Effects of Sweet Potato Protein Hydrolysates on Formation of Calcium Ion-Induced Sodium Alginate Gel(甘薯蛋白水解物对钙离子诱导下海藻酸钠凝胶形成的影响)

To study the effects of sweet potato protein hydrolysates (SPPHs) on the gel structural properties of sodium alginate (SA) and to achieve the high quality utilization of sweet potato processing residues, SPPHs with different molecular weights (1000,2000,3000,8000Da) were added to SA to investigate their effects on the formation process and gel properties of SA gels induced by calcium ions in terms of gelation process, critical gel behavior, textural properties, water distribution and microstructure. The results showed that the interaction between SPPHs and SA promoted its cross-linking with calcium ions, which could strengthen the intermolecular structure, accelerate the appearance of critical gel point in the process of calcium cross-linking and reduce the amount of calcium ions required for the critical point. Among them, SPPHs with molecular weight of 8000Da had a more significant strengthening effect on SA gel, and the reaction sensitivity with calcium ions was the strongest, resulting in the formation of the largest gel strength. The average value of the storage modulus G′ value of SA-SPPHs8000 during the gelation process with 0.100% CaCl2 was 17.05kPa. It was much higher than that of blank group SA (2.14kPa). The composite gel with the addition of SPPHs behaved as a typical non-Newtonian fluid, and the larger the molecular weight of the added SPPHs, the stronger the internal structural cross-linking of the formed composite gel, the stronger the pseudo plasticity, and the greater the viscosity. In addition, the addition of SPPHs significantly improved the hardness, elasticity and chewiness of SA gel beads, and improved the water holding capacity and internal structural stability of the gel beads. The results showed that the addition of SPPHs could strengthen the internal structure of SA gels and promote calcium cross-linking to form more compact three-dimensional network gels, which in turn improved the texture and other properties of SA gels. Compared with other protein hydrolysates, SPPHs had greater advantages. Meanwhile, this study could broaden the application scope of sweet potato protein, improve its added value and further realize the comprehensive utilization of sweet patato protein resources.(为研究甘薯蛋白水解物(sweet potato protein hydrolyzates,SPPHs)对海藻酸钠(sodium alginate,SA)凝胶结构特性的影响,实现甘薯加工废弃物的高值化利用,在SA中分别添加不同分子质量(1000、2000、3000、8000Da)的SPPHs,从凝胶化过程、临界凝胶行为、质构特性、水分分布及微观结构等方面研究SPPHs对钙离子诱导下SA凝胶的形成过程及凝胶特性的影响。结果表明:SPPHs与SA的相互作用促进了其与钙离子的交联,可强化分子间结构,加快钙交联过程中临界凝胶点的出现,减少临界点所需的钙离子量。分子质量为8000Da的SPPHs对SA凝胶的强化作用更显著,与钙离子反应敏感性最强,形成凝胶强度最大,SA-SPPHs8000复合凝胶在与质量分数为0.100% CaCl2的凝胶化过程中储能模量G′值的平均值达到17.05kPa,远大于SA凝胶(2.14kPa)。添加SPPHs的复合凝胶表现为典型的非牛顿流体,添加的SPPHs分子质量越大,形成的复合凝胶内部结构交联增强,假塑性越强,黏度越大。此外,SPPHs的加入显著提高了SA凝胶珠的硬度、弹性和咀嚼性,提高了凝胶珠的持水能力和内部结构稳定性。研究结果表明,添加SPPHs能强化SA凝胶的内部结构,促进钙交联作用,使其形成更为紧密的三维网络凝胶,进而改善SA凝胶的质构等特性。与其他蛋白水解物相比,SPPHs对SA凝胶的结构特性具有较好的改善效果。研究结果旨在拓宽甘薯蛋白的应用范围,提高其附加值,进一步实现甘薯蛋白资源的综合利用。)