Search

This study examined the use of hot-air drying in the preparation of pumpkin powder. The drying temperature was varied (50, 60 and 70°C) to determine the effect of temperature on physico-chemical properties, powder properties and sorption characteristics of pumpkin powders. The results showed that a drying temperature of 70°C removes moisture from pumpkin slices faster than the lower drying temperatures of 50 and 60°C. The moisture content and water activity values of the pumpkin powder dried at 60 and 70°C were within acceptable limits for safe storage. Pumpkin powder dried at 70°C exhibited the darkest yellow color, while pumpkin powders dried at 50 and 60°C were lighter. Moreover, pumpkin powder dried at 70°C showed the highest percent decrease in carotenoid content (56%) compared to those dried at 50 and 60°C (18% and 33%, respectively). The results also showed that increases in drying temperature are accompanied by decreases in the water solubility, water and oil adsorption capacities of the resulting pumpkin powders. Pumpkin powders dried at 50 and 60°C had water solubilities of more than 50% and higher water adsorption and oil adsorption capacities than those dried temperature at 70°C. Overall, a good quality pumpkin powder can be produced by hot-air drying at a temperature of 60°C in terms of moisture content, water activity, color characteristics, total carotenoid content, bulk density, water solubility, water adsorption, and oil adsorption capacities. When drying at a temperature of 50°C, the moisture content and water activity of pumpkin powder was higher than the acceptable limit of that standard and the dark yellow color of the powder was observed when subjected at a drying temperature of 70°C. Working sorption isotherms of dried pumpkin powder were found to be Type II of all the sorption curves. [ABSTRACT FROM AUTHOR]

A steady-state finite element model of moisture transport in corrugated fibreboard is presented and solved using experimentally determined values of moisture permeability in Kraft and recycled paperboard. The model shows reasonable agreement with experimentally measured moisture fluxes. The model also demonstrates that the majority of moisture flux occurs through the air phase. Simplified models based on the sum of resistances in series are shown to be in good agreement with the more complex finite element model and may have some practical utility in the design of packaging for specific applications where the internal moisture environment and/or structural integrity of the packaging is important. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Ethanol vapor controlled release active packages can delay microbial proliferations in fresh peeled shallots, a value-added product. This study purposely was conducted to develop mathematical models to predict ethanol vapor concentration accumulated in the active packages. The package physically was a solid plastic tray (9.5x 13x6 cm; width x length x depth) covered with the low density polyethylene (LDPE) film lid. The tray contained 100g peeled shallots and a sachet, kept at 10°C for 10 d. The 3x3 cm sachet was made of either LDPE or Nylon/PE film on one side and aluminum foil laminated on the other. The sachet contained 1g silica gel adsorbent pre-adsorbed with food grade ethanol. The mathematical models were developed through conceptualizing key mass transfer processes in the active packages given assumptions made to describe changes in the sachet, package headspace, plastic film lid, and the shallot with respect to ethanol vapor. The mathematical models were tested against experimental data. The steady-state ethanol vapor concentrations in packages predicted by the models were approximately 1.5 to 2- fold lower than those collected from the experiments. However, the models could reasonably predict trends in changes of ethanol vapor concentrations accumulated in different packages. A lack of fit between models predicted and empirical results was attributed to an accuracy of a model input, namely rate constants of ethanol vapor-shallots interactions. The study highlighted that the mathematical modeling approach and assumptions made was reasonable to simplify key mass transfer of the active packages. Further studies to understand complexities of ethanol vapor-shallots interactions are required for obtaining accurate information on the interaction rates. The mathematical model can be used as a mechanistic tool to facilitate designs of active packages incorporating the ethanol vapor controlled release sachet for fresh peeled shallots or other horticultural produce, given accurate model inputs. [ABSTRACT FROM AUTHOR]

The particle size distributions (PSDs) of two portion sizes (2g and 4g) of five foods (cake, cereal bar, muesli bar, cooked pasta and peanuts) after human mastication were determined. The PSD of the expectorated bolus and residual 'debris' rinsed from the mouth were each determined by wet sieving. There were significant differences in the PSD between food types, between portion sizes in the debris fraction and between the bolus and debris fractions. The latter suggests the existence of a two compartment system where particles are comminuted in at least one compartment within the oral cavity., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

It has long been the goal of researchers to develop fast and reliable point-of-care alternatives to existing lab-based tests. A viable point-of-care biosensor is fast, reliable, simple, cost-effective, and detects low concentrations of the target analyte. The target of biosensors is biological such as bacteria or virus and as such, the antibody-antigen bond derived from the real immune response is used. Biosensor applications include lab-based tests for the purposes of diagnostics, drug discovery, and research. Additional applications include environmental, food, and agricultural monitoring. The main merits of the bond-rupture method are quick, simple, and capable of discriminating between specific and non-specific interactions. The separation of specific and non-specific bonds is important for working in real-life complex serums such as blood. The bond-rupture technique can provide both qualitative results, the detection of a target, and quantitative results, the concentration of target. Bond-rupture achieves this by a label-free method requiring no pre-processing of the analyte. A piezoelectric transducer such as the quartz crystal microbalance (QCM) shakes the bound particles free from the surface. Other transducers such as Surface Acoustic Wave (SAW) are also considered. The rupture of the bonds is detected as electronic noise. This review article links diverse research areas to build a picture of a field still in development.