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題 名 | 主要果蔬預冷設備之研製和應用(1):真空預冷設備之研製與應用 |
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作 者 | 郭景儀; 蕭介宗; | 書刊名 | 農業工程學報 |
卷 期 | 33:1 1987.03[民76.03] |
頁 次 | 頁12-23+ |
分類號 | 435.61 |
關鍵詞 | 果蔬; 真空; 設備; 預冷; |
語 文 | 中文(Chinese) |
中文摘要 | 真空預冷為預冷葉菜最有效方法之一;乃於真空室中,使蔬菜水分急遽蒸發,導致其本身溫度迅速下降之過程。本研究提供真空預冷裝置之基本設計資料,探討溫度與壓力探制真空預冷系統之優缺點,做為設計大型真空預冷系統之參考,以減少國內葉菜類的損耗,達至農機國產的目標。 以壓力控制預冷預濕之青蔥與芹菜,探制點應在5.0mmHg(略高於溫度0℃時之對應壓力4.6mmHg),以避免凍傷,而未經預濕之青蔥與芹菜其壓控制點為4.0mmHg。經預冷後其重量損失為2.5﹪到6﹪之間,但不致於產生枯萎現象。 因為乾球與濕球溫度在預冷室可能有20℃之差異,以溫度控制預冷時,必須以濕球溫度控制作為基準,且設定在2℃以上,以避免青蔥與芹菜凍傷。 預冷初溫22℃之青蔥到4.2℃,預冷時間為13.6分;而預冷初溫22℃之芹菜至4.2℃只需11分鐘。主要原因是芹菜和青蔥的組織與面容比不一樣,導致預冷時間之差異。 |
英文摘要 | Vacuum precooling leaf vegetable is one of the most effective methods; and its procedures are to put the vegetable under a vacuum chamber, let the water in the vegetable evaporate and then cool down its temperature rapidly. This paper provides basic design information of the vacuum precooling systems, and investigate the advantages and disadvantages of the vacuum precooling system controlled by temperature and pressure. These results can be used as the reference for designing a large scale vacuum precooling system, reducing the deterioration of domestical leaf vegetables, and reaching the goal of producing agricultural machinery by ourselves. To avoid the frozen damage of the prewetted green onion and celery during the precooling process, the vacuum pressure must be set at 5.0 mmHg which is a little higher than the corresponding pressure 4.6 mmHg at temperature 0℃. For green onion and celery without prewetting, the pressure can be set at 4.0 m.m Hg. After precooling, the weight loss will be between 2.5﹪ and 6﹪ but the result will not cause wilting. Because the temperature differential between dry bulb and wet bulb in the precooling chamber may be about 20℃, the temperature control must be based on the wet bulb temperature, and set about 2℃ to prevent green onion and celery from the frozen damage. To precool the green onion from the initial temperature 22℃ down to 4.2℃, it will take 13.6 minutes. However, it will take 11 minutes to precool the celery from 22℃ to 4.2℃. This result may be due to different tissue and ratio of surfaces and volumes between green onion and celery. |
本系統中英文摘要資訊取自各篇刊載內容。