Microwave-assisted extraction of bioactive compounds from agro-food and fish by-products
George Dimopoulos, Maria Katsouli, Athina Ntzimani, Maria Tsevdou, Efimia Dermesonlouoglou, Virginia Giannou, Dimitris Tsimogiannis, Petros Taoukis
Presented as poster in the
36th EFFoST International Conference, Dublin - IRELAND
November 07-09, 2022
One of the basic pillars with regards to circular bioeconomy strategy, focusing on a sustainable processing, is the extraction of bioactive compounds from agricultural and fish by-products and their transformation into high added biological and economical value products. Bioactive compounds (BACs), such as polyphenols, carotenoids, lipids (omega-3 fatty acids), present in agricultural and fish by-products, have been reported to show antimicrobial, antioxidant, and anti-inflammatory properties.
Microwave-assisted extraction (MAE) has a great potential as an alternative method for the recovery of thermolabile substances from agrο-food and fish by-products, complying with environmental and economical requirements to ensure safe and high-quality extracts. Its main advantages include high extraction performance, while requiring low temperature, short processing time, and reduced energy consumption.
Thus, MAE was performed to rupture the cell wall structures and release compounds from olive pomace, tomato seed and skins, and fish processing discards for increased and efficient recovery of BACs.
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Sunstainable recovery of ω-3 PUFA from fish processing effluents via microwave-assisted extraction
Ioanna Semenoglou, Maria Katsouli, Athina Ntzimani, Petros Taoukis
Presented as poster in the
7th International ISEKI-Food Conference “Next-generation of Food Research, Education and Industry”, Paris - FRANCE
July 05-07, 2023​
Fish side streams during processing can be up to 70% of the initial catch weight, raising economic and environmental concerns. Therefore, the disposal and recycling of these by-products is a main problem to be resolved. These materials are rich in valuable bioactive compounds such as polyunsaturated fatty acids (PUFA), which can be recovered and used as ingredients in added-value food products. Microwave-assisted extraction (MAE) can be used as an alternative to the Soxhlet extraction (SE) method for PUFAs recovery from fish by-products, aiming for high-quality extracts. Seabass (Dicentrarchus labrax) filleting by-products were freeze-dried and lipid extraction was carried out. For SE method, a polar (ethanol) or a non-polar (hexane) solvent were used up to 6 h with solvent to solid ratio 60:1. MAE was carried out at 300-600 W using ethanol as solvent with solvent to solid ratios 10:1 and 30:1 at 30, 40, and 50°C for 5-10 min.
In order to evaluate the efficiency of the MAE method, MAE was compared with the SE in terms of the extraction yield of fish oil. Soxhlet extraction with ethanol achieved higher recovery yield, 40.8 g fish oil/100 g dry weight, compared to hexane (30.5 g fish oil/100 g dry weight) thus, ethanol was selected for MAE. MAE with ethanol at solvent to solid ratio 30:1 was able to extract 60% of the total lipid content within 5 min at 300 W and 50°C. Moreover, PUFA extracted from MAE were less oxidated compared to SE extracts; lower p-anisidine values.
Seabass side-streams are an ω-3 rich source suitable for further valorization. The application of MAE on process effluents could be a viable alternative to traditional extraction methods contributing to industry demands for sustainable development. Taking into account the thermal sensitivity of PUFA, extracted fish oil may have been degraded by Soxhlet method due to the high temperature and long extraction time. MAE method provides lower operating temperature, thus no thermal degradation of most of the unstable compounds and shorter extraction time leading to energy savings.
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Recovery of bioactive compounds from plant and animal origin by-products: the effect of High Pressure and Pulsed Electric Fields processing
George Dimopoulos, Maria Tsevdou, Elena Karampina, Michaela Kougitakou, Petros Taoukis
Presented as poster in the
International Nonthermal Processing Workshop & Short Course, Minnesota, Minneapolis - USA
October 13-17, 2023
The increased demand for functional foods during recent years has lead the research community toward alternative routes to obtain natural bioactive compounds (BACs). Several food processing byproducts contain residual amounts of BACs which remain unvalorized. Their extraction has to strike a balance between yield and retention of functionality, while taking into account the use of environmentally friendly extraction methods. Novel technologies like High Pressure (HP) and Pulsed Electric Fields (PEF) can enhance mass transfer by increasing cell permeability and lead to benefits such as increased yields, selective extraction, alternative solvent use and protection of sensitive molecules. This study investigates the recovery of carotenoids from tomato processing byproducts and ω-3 fatty acids from fish processing discards, using novel technologies combined with the use of ethanol, a commonly accepted green solvent.
Tomato pomace and fish filleting residues were dried, mixed with ethanol at different solid-to-liquid (S:L) ratios, ranging from 1:30 to 1:5, and subjected to HP conditions (250-650 MPa, ambient temperature,0-20 min), and PEF conditions (4 kV/cm, 250-2000 pulses). The efficacy of HP and PEF-assisted extraction was evaluated in terms of carotenoid and ω-3 fatty acid yield and functionality with analytical methods such as spectrophotometry, HPLC and GC-MS.
HP treatment results indicated that the extraction process was independent from pressure time. A S:L ratio of 1:30 exhibited the highest recovery yields even at low pressures (250 MPa), which led to an increase of 28.8% and 55.6% for the extracted carotenoids and ω3-fatty acids at reduced time compared to untreated samples (24 h and 60 min respectively). An increase in the applied pressure did not significantly promote BACs recovery from either material. PEF treatment increased the extractability of carotenoids from tomato pomace up to 58.2% (750 pulses) after 120 min of extraction (1:30 S/L), compared to untreated samples. Similarly, the extraction yield of ω-3 fatty acids from fish discards was increased by 77.1% after 10 min of extraction (1200 pulses), a value obtained for untreated samples after over 2 h of extraction.
This work shows the potential for using nonthermal processes to improve extractability of bioactive compounds from food byproducts using ethanol as a solvent.
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Evaluation of microwave-assisted extraction technique as a potential green technology compared to conventional extraction on recovering ω-3 fatty acids from fish side streams
Ioanna Semenoglou, Maria Katsouli, Athina Ntzimani, Andreas Kontopoulos, Thomas Tsaknakis, Petros Taoukis
Oral presentation in the
10th Panhellenic Conference of the Greek Lipid Forum “Current Trends in the Fields of Lipids”, Athens - GREECE
November 25, 2022
Fish side streams during processing can be up to 70% of the initial catch weight, creating huge economic and environmental concerns. Therefore, the disposal and recycling of these wastes is a main problem to be resolved. These materials are rich in valuable bioactive compounds such as polyunsaturated fatty acids (PUFA), which can be recovered and used as ingredients in added value food products. Microwave-assisted extraction (MAE) can be used as an alternative to the conventional extraction method for PUFAs recovery from fish by-products, ensuring high-quality extracts.
Seabass by-products (Dicentrarchus labrax) were freeze-dried and lipid extraction was carried out. In terms of conventional extraction, a polar (ethanol) or a non-polar (hexane) solvent were used and the effect of time (up to 30 min), solvent to solid ratio (10:1-50:1) and temperature (20-50°C) were investigated. Different MAE (150-500 W) conditions and ethanol as solvent at 30-50°C for 10-30 min were studied.
Recovery of oil increased with time and reached the maximum value within the first 10 min. Ethanol achieved high recovery yield ranging 16-29% and selected for MAE at 1:30 ratio. MAE was found to result in approximately 50% higher extraction yields compared to conventional extraction.
Seabass side-streams is an ω-3 rich source suitable for further valorization. The application of MAE in natural, inexpensive raw materials could be an economical alternative to traditional extraction methods thus satisfying industry demands for sustainable development.
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Alternative extraction methods for the recovery of bioactive compounds from agro-food by-products: PEF and Microwave assisted extraction from olive pomace and tomato by-products
Athina Ntzimani, George Dimopoulos, Maria Katsouli, Dimitris Tsimogiannis, Petros Taoukis
Presented as poster in the
ICEF14 International Congress on Engineering and Food, Nantes - FRANCE
June 20-23, 2023
The agri-food industry produces significant quantities of by-products that are underutilized or wasted, negatively impacting sustainability and environment. Olive and tomato processing by-products are rich in bioactive compounds (BACs), i.e. polyphenols, carotenoids, which can be used as ingredients for the development of high added-value products and their effective recovery and utilization has been the focus of research. The extraction procedures play a critical role in the yield and functionality of the contained phytochemicals. Novel green extraction technologies improve BACs extraction yields at lower temperatures and short processing times, compared to the conventional methods. Pulsed electric fields (PEF) and Microwave-assisted extraction (MAE) can be used as alternative methods for the recovery of BACs from agrο-food by-products, complying with environmental and economic requirements. This work aims to the evaluation of the efficiency of PEF and MAE extraction for increased recovery of BACs from olive and tomato pomace. Different Microwave (150-600 W) and PEF (1-5 kV/cm, 100-1500 pulses of 15 μs width) conditions, and solvent concentration at 30-50°C for 10-30 min were studied. The characterization and quantification of the extracts were carried out using HPLC analysis (total carotenoids, lycopene), Folin-Ciocalteu method (total phenolics) and DPPH assay (antioxidant activity). Results showed that the use of PEF and MAE is efficient for recovering BACs, i.e. polyphenols and lycopene, from olive and tomato pomace, in significantly shorter time as compared to conventional extraction. The olive pomace extracts with highest antioxidant activity obtained with 40% methanol at 30°C. The optimum conditions regarding recovery yield for lycopene were microwave processing at 150 W for 10 min at 50°C. Similarly, PEF increased phenolic compounds recovery from olive pomace by up to 90%, and total carotenoids by up to 50% from tomato wastes compared to untreated samples. MAE and PEF can be considered fast, effective, and environmentally friendly techniques for extracting BACs from olive and tomato pomace, offering important advantages in terms of yield, selectivity, extraction times and quality.
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Find us on ​ICEF14 International Congress on Engineering and Food...