Effects of insoluble dietary fiber from wheat bran on noodle quality

Benefiting from its favorable effects in promoting intestinal peristalsis, increasing satiety and reducing postprandial blood sugar, wheat bran insoluble dietary fiber (IDF) could be added to noodles to improve the nutrition value of noodle products. However, the addition of IDF usually results in an adverse effect on the quality characteristics of fiber fortified products, leading to unfavorable texture and consumption drop. It was found that IDF could weaken dough characteristics, thereby causing the quality deterioration of noodles, but the mechanism is unclear as yet. This study aimed to investigate the effects of different amounts of IDF on the texture quality and cooking quality of noodles. The water distribution, rheological properties, pasting properties and cooking properties of the noodles were determined by low-field nuclear magnetic resonance (LF-NMR), dynamic rheometer, and rapid visco-analyzer. The results of the LF-NMR showed that the increased IDF in the noodles resulted in a contraction of relaxation time and an increase in the proportion of loosely bound water. At a high amount of IDF, the water absorption and tensile distance of the noodles significantly decreased and the cooking loss rate increased, with a downward trend in peak viscosity, final viscosity and setback values. Moreover, IDF could improve the storage modulus and loss modulus of sheeted dough and enhance the texture of noodles. Furthermore, the correlations between IDF addition amounts and rheological properties as well as cooking properties were analyzed, and the results confirmed that noodles with the IDF amount of 2%–4% had higher nutrition and quality. This study provides the basis for future development and improvement of IDF-enriched health foods.