Measurement of Zeta Potential of Polysaccharides and Fabricating Polysaccharide-polysaccharide Nanotubes

Biopolymer nanotubes (BNTs) are two-open ended cylindrical structures which can be used for nanodevices, medicine, and biology. Especially, fabricating BNTs using proteins is suitable for biological and biomedical applications due to their safety and biocompatibility. This study has been focused on fabricating BNTs using polysaccharides which have been proved to be safe by the FDA and used in food applications. The zeta-potential, surface charge, of different polysaccharides was measured to find the region of stability and isoelectric point from pH 4 to 11 by DLS. Next, xanthan and chitosan have been selected for fabricating BNTs because of their stability and dispersibility compared to the other polysaccharides. Two polysaccharide solutions were adjusted to pH 4 where the charge difference was the largest; and BNTs were fabricated at different mass ratio using a template assisted layer-by-layer method. Then, SEM images were taken to visualize the nanotubes. As a result, some nanotubes were seen in the SEM images; however, they did not have the optimal well defined form yet. Also, there were too many clusters instead of individual clear nanotubes. The interaction and the size of the proteins might be too large, so the polysaccharides tended to form globular structures instead of nanotubes. To fabricate BNTs, xanthan will be hydrolyzed to reduce size, and the mass ratio would be also reduced to decrease the interaction between two polysaccharides

Glutaraldehyde Crosslinked Zein Solutions Make Better Biodegradable Films

The corn protein, zein, is a byproduct of the ethanol production industry. Recently, zein has been used in the production of films and food packaging due to its biodegradability, low production cost, and abundance of corn in the United States. To improve overall quality of zein films, the mechanical properties and surface properties should be enhanced. Therefore, in this study, our aim is to improve the properties of zein films with glutaraldehyde (GDA) as a crosslinker. Zein was solubilized and mixed with 70% ethanol and GDA, then sonicated. Solutions were poured onto different surface materials, including polydimethylsiloxane (PDMS), polystyrene (PS), and glass petri dishes to create films. Cast solutions were placed in the oven for different length of time (i.e. 0 hour, 1 day, 3 day, etc). Water contact angle and FTIR measurements were conducted to understand the crosslinking mechanism of zein films and surface properties of zein to understand how it will perform. Measurements from water contact angle and FTIR showed changes caused by heating, with 6% GDA films having less increase in hydrophobicity than films with 0% GDA and the changes in the ratio of -helices and -sheet structures of zein as the duration of heating was increased. Casting zein films on different surfaces affected the hydrophobicity of films that were not heated, but films that were heated for 3 days in the oven did not have any significant differences

Formation of Lactalbumin Nanoparticles by Desolvation Method

Protein nanoparticles are ideal carriers for bioactive compounds such as nutraceuticals and drugs because they are biodegradable, less immunogenic and non-toxic and can be nanoparticulated. This study focuses on the desolvation method to form lactalbumin protein nanoparticles. Lactalbumin is soluble in water and insoluble in many organic solvents. Different solvent/non-solvent ratios are evaluated in this research project for the effect they have on the size, PDI and stability of protein nanoparticles. Different methods including sonication and centrifugation were used and compared in terms of their effectiveness to produce small nanoparticles during fabrication of the nanoparticles. Data collected including protein nanoparticles average size and zeta potential, also SEM and TEM images were used to study the nanoparticles. It was found that high non-solvent ratio can significantly decrease the average particle size, while it also causes an increase in polydispersity index. Sonication can cause some aggregation of the nanoparticles and makes the average particle size slightly increase. Centrifugation can precipitate the large particles and when the supernatant is collected the average particle size is much smaller. These measurement will contribute to the further understanding of the formation of high quality protein nanoparticles that can serve as efficient drug carriers

Thermal fracture mechanisms in ceramic thermal barrier coatings

Ceramic thermal barrier coatings represent an attractive method of increasing the high temperature limits for systems such as diesel engines, gas turbines and aircraft engines. However, the dissimilarities between ceramics and metal, as well as the severe temperature gradients applied in such systems, cause thermal stresses which can lead to cracking and ultimately spalling of the coating. This paper reviews the research which considers initiation of surface cracks, interfacial edge cracks and the effect of a transient thermal load on interface cracks. The results of controlled experiments together with analytical models are presented. The implications of these findings to the differences between diesel engines and gas turbines are discussed. The importance of such work for determining the proper design criteria for thermal barrier coatings is underlined

Measuring sensory and marketing influences on consumers' choices among food and beverage product brands

Advance in food science depends on measuring the factors in human perception that influence eaters' activities with branded products. Assessed samples must include at least two levels of a sensed material characteristic (e.g. sucrose) or conceptual marketing attribute (e.g. “low fat”), minimally confounded by other features. Each feature needs to be measured for its effect on the individual's objective achievement of choosing among the samples for a familiar context of use. These influences interact, consciously and unconsciously. This theory of how a mind works has generated a wide range of scientifically illuminating and commercially practical examples, illustrated in this review

Interactive Panel on Perspectives and Practical Skills for Men as Advocates for Gender Equity

Men can serve unique and critical roles as advocates of gender equity, particularly in maledominated units or organizations, such as most engineering departments and many universities. This panel brings together a group of men with diverse backgrounds and experiences to discuss their perspectives and offer practical skills for men to effectively serve as advocates for gender equity. This paper augments the panel and captures the backgrounds, experiences, perspectives, and recommendations of the panelists, thereby providing a lasting resource for those unable to attend the panel or future interested individuals. The information we present targets men and administrators, who will better understand the barriers to advocacy, learn best-practices of effective advocacy, and hear first-hand experiences of successful advocacy

Effects of Cultivar and Process Variables on Dynamic-Mechanical and Sensorial Behavior of Value-Added Grape-Based Smoothies

The effects of either cooking temperature (45, 80, and 100 °C) or inclusion of seed particles on the dynamic-mechanical and sensorial properties of value-added Crimson seedless, Black Pearl, or Baresana grape-based smoothies were studied. The inclusion of seed particles resulted in significant increases of the phenolic content, both in Black Pearl and Baresana, but it did not affect in a negative way the sensorial characteristics of smoothies whereas it caused an increase of the viscoelastic behavior of Black Pearl and a slight decrease in Baresana grape-based smoothies. In particular, the investigated rheological parameters were the loss and storage modulus. Moreover, the loss tangent value (the ratio between loss and storage modulus) remained unchanged, indicating a pseudoplastic behavior of all samples, independent on the process conditions. The smoothies produced from Crimson grapes at the intermediate temperature (80 °C) showed sensorial and rheological characteristics similar to those manufactured at 45 °C and better than those manufactured at 100 °C

Relating rheology and tribology of commercial dairy colloids to sensory perception

This study aims to investigate the relationship between rheological and tribological properties of commercial full fat and fat-free/ low fat versions of liquid and soft solid colloidal systems (milk, yoghurt, soft cream cheese) with their sensory properties. Oscillatory measurements (strain, frequency), flow curves and tribological measurements (lubricational behaviour using Stribeck analysis) were conducted. Oral condition was mimicked using artificial saliva at 37 ○C. Discrimination test was conducted by 63 untrained consumers, followed by a qualitative questionnaire. Consumers significantly discriminated the fat-free/low fat from the full fat versions (p0.05). Full fat and fat free yoghurts had similar yielding behaviour and elastic modulus (G'), even in simulated oral conditions. However, in case of soft cream cheese, the full fat version had a moderately higher G’ than the low fat counterpart. Even in presence of artificial saliva, there was slight but significant difference in viscoelasticity between the cream cheese variants depending on fat content (p0.05). Results suggest that sensory distinction between fat-free and full fat versions, particularly in semi-solid systems could be better predicted by lubrication data as compared to bulk rheology

Predicting sensory perceptions of thickened solutions based on rheological analysis

The sensory perceptions of sweetened, flavoured and thickened solutions prepared from xanthan, dextran, sucrose and banana flavour were evaluated and correlated to rheological parameters. The primary aim of this research was to evaluate the relevance of viscosity measured at low shear or at high shear for predicting sensory perceptions. Additionally considered were extensional viscosity estimated from filament thinning experiments and complex shear viscosity. The design of experiments included two groups of 5 samples matched at low shear rate and high shear rate, respectively. Mouthfeel perceptions were well correlated to low shear viscosity, however, including high shear viscosity or extensional viscosity as an additional model parameter improved the predictive quality of the models for thickness, stickiness and mouth coating. Stickiness and mouth coating were better correlated to extensional viscosity than low shear viscosity, although a model including both parameters predicted stickiness and mouth coating best. The complex viscosity at 100 rad/s was also highly correlated to the perception of thickness. Since correlations were not improved over steady shear parameters, complex viscosity was not considered in models based on more than one rheological parameter. Flavour was also scored during sensory evaluation and sweetness and overall flavour were highly correlated. The results of this study have highlighted that there is no single rheological parameter that will ultimately correlate to a range of mouthfeel perceptions. For certain mouth feel perceptions a model comprising shear and extensional rheological parameters will have higher predictive power than a model solely based on shear rheological parameters

Local, three-dimensional strain measurements within largely deformed extracellular matrix constructs

The ability to create extracellular matrix (ECM