Master of Science / Food Science Institute - Grain Science & Industry / Thomas J. Herald / Donghai Wang / The number of people diagnosed with celiac disease has increased and subsequently the market for gluten-free products is rising. Sorghum has been identified to be a safe grain to use as a wheat alternative for the celiac community. There are many sorghum hybrids that are commercial available for use in food and feed. Noodles are selected for the growing market in the US and the lack of research and availability for sorghum noodles. Viscoelastic properties are crucial for making acceptable noodles which makes this research more challengeable. The research hypothesis is that sorghum can be used in making gluten-free noodles and there are end product quality differences that exist among the hybrids in production of gluten-free noodles. A series of chemical and physical analyses were conducted to compare four sorghum hybrids (Orbit, NE #8, F-525, NE #4) in a gluten-free noodle system. The noodles were formulated with 100% sorghum flour and the other functional ingredients including dried whole eggs, egg whites, xanthan gum and corn starch. Sorghum noodles were significantly different in color, texture and cooking quality among hybrids. The starch properties were found to have more effect than protein content on sorghum noodle qualities. Sorghum flour with fine particle size and low ash content was crucial for making acceptable sorghum noodles. Noodles made from sorghum F-525 exhibited some properties significantly closer to the commercial wheat flour noodles.

Master of Science / Food Science Institute / Fadi M. Aramouni / Jeffrey A. Gwirtz / In order to improve the quality of products available for consumers who require a gluten-free diet, this study examined the effects of sorghum flour composition and particle size on functionality in gluten-free batter bread. White, food-grade sorghum was milled to flour of varying extraction rates (60%, 80%, 100%), and was subsequently pin-milled at different speeds (no pin-milling, low- speed, and high-speed) to create flours of both variable composition and particle size. Two commercially-milled sorghum flour samples (AF and TV) were included in the study and subjected to the same pin-milling treatments. Characterization of each flour included measurements of flour composition, total starch content, particle size distribution, damaged starch, and water absorption. Bread characterization included measurement of specific volume, crumb properties, and crumb firmness through the use of digital imaging and texture profile analysis. Significant differences were found (p<0.05) in the composition of sorghum flours of varying extraction rate, most notably for fiber and total starch contents. Flour particle size and starch damage were significantly impacted by extraction rate and speed of pin milling (p<0.05). With the exception of the commercial flour samples, water absorption increased significantly with increasing extraction rate and speed of pin-milling speed (p<0.05). Within all treatments, breads produced from 60% extraction flour had significantly higher specific volumes, better crumb properties, and lower crumb firmness when compared to all other extractions and flour types. These measured bread characteristics were significantly impacted by flour properties, specifically particle size, starch damage, and fiber content (p<0.0001). The commercial flours studied produced breads of low specific volume, poor crumb properties, and dense textures. These results can assist millers and product developers in advancing the quality of sorghum-based gluten-free foods for the consumers that require them. Further research is necessary to better understand the extent to which particle size, and therefore starch damage, can improve sorghum-based gluten-free breads.

Problématique de l'étude : La maladie coeliaque (MC) nécessite un traitement relativement simple, soit le retrait du gluten de l'alimentation, mais qui s'avère très intrusive et exige des modifications importantes des habitudes de vie. Les écrits ne permettent pas de comprendre l'impact de la maladie coeliaque et de son traitement sur la qualité de vie des personnes qui en sont atteintes. But : Cette étude a pour but de décrire et comprendre la perception de la qualité de vie d'adultes atteints de la maladie coeliaque. Méthode : Un devis mixte imbriqué a été utilisé. La population à l'étude comprend des adultes atteints de la maladie coeliaque résidants en Estrie. Un échantillonnage non probabiliste a été utilisé. Des annonces ont été affichées dans le journal local, dans des magasins d'aliments spécialisés, au centre hospitalier et dans des cliniques médicales de Sherbrooke. Des questionnaires sur la qualité de vie, les symptômes ainsi que l'intrusion de la maladie ont été complétés par les 22 participants à l'étude. De ces participants, cinq ont été rencontrés lors d'une entrevue semi-dirigée afin d'approfondir certains aspects de l'impact de la maladie sur leur qualité de vie. Résultats : La perception de la qualité de vie des personnes atteintes de la MC est aussi bonne que celle de la population canadienne générale. La maladie et son traitement s'avèrent cependant très intrusifs. La diète sans gluten entraîne des modifications importantes au plan des habitudes de vie et peut générer une multitude d'impacts sur la personne et ses proches. Le développement de stratégies de coping aide à diminuer la perception d'intrusion de la maladie et ainsi améliorer la qualité de vie. Conclusion : Un système de parrainage entre personnes atteintes de la MC pourrait faciliter l'adaptation à la diète et améliorer la perception de la qualité de vie. Des études supplémentaires s'avèrent nécessaire afin de mieux comprendre la perception d'intrusion de la maladie et les stratégies de coping de personnes atteintes de la MC.

Increased interest in value-added traits of soft winter wheat (SWW; Triticum aestivum L.), such as white-seed coat and gluten strength, has resulted from economic incentives for these traits. The first objective of this study was to determine whether differences existed between red- and white- seeded progeny of 17 populations. When abiotic and biotic stresses were negligible, significant differences were not detected between red- and white-seeded progeny, except for yield: red-seeded progeny had a significantly higher yield than the white-seeded progeny. However, when abiotic and biotic stresses were larger, the yield of white-seeded progeny was not significantly different from red-seeded progeny and the white-seeded progeny accumulated a significantly greater amount of deoxynivalenol (DON) than red-seeded progeny. Therefore, Kentucky producers should be cautious when considering production of white-seeded cultivars. The second objective of this study was to determine whether early- or late- generation selection for white-seeded progeny produced a higher frequency of superior white-seeded lines. Three selection methods were studied. Late-generation bulk selection produced a significantly lower frequency of superior white-seeded lines (1.7%) than single seed descent (SSD; 13.9%); the early-generation bulk (9.6%) did not differ statistically from either method. Although SSD produced the most superior lines, the utility of SSD breeding will have to be assessed by SWW breeders to justify additional labor and space requirements. The final objective was to determine whether early-generation selection of wheat quality, as determined by wheat meal-based assays, was effective. A cross between a strong gluten soft red winter and a weak gluten soft white winter wheat was examined. Significant correlations and regressions between wheat meal assays and flour-based assays were found. High heritability and realized genetic gains were also observed. Therefore, early-generation selection for quality characteristics appears to be effective.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Master of Science / Food Science Institute / Delores Chambers / The rising awareness of celiac disease, an intestinal intolerance to gluten, has increased the demand for gluten-free products. Gluten is a protein that provides structure to breads, cakes, cookies, and other wheat-flour based baked goods. When flour and water are combined and mixed, the proteins glutenin and gliaden present in wheat combine and a network of gluten is formed. In addition to providing structure and elasticity to dough, it also traps air within the matrix and allows baked goods to rise and maintain desirable characteristics such as an open and airy crumb structure and chewiness of bread products. Removing gluten from a baked good formulation affects the finished product in many ways. This review examines research conducted on the effects of many various ingredients on finished product quality of gluten-free baked goods. Quality parameters that are most greatly affected by the exclusion of gluten in baked goods include specific volume (a measure of the amount of air incorporated into the finished product), height, spread ratio (the ratio of diameter to thickness in cookies and like products), color, and hardness. Gluten-free baked goods are recognized to be denser, shorter in height, have a larger spread, have a different color, and be harder in texture than traditional wheat-based baked goods. Various gluten-free ingredients have been studied for their use in producing a finished product that exhibits quality parameters similar to wheat-based baked goods. These include rice, potato, tapioca, corn, and sorghum; pseudocereals such as buckwheat, amaranth, and quinoa; legumes; nuts; and waste from fruit and vegetable processing. The inclusion of additives such as hydrocolloids, protein concentrates, emulsifiers, and acidic ingredients are extensively utilized and studied in gluten-free baked good applications. Gluten-free baked goods commonly have a reduced shelf life as compared to wheat-based products. The weak association of water with the starches present in gluten-free baked goods allows moisture to migrate to the outside of the product and rapidly escape. Shelf life studies are also included in much of the research and are summarized in this review. Because consumers desire gluten-free products that taste like the gluten-containing products they replace, many studies pertaining to gluten-free ingredient research include sensory analysis. Some studies include a wheat-based product as a control, while others use only gluten-free formulations in the research. Future research using better sensory methods are needed in this product category. Food manufacturers who wish to compete in the still growing gluten-free market have many ingredient resources available to them to produce high quality gluten-free baked goods. Through research conducted on alternative flours, starches, hydrocolloids, emulsifiers, and other ingredients, gluten-free consumers can enjoy baked goods that exhibit the same desirable qualities as traditional wheat-flour based products.

Master of Science / Food Science and Industry / Fadi M. Aramouni / Gluten-free products are becoming more prevalent in the market today, however there are a few types of products that have “hidden” gluten and people will not realize until after consumption. Products like soy sauce and beer are sources of gluten that people don’t know about. Soy sauce contains wheat as a main ingredient so replacing it with a gluten-free flour such as sorghum may produce a product similar to wheat-based soy sauce. Sorghum was used in this experiment since it is a grain grown in the mid-western region of the United States and a growing food ingredient in the global market. Sorghum can come in many different varieties and colors so we used different varieties in this study. Four treatments were done using three different sorghum flours (black, white, and waxy sorghum flour) and a wheat flour for a control. Cooked soybeans were mashed in a kitchenaid mixer and the treatment flour was added to make a dough. That dough was formed into a log and cut into slices. The slices were then staked with wet paper towels to mold. After 13 days of molding, the slices that were made were dried, placed in a salt solution, and fermented for 100 days. The solution was mixed with a spatula for 30 seconds to homogenize the mixture every 2-3 days and samples were taken every 10 days to test for pH, salinity, and color. Once the 100 days were complete and the pH of each treatment did not drop for consecutive testing periods, the liquid was removed from the solids and pasteurized. The pH curve did show that a fermentation process did occur, however there was no control over what microorganism could grow. Consumer testing was not performed since all test sauces were deemed unacceptable at the initial screening.

Master of Science / Food Science / Fadi Aramouni / Due to an increase in awareness of celiac disease, the gluten-free market continues to expand. However, gluten-free breads are still characterized by a poor structure and overall mediocre quality. This research was aimed at determining the impact of egg addition as well as an antistaling agent (DATEM) on the quality of a batter-based gluten-free sorghum bread. Gluten-free bread loaves containing 20, 25, or 30% eggs (as is) on a flour basis were evaluated against a control (no egg). The impact of the antistaling agent, DATEM at 0.5% was also studied for each of these formulations. Quality factors evaluated included water activity, color, specific volume, and cell size. Texture profile analysis was performed to evaluate staling rate based on changes in crumb hardness values and a trained panel evaluated staling attributes by descriptive analysis. Finally, a consumer acceptance test on sorghum bread with and without eggs was also conducted. Results showed that sorghum breads with eggs had higher specific volumes than control (increase from 0.06 cm[superscript]3/g to 0.11 cm[superscript]3/g), while DATEM had a negative effect on the volume of gluten-free bread (decrease of 0.73 cm[superscript]3/g). Eggs also improved cell structure and produced significantly darker crust (p<0.05). Additionally, the addition of eggs reduced bread hardness (from 54 g force to 142 g force on fresh bread) and slowed the rate of staling over the 12 day storage period studied. Descriptive analysis results confirmed the findings of the texture analysis, showing control bread significantly harder (p<0.05) than egg-containing bread at days 0 and 4. The consumer test indicated a significant preference (p<0.05) for sorghum bread with eggs over the control. The overall acceptability score for this bread was above 6 on a 1 to 9 hedonic scale. The score was closer to 7 when the bread was rated by consumers with celiac disease. This research proved that the addition of eggs to a gluten-free sorghum bread formulation resulted in delayed staling and better overall quality and acceptability of the product.

Doctor of Philosophy / Food Science Institute / Fadi Aramouni / Scott Bean / Zein, the storage protein of corn, has been shown to form a wheat-like dough; however the exact mechanism is unknown since zein lacks the large polymeric proteins found in wheat. To understand how zein forms a dough, different reagents were added during mixing of zein. Salts from the Hofmeister series were used to determine how hydrophobic interactions influence zein’s dough forming ability. In addition, urea, ethanol, and beta mercaptoethanol (β-ME) were also tested to evaluate the effects of protein denaturation and disulfide bonds on zein dough formation and bread quality. Kosmotropic salts had a negative effect on zein dough formation indicating that increasing hydrophobic interactions prevented dough formation. Surface hydrophobicity was found to decrease significantly (p < 0.05) when zein was exposed to 1M or 2M of the kosmotropic salts. Conversely, chaotropic salts had a slight positive effect on zein dough formation as did urea and ethanol. Interestingly, -ME had little effect on zein dough formation demonstrating that disulfide bonds played no role in zein dough development, and that large disulfide linked polymeric protein complexes were not present as found in wheat dough. Specific volumes of zein-starch bread increased as NaCl content in the bread formula decreased. Likewise, including 5% ethanol (v/v) in the bread formula was found to increase bread quality. Experiments were also conducted to compare the functionality of isolated sorghum proteins (kafirins) to commercially available zein produced during wet milling of corn. The effect of steeping, the first step in wet milling, on kafirin functionality was investigated. Sorghum flour was steeped for 0, 72, or 96 hours. Unsteeped sorghum flour was digested with Alcalase for 90 min at 50°C. After steeping or digestion with Alcalase, kafirins were isolated from the remaining material. Both groups of Kafirins had the ability to form a zein-like visco-elastic resin when mixed with warm water by hand. This is the first time that kafirin has been reported to form a visco-elastic resin using only water as a plasticizer.

Celiac disease is an autoimmune disorder triggered by the ingestion of gluten, which is found in wheat, barley, and rye. The only treatment for celiac disease is a strict gluten-free diet (GFD), which eliminates common gluten-containing foods found in many cultures and cuisines. This research examined how families experienced celiac disease and the GFD in their households, focusing on the ripple effect of celiac disease for all members of the family and how families promoted adherence and quality of life (QOL). A mixed-methods approach used questionnaires, photographs, and semi-structured interviews with families recruited from the Celiac Disease Center at Columbia University Medical Center. Participants were 16 families with children ages 8-18 living at home who had physician-confirmed diagnoses of celiac disease. A total of 71 in-depth semi-structured interviews were conducted (n =16 reference children with celiac disease, 16 mothers, 15 fathers, 24 siblings). Results showed that the reference children with celiac disease had high GFD adherence (mean CDAT = 9) and QOL (mean CDPQOL 81 of 100). Mothers’ and fathers’ ratings of how their child’s celiac disease diagnosis affected their lifestyle, social life, and level of burden in caring for child’s dietary needs differed significantly (all p-values < 0.05), with mothers reporting more change and burden. Emerging themes related to a negative ripple effect included the burden of assuming the majority of food tasks related to GFD (mothers), the limited restaurant choices for the family (fathers), and feeling annoyed by having to limit certain foods at home (siblings). Emerging themes related to a positive ripple effect, included becoming more creative cooks (mothers), incorporating new family traditions (fathers), and developing empathy for others (siblings). Overall, there was substantial evidence of a ripple-effect of a child’s celiac disease diagnosis on other family members, including how mothers and fathers may experience the change in lifestyle and added responsibilities of maintaining the GFD differently. Including parents and siblings in research provides insight into the entire family experience and can help inform family-centered interventions on how to maximize QOL for everyone impacted by a child’s celiac disease diagnosis.