可得然胶-大米淀粉异质多糖共混体系热不可逆凝胶物性分析

Physicochemical Property Analysis of Thermally Irreversible Gels on Curdlan Gum-Rice Starch Heteropolysaccharide Blends

摘要:

为提升大米淀粉（RS）物性和拓展其应用领域，该研究采用流变、扫描电镜、低场核磁及XRD等分析技术系统研究了可得然胶（CL）添加量对CL-RS共混体系热不可逆凝胶结构与性能的影响。结果表明：当CL添加量达到0.60%质量分数阈值时，与对照组相比，糊化温度降低1.69 ℃，回生黏度提升25.00%，析水率降低47.73%，横向弛豫时间T22缩短58.01%至6.45 ms；较0.40% CL添加组，其储能模量峰值提升40.20%，降温末G'值增加21.46%，咀嚼性提高24.76%。CL添加量≤0.60%时，回生黏度、各相变温度节点的黏弹模量和咀嚼性、结合水峰面积占比值（A21）均随CL添加量增加呈显著提升趋势，而水分子横向弛豫时间T22及T23值、凝胶析水率则持续降低，伴随微观结构孔隙率降低且分布均匀性改善。超阈值添加（0.80%）则导致降温末G'与咀嚼性分别回落11.37%及42.89%，微观结构由多孔网络转变为致密层状。CL的引入促使RS通过增强氢键交联密度构建稳定的三维网络。综上所述，CL添加量阈值效应可有效调控RS基材共混凝胶性能，为开发含RS新型异质多糖食品提供了理论参考。

Abstract:

In order to improve the physical properties of rice starch (RS) and expand its application fields, analytical techniques such as rheological analysis, scanning electron microscopy (SEM), low-field nuclear magnetic resonance (LF-NMR), and X-ray diffraction (XRD) were used to systematically study the influence of curdlan (CL) addition amount on the structure and properties of the thermally irreversible gel of the CL - RS blends. It was found that when the CL addition amount reached the threshold of 0.60%, compared with the control, the gelatinization temperature was decreased by 1.69 °C, the retrogradation viscosity was increased by 25.00%, the syneresis rate was reduced by 47.73%, and the transverse relaxation time T22 was shortened by 58.01% to 6.45 ms. Compared with the group with 0.40% CL addition, the peak value of the storage modulus was increased by 40.20%, the G' value at the end of cooling was increased by 21.46%, and the chewiness was improved by 24.76%. When the CL addition amount was ≤ 0.60%, the retrogradation viscosity, the viscoelastic modulus at each phase-change temperature node, the chewiness, and the ratio of the bound-water peak area (A21) were increased significantly with the increase of the CL addition amount, while the transverse relaxation times T22 and T23 of water molecules, and the gel syneresis rate were decreased. Meanwhile, the porosity of the microstructure was decreased and the distribution uniformity was improved. When the CL addition was exceeded the threshold (0.80%), a reduction of 11.37% in G' at the end of cooling and a 42.89% decrease in chewiness were observed, accompanied by a transformation of the microstructure from a porous network to a dense layered structure.The mechanism was attributed to CL-induced enhancement of hydrogen-bond crosslinking density, which facilitated the formation of stable three-dimensional RS networks.In conclusion, the properties of the RS-based blend gel were effectively regulated by the threshold effect of CL addition amount, and a theoretical reference was provided for the development of new RS-based heterogeneous polysaccharide blend system foods.