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Baking Temperature (baking + temperature)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

Factors affecting wafer sheet quality

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2006
Ismail S. Dogan
Summary Wafers are low-moisture-baked foods. They are formed from a batter and baked between hot plates. The quality of wafer sheets is mainly controlled by flour property, water level and temperature, mixing action, baking time and temperature. The quality is judged by attributes of the batter such as the density, viscosity, holding time and temperature, and by properties of the wafer such as weight, surface colour, fragility and moisture content. In this study, the batter-specific gravity of 1.11,1.19 was recorded. Water and gluten content did not affect density. Water level, but not gluten content, however affected viscosity. Batter holding time drastically changed viscosity. The temperature of plates did significantly affect bake time. For wafer sheets with a high quality, 155,165% water level, 170 °C baking temperature and 2 min of bake time were found to be adequate. Wafer sheets baked at the lower temperatures stuck to the plates and broke up to several pieces. At a lower water level (<145%) and baking temperature of 150 °C, tough and flinty sheets were obtained, whereas at a water level higher than 160% and a higher temperature (190 °C), fragile sheets were obtained. [source]

A NUMERICAL APPROACH WITH VARIABLE TEMPERATURE BOUNDARY CONDITIONS TO DETERMINE THE EFFECTIVE HEAT TRANSFER COEFFICIENT VALUES DURING BAKING OF COOKIES

JOURNAL OF FOOD PROCESS ENGINEERING, Issue 5 2006
EREN DEMIRKOL
ABSTRACT The increasing trade of ready-to-eat foods such as cookies highlights an interest in quality defects during baking. Heat (h and thermal diffusivity) and mass (mass transfer and diffusion coefficients) transfer parameters are significant parameters affecting the quality changes. Therefore, it is important to determine these parameters for modeling and process optimization studies. Among these, the h is important, revealing the relationship between the heating medium and product surface. As baking involves a simultaneous heat and mass transfer involving moisture diffusion and heat conduction inside and convective heat and mass transfer outside, a lumped system method may not be an accurate choice to determine the h value. Changes in the product volume and contact heating from bottom of the product also bring extra challenges to the determination of h. Therefore, the objective of this study was to use realistic approaches including simultaneous heat and mass transfer to determine the changes in h. The heffvalues for the bottom and top surface of the cookies were then determined, applying a numerical procedure where the surface temperature changes were the boundary conditions with evaporation on the surface. The hband ht values increased with baking temperature and varied with baking time. The results of this study showed that evaporative mass flux for the top surface, heat flux for the bottom surface and the product's volume changes were significant in the variation of h values. [source]

Estimating baking temperatures in a Roman pottery kiln by rock magnetic properties: implications of thermochemical alteration on archaeointensity determinations

GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2006
Simo Spassov
SUMMARY Absolute past geomagnetic field intensity determinations requiring laboratory heating are labourious and the success rate is rather low, mostly because of induced thermochemical magnetic mineral alterations. Archaeomagnetic intensity determinations are mainly limited to displaced ceramics produced in kilns. In this study, the suitability of an in situ baked structure is investigated. Different magnetic properties of baked material taken from the combustion chamber wall and floor of a Roman pottery kiln, with variable colouring, are examined in dependence on the distance to the combustion chamber. The temperature distribution is re-constructed based on rock magnetic experiments after stepwise heating. The rock magnetic temperature estimates agree fairly well with a mathematical heat conduction model demonstrating the penetration of heat into the combustion chamber wall. The rock magnetic results show that blackish- and greyish-coloured kiln parts, that had been in close contact with the fuel, during ancient kiln operation, are not suitable for intensity determinations. Although sufficiently baked, they strongly alter during laboratory heating and new remanence-carrying minerals are formed. The brownish-coloured material at a distance 65,80 mm away from the combustion chamber seems to be most suitable as its magnetic properties remain nearly unchanged during laboratory heating. Rock magnetic and modelled temperature estimates for this material consistently indicate ancient baking temperatures of about 600°C. The model demonstrates that cooling takes longer in the inner parts of the combustion chamber wall. Retarded cooling affects the blocking temperatures and hence the strength of the thermoremanent magnetization. The variability of cooling rates should be taken into account when investigating archaeointensities of specimens cut from large samples, or of samples taken from different parts of a kiln. [source]