Effects Of Susceptor Component And Food Ingredients On Bread Microwave Baking Quality

This paper mainly investigated the influence of the microwave susceptor componentsand food ingredients of bread on the quality of bread microwave. Firstly, this paper exploreddielectric properties of microwave susceptor essential composition and its effect ontemperature of the bread in the process of microwave heating. Secondly, food ingredients andthe conditions of microwave heating were adjusted in order to improve quality of microwavebread. Thirdly, modeling software was used to simulate microwave heating process,calculated the microwave absorption rate of the dough, simulated the temperature and electricfield distribution of the dough in the process of heating. Finally, the effect of susceptor on theproperties of bread baked by microwave was determined.In detail, the mixture of metal aluminum powder and inorganic salt, with glass sand,colloid and other accessories were firstly selected as susceptor. And relative dielectricconstant and dielectric loss factor of common main group metal salt was studied in thefrequency range of0.3～3.0GHz. Results showed that dielectric value of sodium salt waslow but potassium presented good dielectric properties with the mass ratio of sodiumcarboxymethyl cellulose with metal salts as1:5, and that calcium salt and magnesium saltalways demonstrated good dielectric properties. Therefore, with the center and externaltemperature of the bread as index, calcium salt was selected as susceptor components.Then, this paper investigated the effect the mass ratio of the sodium carboxymethylcellulose and calcium salt (in the range of1:0.5～1:5.0) on the relative dielectric constant anddielectric loss factor. Results showed that relative dielectric constant of mixture increasedwith the increasing of the content of calcium salt, and that dielectric loss factor of calciumchloride reached below zero, while dielectric loss factor of calcium carbonate was in the range0～0.4. Data indicated that the final dough center temperature and external temperaturereached120℃and134℃, respectively, when the mass ratio of the sodium carboxymethylcellulose and calcium carbonate was1:3.5.This paper also investigated the effect of sodium carboxymethyl cellulose and metalaluminium powder mass ratio (1:0.5～1:3.5) on dielectric properties and temperaturemeasured by microwave fiber optic, The present data suggested that center temperature andexternal temperature was118℃and119℃,when the aluminium powder mass ratio was1:1.5. With dielectric properties and temperature measured by microwave fiber optic asindicators, center temperature and the external temperature was134℃and163℃,respectively, when the ratio of the aluminum powder and calcium carbonate was5:7.Additionally, hardness was used to evaluate the effect of microwave baking on breadquality. Results showed that the hardness of bread decreased with microwave gear decreasing. Under the condition of the same gear, the hardness and center temperature of the dough risedwith heating time extending. Results indicated that the optimal heating time was90s. Underthis condition, hardness was1351±158g, and the temperature reached163℃. The resultsfrom the effect of the food ingredients on bread quality suggested that the optimal conditionwas adding1.2%of yeast addition amount,18%of fructose and10%of egg.Software was used to simulate microwave heating of bread. Results suggested that whencenter temperature of blank sample was165℃, the microwave susceptor sample reduced by20%at132℃. These results were in agreement with the results from microwave fiberexperiment. Moreover, microwave absorption of bread increased by34.45%, and the electricfield appeared deformation.Finally, this paper compared the quality of bread prepared by traditional oven,microwave oven and microwave with susceptor. The results showed that compared with thebread baked by traditional microwave oven, the external temperature, specific volume, andthe water content of the core of the breads baked by microwave susceptor increased18.80%,18.00%～23.35%,7.10%～27.42%, respectively, and the internal temperature, thebaking loss, and the hardness of the breads decreased15.71%,2.05%, and80.81%～85.52%respectively. Compared with bread baked by oven, the baking loss and specific volume ofbread baked by microwave susceptor increased by113.10%and24.87%～24.87%,respectively, and the water content of the core decreased by47.98%～59.11%. However thehardness value needs to be improved.