Petroula Tsitlakidou

This study investigated the valorization of rosemary (Rosmarinus officinalis L.) post-distillation residues—by-products derived from essential oil production—using cyclodextrins (CDs) as green co-solvents for the efficient extraction of bioactive compounds. This work aimed to explore key extraction parameters, i.e., extraction time, liquid-to-solid ratio, type of CD (β-CD or HP-β-CD), and CD concentration, and assess the antioxidant potential of the resulting extracts. Total phenolic content (TPC), total flavonoid content (TFC), DPPH radical scavenging activity, and ferric reducing antioxidant power (FRAP)assays were performed to evaluate the composition and antioxidant potency of the extracts. Regression analysis identified CD concentration and liquid-to-solid ratio as the most influential factors. Both β-CD and HP-β-CD significantly enhanced polyphenol recovery and antioxidant activity compared to conventional solvents (water, ethanol, methanol), with HP-β-CD showing slightly superior performance. The β-CD-assisted extract exhibited up to four-fold higher DPPH radical scavenging capacity than ethanol-based extracts. Among the extracts, the activity to scavenge superoxide and peroxyl (AAPH) radicals notably varied depending on the type of solvent. The findings demonstrated that rosemary post-distillation residues can be valorized to produce extracts rich in bioactive compounds suitable for food, cosmetic, and pharmaceutical applications. CD-assisted extraction offers an efficient, low-cost, and environmentally friendly approach to achieve this. As a continuation of this work, future studies should include LCA, thermodynamic, and techno-economic analyses to confirm the reduced environmental impact and operational costs indicated by the green metrics.

An eco-friendly extraction process of polyphenols from conventional dried rosemary tissues and post-distillation waste residues was applied using β-cyclodextrin as a co-solvent. The aqueous extracts were characterized by measuring the total phenolic content, and their phenolic compounds were identified and quantified by LC-MS. Sodium alginate solutions (2% w/w) with/without incorporation of rosemary aqueous extracts were prepared and used for the preparation of O/W emulsions containing 20% rapeseed oil and an 80% water phase. Hydrogel beads were then stored at 20 °C for 28 days. The quality of encapsulated oil during storage was evaluated by measurements of the peroxide value, p-anisidine value, free fatty acids, total oxidation value, and fatty acid composition, whilst the aqueous phase of the beads was analyzed for its total extractable phenolic content (TEPC). The experimental findings indicate that the incorporation of aqueous extracts from post-distillation rosemary residues in emulsion-filled hydrogel beads resulted in the lowest level of oxidation products in the encapsulated rapeseed oil (PV = 10.61 ± 0.02 meq/Kg oil, p-AnV = 4.41 ± 0.09, and FFA = 0.14 ± 0.00, expressed as % oleic acid content), indicating an acceptable oil quality until the end of the storage period.

Coffee pulp, a by-product of coffee production, contains valuable compounds such as caffeine and chlorogenic acid with high antiradical activity. In this study, aqueous solutions of β-cyclodextrin (β-CD) were used as a non-conventional solvent for the extraction of targeted compounds from coffee pulp. The parameters of β-CD concentration (C_βcd), liquid-to-solid ratio (L/S), and temperature (T) were evaluated based on the antiradical activity (A_AR) and the caffeine content (C_Caf). The optimum operational conditions were found to be C_βcd: 9.25 mg/mL, L/S: 30 mL/g and T: 80 °C. The sensory profiles of brews prepared with coffee and coffee pulp with or without cyclodextrin were studied with quantitative descriptive analysis. The brew from the by-product had fruity, botanic, sweet and sourness sensory properties, and cyclodextrin was found to be able to affect the overall taste of the brew.