List of Titles

A benign approach to the preparation of freshwater bryozoan statoblasts for scanning electron microscopy (SEM) imaging

- Mitra, Robin, Crawford, Simon, Barton, Andrew, Briggs, Steven, Orbell, John

Authors: Mitra, Robin , Crawford, Simon , Barton, Andrew , Briggs, Steven , Orbell, John
Date: 2013
Type: Text , Journal article
Relation: New Zealand Journal of Zoology Vol. 40, no. 2 (2013), p. 154-159
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Description: Several different species of freshwater Bryozoa, belonging to the genera Plumatella, Rumarcanella and Fredericella, were detected within the Northern Mallee Pipeline (NMP) system in Victoria, Australia, that required definitive identification. These organisms produce asexual buds called statoblasts, with valves composed of sclerotised chitin that bear minute micro-ornamentations of considerable taxonomical significance. Imaging and analysis of these distinctive micro-ornamentations using scanning electron microscopy (SEM) is often employed for species identification. Meticulous preparation of statoblast samples is therefore required that necessitates the removal of adhering debris, dehydration and drying - whilst mitigating specimen damage and distortion. This technical note describes an approach whereby each of these three steps have been individually designed to be as benign as possible, using mild detergent/sonication to remove debris, a gradual and gentle dehydration procedure using ethanol, and critical point drying. For the overall process, these methods are chosen to optimise control and to minimise the use of harsh and hazardous chemicals. © 2013 The Royal Society of New Zealand.

Effects of cyclodextrins on the antimicrobial activity of plant-derived essential oil compounds

- Liang, Hao, Yuan, Qipeng, Vriesekoop, Frank, Lv, Fei

Authors: Liang, Hao , Yuan, Qipeng , Vriesekoop, Frank , Lv, Fei
Date: 2012
Type: Text , Journal article
Relation: Food Chemistry Vol. 135, no. 3 (2012), p. 1020-1027
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Description: Essential oils (EOs) from plants are considered to be a safer alternative when compared to synthetic antimicrobial food additives. However, a major drawback of many EOs is their hydrophobic nature, which makes them insoluble in water based media and matrices. Although cyclodextrins (CDs) can increase the solubility of EO compounds, the effects of CDs on the antimicrobial activity of EOs have not been reported. In this paper, four different EO compounds (carvacrol, eugenol, linalool and 2-pentanoylfuran) were chosen to study the influence of CDs on the solubility and antimicrobial activity on bacteria and yeast. The greatest enhancement with regards to solubility of the four test compounds was achieved by hydroxypropyl-β-CD. In most instances, not only were the minimal antimicrobial concentrations of EO compounds decreased, but the interactivity of two combined EO compounds could be strengthened by the co-addition of CDs. Furthermore, the combination of carvacrol with hydroxypropyl-β-CD caused a marked change in the major membrane lipid composition of all microorganisms investigated; while scanning electron microscopy revealed that cellular integrity was significantly affected by 2× MIC, ultimately resulting in cell lysis. © 2012 Elsevier Ltd. All rights reserved.

The effects of proteins and low molecular weight surfactants on spray drying of model sugar-rich foods: Powder production and characterisation

- Jayasundera, Mithila, Adhikari, Benu, Adhikari, Raju, Aldred, Peter

Authors: Jayasundera, Mithila , Adhikari, Benu , Adhikari, Raju , Aldred, Peter
Date: 2011
Type: Text , Journal article
Relation: Journal of Food Engineering Vol. 104, no. 2 (2011), p. 259-271
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Description: The effects of proteins and low molecular weight surfactants (LMS) on spray drying and powder characteristics of model sugar-rich foods have been studied. Fructose and sucrose were selected as model sugar-rich foods and sodium caseinate (NaCas) was selected as a model protein. Sodium stearoyl lactylate (SSL) and Polysorbate 80 (Tween-80) were chosen as model ionic and non-ionic low molecular weight surfactants. The feed solutions for spray drying had 25% solid concentration in all. To achieve identical powder recoveries of the order of 80% much higher NaCas:fructose ratio (30:70) was required compared to NaCas:sucrose ratio (0.5:99.5) which corresponded to 7.89% and 0.13% of sodium caseinate (initial bulk concentration), respectively. There was no change in powder recovery when the SSL concentration was increased from 0.01% to 0.05% in fructose-NaCas-SSL solution and also addition of 0.01% Tween-80 into fructose-NaCas solution did not affect the powder recovery (76.7 Â± 2.3%), however, it was slightly affected with the increase of Tween-80 to 0.05% (69.0 Â± 1.9%). At NaCas concentration above critical micelle concentration of NaCas (3% w/w), the presence of up to 0.05% low molecular weight surfactants had either no effect or minimal effect on the surface coverage of the droplets/particles and also on the powder recovery depending on the nature of the low molecular weight surfactants. The surface protein coverage and the recovery of the powder in sucrose-protein systems were very sensitive in the presence of low molecular weight surfactants due to being below the critical micelle concentration of NaCas. SSL displaced 2.0% and 29.3% of proteins from the droplet surface of sucrose-NaCas-SSL, respectively, when its concentration was varied from 0.01% to 0.05% thereby reducing the powder recovery from 75.5% to 30%. The addition of 0.01% Tween-80 in sucrose-NaCas solution resulted in a 48.2 Â± 1.5% reduction in powder recovery and at 0.05% concentration, it displaced a substantial amount of NaCas from the droplet surface and no powder was recovered. These phenomena are explained on the basis of surface-glass transition temperature, dynamic surface tension, nature of surfactants and glass transition temperature of sugars used. X-ray diffraction and scanning electron microscopy results showed that the powders of sucrose-NaCas, sucrose-NaCas with 0.01% SSL and all powders of fructose were amorphous. Â© 2010 Elsevier Ltd. All rights reserved.

Effects of ultrasound on glass transition temperature of freeze-dried pear (Pyrus pyrifolia) using DMA thermal analysis

- Islam, Nahidul, Zhang, Min, Liu, Huihua, Xinfeng, Cheng

Authors: Islam, Nahidul , Zhang, Min , Liu, Huihua , Xinfeng, Cheng
Date: 2015
Type: Text , Journal article
Relation: Food and Bioproducts Processing Vol. 94, no. (2015), p. 229-238
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Description: The effect of ultrasound pretreatment at various power (360 W, 600 W and 960 W, frequency 20 kHz) on the glass transition temperature of freeze dried pear (Pyrus pyrifolia) has been studied. DMA temperature plots were divided into four sections (A - glassy region, B - transition region, C - Rubbery plateau region and D - terminal region) with the aim to analyze their properties changed with sonication. Under the same freeze drying condition, with the increase in ultrasonic power, dried pear showed higher glass transition in terms of storage modulus, loss modulus and loss tangent peak. Also a decrease in a

A comparison of grain-size analysis methods for sand-dominated fluvial sediments

- Cheetham, Michael, Keene, Annabelle, Bush, Richard, Sullivan, Leigh, Erskine, Wayne

Authors: Cheetham, Michael , Keene, Annabelle , Bush, Richard , Sullivan, Leigh , Erskine, Wayne
Date: 2008
Type: Text , Journal article
Relation: Sedimentology Vol. 55, no. 6 (2008), p. 1905-1913
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Description: Grain-size distribution is a fundamental tool for interpreting sedimentary units within depositional systems. The techniques assessed in this study are commonly used to determine grain-size distributions for sand-dominated sediments. However, the degree of consistency and differences in interpretation when using a combination of grain-size methods have not yet been assessed systematically for sand-dominated fluvial sediments. Results obtained from laser diffraction, X-ray attenuation and scanning electron microscopy grain-size analysis techniques were compared with those obtained from the traditional sieve/ hydrometer method. Scanning electron microscopy was shown to provide an inaccurate quantitative analysis of grain-size distributions because of difficulties in obtaining representative samples for examination. The X-ray attenuation method is unsuitable for sand-dominated sediments because of its upper size range of only 300 Î¼m. The consistently strong correlation between the laser diffraction results and the sieve/ hydrometer results shows that these methods are comparable for sand-dominated fluvial sediments. Provided that sample preparation is consistent, the latter two methods can be used together within a study of such sediments while maintaining a high degree of accuracy. These results indicate that data for sand-dominated fluvial sediments gained from the long-established sieve/hydrometer method can be compared with confidence to those obtained by modern studies using laser diffraction techniques. © Journal compilation © 2008 International Association of Sedimentologists.

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