Vicente Ainhoa, Mauro Raúl R, Villanueva Marina, Caballero Pedro A, Hamaker Bruce, Ronda Felicidad
Department of Agriculture and Forestry Engineering, Food Technology, College of Agricultural and Forestry Engineering, University of Valladolid, Av. Madrid, 44, 34004 Palencia, Spain; Research Institute on Bioeconomy - BioEcoUVa, PROCEREALtech Group, University of Valladolid, Spain.
Whistler Center for Carbohydrate Research, Department of Food Science, Purdue University, West Lafayette, IN, USA.
Int J Biol Macromol. 2025 Jul;318(Pt 4):145094. doi: 10.1016/j.ijbiomac.2025.145094. Epub 2025 Jun 8.
This study investigated the effects of microwave treatment (MWT) on the molecular structure and properties of starch and proteins, as well as on the pasting properties of flours. MWT was performed under uniform conditions (25 % moisture, 100 °C, 30 min) for amaranth, buckwheat, quinoa, and sorghum in two forms: grain and flour. MWT generally caused fragmentation of amylose and amylopectin, reducing amylopectin molar mass by up to 39 % and amylose long chains by up to 18 %, disrupting protein secondary structure (α-helix content up to -5 %), and altering morphology of starch granules and protein. All flours presented an orthorhombic crystal structure that was maintained after MWT. MWT changes were generally more pronounced in flour than in grain treatments, with amaranth showing the greatest change and buckwheat the least. Microwave-induced changes in pasting properties depended on intrinsic flour properties and structural modifications. Principal component analysis revealed a consistent change in all treated samples, but to varying degrees depending on botanical origin and treatment form. This study contributes to a deeper understanding of structural changes of starch and proteins by MWT and their contribution to altered pasting properties depending on whether the treatment is applied to grain or flour.
本研究调查了微波处理（MWT）对淀粉和蛋白质分子结构与性质以及对面粉糊化特性的影响。对籽粒苋、荞麦、藜麦和高粱的籽粒及面粉两种形式，在均匀条件（25%水分、100°C、30分钟）下进行微波处理。微波处理通常会导致直链淀粉和支链淀粉断裂，使支链淀粉摩尔质量降低多达39%，直链淀粉长链降低多达18%，破坏蛋白质二级结构（α-螺旋含量降低多达5%），并改变淀粉颗粒和蛋白质的形态。所有面粉呈现出正交晶体结构，微波处理后该结构得以保持。微波处理引起的变化在面粉处理中通常比在籽粒处理中更明显，籽粒苋变化最大，荞麦变化最小。微波诱导的糊化特性变化取决于面粉的固有特性和结构改变。主成分分析表明，所有处理样品都有一致变化，但根据植物来源和处理形式变化程度不同。本研究有助于更深入了解微波处理对淀粉和蛋白质结构变化的影响，以及根据处理对象是籽粒还是面粉，其对糊化特性改变的作用。
