This study is a netnography of an online gluten-free community through the scope of the Facebook group "Gluten Free." The objective of this qualitative inquiry is to investigate the key characteristics of this online gluten-free community and gain a deeper understanding of member purposes for participation. Employing the method of netnography allows for an unobtrusive exploration of the community by discreetly utilizing anthropological techniques in an online setting. Despite growing awareness, no academic research has yet been conducted on the social aspects of the online gluten-free community. The thematic findings that emerged from this study were two-fold. First, this investigation revealed three key characteristic themes in the content of community posts: suspiciousness and distrust, defensiveness and frustration, and passion and determination. Second, this analysis discovered three purposive themes for member participation: validation, friendship, and education. The findings of this study render a thick description of the unique culture of the online gluten-free community, sharpen the academic understanding of online communities, and strengthen the valuable method of netnography.

In an effort to mimic the continuous protein matrix found in gluten-containing breads, the effects of the enzyme microbial transglutaminase were tested in gluten-free (GF) sourdough breads containing five different GF flours: chickpea, brown rice, white rice, oat, and quinoa. The utilization of transglutaminase in GF sourdough bread applications was shown to improve some of the final bread characteristics of GF breads. White and brown rice GF sourdough loaves at 24 hours showed a 28% and 13% decrease in crumb firmness with the addition of 2 U/g dough, respectively. Quinoa-GF sourdough breads at 24 hours showed a 6% increase in specific volume with the addition of 1 U/g dough. Oat and chickpea-GF sourdough loaves did not show improvements in loaf quality with mTG addition. SDS-PAGE analysis revealed that white rice, brown rice, quinoa, and chickpea proteins are adequate substrates for mTG activity, while oat proteins, without the addition of exogenous proteins, lack the characteristics suitable for mTG action.

Master of Science / Food Science Institute, Grain Science and Industry / Jeffrey A. Gwirtz / There is a limited market of gluten-free beer for the 1% of the US population that is diagnosed with an autoimmune response to gluten protein known as celiac disease. Sorghum can be malted and used in the brewing process to replace malted barley, a grain toxic to celiac patients. The objective of the study was to develop an optimum brewing procedure for a gluten-free ale-style beer. Four different sorghum hybrids (82G63, 83G66, RN315, and X303) were malted and used in brewing gluten-free ale and evaluated for physical and chemical property differences. The four sorghum hybrids were characterized first as grain and then as malt using proximate analysis, single kernel characterization system (SKCS), amylose, α-amylase, and β-amylase contents. Isolated starch from unmalted and malted samples was evaluated with differential scanning calorimetry (DSC). Malt was evaluated throughout the malting process and percent nitrogen, percent moisture, 72 hr germinative energy, steep out moisture, germination-end, and malting loss were measured. Malted sorghum hybrid samples were milled into grist, and employed in a double mash, double decoction brewing process. Following the brewing process the wort was evaluated for specific gravity, Brix, pH, color and free α-amino nitrogen (FAN). Wort was also analyzed using HPLC for ethanol and glucose content. The fermented beer was analyzed for specific gravity, Brix, pH, alcohol by volume, and color. HPLC was also used to measure ethanol and glucose content. Results of analysis found that a significant difference (p=0.05) was found for the DSC data onset temperature, which ranged from 61.75 to 65.51, illustrating the difference in starch gelatinization temperature compared to other cereals. A significant difference was found in α-amylase content (p=0.05) which ranged from 0.16 to 058 in unmalted sorghum and 71.63 to 96.44 in malted sorghum. In addition, α-amylase and β-amylase contents increased during malting. HPLC analysis of wort indicated a significant difference was found in percent maltose which ranged from 1.27 to 2.81. FAN content of wort was also significantly different and ranged from 65.15 to 151.37. HPLC of beer showed a significant difference in percent ethanol and percent glucose. Percent ethanol in the final beer ranged from 3.28 to 4.17 and percent glucose range from 0.16 to 0.31. Process development evaluation indicated a gluten-free ale style beer could be successfully produced with 100% sorghum malt.

Master of Science / Food Science Institute, Animal Science & Industry / Fadi M. Aramouni / In order to improve the quality of products available for consumers who require a gluten-free diet, this study examined the effects of heat and ozone treatments on sorghum flour functionality in gluten-free bread and cake. In the ozone treatment experiment, commercially milled food-grade sorghum flour was subjected to ozone at the rate of 0.06 L/min for 15, 30, and 45 minutes. In the heat treatment experiment, commercially milled food-grade sorghum flour was subjected to dry-heat at two temperatures (95ºC and 125º) for 15, 30, and 45 minutes. Characterization of flour from each treatment included measurements of flour pH, color, and pasting properties. Evaluation of bread quality from each treatment included measurements of specific volume, color, crumb properties, and crumb firmness. Evaluation of cake quality from each treatment included measurements of specific gravity, volume, symmetry, uniformity, color, crumb structure, and crumb firmness. Bake testing using ozonated sorghum flour in a high-ratio white layer cake formulation showed that volume significantly increased (p<0.05) as ozonation time increased. Additionally, longer ozonation exposure times increased cells per slice area, lightness, and slice brightness values in gluten-free cakes while reducing crumb firmness. Despite improving lightness and slice brightness values, ozonation did not significantly increase (p>0.05) the specific volume of gluten-free batter based bread. In the heat treatment experiment, the optimum time and temperature relationship for improving sorghum flour was 125ºC for 30 minutes. This treatment level produced bread with the highest specific volume (3.08 mL/g) and the most cells per slice area (50.38 cells/cm2). This treatment level also produced cakes with the highest volume (72.17 cc) and most cells per slice area (79.18 cells/cm2). Additionally, cake and bread made from this heat treatment was deemed more acceptable in comparison to the control during consumer testing. The control sorghum flour in both studies produced breads and cakes with low volume, poor crumb properties, and dense textures. These results can assist in the product development process in advancing the quality of sorghum-based gluten-free foods for the consumers who require a gluten-free diet.

Doctor of Philosophy / Department of Grain Science and Industry / Sajid Alavi / Sorghum grain (Sorghum bicolor) is safe for consumption by individuals afflicted with celiac disease, and its proteins can be used as a supplement in gluten-free foods. However, utilization of sorghum in human foods is limited by the poor digestibility and lack of functionality of its proteins, which result from their entrapment in protein bodies, tight association with starch, and high degree of cross-linking induced by cooking. The first part of this study presents an extensive review of current methods for concentration and isolation of sorghum proteins, which are laboratory-scale techniques used for protein characterization and have no potential for commercial scale-up. Furthermore, these methods typically use non-food grade reagents and do not improve protein digestibility and functionality. In the second part, a novel extrusion-enzyme liquefaction (EEL) process was used to produce sorghum protein concentrates to overcome the aforementioned limitations. EEL involves extrusion pre-treatment of sorghum flour and starch liquefaction with a thermostable α-amylase, followed by enzyme inactivation, protein separation and drying. To demonstrate the concept, a laboratory-scale EEL process was used to produce concentrates with higher protein content (PC; 80% db) and digestibility (D; 74%) than those made by batch liquefaction. The optimum conditions for producing concentrates with both high PC and D were 32% wb in-barrel moisture content and 2.5% α-amylase added after extrusion. Using these conditions, EEL was scaled-up to a pilot-scale process to produce sorghum protein concentrates with 72-80% db PC and 62-74% D, while the batch liquefied control had only 70% db PC and 57% D. Dynamic oscillatory measurements of dough (55% moisture) and batter (65% moisture) containing sorghum protein concentrates (5 and 10%) and potato starch were performed to evaluate protein functionality. At lower moisture, pure potato starch and dough containing 10% sorghum protein concentrate had similar elastic and viscous moduli. At higher moisture, potato starch was more stable and exhibited significantly higher moduli than the batters with protein concentrates. Sorghum protein concentrates can improve the quality of some gluten-free foods. EEL shows promise for commercial production of sorghum protein concentrates because of its high throughput and potential for delivering high protein content and digestibility.

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.

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.