•Relevance of ultrasound in food processing.•Ultrasound-assisted extraction and freezing process.•Mechanisms on the basis of sono-physical and chemical effects of ultrasound.•Food components ...modifications under sonication treatments.•Trends, challenges and recommendations on ultrasound in food processing.
Ultrasound is an advanced non-thermal food-processing technology that has received increasing amounts of interest as an alternative to, or an adjuvant method for, conventional processing techniques. This review explores the sono-physical and sono-chemical effects of ultrasound on food processing as it reviews two typical food-processing applications that are predominantly driven by sono-physical effects, namely ultrasound-assisted extraction (UAE) and ultrasound-assisted freezing (UAF), and the components modifications to food matrices that can be triggered by sono-chemical effects. Efficiency enhancements and quality improvements in products (and extracts) using ultrasound are discussed in terms of mechanism and principles for a range of food-matrix categories, while efforts to improve existing ultrasound-assist patterns was also seen. Furthermore, the progress of experimental ultrasonic equipments for UAE and UAF as food-processing technologies, the core of the development in food-processing techniques is considered. Moreover, sono-chemical reactions that are usually overlooked, such as degradation, oxidation and other particular chemical modifications that occur in common food components under specific conditions, and the influence on bioactivity, which was also affected by food processing to varying degrees, are also summarised. Further trends as well as some challenges for, and limitations of, ultrasound technology for food processing, with UAE and UAF used as examples herein, are also taken into consideration and possible future recommendations were made.
Ultrasound, an efficient and virtually innocuous means of activation in synthetic chemistry, has been employed for decades with varied success. Not only can this high-energy input enhance mechanical ...effects in heterogeneous processes, but it is also known to induce new reactivities leading to the formation of unexpected chemical species. What makes sonochemistry unique is the remarkable phenomenon of cavitation, currently the subject of intense research which has already yielded thought-provoking results. This critical review is aimed at discussing the present status of cavitational chemistry and some of the underlying phenomena, and to highlight some recent applications and trends in organic sonochemistry, especially in combination with other sustainable technologies. (151 references.).
The design of green and sustainable extraction methods of natural products is currently a hot research topic in the multidisciplinary area of applied chemistry, biology and technology. Herein we ...aimed to introduce the six principles of green-extraction, describing a multifaceted strategy to apply this concept at research and industrial level. The mainstay of this working protocol are new and innovative technologies, process intensification, agro-solvents and energy saving. The concept, principles and examples of green extraction here discussed, offer an updated glimpse of the huge technological effort that is being made and the diverse applications that are being developed.
Recent findings evidence that cavitational and mechanical effects of ultrasound waves trigger molecular assembly and pattern formation, exemplified by organogels and ordered structures. Although ...sonication-assisted aggregation has become a well-established protocol, the science behind it is often overlooked. In this tutorial review various aspects of ultrasound-driven reactions are introduced, highlighting organic and metal coordination compounds, as well as recent applications focused on polymer structures. Given the importance of supramolecular assemblies, especially hydrogels, as biomaterials and vehicles for drug transport and delivery, sound waves thus provide a facile entry to new forms of soft matter and functionalized materials.
Chemists have discovered, and recently actively exploited, the fact that subjecting certain molecules to ultrasound waves can bring about transformations that give insight into the correlation ...between classical tribological processes and the mechanical action caused by collapsing microbubbles when sonic waves propagate through a liquid medium. Chemical transformations induced by ultrasound take place in solution via mechanisms that are markedly different from those associated with molecular activation in the solid state. Both fields, however, share some striking similarities and numerous sonochemical reactions can be rationalized in purely mechanical terms. This tutorial review examines the tribochemical interpretation of sonochemical reactivity and how the multifaceted action of cavitational phenomena determines molecular evolution. A series of case studies involving solids, crystals, and polymers illustrate the mechanical properties of sound waves.
Note: US, Ultrasound; PS, peroxydisulfate; PS, peroxymonosulfate. The sonication-involved processes in water matrices.
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•The generation of •OH radicals by ultrasound is insufficient to ...cause significant antibiotics cleavage.•Sonication improves mass transfer and oxidation with Fenton reagents, S2O82−, HSO5− and O3.•Sonophotocatalysis remarkably enhances antibiotics mineralization and detoxification.
Antibiotic residues in water are general health and environmental risks due to the antibiotic-resistance phenomenon. Sonication has been included among the advanced oxidation processes (AOPs) used to remove recalcitrant contaminants in aquatic environments. Sonochemical processes have shown substantial advantages, including cleanliness, safety, energy savings and either negligible or no secondary pollution. This review provides a wide overview of the different protocols and degradation mechanisms for antibiotics that either use sonication alone or in hybrid processes, such as sonication with catalysts, Fenton and Fenton-like processes, photolysis, ozonation, etc.
In recent years, increased awareness of the health benefits associated with consuming soy-based foods, knowledge of milk-related allergies and a move towards more sustainable food production have led ...to an increase in the number of available soy-based products. The biggest producers in the world, the USA, South America and China, are from the Pacific region. This enormous production is accompanied by the accumulation of related by-products, in particular, a substance that is known as okara. Okara is a paste that is rich in fibre (50%), protein (25%), fat (10%), vitamins and trace elements. Its proper use would lead to economic advantages and a reduction in the potential for polluting the environment. Its high fibre content and low production costs mean that it could also be used as a dietary supplement to prevent diabetes, obesity and hyperlipidaemia. Chemical or enzymatic treatment, fermentation, extrusion, high pressure and micronisation can all increase the soluble fibre content, and thus improve nutritional quality and processing properties. However, the product also degrades rapidly due to its high moisture content (70-80%), which makes it difficult to handle and expensive to dry by conventional means. The aim of this paper is therefore to thoroughly study the existing literature on this subject in order to develop a general protocol for okara exploitation and valorisation. A cost/benefit analysis could drive the design of eco-friendly, sustainable protocols for the preparation of high-value nutritional products.
Chemistry of and with graphene constitutes a rapidly evolving field that holds much promise for the generation of advanced materials with salient, and often unique, properties and potential ...applications in different fields. However, reliable, mild, and scalable methods to produce this layered carbonaceous material represent an important bottleneck and are critical for progress in this research area to continue. In this context, the use of ultrasound has become a routine and indispensable step in numerous synthetic protocols, even though most researchers usually overlook the science behind it. This minireview provides some fundamentals on the interaction of sound waves with matter and equally illustrates how sonication assists further synthetic decorations under benign conditions.
Sound—action! Inexpensive graphitic precursors can be transformed into invaluable graphenes (both single and few layers) using ultrasonication as the key step. This safe wet chemistry enables rapid dispersion and formation of stable colloids (see figure). This minireview unveils the rich and sound science behind the lab trick.
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