Abstract: To explore the microscopic mechanism of different small‑molecule sugars in texture formation and their effects on the quality of vacuum‑freeze‑dried pear slices，pear slices were pretreated with glucose，fructose，and sucrose as penetrants，and then the samples were prepared by vacuum freeze‑drying.The physicochemical properties，texture characteristics，microstructure and cell wall chemical constitution of pear slices were systematically analyzed by conventional physical and chemical detection combined with Fourier transform infrared spectroscopy and X‑ray diffraction，with blank group as control（CK）.The results showed that compared with the CK group，small molecule sugar treatments significantly increased the brightness index of the samples，with the largest increase observed in the sucrose group（11.30%）.The total sugar content of the samples increased obviously，and the total sugar content significantly increased by 133.50% after glucose treatment. The total phenol content and total antioxidant capacity significantly decreased by 68.77%—70.35% and 51.12%—51.40%，respectively.Compared with the CK group，sugar osmotic treatment significantly increased the glass transition temperature of the samples，with an increase of 60.05% in the sucrose group.The moisture absorption rate obviously decreased，and the moisture absorption rate of the sucrose group decreased most significantly，with a decrease of 26. 22%. After sugar osmosis，the structure of the samples was more compact，the pore wall was thickened，and the hardness was significantly improved.Sucrose treatment also improved the uniformity of the pore structure，increasing the brittleness of the samples by 70.32%.The results of Fourier transform infrared spectroscopy showed that the hydrophilic groups of small molecular sugars could form hydrogen bonds with the components containing O-H in the cell wall of pear slices.The results of X‑ray diffraction showed that the sugar molecules did not change the original crystal form of the samples，but combined with the amorphous polysaccharide of the cell wall through hydrogen bond competition to form a more stable system.In conclusion，different small‑molecule sugars exhibit different effects on the physicochemical properties of freeze‑dried pear slices.Sucrose can effectively improve the commercial quality of vacuum freeze‑dried pear slices，especially in terms of texture characteristics.

Key words: Pear slices, Vacuum freeze?drying, Sugar permeation, Quality, Textural property, Moisture absorption rate

摘要： 为探究不同小分子糖对真空冷冻干燥梨片质构形成的微观作用机制及品质影响，以葡萄糖、果糖、蔗糖作为渗透剂对梨片进行预处理，再经真空冷冻干燥制备样品；以空白组为对照（CK），采用常规理化检测结合傅里叶变换红外光谱、X射线衍射等方法，对梨片的理化性质、质构特性、微观结构及细胞壁化学结构进行系统分析。结果表明，与CK相比，小分子糖处理显著提高样品的明度指数，其中蔗糖组提升幅度最大（11.30%）；样品总糖含量明显升高，葡萄糖处理后总糖含量显著提高133.50%；而总酚含量与总抗氧化能力分别显著降低68.77%~70.35%和51.12%~51.40%。糖渗透处理后样品的玻璃化转变温度显著升高，其中蔗糖组升高幅度达60.05%；吸湿率明显降低，蔗糖组吸湿率下降最多，降幅为26.22%。糖渗透后产品组织结构更为紧实，孔壁增厚，硬度显著提高；蔗糖处理还改善了孔隙结构均匀性，使样品脆度提高70.32%。傅里叶变换红外光谱结果显示，小分子糖的亲水基团可与梨片细胞壁中含O-H的组分形成氢键；X射线衍射结果表明，糖分子未改变样品原有晶型，而是通过氢键竞争与细胞壁无定形多糖结合，形成了更稳定的体系。综上，不同小分子糖对冻干梨片物理化学性质影响不同，蔗糖可有效提高真空冷冻干燥梨片的商品品质，特别在质构特性方面。

关键词: 梨片, 真空冷冻干燥, 糖渗透, 品质, 质构特性, 吸湿率