Yang Dan, Wu Gangcheng, Li Peiyan, Qi Xiguang, Zhang Hui, Wang Xingguo, Jin Qingzhe
National Engineering Research Center for Functional Food, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China.
National Engineering Research Center for Functional Food, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China.
Food Res Int. 2020 Nov;137:109338. doi: 10.1016/j.foodres.2020.109338. Epub 2020 May 19.
The properties of moisture and starch in potatoes affect the quality and oil absorption of final fried products. In this study, changes in moisture state, starch properties, and micromorphology of potato strips pretreated by microwave heating (MH) and vacuum oven drying (VOD) were investigated using low-field nuclear magnetic resonance, magnetic resonance imaging (MRI), differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy (SEM) analyses. The influence of changes in these properties on the oil content and distribution of fried potato strips was analyzed. Results showed that the decreased moisture content and changed moisture state in the pretreated samples had a positive effect on reducing the oil content. The pregelatinized starch facilitated the formation of V-type starch-lipid complexes, which formed a protective layer to prevent oil absorption. Analysis of MRI and confocal laser scanning microscopy images confirmed this finding. SEM observation showed microstructural changes might have an effect on oil absorption and its results exhibited crusts of the MH-pretreated samples thickened after frying, and the internal pores and structures of the VOD-pretreated samples became small and dense, respectively; both changes negatively affected oil absorption. Results could help understand the oil absorption behavior of starch-based food during frying and provide a basis for improving the quality and controlling the final oil content of the product.
土豆中的水分和淀粉特性会影响最终油炸产品的品质和吸油量。本研究采用低场核磁共振、磁共振成像（MRI）、差示扫描量热法、X射线衍射和扫描电子显微镜（SEM）分析，研究了经微波加热（MH）和真空烘箱干燥（VOD）预处理的土豆条的水分状态、淀粉特性和微观形态的变化。分析了这些特性变化对油炸土豆条含油量和分布的影响。结果表明，预处理样品中水分含量的降低和水分状态的改变对降低含油量有积极作用。预糊化淀粉促进了V型淀粉-脂质复合物的形成，该复合物形成了一层防止吸油的保护层。MRI和共聚焦激光扫描显微镜图像分析证实了这一发现。SEM观察表明，微观结构变化可能会影响吸油，其结果显示，MH预处理样品油炸后外皮增厚，VOD预处理样品的内部孔隙和结构分别变小变密；这两种变化均对吸油产生负面影响。研究结果有助于理解淀粉基食品在油炸过程中的吸油行为，并为提高产品质量和控制最终含油量提供依据。
