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High-intensity Ultrasound (high-intensity + ultrasound)
Selected AbstractsExtraction of policosanols from hydrolysed rice bran wax by high-intensity ultrasoundINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2008Yuanfa Liu Summary This study provided a detailed method for extraction and purification of policosanols from hydrolysed rice bran wax (RBW) by high-intensity ultrasound (HIU), where the hydrolysis of RBW under HIU was focused. The optimised operating conditions for hydrolysis were as the following: 20 kHz, 100 W, 1:2 of wax to 4% sodium hydroxide (w:v) and 50 min at ambient temperature, under which the hydrolysis rate of 94.3% was obtained. Thereafter, policosanols were extracted and purified from the hydrolysed RBW. With the analysis by GC, it was shown that even-numbered aliphatic alcohols were the major components of the policosanols, accounting for 95% or so, where triacontanol (C30) was the predominant component with 26.95%, followed by octacosanol (C28) with 17.04%, dotriacotanol (C32) with 16.01%, tetracosanol (C24) with 11.13%, hexacosanol with 10.90%; however, the odd-numbered alcohols only accounted for about 5% and they were non-acosanol (C29) with 2.92%, heptacosanol (C27) with 1.57% and pentacosanol (C25) with 0.65%. [source] Synthesis of cyclodextrin-based polymers and their use as debittering agentsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2008Arianna Binello Abstract Cyclodextrins (CDs) and their derivatives are used to suppress unpleasant tastes and odors or to achieve a controlled release of certain food constituents. This article describes the synthesis by nonconventional methods of (1) crosslinked, insoluble CD polymers and (2) water-soluble, CD-grafted carboxymethylchitosan and carboxymethylcellulose. The CD polymers were obtained by the reaction of ,-CD with one of the following crosslinking agents: epichlorohydrin, diphenyl carbonate, or hexamethylene diisocyanate. Their preparations were usually carried out under high-intensity ultrasound, which resulted in much shorter reaction times and narrower distributions of particle size (as determined by scanning electron microscopy measurements). A novel, insoluble CD polymer was obtained by reticulation under microwaves of propargyl-,-CD with 1,3-bis(azidomethyl)benzene through Huisgen 1,3-dipolar cycloaddition. Short columns packed with the insoluble polymers were found to efficiently sequester naringin from aqueous solutions; successively, they could be easily regenerated by a counter-current ethanol wash that also achieved an excellent recovery of the flavonoid. Differential scanning calorimetry thermograms showed that the crosslinked CD polymers formed inclusion complexes with naringin. The soluble polymers also interacted with bitter flavonoids of citrus fruits (naringin and limonin), as shown by the results of sensorial panel tests, in which they behaved as bitter-masking agents. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Effects of ultrasound on culture of Aspergillus terreusJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2008Nuria Sainz Herrán Abstract BACKGROUND: Fermentations of Aspergillus terreus are commercially used to produce lovastatin. How ultrasound might influence this fermentation is unknown. While high-intensity ultrasound is effective in disrupting microbial cells, ultrasound of low intensity is known to improve productivity of some fermentation processes without damaging cells. Mechanisms behind productivity improvements have not been clearly identified in earlier studies. This work reports on the effects of ultrasound on A. terreus fermentation for low (957 W m,3), medium (2870 W m,3) and high (4783 W m,3) values of sonication power input in a slurry bubble column sonobioreactor. RESULTS: Sonication at any power level did not affect biomass growth profiles in comparison with negative controls. In contrast, medium- and high-intensity sonication greatly reduced production of lovastatin and substantially altered the growth morphology. At medium and high intensity, ultrasound disrupted fungal pellets and caused the biomass to grow mainly as dispersed hyphae. Sonication affected broth rheology because rheology depends on the morphology of the suspended biomass. CONCLUSION: Sonication can be used to modify growth morphology and broth rheology without affecting growth of filamentous fungi. Sonication appears to influence the primary growth metabolism and secondary metabolism differently in different situations. Copyright © 2008 Society of Chemical Industry [source] Preparation and Properties of Proteinaceous Microspheres Made SonochemicallyCHEMISTRY - A EUROPEAN JOURNAL, Issue 13 2008Aharon Gedanken Prof. Abstract In 1990, Suslick and co-workers developed a method in which they used high-intensity ultrasound to make aqueous suspensions of proteinaceous microcapsules filled with water-insoluble liquids, and demonstrated the chemical mechanism of their formation.1 Suslick's paper opened up a new field that is reviewed in the current manuscript, and this article will attempt to review the experiments that have been conducted since the discovery of this phenomenon. It will answer questions regarding the mechanism of the formation of the microspheres, whether the sonication denaturates the protein or if its biological activity is maintained, and, finally, will address possible applications of the proteinaceous microspheres. Proteinaceous microbubbles will be referred to as proteinaceous microspheres (PM) throughout this review, although they may not have a perfect spherical shape in all cases. This review will start with a short introduction to sonochemistry, although this topic is, and has been reviewed frequently.2,7 The review covers literature published until December 2006. [source] | ||||||||||