Effects of Four Functional Sugars on the Quality and Starch Structure of Fermented Maize Dough

To develop a mixed starter culture of lactic acid bacteria for maize products, this study systematically investigated the effects of adding functional sugars (fructooligosaccharides, xylooligosaccharides, inulin, and trehalose) as auxiliary ingredients at different levels (0.5%, 1.0%, and 1.5%) on the processing quality and starch structure of fermented maize dough. The dough was examined for texture properties, microstructure, gelatinization characteristics, rheological properties, thermal properties, and moisture distribution, and the particle size, molecular mass, and crystallinity of starch extracted from the dough were measured. The results revealed that FOS resulted in a more compact and uniform dough microstructure. The dough added with 1.5% FOS exhibited the lowest hardness (80.93 N) and softest texture, along with the lowest breakdown and setback values. Meanwhile, it had the best thermal stability and the lowest retrogradation tendency. Its storage modulus (G’) and loss modulus (G”) decreased most significantly. FOS promoted the conversion of quasi-bound water to bound water and consequently enhanced water-holding stability. Starch isolated from the dough with 1.5% FOS had the highest amylose content (37.0%), the smallest weight-average/number-average molecular mass ratio and radius of gyration, and the highest crystallinity (37.55%). All four functional sugars enhanced the short-range ordered structure of starch and reduced the content of amorphous regions. Inulin significantly decreased the volume-average particle size of starch but had no significant effect on the surface-area-average particle size. These findings demonstrated that the four functional sugars improve the processing properties of dough by regulating the molecular structure of starch, with FOS exhibiting the most pronounced effect. This provides a theoretical basis and technical pathway for developing high-quality fermented maize-based foods.