Haltbarkeit und Sorptionsverhalten wasserarmer Lebensmittel

Evaluation of the Moisture Permeability Characteristics of Chocolate Films as an Edible Moisture Barrier

“…These changes can result in reduction of shelf life. For example, products such as raisins (Bolin, 1976;Kochhar and Rossell, 1982;Lowe et al, 1963;Marston, 1983;Watters and Brekke, 1961), candies and chocolate-coated products (Andres, 1984;Barron, 1977;Cosler, 1957;Feuge, 1970;Jokay et al, 1967) and dry crackers, biscuits, pizza crust, and filled bakery crust (Heiss, 1968;Katz and Labuza, 1981;Labuza, 1985a;) may become unsatisfactory as a result of moisture gain or loss.…”

“…The water activity of plain chocolate is generally in the range 0.2 to 0.4 with a moisture content between 0.4 to lg H,O/lOOg dry solids. Moisture sorption isotherms for cocoa products (Fincke, 1965;Gane, 1950;Gough and Pilliatt, 1979;Heiss, 1968;Lomauro et al, 1985b;Reade, 1969;Van den Berg, 1983), sucrose (Iglesias and Chirife, 1982;Labuza, 1984) and lecithin (Elworthy, 1961(Elworthy, , 1962Wilkinson et al, 1977) have been published. No moisture sorption isotherm has yet been published for cocoa butter, however, Niediek (1981) reported approximately 0.8% moisture at 60°C and 46% relative humidity.…”

Development of a Microwave Moisture Sensor for Application in the Food Industry

“…The rapeseed swells and hence the volume of the bulk material increases. The mass of the bulk being constant in every experiment, this results in a decrease in bulk density (Eqn [4]). With higher pressure, bulk density increases because of particle deposition in the bed and compression of the solids themselves while the shape of the isobars changes: the negative derivative ∂ρ b / ∂Ψ at ambient conditions converts to positive.…”

“…The determination method for natural materials applied here is the dry-weighing method (2). Water activity is correlated to moisture content with the water adsorption isotherm and describes the amount of free water available for microbiological reactions with bacteria, yeasts and moulds (3,4). Therefore, the quality and durability of foods is strongly dependent on moisture content.…”

Sorption Phenomena in Foods: Theoretical and Practical Aspects

“…The physical-chemical factors responsible for the lowering of Aw have been reviewed extensively by Heiss (1967), Van Arsdel (1963, and Labuza (1971). The important principles should be reemphasized as it explains the fundamental interactions of water within a food in terms of storage stability.…”