谷朊粉调控高含糖食品物料冻干品吸湿性及机理研究

High hygroscopicity of fruit powders such as jujube and wolfberry powder causes agglomeration, stickiness, and deliquescence of the material in processing and storage, which is a difficult problem to be solved urgently in industry. Previous study found that adding a small amount of wheat gluten with low solubility could significantly reduce the hygroscopicity of aforementioned food materials and it works better with polysaccharides. However, its mechanism is unclear. This project intends to choose fructose, glucose, sucrose to form simulated syrup, and firstly, the effect of wheat gluten on the hygroscopic characteristics of lyophilized simulated syrup is studied. Secondly, the effects of gliadin, glutelin and gluten macropolymers on hygroscopic behavior of typical lyophilized simulated syrup are studied. Then different types of polysaccharides are selected as the representatives to explore the influence of interaction between wheat gluten and coexisting polysaccharide on structures and hygroscopic characteristics of typical lyophilized simulation syrup and establish a correlation between them. Finally, the effect of water on the interaction and structure of typical lyophilized polysaccharide-wheat gluten complex in the presence of high sugar was studied. These are to find out the effect and mechanism of wheat gluten and its interaction with coexisting polysaccharide on hygroscopicity of high sugar matrix, which would provide practical theoretical guidance for moisture resistance in the processing and storage of hygroscopic fruit powders and enrich the theory of water migration and control in food processing.

枣粉、枸杞粉等高糖果粉的高吸湿性，致使其在加工、贮藏中易发生结块、发粘、潮解的问题亟待破解。溶解度极低且添加量很少的谷朊粉可明显降低该类原料的吸湿性，且共存多糖能够进一步增进阻湿性，但相关机制不明。本项目拟选择果糖、葡萄糖、蔗糖形成组分清晰的模拟糖浆，首先研究谷朊粉添加对模拟糖浆冻干品吸湿特性的影响规律；其次探讨麦醇溶蛋白、麦谷蛋白及其聚合体与典型模拟糖浆冻干品吸湿行为的关系；然后选择若干不同类型的多糖作为共存多糖代表，探索谷朊粉与共存多糖互作对典型模拟糖浆冻干品结构及吸湿特性的影响，建立三者相关性；最后研究水分对典型多糖-谷朊粉在高糖下冻干后的相互作用和结构的影响。以期探明谷朊粉添加及其与共存多糖的相互作用对高糖基质吸湿性的影响规律和机制，为高吸湿性果粉等食品配料的加工贮藏中的阻湿提供现实理论指导，并丰富食品加工中水分迁移与控制的相关理论。

苹果粉、枣粉等高糖果粉的高吸湿性，致使其在加工、贮藏中易发生结块、发粘、潮解的问题亟待破解。本项目首先选择果糖、葡萄糖、蔗糖形成组分清晰的模拟糖浆，研究了谷朊粉添加对模拟糖浆冻干品吸湿特性的影响规律，发现果糖的平衡含水率显著高于蔗糖和葡萄糖，且随着相对湿度的增加差距增大。研究了添加不同比例的谷朊粉调控果糖冻干品吸湿的影响规律，谷朊粉的加入对于果糖的吸湿有非常明显的抑制效果，并且在相对湿度高于43%的环境中Fru:WG=2:8的抑制效果更好。在25℃、75%相对湿度下，果糖与谷朊粉比例为3:7和2:8的冻干样品EMC分别降至16.00%和14.61%。谷朊粉的添加可显著增强样品表面的疏水能力，并可限制果糖冻干品中水分向高自由度的迁移，降低果糖的吸水能力。.考察了麦谷蛋白和麦醇溶蛋白对冻干果糖吸湿性的抑制作用。结果表明，在果糖:麦谷蛋白/麦醇溶蛋白为3:7的体系中，添加麦谷蛋白的样品平衡含水率低于添加麦醇溶蛋白的样品，且在69%相对湿度下，两者差距达到最大值0.68%；当果糖与两种蛋白质质量比为2:8时，两种体系的平衡含水率无明显差距，所以在果糖占比较高的体系中，麦谷蛋白的抑湿效果更好。麦谷蛋白和麦醇溶蛋白均可以降低其吸湿性，但麦谷蛋白效果更突出，这可能与麦谷蛋白具有更强的疏水性有关。另外，麦醇溶蛋白和麦谷蛋白的加入能够影响样品中水分的状态，降低吸水量，并减少水分向高自由度方向的迁移程度，相较于麦醇溶蛋白，麦谷蛋白对降低水分自由度产生了更有效的影响。.选择乙基纤维素、魔芋葡甘聚糖和D-甘露糖醇作为共存多糖代表，探索了谷朊粉与共存多糖互作对典型果粉冻干品结构及吸湿特性的影响。发现不同多糖协同谷朊粉抑制吸湿具有不同的效果，并对其规律和机制进行了研究。.本研究可为高吸湿性果粉等食品配料的加工贮藏中的阻湿提供现实理论指导，并丰富食品加工中水分迁移与控制的相关理论。