摘要:
以罗非鱼鱼皮为原料制备鱼皮明胶,通过单轴压缩实验、差示扫描量热实验(DSC)和红外光谱法(FT-IR)探讨了不同氯化钠添加量(0、0.5%、1.0%、1.5%、2.0%、3.0%,w/v)对不同浓度鱼胶凝胶样品(2%、4%、6.67%,w/v)的真实应力、杨氏模量、热焓值和结构的影响。结果表明,随着鱼胶浓度增加其真实应力和杨氏模量显著增加,表明鱼胶的凝胶强度和硬度显著增加,添加氯化钠后,鱼胶体系的凝胶强度和硬度随氯化钠添加量的增加呈现显著下降趋势,当氯化钠添加量达到3%时,鱼胶凝胶强度和硬度的值最小。差式扫描量热量热分析结果表明,随着氯化钠浓度的增加,热焓值下降,鱼胶的凝胶网络交联程度变弱。傅里叶变换红外光谱分析结果表明,随着氯化钠添加量增加,酰胺Ⅰ带吸收峰逐渐向低波数方向移动,氢键形成受到抑制,鱼胶凝胶强度降降低。研究表明氯化钠的存在破坏了鱼胶凝胶样品的空间结构,降低了鱼胶的凝胶性能。
Abstract:
The effect of sodium chloride concentration (0, 0.5%, 1.0%, 1.5%, 2.0%, 3.0%, w/v) on the true stress, Young's modulus, enthalpy and structure of different tilapia fish skin gelatin gel concentrations (2%, 4%, 6.67%, w/v) was measured by uniaxial compression, differential scanning calorimetry (DSC) and Fourier transform infrared spectrometry (FT-IR).The results showed that the true stress and Young's modulus incresed which indicated gel strength and firmness increased with the increaseing of gelatin concentrations. After the addition of sodium chloride, the gel strength and firmness decreased, while sodium chloride content was reached to 3%, the gelatin gel strength and firmness achieved a least value.DSC analysis showed that heat flow decresed which indicated the cross-linking degree of the fish gelatin gel network systerm weakened. FT-IR analysis showed that amide I band moved to low wave numbers with the increaseing of sodium chloride concentrations, the formation of hydrogen bonds in gelatin gels was inhibited, the gel strength was decreased.The experimental results showed that the presence of sodium chloride destroyed the spatial structure of the gelatin samples and reduced the gelation properties of the fish gelatin gel.
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