Call number: LD2668 .T4 1985 D59 / Master of Science

Call number: LD2668 .T4 1985 M43 / Master of Science

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.

Physiological responses of six sorghum (Sorghum bicolor (L.) Moench) hybrids and their respective parental lines were evaluated under high and low soil moisture conditions at Tucson, Arizona in 1980 and 1981. Apparent photosynthesis, transpiration, diffusive resistance, and temperature differential (ambient temperature minus leaf temperature) were measured under field conditions at weekly intervals. To measure apparent photosynthesis, a small plexiglas chamber was sealed over a section of leaf blade and gas was sampled with two syringes pulled at a 30 or 60 second interval. The gas samples were injected from the syringes into an infrared gas analyzer to measure CO(,2) concentrations. Transpiration, diffusive resistance, and temperature differential were measured with a steady state porometer. Regression analysis was used to compare the physiological performance of the germplasm sources over a wide range of environmental conditions. The physiological characteristics of the highest yielding sorghum hybrid in 1980 were the most stable across all environments. This hybrid was superior to both its male and female parent for all four physiological characteristics. In 1980, this hybrid was superior to the other hybrids in temperature differential and transpiration. The superior yielding hybrid had the highest mean apparent photosynthesis and the lowest mean diffusive resistance. All hybrids had higher yields than their respective male parents under both irrigation treatments. Thirty-five days after planting, the superior yielding hybrid had the greatest leaf, stem, and root dry weights. This hybrid also had the highest relative leaf area expansion rate. Heterosis for stomatal density was not observed either year. Regression analysis proved to be an effective tool for analyzing the sorghum germplasm over a diverse range of environmental conditions. By comparing the response of an individual germplasm against the mean response of the population under numerous environmental conditions, the slope, mean, and coefficient of correlation may be used to evaluate genotype-environment interactions.

Three high-yielding and three low-yielding grain sorghum hybrids were grown for a full season for grain yield and total dry weight of forage with two levels of irrigation (dry and wet) and two levels of nitrogen (0 and 100 lbs /acre). The experiment was conducted at the University of Arizona Marana Agricultural Center. The combined high nitrogen fertilizer and high water irrigation increased grain yield and total dry matter of sorghum over the dry moisture condition and no nitrogen fertilizer application more than the applied increases of nitrogen fertilizer or irrigation water alone as expected. Both high- and low-yielding groups of sorghum hybrids had the same basic relative percentage potential for increased grain yield from additional nitrogen fertilizer under either wet or dry conditions.

Seventy-two commercial hybrid grain sorghums, representing 20 commercial sources, were grown full season for grain yield with irrigation water applied as necessary to prevent moisture stress. The test, grown at the University of Arizona Marana Agricultural Center, had grain yields ranging from a high of 6375 lbs/acre down to 3292 lbs/acre.

Three high yielding and three low yielding grain sorghum hybrids were grown for grain yield and total dry weight in late planted simulated double-crop after barley or wheat harvest with two levels of irrigation (dry and wet) and two levels of nitrogen fertilizer (0 and 100 lbs/acre). The experiment was conducted on the University of Arizona Marana Agricultural Center. Nitrogen fertilizer and the interaction between nitrogen fertilizer and water irrigation had no significant effect on the grain yield of sorghum hybrids. Additional nitrogen fertilizer applied under dry conditions reduced both grain and total dry matter production, and when applied under wet conditions produced gains in grain or dry matter production of only 1% to 4% for the high and low yielding groups. Additional irrigation water produced 61% to 77% additional grain under low and high fertilizer levels for high and low yielding sorghum groups. Additional irrigation water produced 8% to 38% more plant dry matter under low and high fertilizer levels.

Seventy-two commercial hybrid grain sorghums representing 17 commercial seed companies were grown full season for grain yield with limited irrigation for medium moisture stress. The test, grown at the University of Arizona Marana Agricultural Center, had grain yields ranging from a high of 5098 lbs/acre down to 2100 lbs/acre.

Seventy-two commercial hybrid grain sorghums representing 17 commercial sources were grown for grain in a late planted, simulated double-crop after barley or wheat harvest. The test, grown at the University of Arizona Marana Agricultural Center, was planted in a pre-irrigated seed bed, but was rainfed thereafter. Grain yields ranged from a high of 3420 lbs/acre down to a low of 1750 lbs/acre.

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