize apple seeds, a by-product from the food industry, by extracting apple seeds oil and by using it to produce a cosmetic cream. Due to its richness in components that are beneficial for the body, such as polyphenols, minerals and fatty acids, the oil may find application as functional component in cosmeceutical industry. To this aim, apple seeds were separated from apple pomace and, after being grinded, the oil was extracted with Soxhlet method with the use of hexane. The Soxhlet extraction was carried on for 4 and 6 hours in combination or not with ultrasound pre-treatment, performed for 5 or 10 minutes.
The different oil samples extracted by the different combination of Soxhlet and ultrasound duration were checked for their phenolic concentration (Folin-Ciocalteu method).
The phenolic concentration was not affected by the extraction procedure, and were consistent with data reported in other studies, despite the variability due to the variety used.
The extracted apple oil was then used to prepare a water-in-oil emulsion to produce a dense cream, which included other components: paraffin oil, shea butter, stearic acid and lecithin as lipid phase, and distilled water, glycerine, and xantan gum, as water phase. All the components were treated in heat bath at 80°C.
Creams with different apple oil percentage (0, 1, 2, and 3%) were produced. To evaluate and compare the rheological properties, viscosity and viscoelasticity were determined.
Additionally, the color of the different formulates was evaluated with a colorimeter to detect possible differences due to the presence of increasing percentage of oil.
The rheological analysis results demonstrate that the creams exhibit the expected behavior, characteristic of non-Newtonian fluids. As the oil concentration increases, viscosity progressively converges at higher shear rates, a typical feature of cosmetic formulations. The viscoelastic response further substantiates this observation, as evidenced by the analysis of the storage modulus (G') and the loss modulus (G''). A higher oil concentration in the cream is associated with increased values of both modules, with G' prevailing over G'', indicating a more solid and elastic structure that enhances the formulation’s long-term stability.
Furthermore, the color analysis yielded favorable results, revealing a more intense yellow hue in the cream with the highest oil concentration.
The results obtained in this thesis indicate the possibility to use oil extracted from apple seeds to produce a cosmetic cream, thus contributing to the sustainable recovery of a by-product of the food chain in the cosmetic industry.