Abstract
Red apple pomace as a source of biomolecules: green techniques for recovering compounds with potential human and environmental health applications (Acronym RAP BiG). State of the art. Fruit and vegetable wastes and by-products are the highest among all types of foods, reaching up to 60% for some products. In the last decades, they have been recognized as a valuable source of bioactive compounds, which can be obtained through extraction processes and/or chemical transformation to produce functional foods, supplements, and cosmetics, among others. However, many of the solvent-based extraction processes are nowadays considered to be harmful and inefficient, due to the long time needed to extract/purify the target compounds and to the large solvent volumes required, which generate huge amounts of toxic, polluting waste. This produces a negative impact on both health and environment, thus the search for solvent consumption reduction and greener extraction techniques has been strongly fostered. Circular economy promises to be an efficient option to reuse natural resources and derived by-products; the goal is to re-introduce the latter into the production line as raw materials for obtaining new products with high health benefits and added value through sustainable technologies. Aim of the project. This project investigates the possibility of applying an innovative green approach based on the use of Natural Deep Eutectic Solvents (NaDESs) to obtain valuable products/compounds from the waste and by-products (peels, seeds and pomace) of red apples. This material is still very rich in phenolic compounds belonging to different subclasses, especially anthocyanins, dihydrochalcones, and flavonols, which are known for their multifaceted biological activities. NaDES have been recently developed as a new generation of environmentally friendly solvents, and several studies have already demonstrated that they act not only as extraction solvents for anthocyanins and polyphenols, but may also play an important role in the enhancement of their bioactivity. The final objectives of the RAP-BiG project are to obtain an innovative product, endowed with valuable biological activities, starting from a common renewable agri-food waste material, and, at the same time, to explore the possibility of a full exploitation of some new red apple varieties, which have not yet been investigated for its phytochemical profile, despite having excellent organoleptic features. Expected results. The project aimed to develop a sustainable strategy for the valorisation of red apple pomace through green extraction technologies, to identify the most promising apple varieties, to characterise their phytochemical profiles, and to evaluate the biological activities of the obtained extracts in view of potential nutraceutical, pharmaceutical and environmental applications. Obtained results: Preliminary experiments were carried out using commercial red apple pomace (CP, VOG Company, Italy) to compare conventional extraction procedures with innovative green extraction approaches based on Natural Deep Eutectic Solvents (NaDES). Among the tested formulations, choline chloride/citric acid (2:1) containing 50% water proved to be the most effective solvent for anthocyanin recovery and was selected for optimisation through a Response Surface Methodology (RSM) approach. The optimised extraction conditions allowed efficient recovery of phenolic compounds while maximizing antioxidant activity, and the predictive models were experimentally validated. The optimised protocol was subsequently applied to pomace obtained from different commercial and novel red-fleshed apple varieties. Phytochemical characterisation by HPLC-MS/MS identified and quantified phenolic compounds belonging to different classes, including anthocyanins, flavonols, flavan-3-ols, phenolic acids, procyanidins and dihydrochalcones. Significant differences in the phytochemical profiles among the investigated varieties were observed, allowing the identification of the most promising genotypes for further valorisation. The biological properties of the extracts were then investigated using several in vitro disease models. Conventional extracts showed negligible cytotoxicity, whereas NaDES extracts exhibited enhanced biological activity. Since NaDES displayed an intrinsic biological effect, their removal prior to biological testing proved necessary to correctly evaluate the activity of the plant phytocomplexes. After solvent removal, the extracts demonstrated significant anti-inflammatory activity, as shown by inhibition of protein denaturation and modulation of pro-inflammatory cytokines in cell-based models. The most active extract also preserved intestinal epithelial barrier integrity under inflammatory conditions. Antioxidant assays confirmed that NaDES extraction enhanced polyphenol enrichment and antioxidant capacity compared with conventional extraction methods. Conversely, no significant antimicrobial activity was detected against the tested bacterial strains. Overall, the project demonstrated that NaDES combined with microwave-assisted extraction represent an efficient and environmentally sustainable strategy for the valorisation of red apple pomace, yielding phenolic-rich extracts with promising antioxidant and anti-inflammatory properties. At the same time, the study highlighted that the intrinsic biological activity of NaDES requires solvent removal before biological evaluation, identifying this step as one of the main challenges for the future industrial application of these green solvents. The project has generated two manuscripts that are currently in preparation. 1) Valorisation of Red Apple Pomace through NADES-Based Microwave-Assisted Extraction: From analytical optimization to Biological Characterization. Roberta Di Lecce*, Valentina Laghezza Masci*, Elisabetta Tesei, Chiara Fanciaresi, Silvia Bertolucci, Sherif Afifi, Roberto Mandrioli, Elisa Ovidi, Fabiana Antognoni. Manuscript to be sent to the Journal: Journal of Agricultural and Food Chemistry, ACS Publisher. 2) Comparative phytochemical and biological characterisation of red apple pomace extracts from commercial and novel varieties. Valentina Laghezza Masci, Roberta Di Lecce, Elisabetta Tesei, Chiara Fanciaresi, Sherif Afifi, Roberto Mandrioli, Elisa Ovidi, Fabiana Antognoni. Manuscript to be sent to the Journal: Frontiers in Natural Products.
Dettagli del progetto
Responsabile scientifico: Fabiana Antognoni
Strutture Unibo coinvolte:
Dipartimento di Scienze per la Qualità della Vita
Coordinatore:
ALMA MATER STUDIORUM - Università di Bologna(Italy)
Contributo totale di progetto: Euro (EUR) 196.306,00
Contributo totale Unibo: Euro (EUR) 100.523,00
Durata del progetto in mesi: 24
Data di inizio
12/10/2023
Data di fine:
28/02/2026
