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dc.contributor.authorKirby, Ratiaen_US
dc.description.abstractThe Effects on Gluten Strength and Bread Volume of Adding Soybean Peroxidase Enzyme to Wheat Flour Ratia Kirby ABSTRACT Soy peroxidase enzyme obtained from isoelectic precipitation procedures was added to all-purpose flour (APF) to assess its effects on the rheological properties and consumer acceptability of yeast bread. A pH 4.8 isoelectrically precipitated fraction from soybeans was used because it produced the most precipitate and had about the same peroxidase activity as the other fractions. Gluten strength was determined using a farinograph for seven treatment groups: control (all-purpose flour), bread flour, all-purpose flour + soy flour, bread flour + soy flour, all purpose flour + pH 4.8 precipitate, all-purpose flour + 15 mg soybean peroxidase, and all-purpose flour + 25 mg soybean peroxidase. Four types of yeast bread were baked for loaf volume determination, texture analysis, and consumer acceptability: a control loaf using only all-purpose flour, a reference loaf using all bread flour, a loaf with all purpose flour + whole soy flour, and a loaf with all-purpose flour + pH 4.8 soy precipitate. The APF+soy flour, bread flour, bread flour + soy flour, and the APF + pH 4.8 precipitate produced an improvement in the gluten strength and mixing tolerance compared to the control (p<0.05). However, the improvement by the addition of the pH 4.8 precipitate cannot be attributed to the peroxidase enzyme because peroxidase needs hydrogen peroxide as a substrate and no hydrogen peroxidase could be added to the farinogragh; therefore, it was concluded that the increase in gluten strength produced by the pH 4.8 soy precipitate was due to an unknown component present in the pH 4.8 fraction. No significant differences (p<0.05) were found in crumb or crust texture for any of the treatment groups. The addition of pH 4.8 precipitate to APF significantly decreased (p<0.05) loaf volume compared to bread made from bread flour. The results from sensory analysis showed there was no difference in preference for any of the breads. This study showed no conclusive evidence that peroxidase enzyme improved gluten strength or loaf volume of yeast bread, but further research is warranted.en_US
dc.publisherVirginia Techen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectsoybean peroxidaseen_US
dc.subjectgluten strength bread-making bread volumeen_US
dc.titleThe Effects on Gluten Strength and Bread Volume of Adding Soybean Peroxidase Enzyme to Wheat Flouren_US
dc.contributor.departmentHuman Nutrition, Foods, and Exerciseen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineHuman Nutrition, Foods, and Exerciseen_US
dc.contributor.committeechairBarbeau, William E.en_US
dc.contributor.committeememberConforti, Frank D.en_US
dc.contributor.committeememberO'Keefe, Sean F.en_US

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