真空冷冻干燥果胶-纤维素-小分子糖气凝胶质构研究

为探究不同小分子糖对真空冷冻干燥(FD)果蔬质构的影响,并寻找蔗糖的替代品,本试验通过建立FD果蔬天然网络结构模拟体系——果胶-纤维素气凝胶体系,并在该多孔骨架结构上搭载11种小分子糖,考察了不同小分子糖对FD气凝胶的微观结构、质构、吸湿性和玻璃化转变温度(T_g)等品质的影响。结果表明,添加果糖、水苏糖、麦芽糖醇样品的硬度显著高于添加蔗糖样品,而添加海藻糖和低聚异麦芽糖样品的硬度显著低于添加蔗糖样品;所有样品中,仅果糖样品的脆度显著高于蔗糖样品;低聚果糖样品的外观、质构以及吸湿性品质均与蔗糖样品相近,且T_g较高。因此,在FD果蔬工业生产中,低聚果糖是极具发展前景的一种蔗糖取代糖。本研究结果证实了小分子糖是果胶-纤维素气凝胶形成硬度和脆度的物质基础,可为FD果蔬生产过程中小分子糖的选择提供理论依据。

Study on Texture Properties of Freeze-Dried Pectin-Cellulose-Small Molecule Sugar Aerogels

The contribution of various small molecular sugars to the textural properties of freeze-dried (FD) fruits and vegetables is investigated in this study to explore the possibility of sucrose replacement. The pectin-cellulose aerogel systems with porous scaffolds carrying 11 small molecular sugars were established to simulate the natural network structure of FD fruits and vegetables. The microstructure, textural properties, hygroscopicity and the glass transition temperature (T_g) of FD aerogels were studied. The results showed that the hardness of aerogels with fructose, stachyose and maltitol was significantly higher than that of sucrose, while the hardness of trehalose and isomaltooligosaccharide aerogels was significantly lower than that of sucrose. Only fructose treatment exhibited a significantly higher crispness than sucrose among all the samples; the fructooligosaccharide aerogels shared the similar appearance, texture and hygroscopicity of sucrose samples, but with a higher T_g. Therefore, fructooligosaccharide could be regarded as a promising substitute for sucrose in the industrial production of FD fruits and vegetable. This study also confirmed that small molecule sugar is one of the determinants of the hardness and crispness in pectin-cellulose aerogels, providing a theoretical basis for the selection of small molecular sugars in the process of FD fruits and vegetables production.