关键词: 驴皮, 阿胶, 酶解脱毛, 质量

Abstract: [Objective]To develop a high-efficient dehairing method of donkey hides suitable for industrial production of donkey hide gelatins. [Method]The dried donkey hides were soaked with water and then enzymatically dehaired with 1% alkaline protease and 1% neutral protease at low temperature （4 ℃）, respectively. The dehairing time, dehairing rate and odor during dehairing process of the donkey hides dehaired with different methods were determined, evaluated and compared. The gelatins were prepared with the soaked dry donkey hides enzymatically dehaired with 1% alkaline protease and 1% neutral protease, and with the fresh donkey hides mechanically dehaired. Furthermore, the yield, output rate, appearance and odor of the donkey hide gelatins prepared with different raw materials were compared; the quality associated indicators, including the contents of water, ash, water-insoluble matter and four kinds of amino acids, of the gelatins prepared with the enzymatically dehaired donkey hides were determined and compared with their corresponding quality standards provided in China Pharmacopoeia （2015 edition, first part). [Result]The dehairing effects were observed in donkey hides on 2^nd day after enzymatically dehaired with 1% alkaline protease （pH=10.5） and 1% neutral protease （pH=7.5） at low temperature （4 ℃）, and the dehairing rate of the enzymatically dehaired donkey hides reached up to 90% on 5^th day; the enzymatically dehaired donkey hides had normal odor produced during dehairing, but not the decomposed odor. The yields and output rates of gelatins prepared with 1% alkaline protease enzymatically dehaired donkey hides, 1% neutral protease enzymatically dehaired donkey hides, and mechanically dehaired fresh donkey hides were 113.0 g, 109.4 g, 129.3 g and 13.8%, 13.1%, 13.2%, respectively; the color and flavor of the gelatins prepared with the enzymatically dehaired donkey hides were red and aromatic, and the color was brighter than that of the gelatins prepared with the mechanically dehaired fresh donkey hides. The contents of water, ash and water-insoluble matter in the gelatins prepared with the enzymatically dehaired donkey hides were in accordance with and superior to their corresponding quality standards provided in China Pharmacopoeia （2015 edition, first part）, and the contents of L-hydroxyproline, glycine, alanine and L-proline were much higher than those in the above standards. [Conclusion]At low temperature （4 ℃）, 1% alkaline protease and 1% neutral protease exhibit good enzymatic dehairing effects in the soaked dry donkey hides, and the quality of the gelatins prepared with the enzymatically dehaired donkey hides are in accordance with the standards provided in China Pharmacopoeia （2015 edition, first part）.

Key words: donkey hides, donkey hide gelatins, enzymatic dehairing, quality