Ang Cai Ling, Goh Kelvin Kim Tha, Lim Kaiyang, Matia-Merino Lara
School of Food and Advanced Technology, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
Riddet Institute, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
Gels. 2022 Jun 23;8(7):399. doi: 10.3390/gels8070399.
This study focuses on understanding the effect of ionic strength on the mechanical and microstructural properties of novel composite gels containing 13% whey protein isolate (WPI) and 4% de-structured waxy potato starch (DWPS). The DWPS is a physically modified waxy potato starch treated at 140 °C for 30 min under constant shear. Thermodynamic incompatibility between WPI and DWPS was observed upon the addition of NaCl (~75 mM) or CaCl (10-75 mM). The combined effects of such thermodynamic incompatibility with the changes in protein connectivity induced by varied ionic strength led to the formation of distinctive gel structures (inhomogeneous self-supporting gels with a liquid centre and weak gels with paste-like consistency) that were different from thermodynamic compatible homogeneous self-supporting gels (pure WPI and WPI + maltodextrin gels). At ≥ 250 mM NaCl, instead of a paste-like texture, a recovered soft and creamy self-supporting gel structure was observed when using DWPS. The ability to generate a range of textures in WPI gelation-based foods by using DWPS under different ionic conditions, is a feasible strategy for formulating high-protein foods for dysphagia-aimed to be either thickened fluids or soft solids. Additionally, this acquired knowledge is also relevant when formulating food gels for 3-D printing.
本研究着重于理解离子强度对含有13%乳清分离蛋白（WPI）和4%变性糯马铃薯淀粉（DWPS）的新型复合凝胶的力学和微观结构特性的影响。DWPS是一种在140°C和恒定剪切力下处理30分钟的物理改性糯马铃薯淀粉。添加氯化钠（约75 mM）或氯化钙（10 - 75 mM）后，观察到WPI和DWPS之间存在热力学不相容性。这种热力学不相容性与不同离子强度引起的蛋白质连接性变化的综合作用，导致形成了独特的凝胶结构（具有液体中心的非均匀自支撑凝胶和具有糊状稠度的弱凝胶），这与热力学相容的均匀自支撑凝胶（纯WPI和WPI + 麦芽糊精凝胶）不同。当氯化钠浓度≥250 mM时，使用DWPS时观察到的不是糊状质地，而是恢复的柔软且呈奶油状的自支撑凝胶结构。在不同离子条件下使用DWPS在基于WPI凝胶化的食品中产生一系列质地的能力，是为吞咽困难人群配制高蛋白食品（旨在制成增稠液体或软固体）的一种可行策略。此外，在为3D打印配制食品凝胶时，这些获得的知识也具有相关性。
