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.

Master of Science / Food Science / Fadi Aramouni / Nutrition from whole grains has become an integral part of a healthy diet. Consumers are focused on adding fiber and whole grains to be healthy and want the benefits of whole grain with the taste and appearance of refined flour. A review of current commercial whole wheat flour in the marketplace indicated many options for food processors to use. However, many of these options required processing changes and added ingredients to provide the consumer with a quality product. A milling and baking study was done to compare commercially and experimentally milled whole wheat flours from both white and red wheat varieties. Both white and red wheat varieties were kept identity preserved. Experimental milling was done with a hammer mill and a roll stand to closely replicate the commercial milling process. Baking was done using a sponge and dough method to closely replicate commercial baking conditions. The results showed both particle size and wheat variety impact bake performance of whole wheat flour. The most significant impact appeared to be dependent on the variety of wheat being milled. The milling process also had an impact. As particle size decreased, bake functionality improved. However, some decreased functionality was seen when particle size became very fine. It was concluded that additional work on a commercial flour mill needed to be done to determine if an optimal particle size for milling whole wheat flour exists. Experimental milling equipment was not adequate enough to replicate particle size distributions of commercial whole wheat mills.

Master of Science / Food Science / Fadi Aramouni / Little in vivo research on glycemic index (GI) values or the digestive impact of sorghum based food products currently exists. Because sorghum is a gluten-free grain, its utilization in the United States is growing, especially in baking applications. Information on how sorghum affects blood sugar levels would be beneficial as new products emerge because glycemic effect has an impact on human health and in controlling diabetes. The objective of this study was to determine the GI of a sorghum muffin, and compare this value to the GI of muffins made from commonly consumed grains in the United States. The effects of particle size and damaged starch on GI were also studied. GI values were determined for muffins made from white sorghum, corn, brown rice, whole wheat, and all-purpose flours. All muffin formulations were composed of flour, water, baking powder and salt. To determine the GI, weighed portions of muffin containing 20g of available carbohydrates were eaten on separate occasions by eight healthy volunteers (ages 18-40) after an overnight fast (10 hours). Each muffin was administered twice. Two capillary blood samples were taken at 0 (fasting), 30, 45, 60, 90 and 120 minutes after consumption and averaged. Blood glucose curves were constructed from mean blood glucose values. The GI was calculated by dividing the incremental area under the curve for the test food (muffin) by that for the standard (20g dextrose drink) and multiplying by 100. The GI for the muffins was calculated as the mean from the respective average GIs of the 8 volunteers. The data indicated that sorghum flour milled at particle size < 400 um resulted in the lowest GI of 32 ± 16.8. These findings should assist in development of lower GI sorghum foods.

Master of Science / Food Science Institute / Weiqun Wang / Anthocyanins, a sub-class of flavonoids, are natural pigments derived from phenylpropanoid pathway. Most tomato cultivars found in nature have very low content of anthocyanins, but dark purple tomatoes by ectopic co-expression of two transcription factors Delila (Del) and Rosea1 (Ros1) from snapdragon and chalcone isomerase (CHI) from onion accumulated high levels of anthocyanins. This study is to identify and quantitate anthocyanins in these transgenic tomato lines. Seven anthocyanins including two new anthocyanins [malvidin-3-(p-coumaroyl)-rutinoside-5-glucoside and malvidin-3- (feruloyl) -rutinoside-5-glucoside] have been identified in transgenic lines by HPLC-MS. The top two anthocyanins are petunidin 3-(trans-coumaroyl)-rutinoside- 5-glucoside and delphinidin 3-(trans-coumaroyl)-rutinoside-5-glucoside that contribute for 85% of total anthocyanins in whole fruit. Comparing with undetectable anthocyanins in the wild type, Del/Ros1-expressing tomatoes contain total anthocyanins at 4.95±0.42 g/kg dry matter in whole fruit, 5.09±0.62 g/kg dry matter in peel, and 5.56±0.29 g/kg dry matter in flesh, while CHI×Del/Ros1-coexpressing tomatoes have 9.61±0.71 g/kg dry matter in whole fruit, 29.9±1.64 g/kg dry matter in peel, and 8.65±0.39 g/kg dry matter in flesh. No anthocyanins are detectable in the seeds of each line tested. Enrichment of tomato fruit with new and high anthocyanins may provide potential health-promoting benefits.

Master of Science / Food Science Institute / Kadri Koppel / Black walnut (Juglans nigra L.) is a Juglans species native to the United States. Nuts are collected each fall from black walnut trees and the kernels are consumed in many food products like ice cream, candies, and baked goods. Flavor profiles of black walnut cultivars have been examined, but no studies have looked at the effect of growing season on flavor profile, and few studies have determined consumer acceptance of black walnut food products. The sensory profiles of 10 black walnut cultivars (Football, Vandersloot, Brown Nugget, Pounds, Sparks 127, Davidson, Sparrow, Neel, Emma K, and Tomboy) were evaluated using descriptive sensory analysis. A trained panel scored the intensity of 3 appearance, 7 aroma, 23 flavor, and 6 texture attributes. Results showed that the cultivars differed significantly (P≤0.05) on 11 of these attributes. The results from this study were also compared to results collected in 2011 of 7 black walnut cultivars. Two flavor attributes (black walnut ID and overall nutty) had an interaction effect of year and cultivar, while 7 attributes showed a main effect of year (brown, caramelized, floral/fruity, fruity,-dark piney, musty/dusty, and oily). In general, flavor attributes had higher intensities in 2011 than in 2013. Six of the black walnut cultivars were also incorporated into a gelato base and evaluated by both a trained panel and consumer panel. Trained panelists developed a lexicon for the gelato samples and scored the intensity of 18 flavor attributes. The gelato samples differed on 3 main flavor attributes: black walnut ID, overall nutty, and sour (P≤0.05). Based on consumer liking, there were 3 distinct clusters of consumers. One cluster preferred samples with a milder black walnut flavor, another preferred a more intense black walnut and overall nutty flavor, and the third cluster liked all of the samples. Results from this study indicate that growing season should be considered when determining flavor profile of agricultural products. These results can also help guide growers in selecting cultivars that may produce a more consistent crop year after year, and cultivars that consumers find acceptable in food products.

Master of Science / Food Science Institute / J. Scott Smith / Heterocyclic amines (HCAs) are potentially carcinogenic and highly mutagenic byproducts of the Maillard browning reaction that form specifically in high temperature cooked meat products. Consumption of HCAs has been associated with various cancers including prostate, breast, colon, and pancreatic cancers and efforts have been made to understand formation and inhibition of these compounds. Chemical model systems are a preferred method to study the in vitro formation and inhibition of HCAs as the complex matrix effects found in meat are eliminated. Two black pepper extracts were evaluated for their efficacy on PhIP formation in model systems, but no significant results were observed. Secondly, four Maillard reaction variables were evaluated for their effect on formation of five HCAs (IQ, IQx, MeIQ, MeIQx, and 4,8-DiMeIQx) in chemical model systems with an effort to define an ideal model system. Precursor molar concentration (0.2/0.2, 0.4/0.4, 0.6/0.6, and 0.8/0.8 mmol), water percentage (0, 5, 10, and 15%), sugar type (fructose, galactose, glucose, and lactose), and sugar molar amount (quarter, half, equi, and double molar) were the four Maillard variables examined in the study. Additionally, four antioxidants (butylated hydroxyanisole (BHA), epigallocatechin gallate (EGCG), rosmarinic acid, and naringenin) were evaluated for their effect on HCA formation in chemical model systems. All four Maillard variables had a significant effect (p < 0.05) on the formation of HCAs in the model system, with an interaction effect occurring between water percentage and precursor concentration. The four antioxidants had no effect on the formation of HCAs in the model system. A model system containing 0.6/0.6/1.2 mmol of threonine, creatinine, and glucose, with 15% water was determined to be the best representative chemical model system for the formation of HCAs commonly formed in meats.

Master of Science / Food Science Institute - Animal Sciences & Industry / Jayendra K. Amamcharla / High-protein dairy powders are added to a variety of products to improve nutritional, functional, and sensory properties. To have the intended properties, the powder must be soluble. The solubility is effected by processing storage, and dissolution conditions, as well as the type of powder. Various tests are used to determine solubility, but they are time-consuming and subjective. Literature has shown that ultrasound spectroscopy can characterize the solubility of high-protein dairy powders, but it requires expensive equipment and skilled technicians. An economical alternative is to use an ultrasonic flaw detector, which is commonly used in the construction industry. For this study, an ultrasonic flaw detector based method was developed to characterize the solubility of high protein dairy powders. To evaluate the method, commercially available milk protein concentrate (MPC) was obtained and stored at 25°C and 40°C and stored for four weeks to produce powders with different dissolution properties. To test the powders, a 5% (w/w) concentration of powder was added to water. A focused beam reflectance measurement (FBRM) and solubility index were used as a reference method. After powder addition, data was collected at regular intervals for 1800s. The FBRM and solubility index showed that the powders lost solubility as the storage time and temperature increased. From the ultrasound data, one parameter was extracted from the relative velocity and three parameters were extracted from the attenuation data. A soluble powder had a low relative velocity standard deviation from 900-1800s, high area under the attenuation curve, low peak time, and high peak height. The ultrasonic flaw detector detected differences in solubility before the solubility index. When testing MPC with protein contents ranging from 85% to 90% and at a dissolution temperature of 40°C and 48°C, data from the ultrasonic flaw detector and FBRM showed that the solubility decreased as the protein content increased and increasing the dissolution temperature improved the solubility of the powder. Overall, the ultrasonic flaw detector can characterize the solubility of high-protein dairy powders.

Doctor of Philosophy / Human Nutrition / Edgar Chambers IV / Consumer food safety often is lacking, with many studies showing that we need to understand consumer behavior better and find new ways to provide information. The objective of this research was to better understand consumer food safety behaviors, find possible avenues for communicating food safety instructions to consumers, and determine how those avenues could work for demonstrating food safety today. Results from this research showed that two of the main potential avenues for communicating food safety instructions, namely recipes and cooking shows, were wholly lacking in good information and behaviors. A survey of egg dish recipes found that almost none contained temperature information, despite recommendations of food safety agencies. Observing celebrity chefs prepare food showed that every chef repeatedly had poor food safety practices which would lead to foodborne illness if followed by consumers at home. Two consumer studies were done with observers watching consumers prepare poultry and egg items. In the first study, consumers were asked to prepare poultry and egg items using both stovetop and oven methods. This study demonstrated that consumers do not follow many food safety behaviors, such as hand washing and using thermometers, and that those who used a thermometer were not better at reaching a safe temperature than those who didn’t use one. The second study had consumers prepare poultry items following a recipe, with half receiving food safety instructions on hand washing and thermometer use with their recipes. This study demonstrated that the addition of food safety instructions dramatically improved food safety behaviors in consumers. A separate study looked at the effect of changing lighting due to recent changes in efficiency regulations. This study found that some forms of modern lighting, such as LEDs, are more likely to make consumers think that poultry products are finished cooking before they are done, showing an even greater need for thermometer use. These studies present a message for the industry: food safety information and behaviors are lacking in consumers, but simple efforts such as adding food safety instructions to recipes can make consumers more aware of appropriate behaviors and improve their food safety.

Master of Science / Food Science Institute / Edgar Chambers, IV / A total of more than 100 different coffee samples from 14 countries around the world were used to create a coffee lexicon. The first list of terms consisted of 74 attributes that were developed from the review of 13 samples from Colombia. A second development incorporated an existing commercial lexicon and examined an additional of 72 coffee samples from different parts of the world. Validation sessions were also performed with 20 samples from the area of San Adolfo, Colombia. Principal Component Analysis (PCA) was used to mapped the scores obtained during the validation phase of the terminology, the panelists were able to described specific characteristics that were present in the coffee samples such as sweet, nutty and fruity notes, as well as the differentiation of notes such as burnt, smoky, astringent, acrid and bitter. At the end of the process, a total of 110 attributes and their references were identified. Another study was conducted to identify the sensory properties of three coffee samples using four different brewing methods. The coffee samples were prepared using a consumer drip coffee maker, a home or food service automated espresso machine, a coffee grader “cupping” method and a filtered infusion method. The cupping method produced a higher intensity for the “roasted” flavor attribute across all samples. This method also tended to produce higher scores for burnt and acrid than other brewing methods. Flavor and aroma attributes both varied with preparation methods, but not necessarily in the same ways. The drip brewing method showed the most differences in the three coffee samples for aroma, flavor and aftertaste attributes, but other methods may be appropriate depending on the objectives of each study.

Master of Science / Department of Grain Science and Industry / Subramanyam Bhadriraju / Heat treatment involves raising the ambient temperature of food-processing facilities such as flour mills to 50-60oC for killing stored-product insects. However, very little is known about the influence of sanitation on responses of stored-product insects to structural heat treatments. The impact of sanitation on responses of life stages of the red flour beetle, Tribolium castaneum, an economically important pest in flour mills, were investigated during three 24 h structural heat treatments of the Kansas State University pilot flour mill. Two sanitation levels, dusting of wheat flour (~0.5 g) and 2-cm deep flour (~43 g), were created in 25 plastic bioassay boxes each holding 50 eggs, 50 young larvae, 50 old larvae, 50 pupae, and 50 adults of T. castaneum in separate compartments. Five boxes were placed on each of five floors of the pilot mill during 13-14 May 2009, 25-26 August 2009, and 7-8 May 2010 heat treatments using forced air gas heaters. During the August 2009 and May 2010 heat treatments, 100 eggs or 100 adults of T. castaneum were exposed inside each 20 cm diameter by 15 cm high PVC ring placed only on first and third floors and holding 0.1 (15 g), 0.2 (38 g), 1 (109 g), 3 (388 g), 6 (937 g), or 10 (1645 g) cm deep wheat flour. Among the mill floors, first floor had lower maximum temperature. The first floor rests on a thick concrete foundation, did not get heated from both sides unlike other floors, and had poor air movement resulting in cold pockets (temperatures <50oC). Mortality of life stages was lower on first floor than other floors and adults were less susceptible than other life stages especially on first floor. In general, both these tests have shown that the mortality of T. castaneum life stages were influenced by how quickly temperatures reached 50oC, how long temperatures were held above 50oC, and the maximum temperature. Protective effects of sanitation were evident only if temperatures did not reach 50oC. However, removal of flour accumulations is essential to improve heat treatment effectiveness against all T. castaneum life stages during a 24 h treatment.