Research And Application Of Structurized Soybean Dietary Fiber

Objective: The impact of soybean dietary fibers (SDF) and pectin as well as their complexation on the food texture, sensory property of the cookies, and the physiological functions was investigated in order to find a better way to apply dietary fiber in food products for improved health.Methods: The rheological properties, water and oil hoding capacities of SDF, pectin and their composite fibers were studied after different pretreatments w/o the addition of certain percentage of wheat flour. The impact of dietary fibers on the food texture and sensory acceptability were carried out when 20% flour was replaced by dietary fibers.SDF, pectin, and their composite dietary fiber were also used as raw material to make feed for mice to investigate their effect on body weight, postprandial blood glucose and blood lipids after two weeks of feeding in order to evaluate their health benefits. Results: The composite dietary fiber with a relatively better property was found to be made by mixing SDF and soluble pectin in a ratio of 1:2 after spray drying. The acid pre-treatment removed most of the lignin and part of hemicellulose of SDF, and alkali treatment greatly reduced the lignin content. Acid treatment could break down the non-crystalline area to get more loose fibers, and the following low-temperature alkali treatment weakened the hydrogen bonding of cellulose crystalline region to further the loosing of the three-dimensional structure by reducing their crystallinity. But acid and alkali treatment of SDF has little effect on water holding capacity, oil holding capability, viscosity and other propertiesof the composite dietary fiber. The rheological analysis indicated that adding a large amount of dietary fiber alone could increase the batter system's flexibility, and result in worse processing properties than adding flour alone which are closely related with the high water holding capacity and viscosity. However, replacing 20% flour with composte dietary fiber(pectin: SDF=2: 1) could make the food system have moderate water holding capacity and lower viscosity than replacing with pectin alone, which made the processing property of the high-fiber food improved. The texture analysis and sensory evaluation confirmed that adding composte dietary fiber could improve the cookies'texture, taste, appearance, etc. comparing with adding SDF, pectin alone, and high fiber content is another merit of the cookies. The vivo experiment confirmed that postprandial blood glucose and blood lipids in mice declined along with duration of consumption of high dietary fiber diet.Comparing the group adding composte dietary fiber with the group adding physical mixed dietary fiber of the same ratio of SDF and pectin, the physiological effects are different with different structures of the dietry fiber in food.Conclusion: Mix the SDF and pectin in a certain ratio, then homogenize, spray-dry ,we could get the composte dietary fiber , which had lower oil holding capacity than the physical mixed dietary fiber and could improve the rheological properties of the paste system for processing. Sensory evaluation results also confirmed that the composte dietary fiber could improve the high dietary fiber cookies'texture and taste. The vivo experiment verified that the composte dietary fiber could lower the level of blood glucose and blood lipids of mice.