摘要:
本文以碎牛皮为原料,通过差式扫描量热仪、红外光谱、扫描电镜等检测手段,考察了吸水指数、水溶性、表观形貌、质构特性及热力学特性等参数,研究了模压成型工艺和单螺杆挤压成型工艺对狗咬胶品质的影响,特别是蛋白质结构对产品性能的影响。实验结果表明:和模压成型工艺相比较,经单螺杆挤压成型工艺所得到产品的表观密度、吸水性指数、硬度和咀嚼度均显著提升(p<0.05)。这与两种制备工艺对蛋白质分子结构的改变程度有一定的相关性,即牛皮经过螺杆挤压处理后,蛋白质分子结构发生改变,α螺旋结构部分展开,β-折叠结构及无规卷曲含量相应增多,分子间交联程度增强,进而改变了产品的质构等表观特性。螺杆挤压工艺所得的产品的总体性能指标好于模压成型工艺所得的产品。
关键词:
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碎牛皮
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狗咬胶
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成型
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螺杆挤压
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微观结构
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理化性质
Abstract:
The common tailing, cowhide offcuts, was selected as raw material for dog chew products. Meanwhile, several techniques, such as differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and so on, were applied to analyze physicochemical properties of product in order to distinguish the influences of two processes on properties of products. Many efforts were invested on the effect of protein structure modification on product properties. The results revealed that compared with the product made by the injection molding process, the one obtained by the single screw extrusion forming process had significant better performance in apparent density, hardness and chewiness (p<0.05), which ascribed to the different extent of protein molecule structure modifications in these two processes. In the extrusion process, protein molecules preferred to contain more β-sheet and random coil with the cost of α-helic and enhanced cross-linking process. As a result, in generally, the product made by single screw extrusion forming process presented better quality than the one made by the injection molding process.