Microwave-assisted Extraction for Bioactive Compounds

Theory and Practice

herausgegeben von: Farid Chemat, Giancarlo Cravotto

Verlag: Springer US

Buchreihe : Food Engineering series

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik"

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Über dieses Buch

With increasing energy prices and the drive to reduce CO2 emissions, food industries are challenged to find new technologies in order to reduce energy consumption, to meet legal requirements on emissions, product/process safety and control, and for cost reduction and increased quality as well as functionality. Extraction is one of the promising innovation themes that could contribute to sustainable growth in the chemical and food industries. For example, existing extraction technologies have considerable technological and scientific bottlenecks to overcome, such as often requiring up to 50% of investments in a new plant and more than 70% of total process energy used in food, fine chemicals and pharmaceutical industries. These shortcomings have led to the consideration of the use of new "green" techniques in extraction, which typically use less solvent and energy, such as microwave extraction. Extraction under extreme or non-classical conditions is currently a dynamically developing area in applied research and industry. Using microwaves, extraction and distillation can now be completed in minutes instead of hours with high reproducibility, reducing the consumption of solvent, simplifying manipulation and work-up, giving higher purity of the final product, eliminating post-treatment of waste water and consuming only a fraction of the energy normally needed for a conventional extraction method. Several classes of compounds such as essential oils, aromas, anti-oxidants, pigments, colours, fats and oils, carbohydrates, and other bioactive compounds have been extracted efficiently from a variety of matrices (mainly animal tissues, food, and plant materials). The advantages of using microwave energy, which is a non-contact heat source, includes more effective heating, faster energy transfer, reduced thermal gradients, selective heating, reduced equipment size, faster response to process heating control, faster start-up, increased production, and elimination of process steps. This book will present a complete picture of the current knowledge on microwave-assisted extraction (MAE) of bioactive compounds from food and natural products. It will provide the necessary theoretical background and details about extraction by microwaves, including information on the technique, the mechanism, protocols, industrial applications, safety precautions, and environmental impacts.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Microwave-Assisted Extraction: An Introduction to Dielectric Heating

Abstract

Low environmental impact and high efficiency in chemical processing and manufacturing can be attained with the use of “light” instead of conductive heating. At microwave (MW) frequencies (300 MHz–300 GHz), the electromagnetic field can be dissipated by matter in the form of heat via polarization mechanisms, magnetic interactions, and ionic conduction. The conversion is extremely rapid, and heat is volumetrically diffused into the solvents, leading to an incredibly fast temperature increase that can speed up extraction processes in a way no other technique can match. In closed systems, microwave-assisted extraction can be performed at higher temperatures, and extraction times can be reduced drastically. In fact, enhanced plant matrix swelling increases the diffusion rate and promotes faster extraction kinetics. However, the user must take into account that the temperature distribution in a solvent exposed to microwave radiation is strictly dependent on the electromagnetic field distribution in the reactor, on the dielectric properties of the material, and on the presence of mass transport phenomena such as natural convection and stirring. Shorter extraction times and shorter cooling times usually avoid material degradation and afford high-quality extracts.

Cristina Leonelli, Paolo Veronesi, Giancarlo Cravotto

Chapter 2. Fundamentals of Microwave Extraction

Abstract

Microwave-assisted extraction (MAE) is a process that removes solutes from a solid matrix into a solvent. Phenomena such as electromagnetic transfer, heat transfer, mass transfer, and momentum transfer make the process complex. For developing process engineering, the characteristics of heat and mass transfer are extremely significant. Accurate and controlled heat is possible because of the capacity of microwave radiation to penetrate and combine with a substrate. Therefore, the microwave procedure can be designed to transport electromagnetic energy with specific power to the location of the compounds of interest in the substrate. The energy-saving factors and short processing times lead to a reduction in manufacturing costs, and improvement of product uniformity and yields, resulting in products with high quality compared with other extraction techniques. This chapter provides a general review of heat and mass transfer and gives a brief discussion on the factors influencing the extraction efficiency of MAE. The performance of MAE is also compared to other classical methods, thus explaining the advantages of MAE technology as applied to plant extraction research.

Priscilla C. Veggi, Julian Martinez, M. Angela A. Meireles

Chapter 3. Microwave-Assisted Extraction of Essential Oils and Aromas

Abstract

This chapter presents a complete picture of current knowledge on microwave-assisted extractions (MAE) of essential oils and aromas. It elaborates the necessary theoretical background about essential oils and aromas. Various microwave-related techniques, and their advantages and applications in extracting essential oils and aromas, are reviewed in detail. All the reported microwave-assisted extraction techniques and their applications have shown that MAE can be considered an alternative to conventional techniques because of its benefits in reduction of extraction times, of cost, energy, and solvent consumption, and of CO₂ emission, which have also been validated by subsequent environmental impact assessment. In addition, some MAE techniques have already successfully applied at an industrial scale in the cosmetic, perfume, and nutraceutical industries.

Farid Chemat, Maryline Abert-Vian, Xavier Fernandez

Chapter 4. The Role of Microwaves in the Extraction of Fats and Oils

Abstract

The microwave-assisted extraction (MAE) of fats and oils at laboratory and industrial scales, the most common raw materials from which they are extracted, and the extractant required in each case are reviewed. The extractors used for this purpose, which range from conventional household devices to sophisticated commercial equipment, and their use at pilot and industrial plants, are discussed. Selected applications of MAE are compared with those of other energy-assisted extraction techniques (e.g., ultrasound-assisted extraction and superheated liquid extraction) and with conventional extraction to highlight its advantages and disadvantages. Finally, potential trends in the broad field of fat and oil extraction are outlined.

M. D. Luque de Castro, M. A. Fernández-Peralbo, B. Linares-Zea, J. Linares

Chapter 5. Microwave-Assisted Extraction of Antioxidants and Food Colors

Abstract

In recent years, microwave-assisted extraction (MAE) has rapidly developed as a widely used innovative technique of high efficiency that allows high yields of antioxidants and food colors from appropriate plants in shorter time as compared to conventional techniques. This chapter presents a panorama of current knowledge on microwave-assisted extractions of antioxidants and food colors. It provides the necessary theoretical background and some details (e.g., chemical structures and mechanisms) about the importance of antioxidants and food colors, relevant microwave techniques, and their applications in extracting antioxidants and food colors. All the reported MAE-related techniques and applications have shown that microwave-assisted extraction can be considered a substitute to conventional techniques because of its advantages of reducing extraction times, energy and solvent consumption, and CO₂ emission. Moreover, all these mentioned successful laboratory-scale research efforts have led to industrial-scale application in some pioneering companies.

Ying Li, Anne-Sylvie Fabiano-Tixier, Maryline Abert-Vian, Farid Chemat

Chapter 6. The Role of Microwaves in Omics Disciplines

Abstract

Microwave irradiation can be of assistance to accelerate some steps in genomics, proteomics, metabolomics, and their derived subdisciplines. The particular operations that can be expedited by using microwaves (MWs) differ among omics, and so do the specific MW devices used to this end, which include focused or multimode MWs, single continuous or high-throughput formats, and laboratory-adapted, commercial, or dedicated equipment. The specific operations most efficiently assisted by MW in genomic applications are cell fixation, DNA extraction, deparaffination, digestion, PCR hybridization, rolling circle amplification, and metal-enhanced fluorescence. Proteomics can benefit from the effects of MWs for operations such as enzyme quenching and proteolysis (whether enzymatic or chemical), identification and characterization of post-translational modifications or metal-catalyzed reaction sites on proteins and lipase selectivities, dissociation of protein complexes and protein quantitation with commercially available procedures such as ICAT^R and iTRAQ^R, or traditional procedures based on sensitive phenomena such as fluorescence or chemiluminescence. In any case, it is metabolomics that has profited most greatly from MW assistance, especially for purposes such as drying, digestion, solid–liquid extraction (or, more accurately, “leaching”), steam distillation, liquid–liquid extraction, and derivatization of a large variety of metabolites from widely different matrices.

M. D. Luque de Castro, M. A. Fernández-Peralbo

Chapter 7. Pharmaceutical and Nutraceutical Compounds from Natural Matrices

Abstract

The growing quest for highly efficient methods for plant extraction and the recovery of bioactive compounds and nutraceuticals found a promising alternative in microwave-assisted extraction. The studies reported in this chapter demonstrate the advantages of microwave-assisted processes compared to traditional methods in the extraction of pharmaceutical and nutraceutical compounds from natural matrices. The main families of natural products obtained in this way and the detailed procedures are discussed.

Pedro Cintas, Emanuela Calcio-Gaudino, Giancarlo Cravotto

Chapter 8. From Laboratory to Industry: Scale-Up, Quality, and Safety Consideration for Microwave-Assisted Extraction

Abstract

The application of microwave technologies has been scaled up in the food and cosmetic industries because of its economic and environmental advantages, which have been increasingly proved by plentiful laboratory-scale successes. However, this kind of emerging technology often causes hazards for product safety and risks in manual operation. Because conventional quality control methods are insufficient to control these hazards and risks, Hazard Analysis Critical Control Points (HACCP) and Hazard and Operability (HAZOP) study, which are considered effective analyses of respective controlling potential hazards and operator security, must be taken into account in the design of microwave application in production processing chain.

HACCP is the most secure and cost-effective method for controlling possible contamination caused by physical or chemical hazard during production, whereas HAZOP is a structured and systematic technique for identifying potential hazards and operability problems in a system, so as to further guarantee the security of operators. This chapter on the application of HACCP and HAZOP to a microwave-assisted extraction used from laboratory to industry demonstrates how the hazards at the critical control points (CCPs) of the process are effectively controlled through the implementation of HACCP and how to secure operator safety through the adoption of HAZOP.

Ying Li, Marilena Radoiu, Anne-Sylvie Fabiano-Tixier, Farid Chemat

Backmatter

Titel: Microwave-assisted Extraction for Bioactive Compounds
herausgegeben von: Farid Chemat
Giancarlo Cravotto
Verlag: Springer US
Electronic ISBN: 978-1-4614-4830-3
Print ISBN: 978-1-4614-4829-7
DOI: https://doi.org/10.1007/978-1-4614-4830-3