Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/51785
標題: 乾燥對胡蘿蔔生理活性和品質的影響
Effect of Dehydration on the Physiological Activity and the Quality of Carrot
作者: 藍子強
Lan, Zi-Qiang
關鍵字: carrot;胡蘿蔔;dehydration;respiration;乾燥;呼吸作用
出版社: 食品科學系
摘要: 
中文摘要
乾燥為食品保存的一種方法,但在乾燥過程中亦會引起某些物理、化學及生化改變於食品材料上。這些改變的影響如何,則視乾燥前處理、乾燥方法及復水程序等而定。當考慮以乾燥為保存方法時,值得注意的是,處理之目的是在獲得生化代謝路徑不受傷害的原料,亦即趨向於獲得細胞具有生存性的產品與否。穀類發粉及活性麵包酵母之乾燥,即為保存細胞生存性及不危害生化代謝活性等的例子;另一方面,水果、蔬菜、肉、蛋等之乾燥,則擔負了得到具有穩定感官及營養特質保存性產品之責任。此外,觀察植物組織的呼吸作用變化亦可以對其組織細胞活性有一粗略的了解。本研究的目的在觀察不同乾燥方法及其後續的復水,對胡蘿蔔組織呼吸作用活性的影響。實驗中,對新鮮及不同乾燥程度胡蘿蔔組織的呼吸作用皆有測量,對復水後的樣品亦作有呼吸作用的測定。樣品的水活性、硬度測定以及電子顯微鏡觀察,皆可以對胡蘿蔔組織結構所受到的乾燥加工操作之破壞和其呼吸作用的關係,作進一步的了解。
研究結果顯示胡蘿蔔組織以乾燥處理後,會導致細胞結構及組織的傷害及改變,此一傷害改變會表現在呼吸作用活性上,且乾燥對組織結構的傷害是不可逆的。乾燥對胡蘿蔔組織結構及呼吸作用路徑之傷害,多在乾燥初期造成。而冷凍乾燥對胡蘿蔔組織結構及呼吸作用路徑所造成之傷害較低且較和緩。冷凍乾燥中,在較低的冷凍溫度所致的較高冷凍速率及較短的預凍時間下,胡蘿蔔組織復水後會有較高的呼吸作用活性恢復。滲透脫水對胡蘿蔔組織呼吸作用活性之影響方式和熱風乾燥與冷凍乾燥不同,而經過滲透處理後再進行乾燥的產品,在復水後其呼吸作用活性會有較高之恢復。保水性、硬度和SEM觀察等所得到之結果,會和呼吸作用活性的分析結果具有相當程度的相似性。

英文摘要
Drying as a method of food preservation causes many physical, chemical, and biochemical changes in processed materials. Effects of these changes are dependent on predrying treatments, drying methods and parameters as well as rehydration procedures. Considering drying as a method of preservation it is worth noting that some dehydration methods are aimed at obtaining materials with uninjured biochemical pathways, while others lead to products in which the viability of cells is not an important issue. Drying of seed grain, powder starters or active baker’s yeast are the examples of those drying processes in which preservation of viability of cells and undamaged biochemical activity are the aims of the process. On the other hand, drying of fruits, vegetables, meat, eggs is undertaken in order to obtain shelf-stable products with preserved sensory and nutritional attributes. Moreover, observing changes of respiratory activity can roughly understand the activity of tissue cells. The aim of this study was to observe changes of respiratory activity of cube carrot tissue subjected to different drying ways and subsequent rehydration. In this work, respiration of carrot tissue was measured in the fresh state and at different degrees of dryness after treated with different drying methods. Moreover, respiration of rehydration samples was measured. Measurement of water holding capacity, firmness and scanning electron microscopic examination can further understand the relationship between structural damages and respiratory activity.
Results showed that dehydration of carrot tissue caused substantial changes in cell structure and organization. It was manifested by a decrease in respiration activity. Most of the injury to tissue structure and respiration pathways was done at the initial stages of drying. Freeze drying caused less and tender damage to the structural and respiratory activity of carrot samples. In freeze drying, lower pre-freezing temperature and shorter pre-freezing time would make carrot tissue have higher respiratory activity after rehydration. Osmotic dewatering also affected respiration of carrot tissue but the mechanism of injury seemed different from that occurring during convective drying and freeze drying. After osmotic treatment, the dried carrot would possess higher respiratory activity after rehydration. Moreover, the results of water holding capacity, firmness, and scanning electron microscopic examination were similar to the results of respiratory activity experiment.
URI: http://hdl.handle.net/11455/51785
Appears in Collections:食品暨應用生物科技學系

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