Salem Ali, Fakhfakh Nahed, Jridi Mourad, Abdelhedi Ola, Nasri Moncef, Debeaufort Frédéric, Zouari Nacim
Laboratory of Enzyme Engineering and Microbiology, Engineering National School of Sfax (ENIS), University of Sfax, Sfax, Tunisia; High Institute of Applied Biology of Medenine, University of Gabes, Medenine, Tunisia.
Laboratory of Enzyme Engineering and Microbiology, Engineering National School of Sfax (ENIS), University of Sfax, Sfax, Tunisia; Higher Institute of Biotechnology of Beja, University of Jendouba, Beja, Tunisia.
Int J Biol Macromol. 2020 Nov 1;162:1-10. doi: 10.1016/j.ijbiomac.2020.06.033. Epub 2020 Jun 15.
The effects of two pretreatments (microwaves or oven-drying) on the dogfish (Squalus acanthias) skin as well as two drying processes (freeze-drying or spray-drying) on the extracted gelatins were studied. Thus six types of gelatins were obtained, three of which were freeze-dried (FG) and the others were spray-dried (SG), from the untreated skin (US), microwaves-pretreated skin (MS) and oven-pretreated skin (OS). The highest yield (8.67%) was obtained for the OSFG, while the lowest one (3.06%) was measured for the OSSG. Interestingly, all gelatins exhibited relatively high protein (84.02-89.53%), and low lipid (0.50-1.71%) and ash (3.05-7.17%) contents. In addition, gelatins were analyzed by the Fourier transform infrared and the spectra displayed important differences in some specific peaks, particularly in the amide I, amide II and amide III. The gelatins extracted from the untreated skin, regardless the drying method, presented the highest foaming capacity. The textural profile analysis showed that USSG was the hardest (213.6 g) and the chewier (23.8 N × mm) gelatin. Moreover, analysis of thermal properties showed that USSG also has the highest glass-transition temperature. The interesting properties of gelatin extracted from dogfish skin encourage their future use as a functional ingredient in industrial food formulations.
研究了两种预处理方法（微波或烘干）对角鲨（棘鲨）皮肤的影响，以及两种干燥工艺（冷冻干燥或喷雾干燥）对提取的明胶的影响。由此获得了六种类型的明胶，其中三种是冷冻干燥的（FG），另外三种是喷雾干燥的（SG），分别来自未处理的皮肤（US）、微波预处理的皮肤（MS）和烘干预处理的皮肤（OS）。OSFG的产率最高（8.67%），而OSSG的产率最低（3.06%）。有趣的是，所有明胶的蛋白质含量相对较高（84.02 - 89.53%），脂质含量较低（0.50 - 1.71%），灰分含量较低（3.05 - 7.17%）。此外，通过傅里叶变换红外光谱对明胶进行分析，光谱在一些特定峰处显示出重要差异，特别是在酰胺I、酰胺II和酰胺III处。无论采用何种干燥方法，从未处理皮肤中提取的明胶具有最高的发泡能力。质地剖面分析表明，USSG是最硬的（213.6克）和咀嚼性最强（23.8牛×毫米）的明胶。此外，热性能分析表明，USSG还具有最高的玻璃化转变温度。从角鲨皮肤中提取的明胶的有趣特性促使其未来有望用作工业食品配方中的功能性成分。
