牡蛎冷冻干燥后复水特性及微观结构的研究

Rehydration characteristics and microstructure of freeze-dried oyster

研究牡蛎冷冻干燥后的复水特性,将新鲜牡蛎分为直接冻干组(Fresh+FD组)、预煮处理后冻干组(Boiled+FD组)和自然干燥组(Fresh+ND组),考察干燥后牡蛎的干燥比、复水比、复水率和微观结构的差异。结果表明:两冻干组牡蛎的含水量远低于自然干燥组,在常温和沸水中的复水比和复水速率均大于自然干燥组,冷冻干燥更有利于牡蛎中水分的去除和复水;干燥后牡蛎闭壳肌微观形态优劣程度依次为Fresh+FD组>Boiled+FD组>Fresh+ND组,其中Fresh+FD组闭壳肌纤维细长、舒展,间隙均匀,Fresh+ND组闭壳肌纤维束堆叠,组织致密;常温复水80min,两冻干组牡蛎的复重系数和复水率均高于自然干燥组。

To study the effect of drying methods on rehydration prop erties of the dr;.ed oyster, the fresh oysters were divided ;.nto three groups, direct freeze drying （Fresh＋FD）, freeze drying after boiling pretreatment （Boiled＋FD）and natural drying group（Fresh＋ ND）, respectively. Drying ratio, rehydration ratio, rehydration percentage and microstructural differences were investigated. The results showed that the water content of the two freeze-dried groups was far lower than the Fresh＋ND oysters. And the two freeze-dried oyster groups both had a higher rehydration ratio and rehydration velocity than the Fresh＋ ND oyster in water bath at room temperature and 100 ＊C, suggesting that freeze drying facilitated the oysters for water removal and rehydration. The effect of drying method on the adduet muscle＇s structure was in a superior to inferior order.. Fresh＋ FD〉 Boiled＋FD〉 Fresh＋ ND. The adduct muscle fibre of Fresh＋ FD was slender, and stretched with well-distributed interfibrillar gaps, whereas the tissue of Fresh＋ ND group was compacted with aggrega ted muscle fibres. After rehydration at room temperature for 80 min, rehydration coefficient and rehydration percentage of the two freeze-dried oyster were higher than that of naturally dried oyster.