[关键词]
[摘要]
研究不同聚合度柿单宁(DP 26/5)对高酯/低酯(HM/LM)果胶在变剪切速率及变温下稳态和动态流变性的影响。利用TA-DHR2流变仪测定柿单宁-果胶复合物的流变学性质。静态流变特性测试结果表明,柿单宁未改变HM/LM果胶的流体类型,符合Cross模型,表现为剪切变稀,呈假塑性非牛顿流体特征。随着温度的升高柿单宁-果胶复合体系显示出粘度下降的趋势,符合Arrhenius方程。在同等温度条件下,0.2%柿单宁能显著增强HM/LM果胶粘度(p<0.001),且柿单宁-HM果胶复合物的粘度值略高于柿单宁-LM果胶复合物的粘度值。柿单宁聚合度对果胶粘度的影响不明显。此外,动态流变性质测试结果表明,DP26/5柿单宁能够缩短HM/LM果胶凝胶化相转变时间,降低其凝胶化相转变温度。柿单宁对果胶流变性质的影响对开发柿单宁-果胶功能性复合配料提供理论依据。
[Key word]
[Abstract]
The effects of different polymerization degrees of persimmon tannin (DP 26/5) on the steady and dynamic rheological properties of high-methoxyl/low-methoxyl pectin (HM/LM) were investigated under various shear rates and temperatures. TA-DHR2 rheometer was used to measure the rheological properties of persimmon tannin-pectin complex. The results of static rheological tests indicated that persimmon tannin did not change the fluid type of HM/LM pectin, which was in line with Cross model, showing a shear-thinning and the pseudoplastic non-Newtonian fluid characteristic. Furthermore, the persimmon tannin-pectin composite system showed a tendency of decreasing viscosity with the increase of temperature, which was in accordance with the Arrhenius equation. Under the same temperature conditions, 0.2 % of persimmon tannin could significantly enhance the viscosity of HM/LM pectin (p < 0.001), and the viscosity of tannin-HM pectin complex was slightly higher than that of tannin-LM pectin complex. The degree of polymerization of persimmon tannin had no obvious effect on the viscosity of pectin. In addition, the results of dynamic rheological properties showed that DP26/5 persimmon tannin could shorten the HM/LM pectin gelation time and gelation temperature. Consequently, the effects of persimmon tannin on the rheological properties of pectin provided a theoretical basis for the development of functional compound ingredients of persimmon tannin-pectin.
[中图分类号]
[基金项目]
公益性行业专项“现代柿产业关键技术研究与试验示范”(NO.201203047)