Ultrasound is well known to have a significant effect on the rate of various processes in the food industry. Using ultrasound, full reproducible food processes can now be completed in seconds or minutes with high reproducibility, reducing the processing cost, 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 time and energy normally needed for conventional processes. Several processes such as freezing, cutting, drying, tempering, bleaching, sterilization, and extraction have been applied efficiently in the food industry. The advantages of using ultrasound for food processing, includes: more effective mixing and micro-mixing, faster energy and mass transfer, reduced thermal and concentration gradients, reduced temperature, selective extraction, reduced equipment size, faster response to process extraction control, faster start-up, increased production, and elimination of process steps. Food processes performed under the action of ultrasound are believed to be affected in part by cavitation phenomena and mass transfer enhancement. This review presents a complete picture of current knowledge on application of ultrasound in food technology including processing, preservation and extraction. It provides the necessary theoretical background and some details about ultrasound the technology, the technique, and safety precautions. We will also discuss some of the factors which make the combination of food processing and ultrasound one of the most promising research areas in the field of modern food engineering.

The consumption of Citrus fruits and juices has been widely investigated for its possible role in the prevention of cardiovascular disease and cancer. These beneficial effects are mainly attributed to flavanones, the typical polyphenols of Citrus species. Major flavanones in plant species include hesperetin, naringenin, eriodictyol, isosakuranetin and their respective glycosides. Hesperetin and its derivatives are characteristic flavanones of sweet orange, tangelo, lemon and lime, while naringenin and its derivatives are those of grapefruit and sour orange. Advances in analytical techniques like ultra high performance liquid chromatography (UPLC) coupled with mass spectrometry has facilitated (a) the estimation of flavanone contents in other plant species and in humans after ingestion and (b) the determination of flavanone metabolites more rapidly and with greater efficiency. The present review will summarize the current knowledge about flavanones from their occurrence in plants to the bioactivity of their metabolites in humans.

After processing, every extraction process generates huge amount of unintended wastes, especially from fruits and vegetables which represent a major disposal problem for the food industry. They are promising sources of bioactive compounds that could be used for their favourable nutritional properties. Sea buckthorn juice production results in generation of large amount of by-products, which are suggested to contain substantial amounts of valuable natural antioxidants. Extracts obtained by solvent-free microwave hydrodiffusion and gravity (MHG) technique and conventional solvent extraction (CSE) method were analysed with HPLC for quantification of flavonoids along with evaluating their phenolic contents by Folin-Ciocalteu method and reducing power by the reduction of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. MHG is a green extraction method which offers important advantages like shorter extraction time (15 min), cleaner feature (no solvent or water used) and extraction of valuable flavonoids (Isorhamnetin, isorhamnetin 3-O-glucoside, isorhamnetin 3-O-rutinoside and quercetin 3-O-glucoside) at optimised power (400 W). Along with extracting similar flavonols in enough concentratioin, MHG extract has shown much higher phenolic contents (1,147 milligram gallic acid equivalents (GAE) per gram) against CSE extract (741 mg GAE/g) with greater antioxidant activity determined by DPPH assay.

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