罗非鱼鱼鳞明胶蛋白膜的制备及特性
Preparation and characterization of edible gelatin films from tilapia (Tilapia zillii) scales
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摘要: 利用罗非鱼鱼鳞提取明胶制备蛋白可食膜,考察了明胶蛋白的浸提温度、浸提时间以及甘油添加量对蛋白膜抗拉伸强度(TS)、断裂延伸率(EAB)等理化性质的影响。结果发现明胶蛋白提取率随浸提温度的升高和浸提时间的延长逐渐增大。利用80℃加热0.5、1h浸提时,明胶蛋白不易被降解,以其为原料制备的蛋白膜TS可高达44MPa。另一方面,当蛋白膜中的甘油含量从20%增加到40%时,膜的TS从44.09MPa下降至16.45MPa,而EAB、水蒸汽透过率(WVP)和透明度值则逐渐升高。然而膜的颜色不受甘油添加量的影响。SDS-PAGE结果显示甘油对明胶膜的蛋白组分没有明显的影响。根据DSC的分析结果可知,甘油含量为20%时,明胶蛋白膜的玻璃化转变温度(Tg)高达113.97℃,但随着甘油含量的增加,膜的Tg逐渐降低。Abstract: Edible films based on the gelatin from tilapia scales were prepared. The effects of temperature and time of gelatin extraction, along with glycerol concentration on the film properties such as tensile strength (TS) and elongation at break (EAB) were also investigated. The extraction yield of scale gelatin was increased with increasing extraction temperature and time. TS of films prepared from the scale gelatin which was hardly degraded when extracting at 80℃ for 0. 5h or 1h, could reach a higher value at around 44MPa. When glycerol concentration in gelatin films was increased from 20% to 50%, TS of films was decreased from 44. 09MPa to 16. 45MPa, while EAB, water vapor permeability and transparency value was increased. However, the color of gelatin films was not markedly influenced by glycerol. SDS-PAGE patterns of gelatin films containing glycerol of different concentration showed no differences in the protein bands. Based on the DSC analysis, the glass transition temperature (Tg) of scale gelatin films with glycerol concentration of 20% could reach to 113. 97℃, but decreased significantly with the glycerol concentration increasing.