Technologies for recycling of organic agrofood waste (public summary)

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. D2.5 – Technologies for recycling of organic agrofood waste (public summary) November 2023 Authors: Sofía Martinez López (CTNC) Ref. Ares(2025)6344123 - 04/08/2025 A2C – Deliverable D2.5V1.0 2 Technical references Project Acronym Agro2Circular Project Title TERRITORIAL CIRCULAR SYSTEMIC SOLUTION FOR THE UPCYCLING OF RESIDUES FROM THE AGRIFOOD SECTOR Project Coordinator Fuensanta Monzó CETEC [email protected] Project Duration October 2021 – September 2024 (36 months) Deliverable No. D2.5 Dissemination level* PU Work Package WP2 – A2C technologies for the recycling of the organic agrifood wastes Task This deliverable summarises the activities related to the classification, extraction, purification and evaluation of valuable compounds from agri-food wastes, performed within Work Package 2. Lead beneficiary 13(CTNC) Contributing beneficiary/ies 14(MCT), 15(ALM), 16(PROEX), 17(DMC), 18(CITRO), 20(SSICA) Due date of deliverable 31 May 2023 Actual submission date 09 Nov 2023 * PU = Public PP = Restricted to other programme participants (including the Commission Services) RE = Restricted to a group specified by the consortium (including the Commission Services) CO = Confidential, only for members of the consortium (including the Commission Services) Document history V Date Comments v0.1 08/11/2023 First draft of document v1.0 09/11/2023 First final version, approved by the WP leader and the project coordinator, (will be) submitted to EC. v1.1 First draft based upon first final version v2.0 Second final version, approved by the WP leader and the project coordinator, (will be) submitted to EC. A2C – Deliverable D2.5V1.0 3 Document Distribution Log Version Date Distributed to v0.1 08/11/2023 Fuensanta Monzó-Coordinator Verification and approval Name Date Verification Final Draft by WP leader Sofía Martínez 09/11/2023 Approval Final Deliverable by coordinator Fuensanta Monzó 09/11/2023 Disclaimer and acknowledgement This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101036838 Disclaimer This document reflects only the views of the author(s) the European Research Executive Agency (REA) is not responsible for any use that may be made of the information it contains. Whilst efforts have been made to ensure the accuracy and completeness of this document, the A2C consortium shall not be liable for any errors or omissions, however caused. A2C – Deliverable D2.5V1.0 4 Table of contents 1 List of abbreviations ..................................................................... 5 2 Executive summary ..................................................................... 6 3 CLASSIFICATION & CONDITIONING ........................................ 7 4 EXTRACTION METHODOLOGIES ............................................. 8 4.1 GREEN SOLVENTS ............................................................................................. 8 4.2 ASSISTIVE TECHNOLOGIES .............................................................................. 8 4.3 SELECTED METHODOLOGIES ........................................................................... 8 5 PURIFICATION & STABILISATION .......................................... 10 5.1 FIBRE PURIFICATION AND STABILISATION .................................................. 10 5.2 PHENOLIC COMPOUNDS PURIFICATION AND STABILISATION .................. 11 6 CONCLUSIONS ........................................................................ 12 7 REFERENCES .......................................................................... 14 List of Figures Figure 1. Particle size difference of apple (left) and broccoli (right) waste. ......................... 7 Figure 2. Fibre (A) unpurified; (B) purified ......................................................................... 10 Figure 3. Purification with resins (A) at laboratory scale (B) equipment to be used for semiindustrial scale-up ....................................................................................................... 11 A2C – Deliverable D2.5V1.0 5 1 List of abbreviations DES: Deep Eutectic Solvents IL: Ionic Liquid MAE: Microwave Assisted Extraction NADES: Natural Deep Eutectic Solvents SWE: Subcritical Water Extraction UAE: Ultrasound Assisted Extraction UF: Ultrafiltration UPLC: Ultra Performance Liquid Chromatography WP: Work Package A2C – Deliverable D2.5V1.0 6 2 Executive summary Work package 2 (WP2) aims at implementing and optimizing technologies for the extraction and recycling of the agri-food waste generated in the Region of Murcia (Spain): citrus, apple, grape, cauliflower, broccoli and artichoke. The specific objectives are: • Establishing the conditioning of agrifood waste. • Developing the optimal green hybrid extraction routes. • Purifying and stabilizing extracts for their application in new formulations. • Assessing the quality of extracts and their antioxidant and antimicrobial capacity. Using different technological combinations, extraction processes have been optimised by means of extraction technologies, and purification and stabilisation technologies: green solvents + extraction assistance technologies + purification + stabilisation. The routes applied can be defined as a first phase of treatment with green solvents, followed by a second phase of assistance with technologies such as ultrasound or microwaves. Unassisted green solvent extractions have also been evaluated. These routes also include purification and stabilisation steps. Based on the results obtained, both from a technical and economic point of view, technological routes for the recycling of agri-food waste that are viable on an industrial scale have been selected: ― Fibre recovery: Enzymatic extraction combined with purification treatments by washing with oxidising agents and ultrafiltration has reported the highest extraction yields and purity. ― Phenolic compounds recovery: Microwave-assisted enzymatic extraction combined with purification treatments by adsorption/desorption with resins has reported the highest extraction yields and purity. Depending on further use, freeze-drying or microencapsulation of the actives has been selected as a delivery system. A2C – Deliverable D2.5V1.0 7 3 CLASSIFICATION & CONDITIONING Once the waste is received from the supplying companies, it is stored refrigerated/frozen depending on the time of processing for recycling. It has not been necessary to carry out a prior waste classification process as waste is generated separately in the supplying companies which, as they work by production campaigns, generate waste from a single product. In case there is no separate generation of agri-food waste, a first separation step should be carried out (this is because each waste has different compounds of interest to be recovered). In general, different agri-food wastes have been subjected to mechanical or physical pretreatments to reduce the size of the plant matrix and homogenise the sample. Particle size reduction is a factor that has long been taken into account as it facilitates mass transfer since the compounds of interest are more exposed to the solvent and therefore increases extraction speed and yields (Panzella et al., 2020). Thus, the plant material is shredded into 20 mm x 20 mm cubes (pre-treatment). Pre-treatments to reduce the granulometry of the waste have been carried out on all waste except for waste that initially has a small granulometry, as was the case with apple waste (Figure 1). Figure 1. Particle size difference of apple (left) and broccoli (right) waste. A2C – Deliverable D2.5V1.0 8 4 EXTRACTION METHODOLOGIES 4.1 GREEN SOLVENTS In the field of extraction of compounds of interest, it is imperative to reduce the use of reagents and excipients in general and to eliminate the use of hazardous solvents in particular, or at least replace them with safer ones (Janicka et al., 2022). This change must be achieved by ensuring sensitive, selective, accurate and robust methods, which allow high purity extracts to be obtained, require low treatment times and are cheap, sustainable and energy efficient (Janicka et al., 2022). It has thus suggested an effort in the search for alternative solvents to conventional solvents, which can be detrimental to public health, safety and the environment due, in particular, to their volatility and toxicity. These new solvents can be considered green solvents (Yu et al., 2022). Many of these solvents exhibit excellent results but require long processing times, so in many cases assistive or acceleration technologies are used to improve extraction efficiency and performance. 4.2 ASSISTIVE TECHNOLOGIES Assisted extraction techniques are an attractive alternative to conventional solvent extraction methods for extracting bioactive analytes from vegetable materials, as they allow significant improvements in extraction efficiency, provide high yields in short extraction times and reduce solvent requirements (Bachtler & Bart, 2020). 4.3 SELECTED METHODOLOGIES The solvents initially selected were aqueous solvents, enzyme solutions, ionic liquids (IL), deep eutectic solvents (DES) and natural deep eutectic solvents (NADES). Since the use of ionic liquids has been associated with some toxicity in the most current literature (and as evaluated using two different cell cultures), these solvents were discarded during the execution of WP2. As an alternative, the use of subcritical water (SW) was proposed. As auxiliary technologies, the study of ultrasound-assisted extraction (UAE) and microwaveassisted extraction (MAE) were proposed. For this purpose, the extraction conditions using aqueous solvents, enzymatic extraction, extraction with subcritical water, extraction with DES, ultrasound-assisted extraction and microwave-assisted extraction were optimised, considering the different operational A2C – Deliverable D2.5V1.0 9 parameters of each technology. The optimised operational parameters are shown in Table 1: Table 1. Optimised operational parameters according to extraction technology. Technology Operational parameters Aqueous extraction Solid:liquid ratio (waste:solvent) Extraction temperature Treatment time Enzymatic extraction Enzyme used Enzyme dose Ultrasound-assisted extraction US amplitude Microwave-assisted extraction Solvent (NADES) MW power/temperature Treatment time Subcritical water extraction Extraction temperature Treatment time Deep eutectic solvents extraction DES used After carrying out extraction trials for each technology with each of the selected agri-food waste, the following extraction routes have been selected as the most viable for semiindustrial scale-up: ― Enzymatic extraction ― Ultrasound-assisted extraction ― Microwave-assisted extraction