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Soymilk residue extract (SRE) with high soluble dietary fiber (SDF) was prepared and its effect on bread quality was investigated. Conditions for preparation of SRE were examined by measuring alcohol-insoluble solid (AIS), protein, and reducing sugar contents. The extraction conditions established were 121℃, pH 12, and 1 hr. The SDF content of the extract under these conditions increased to 48.3% compared with 3.3% in 1 g dry defatted soymilk residue. Four types of bread containing 4% soymilk residue dietary fiber (SRDF), SRE, polydextrose, or no added fiber (control) were prepared. Quality attributes such as bread staling, moisture content, color of crust and crumb, and texture by instrumental and sensory analyses were examined during storage at 4℃. Analysis of the thermograms obtained by differential scanning calorimetry (DSC) revealed that the addition of SRDF, polydextrose, or SRE effectively retarded bread staling compared to the bread without added dietary fiber. Crust colors were not significantly different, whereas crumb colors depended upon the degree of moisture loss. The values for the hardness and chewiness after 5-day storage, obtained by instrumental measurement, of the bread containing SRDF or SRE, were lower than those of the control. These results suggested that SRE might be utilized as a functional ingredient in bread.
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