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Experimental Study on Drying Process of Vacuum Freezing and Hent Pump-microwave

Author: ZhengLiJing
Tutor: GuanZhiQiang
School: Guangdong Ocean University
Course: Aquatic Products Processing and Storage Engineering
Keywords: Vacuum freeze-drying Color protection Heat pump drying Microwave drying Combined drying Process parameters
CLC: TS254.4
Type: Master's thesis
Year: 2010
Downloads: 193
Quote: 0
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Abstract

Farreri, lychee, and tilapia for raw materials, vacuum freeze-drying and heat pump drying - Microwave Combined two drying process characteristics of the method. Vacuum freeze-drying process of the adductor muscle of Chlamys farreri experimental material twice relented once transformer process parameter adjustment method of freeze-dried experiments in the freeze-drying process, the results show that: first variable temperature materials center temperature affect the rehydration rate and energy consumption of the freeze-dried samples, when the the materials center temperature 1 ℃ first temperature adjustment, the sample rate of rehydration and rehydration fastest, best quality and drying energy consumption to a minimum. Single factor test based on the five factors and four levels of the orthogonal test, come to the primary and secondary relationship of the various process parameters affect the the lyophilized energy consumption and product quality: the first high temperature of the heating plate heating plate temperature> Drying chamber low pressure> heating plates cryogenic> high pressure of the drying chamber, the best combination of various factors is C4E1B3D3A1, i.e. heating plate first high temperature of 33 ° C, the second elevated temperature is 39 ° C, the drying chamber a low pressure is 40 Pa, the low temperature of the heating plate 36 ° C. the drying chamber the high pressure is between 60 Pa. Heat pump drying device litchi drying experiment, integrated sensory evaluation index for the evaluation indicators, single factor investigated the of blanching and L-cysteine ??(L-Cys), citric acid and Vc health ring protective coloring agent content dried lychee protecting color effect and color protection technology with four factors and three levels of orthogonal experimental optimization. The results show that the blanching time and content of the color fixative can significantly affect the color and shape of dried lychee, primary and secondary effects of the order: hot drift time gt; L-Cys gt; the citric acid gt; the Vc optimized care color process parameters: blanching time 160s, L-Cys content 0.2%, citric acid content of 5%, 0.1% Vc content to optimize the conditions under sensory evaluation index reached 23.5. Litchi as experimental material, the experimental study of the heat pump - microwave combination drying. First, the use of heat pump drying device drying experiments obtained under constant drying conditions litchi drying curve and drying rate curves, which determine a heat pump - the microwave drying moisture conversion point parameter level. And sensory overall performance index for the evaluation criteria by three factors and three levels orthogonal experiment to study the heat pump drying temperature, heat pump - microwave conversion point of moisture content and microwave drying time of the heat pump - the microwave drying lychee quality impact. The results show that: the heat pump drying temperature are the main factors to affect the quality of litchi dry goods, followed by heat pump - microwave conversion point moisture content, and finally the microwave drying time. Based on this, within the experimental range is drawn so that the quality of litchi drying the best combination of parameters: heat pump drying temperature of 50 ° C, the moisture content of the heat pump - microwave conversion 1.0g / g, microwave drying time 2.5min, under the conditions of this combination of parameters, sensory evaluation composite score of 27. The heat pump - Microwave Joint Drying of aquatic products as raw materials to the tilapia fillets. Obtained by single factor experiment of microwave drying of tilapia fillets, tilapia fillets through the heat pump dried to a moisture content of 40% into the microwave drying process, the greater the microwave power, the faster the rate of drying, but power than large, resulting in poor quality of the dried product. Microwave drying time segment comparative test proved: tilapia sheet drying process the single drying period is too long is not suitable, will lead to poor product quality the single drying period is shorter, the quality of the product will be increased accordingly. Preliminary test of heat pump drying of tilapia fillets obtained heat pump wind speed drying time and quality of tilapia fillets have a certain influence, the study showed that: the greater the wind speed, the faster the rate of drying, but as the wind speed increases. smaller wind speed on the drying rate, the drying rate decreases, the heat pump drying process, the drying period using microwave drying relatively reasonable. On the basis of single-factor test to the heat pump temperature, moisture content and microwave power conversion point as the independent variable, complex water was due to the variable drying energy consumption, through the center combination test, response surface analysis, were obtained Luo non fillets optimal combination drying process.

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