The goal of this research is to determine the effects of added soybean lipoxygenase (LOX) on bread dough rheological properties and physical properties of bread loaves compared to controls, and to determine sensory attributes of bread loaves using quantitative descriptive analysis (QDA). Protein fractions were obtained through the use of isoelectric precipitation. The pH 4.8 precipitate was found to yield the greatest LOX activity when compared with other fractions (p<0.05). The addition of pH 4.8 precipitate improved rheological properties of bread dough, examined in a farinograph, when compared to the all-purpose control (p<0.05). Addition of soy flour also increased the gluten strength of all-purpose flour (p<0.05). The addition of pH 4.8 precipitate to all-purpose flour did not improve bread loaf volume or texture. Sensory panelists described pH 4.8 supplemented bread as having firmer crumb when compared with controls (p<0.05). There were slight color differences among the loaves. The crust and crumb of bread flour loaves was lighter in color than any other sample. It was concluded that the addition of pH 4.8 precipitate to all-purpose flour greatly improved the rheological properties when compared with all-purpose flour alone. / Master of Science

The effect of soy as a natural antioxidant against flaxseed rancidity in yeast breads was tested. Variables included: control (100% bread flour); yeast bread with 15% flax meal in place of part of the total bread flour; yeast bread with 15% flax meal and 5% soy; and yeast bread with 15% flax meal and 10% soy. Objective and sensory tests were used to evaluate breads. Peroxide values indicated that the hydroperoxides in breads increased during the first four weeks of the study, and then decreased, as would be expected as breads are exposed to more elements with time. Moisture content was not significantly different between the breads. Breads containing flax were significantly firmer (p < 0.02) in texture. Breads containing flax were also significantly lower in volume (p < 0.005) and significantly darker in crumb color (p < 0.01). The level of 10% soy contributed to a significantly darker crust color (p < 0.04). Quantitative descriptive analysis (QDA) found the level of 10% soy also contributed to an increased stale taste and aftertaste, firmer texture, coarser crumb, and drier loaf (p < 0.05). Musty aroma was not significantly different among breads and all breads containing flax had an increased grainy taste (p < 0.0001). Soy was found to have no significant antioxidant effect on the prevention of flaxseed rancidity in yeast breads. / Master of Science

This study examined the effects of guar gum and xanthan gum on flax supplemented breads through objective and sensory testing. Breads containing flaxseed and gums were found to have a significantly (p<0.05) higher water activity than the control bread. Control bread was also found to have a higher (p<0.05) volume while flax breads containing guar gum had a significant (p<0.05) decrease in volume. Control bread and bread containing guar gum were significantly (p<0.05) harder in crumb texture. Breads with flax and xanthan gum displayed a significant (p<0.05) amount of springiness. While there was no significant (p>0.05) difference in peroxide values among bread samples, control bread had a lower (p<0.05) anisidine value indicating a decrease in hydroperoxide breakdown. While not significant (p>0.05), bread containing xanthan gum had a lower anisidine value than the other treatments. Sensory analysis found bread with both gums to be moister (p<0.05) and have a strong (p<0.05) yeasty aroma and fresher flavor. Control bread was found to have the least (p<0.05) yeasty aroma and taste significantly (p<0.05) less bitter but more stale. / Master of Science

The antioxidants BHA, BHT, and ascorbic acid were added to flaxmeal breads to prevent rancidity. Six types of yeast leavened breads were evaluated: control (100% bread flour), flaxmeal (15%) bread, and flaxmeal (15%) bread that contained 0.01% respectively of BHA, BHT, BHA and BHT, and ascorbic acid. Vital wheat gluten was added in all the flaxmeal breads. Chemical, objective and sensory tests were used to evaluate the breads. The crumb texture of all the experimental breads was significantly softer (p¡à 0.05) than the control breads, but the control breads were significantly moister (p¡à 0.05) than the flaxmeal breads that contained BHA and BHT, separately. No significant differences (p>0.05) were found in loaf volume of the control bread and the experimental breads. The crumb color of the experimental breads was significantly darker (p<0.0001) due to the incorporation of flaxmeal. The acid value of the flaxmeal breads was significantly higher (p¡à 0.05) than the control breads. No significant differences (p>0.05) were found in peroxide values between the control breads and experimental breads after eight weeks. The QDA sensory tests showed that breads containing BHA or in combination with BHT were moister, chewier and had the least noticeable stale taste when compared to the control breads. Ascorbic acid was not as effective as BHA or a combination of BHA and BHT in preventing lipid oxidation, but produced the softest bread. This study showed that flaxmeal breads made with BHA and BHT provided the best protection against lipid oxidation and produced a moist and chewy bread. / Master of Science

Inledning: Surdeg är idag en trend som fångats av många och de flesta bagerier ochdagligvarubutiker säljer bröd som kallas för surdegsbröd. Ett traditionellt surdegsbröd är ettbröd där surdegen används som enda hävningsmedel i brödet. Syfte: Syftet var att undersöka skillnader i sensoriska egenskaper, utifrån ettkonsumentperspektiv, samt GI-värde mellan surdegsbröd, jästbröd och bröd bakat på bådesurdeg och jäst. Material och metod: Metoderna som användes var två olika konsumenttester för att bestämmaskillnader mellan de tre bröden, och en in vitro-metod för att bestämma GI-värde. Resultat: Resultatet visade att konsumenter känner skillnad mellan surdegsbröd och jästbrödoch mellan surdegsbröd och bröd bakat på både surdeg och jäst men däremot inte mellanjästbröd och bröd bakat på både surdeg och jäst. Den syrliga smaken i surdegsbröd minskar ombrödet bakas på både surdeg och jäst. GI-mätningen genom in vitro-metoden visade att brödetbakat på både surdeg och jäst hade lägst GI medan surdegsbrödet hade högst. Slutsats: Ett bröd bakat på både surdeg och jäst är mer likt ett jästbröd än ett surdegsbröd. In vitro-metoden är inte den mest tillförlitliga för att undersöka skillnader i GI för justsurdegsbröd samtidigt som surdegsbrödets pH-värde kan ha varit för högt för att kunna sänkabrödets GI-värde. Inga slutsatser kunde därför dras från GI-mätningen. / Introduction: Sourdough is today a trend that has been caught by many and most bakeries andgrocery stores sell bread called “Sourdough bread”. Traditional sourdough bread is bread wherethe sourdough is used as only leavening agent. Purpose: The purpose was to examine differences in sensory attributes, from a consumerperspective, and glycemic index between sourdough bread, yeast bread and bread baked withboth sourdough and yeast. Material and Method: The methods used were two different consumer tests to determinedifferences between the three breads, and an in vitro-method for determining the glycemicindex. Result: The results showed that consumers can sense the difference between sourdough breadand yeast bread and between sourdough bread and bread baked with both sourdough and yeastbut not between yeast bread and bread baked with both sourdough and yeast. The sourish tasteof sourdough bread decreases if the bread is baked with both sourdough and yeast. Theglycemic index measurements by the in vitro-method showed that the bread baked with bothsourdough and yeast had the lowest glycemic index value whilst the sourdough bread had thehighest. Conclusion: Bread baked with both sourdough and yeast more resembles yeast bread thansourdough bread. The in vitro-method is not the most reliable for examining differences inglycemic index value for sourdough bread meanwhile the pH-value of the sourdough breadmay have been too high to be able to lower the glycemic value of the bread. No conclusionscould therefore be made from the glycemic index measurements.