Master of Science / Department of Food Science / Jon Faubion / There is evolving evidence that intake of whole grains protects against development of chronic diseases. Increasing the appeal of whole grain products proves difficult as they often have poor organoleptic properties attributed to the high water holding capacity, viscosity, and insolubility of components of the bran. Amaranth is a promising grain that is naturally gluten-free and has received much attention in recent years because of its excellent nutritional profile. Studies have shown encouraging approaches to modify the molecular makeup of amaranth by enzymatic hydrolysis. This approach suggests an increase in processability and incorporation of whole grain amaranth into processed foods by ameliorating the challenges inherent in the use of whole grain flours, thereby expanding consumer acceptance and intake of whole grains. This research investigates the effects of a two-level factorial design on the enzymatic hydrolysis of whole grain amaranth with enzymes alpha-amylase, cellulase, xylanase, and protease maintaining constant pH of 6 and temperature, 50°C. The main effects show decreased viscosity and water holding capacity, and increased solubility of whole grain amaranth. The most notable findings show enzymatic treatment decreases viscosity, with alpha-amylase having the most significant impact (P < 0.0001) 21,363-59± 244 cPs. Protease was eliminated from further testing as bitterness was generated with its hydrolysate. To solubilize insoluble components, a second two-level factorial design was employed analyzing pH (4.5 and 7.5) and temperature (50°C-70°C) with the same enzyme dosage as the first design. The main effects of the second design revealed alkaline conditions significantly increase soluble fiber (P < 0.0001) 3.01-5.05% ± 0.3%. Subsequent investigation proposes a response surface design with alpha-amylase in optimizing the effects of reaction time and alkaline conditions.

Whole sorghum kernels were directly processed into whole grain snacks with acceptable texture. Extrudates made from whole sorghum had a harder gritty texture than those made from decorticated materials. Extrusion of whole sorghum provides significant savings in processing: there are no dry matter losses; no equipment or energy is required for decortication or milling; the extruder consumes less power and processes more material per time unit. In addition, the extruder utilized is a simple adiabiatic, friction extruder of relatively low cost. Grinding whole sorghum and removing fines did not improve product expansion during extrusion but altered the gritty pieces in the extrudates. The best products were obtained when whole sorghum (ground or un-ground) was extruded at 14% moisture. The whole sorghum extrudates had larger bubbles with thick cell walls, which made extrudates more crunchy. Decortication of sorghum improved extrusion performance and products by allowing adequate formation and retention of air cells. Decortication to remove 20% of the original sorghum weight was enough to produce extrudates with characteristics comparable to those made from commercial yellow corn meal. Sorghum milled fractions with composition and particle size distribution similar to corn meal produced extrudates with higher expansion, lower bulk density and similar texture. In addition, sorghum extrudates were rated equal to corn meal extrudates by a taste panel for appearance, flavor, texture and overall characteristics. Extrudates made from polished rice were less expanded and whiter than extrudates made from sorghum. When processed under similar conditions, sorghum extrusion required more energy than corn meal extrusion. However, whole sorghum extrusion required less energy than corn meal extrusion. Unground sorghum samples (decorticated or non-decorticated) produced harder extrudates compared to those made from ground raw material. White sorghum is a feasible option for snack extrusion because of its versatility, product characteristics, cost and processing properties.

Whole sorghum kernels were directly processed into whole grain snacks with acceptable texture. Extrudates made from whole sorghum had a harder gritty texture than those made from decorticated materials. Extrusion of whole sorghum provides significant savings in processing: there are no dry matter losses; no equipment or energy is required for decortication or milling; the extruder consumes less power and processes more material per time unit. In addition, the extruder utilized is a simple adiabiatic, friction extruder of relatively low cost. Grinding whole sorghum and removing fines did not improve product expansion during extrusion but altered the gritty pieces in the extrudates. The best products were obtained when whole sorghum (ground or un-ground) was extruded at 14% moisture. The whole sorghum extrudates had larger bubbles with thick cell walls, which made extrudates more crunchy. Decortication of sorghum improved extrusion performance and products by allowing adequate formation and retention of air cells. Decortication to remove 20% of the original sorghum weight was enough to produce extrudates with characteristics comparable to those made from commercial yellow corn meal. Sorghum milled fractions with composition and particle size distribution similar to corn meal produced extrudates with higher expansion, lower bulk density and similar texture. In addition, sorghum extrudates were rated equal to corn meal extrudates by a taste panel for appearance, flavor, texture and overall characteristics. Extrudates made from polished rice were less expanded and whiter than extrudates made from sorghum. When processed under similar conditions, sorghum extrusion required more energy than corn meal extrusion. However, whole sorghum extrusion required less energy than corn meal extrusion. Unground sorghum samples (decorticated or non-decorticated) produced harder extrudates compared to those made from ground raw material. White sorghum is a feasible option for snack extrusion because of its versatility, product characteristics, cost and processing properties.

The 2005 Dietary Guidelines for Americans recommend that Americans consume at least three servings of whole grain foods per day to reduce the risk of chronic disease and to help with weight maintenance. However, most Americans fall short of this recommendation. To reduce the prevalence of chronic disease, overweight, and obesity, health educators should promote healthy behaviors at young ages. The purpose of this study was to measure whole grain intake in college students and to determine its association with body mass index (BMI), a measure of overweight and obesity. The participants (N=164) were recruited from a freshmen level nutrition course (of 485 students) at Virginia Tech in spring of 2004. Students kept food records to record their usual diets for 14 days, and had their height and weight measured by the researchers in order to determine their BMI. On average, the students consumed 5.4±1.7 (mean±SD) servings of grain based foods per day, of which 13% (0.71±0.76 servings) were from whole grain foods. The students who were in the normal weight range (based on their BMI) consumed more servings of whole grains per day than the overweight and obese students (ANOVA with linear contrasts; p<0.05). Results from this study indicate that whole grain intake is low in college students, but similar to the national average, and higher in students with a normal body weight. Efforts should be made to help develop healthy eating habits in this population, including increasing whole grain intake. / Master of Science

The Paleolithic, or ancestral, diet was first proposed by Eaton and Konner in 1985, and it is based on the theory that humans have not diverged greatly from the physiology of the Paleolithic human. Eaton and Konner suggested a diet consisting of meats, fruits, vegetables, nuts and seeds while omitting food such as dairy, grains, legumes, refined sugar and processed foods. The latter of which are incongruous with the diet we evolved with and are likely the cause of the so-called "diseases of civilization" such as type 2 diabetes, coronary heart disease, obesity, osteoporosis and cancer (Konner & Eaton, 2010). This review will first elaborate on the Paleolithic lifestyle and the evidence presented on it before examining the evidence for and against other diet categories not included in the diet such as whole grains, red meat, grass-fed meat, dairy milk and soymilk. The aim of this study is to first evaluate the Paleolithic diet, based on nutrition and ability to address common public health diseases and then to appraise the value of other food categories not included in the lifestyle on the same factors, in order to determine their place in an ideal diet. This study concludes that the Paleolithic diet can lower total body weight, body mass index, cardiovascular risks, triglycerides and low-density lipoprotein among others while increasing insulin sensitivity and ω-3, iron, fiber, vitamins and minerals, including improving the ω-6 to ω-3 ratio and the potassium to sodium ratio when compared to the typical Western diet. The results were consistent even when compared to other diets such as the Mediterranean or the diabetes diet. Studies showing the effectiveness of consuming other foods, such as whole grains, dairy or soymilk, with the intent on losing weight or preventing diabetes, on the other hand, have been inconclusive. Research on soy's estrogenic isoflavone action has been inconclusive. Concerns over the consumption of red meat due to cholesterol and cancer are mitigated and review of the grass-fed literature reveals a potentially richer fatty acid profile with more healthy polyunsaturated fats and less cholesterol-raising saturated fatty acids. It is concluded that an ancestral diet of whole foods, made up of mostly fruits and vegetables, meats, especially grass-fed, nuts and seeds is strongly associated with significantly better outcomes for diseases such as type 2 diabetes and obesity as compared to a typical Western diet, Mediterranean diet or diabetes diet.

Doctor of Philosophy / Department of Grain Science and Industry / Hulya Dogan / The concept of thermal processing of foodstuffs has been used extensively since 1920 when the first scientific basis for calculating the minimum safe sterilization process was developed. There are several methods used in thermal processing of dry foods including infrared, microwave, hydrothermal treatments such as annealing and heat-moisture treatment, thermomechanical treatments (extrusion), and indirect (hot air) and indirect (steam) heating. Thermal processing has been the most widely used method for preserving and extending the shelf-life (via microbial reduction and enzyme inactivation, and for improving quality and functionality. In 2009 the Centers for Disease Control and Prevention released a report of an Escherichia coli outbreak resulting from consumers eating raw refrigerated cookie dough which brought attention to heat treatment of flours and powders. Chlorination of wheat flour in the European Union countries has been replaced in recent years by heat-treated flour which is used to produce high ratio cakes. By applying heat treatment, it is possible to modify the physical and rheological properties. The primary effect of heat treatment is denaturation of the proteins, partial reduction or inactivation of alpha-amylase, and partial gelatinization of the starch. Understanding of relationship between heat transfer, thermal properties of food, heating medium, thermodynamics and the functionality of the resulting heat-treated flour is of critical importance. Research reported in this dissertation has five chapters. Chapter 1 provides a general overview on the state-of-knowledge in the area. Chapter 2 focuses on developing a thermomechanical treatment (extrusion) for improving the functionality of low quality (ash > 1.3%) wheat flour. Chapter 3 deals with developing a direct, rapid and continuous thermal processing technique for treating whole wheat flour and whole wheat grain, and investigates physicochemical changes of heat-treated samples at various moisture-time-temperature combinations. Chapter 4 explores the mixing and development of composite flours in the presence of gluten fractions of at varying proportions, mixing speed and temperatures. Chapter 5 highlights general conclusions and identifies areas for future research.

Whole-grain, high-fiber, or decorticated extrudates of excellent properties were made from white (nonwaxy, heterowaxy, waxy) sorghums or brown tannin-sorghums. Intact grains or prepared raw materials (cracked, cracked and sifted, decorticated) were extruded in a high-temperature, short-time (HTST) extruder. Waxy extrudates expanded less and were softer than those from nonwaxy or heterowaxy sorghums. Waxy extrudates had bigger air cells and thicker cell walls. Low moisture used in this type of extrusion and its interaction with the different amylose contents were the causes of the differences. Whole-grain extrudates from white sorghum had similar sensory acceptability to those from white decorticated sorghum. They had bland flavor and appearance and texture characteristic of whole-grain products. Extrudates from tannin sorghums were reddish brown due to their high levels of phytochemicals. The more expanded, softer products from whole-grain tannin sorghum were obtained when the grain was cracked and sifted. Decreased expansion was caused by higher levels of fiber and greater particle sizes (as in the extruded intact grain), and by reduced particle sizes (as in the cracked non-sifted grain). Expansion was correlated to smaller air cells with smooth walls. A simple enzymatic method was developed that isolates the 'gritty' particles from whole-grain/high-fiber extrudates, which closely correlated with expansion. Gritty particles were fiber (bran) plus undegraded starchy material. Whole grain/high fiber extrudates from white and tannin sorghums are an excellent option for food processors because of their excellent taste, appearance and texture.

Obesity, glucose intolerance or insulin resistance and elevated blood pressure are now prevalent in the U.S. Increased intake of dietary fiber, omega- 3 fatty acids, and antioxidants may help prevent or manage these diseases. Tortillas are now part of the American diet, and are excellent carriers of higher amounts of fiber and other nutraceutical ingredients. This study was conducted to determine the effects of incorporating nutraceutical ingredients (flaxseed, sorghum bran, oat flour, buckwheat flour) on whole white wheat tortilla quality. Tortillas were prepared using a hot-press, gas-fired oven and were evaluated for physical properties, texture and shelf-stability. Objective and subjective tests demonstrated that whole white wheat and multigrain tortilla doughs were harder, rougher and less extensible than refined flour tortilla dough. Multigrain flour tortillas were thinner, larger and more translucent than the refined flour treatment. Incorporation of whole multigrain flours affected color of the product, giving darker tortillas. Tortilla flexibility decreased over time. After 16 days of storage rollability scores of tortillas decreased drastically. The most pronounced decrease in tortilla flexibility was observed for 5% sorghum bran, 10% buckwheat, and for the treatment prepared with of 5% flax, 5% sorghum, 5% oat, 5% buckwheat. The flexibility loss was higher for whole white wheat and multigrain tortillas than for the refined one which was confirmed with objective and subjective tests. To extend shelf stability of whole multigrain tortillas various amounts of commercial hydrocolloid and ?-amylase were added to the formulation. Tortillas with 75 ppm, 100 ppm of ?-amylase, 1% and 1.5% of gum retained their flexibility during 16 days of storage. Consumer acceptability of the whole multigrain tortillas (5% flaxseed, 5% sorghum bran, 5% oat, 5% buckwheat) was compared with commercial multigrain tortillas and whole white wheat flour tortillas using an untrained sensory panel. The multigrain tortillas were liked by the panel as much as the other samples. Prepared multigrain tortillas had improved nutritional value. Each multigrain treatment contained at least 3 g of dietary fiber, 0.29 g of ?- linolenic fatty acid, lignans and antioxidants. It makes possible to claim them as a ?good source of dietary fiber? and ?an excellent source of ?-linolenic fatty acid?. The formulations tested, together with future refinements, provide more options to consumers seeking healthier alternatives to refined wheat flour tortillas.

Limited information exists regarding the effects of light pearling on the properties of physical grain characteristics, composition, and technological and sensory properties of selected varieties of Western Canadian barley especially hulless barley genotypes with modified starch characteristics. Nine barley genotypes with different hull (hulled and hulless) and starch characteristics (normal, waxy, and high amylose (HA)) were pearled to three differing levels. Scanning electron micrographs showed that the pericarp, testa, aleurone, and subaleurone layers were completely removed in heavily pearled barley whereas only a few outer layers were removed in minimally pearled barley. Waxy starch genotype Fibar and HA starch genotypes, SH99250 & SB94893 contained high levels of soluble β-glucan (9-11%). Waxy starch genotypes exhibited higher β-glucan solubility when cooked compared to normal and HA starch genotypes. However, HA starch genotypes had lower in vitro starch digestibility which may provide a lower glycemic response in humans.

Limited information exists regarding the effects of light pearling on the properties of physical grain characteristics, composition, and technological and sensory properties of selected varieties of Western Canadian barley especially hulless barley genotypes with modified starch characteristics. Nine barley genotypes with different hull (hulled and hulless) and starch characteristics (normal, waxy, and high amylose (HA)) were pearled to three differing levels. Scanning electron micrographs showed that the pericarp, testa, aleurone, and subaleurone layers were completely removed in heavily pearled barley whereas only a few outer layers were removed in minimally pearled barley. Waxy starch genotype Fibar and HA starch genotypes, SH99250 & SB94893 contained high levels of soluble β-glucan (9-11%). Waxy starch genotypes exhibited higher β-glucan solubility when cooked compared to normal and HA starch genotypes. However, HA starch genotypes had lower in vitro starch digestibility which may provide a lower glycemic response in humans.