0000000000582458
AUTHOR
Geneviève Blond
Factors affecting the moisture permeability of lipid-based edible films: a review.
Moisture transfers inside food products could be controlled or limited by the use of edible films. These are usually based on hydrophobic substances such as lipids to improve barrier efficiency. Water permeability of films is affected by many factors, depending on both the nature of barrier components, the film structure (homogeneous, emulsion, multilayer, etc.), crystal type, shape, size and distribution of lipids, and thermodynamics such as temperature, vapor pressure, or the physical state of water in contact to the films. After a brief presentation of lipids and hydrophobic substances used as moisture barrier, cited in the scientific literature, this article reviews all of the parameter…
Influence of the physical state of water on the barrier properties of hydrophilic and hydrophobic films.
Water transfer through different films, as a function of the physical state of water in contact with the film, the relative humidity difference, and the water vapor pressure difference, was investigated. The films were two synthetic packagings (hydrophobic polyethylene and hydrophilic cellophane) and an edible film. The physical state of water affects water sensitive films, such as cellophane, inducing a higher liquid water transfer due to interactions with the polymer. For hydrophobic polymers, such as polyethylene, neither the physical state of water nor the relative humidity has an influence on the water permeability. In complex system, such as an edible film composed of hydrophilic part…
Water vapour pressure above saturated salt solutions at low temperatures
Abstract The properties of water–salt systems in relation to their vapour pressure are studied especially at low temperature. The water vapour pressure of saturated salt solutions of strontium chloride, zinc chloride, nickel chloride, nickel nitrate, magnesium chloride, magnesium bromide, magnesium nitrate, calcium chloride, potassium nitrite, lithium chloride, lithium bromide, lithium iodide and sodium bromide are measured in a temperature range −40 to +10°C. The apparatus used in this study, is well adapted to measure very low pressure with an uncertainty of pressure measurement of 2% for a range between 10−3 and 10 mm Hg. The experimental values are fitted by Antoine equation with mean p…
EFFECT OF WATER ACTIVITY ON CRISPNESS OF BREAKFAST CEREALS
Three breakfast cereals (two commercial products and one experimental product made by extrusion cooking) were placed over 10 saturated salt solutions in desiccators for 3 weeks and then studied by sensory and mechanical analysis. A slight decrease of sensory crispness intensity occurs between 0 and 0.50 (aw) or 7% (water content), after which there is a very rapid decrease. The value of critical water activity given by the intersection between the two straight lines which can be adjusted seems not to depend on the product. Moreover this value is confirmed by the mechanical analysis and, partially, by a Differential Scanning Calorimetry analysis. There is a good correlation between sensory c…