Master of Science / Food Science Institute Department of Human Nutrition / Delores H. Chambers / This study was conducted to define and compare typical sensory characteristics of high quality Italian gelati to ice creams produced in the United States. Highly trained descriptive sensory panelists evaluated gelato samples in Italy, purchased direct from local gelaterias, and ice cream samples in the U.S., purchased from grocery stores and local shops. In general, gelati gave higher overall fruity and fruit ID scores, chocolate gelati gave higher chocolate and cocoa notes, and vanilla gelati gave higher vanilla and lower vanillin intensities than most U.S. ice creams. Gelati were consistently associated with higher density, lower firmness, and slower meltdown. When compared to U.S. ice creams, Italian gelati were characterized by specific sensory properties: "true to type" flavors; high intensity flavors that were considered to be typical to that flavor category or specific fruit and are combined with a dense, smooth texture that allows for the development of flavor, body and bloom, enhancing the perception of flavors. The research conducted in this study may be useful for ice cream manufacturers and sensory scientists. This study is the first to define sensory characteristics of high quality Italian gelati and the information may be used to produce ice cream with increased consumer liking. The descriptive attributes developed can be used for the development of new or improved of ice cream products.

Master of Science / Department of Grain Science and Industry / Ekramul Haque / The effect of enzyme in temper water on wheat milling performance and flour quality was studied. Five independent variables, enzyme concentration, incubation time, incubation temperature, tempered wheat moisture content, and tempering water pH, were studied. An enzyme cocktail consisting of cellulase, xylanase, and pectinase was used at 5 different concentrations. A single pure variety of hard red winter wheat was tempered under defined conditions following an RSM central composite design which required 33 tests including 7 replicates. Each treatment had 5 levels: high, medium high, medium, medium low, and low. After tempering, the physical characteristics of the wheat kernel were determined by using the Single Kernel Characterization System. An experimental laboratory mill (Ross Mill) was used to mill wheat into flour. Thirteen streams of flour, and additional streams of bran, shorts, red dog, and germ were obtained. Product yield, protein, ash, and flour color were evaluated. The data were analyzed and compared using the software SAS and RSM Plus. The data showed that incubation time was the only significant factor affecting the tempered wheat hardness (p<0.05). The treatments affected the flour yield from the break rolls more than that from the reduction rolls. However, a maximum point for flour yield was not found. The relationship between treatments and flour yield was established with a prediction model equation. Also, the enzyme effect on the dough properties and bread making were investigated. The treatments did not affect the optimum water absorption for the flours. However, enzyme treated flours showed shorter mixing times. Regardless of the differences in mixing times, the specific loaf volumes were not significantly different for the all treatments. Bread baked from the flour milled from enzyme treated wheat did not show a positive effect on bread staling.

Master of Science / Department of Grain Science and Industry / Finlay I. MacRitchie / Ozone, a triatomic form of oxygen with a Generally Recognized As Safe (GRAS) status from the U. S. Food and Drug Administration, is a strong antimicrobial and sanitizing agent with numerous potential applications in the food industry. One of them is the improvement of wheat flour baking qualities, by replacement of the actual chlorination treatment. Following recent developments realized by the company Goemar (France) which invented and patented an ozone treatment device for wheat grain and a method for making flour from ozone-treated grains, this study aims to determine the effect of ozone treatment on wheat grain and on wheat flour, and to compare them. Three different ozone concentrations with different application times rendering three quantities of absorbed ozone have been investigated. Rheological, physicochemical and baking properties of soft wheat flours stemming from both treatments were evaluated and compared to untreated flour. Results were overall significant and showed that the treatment of flour gives more marked results than the treatment on grain for retention capacity in sucrose and volume of cakes but decreases the [alpha]-amylase activity. On the other hand, action of ozone on grain augments the maximum viscosity of the flour. Bread volume was found to be increased by both treatments in similar proportions. The treatments were also analyzed in particular and showed specific characteristics. A single treatment has not been determined to enhance all characteristics of the flour. Hence, the modification of precise features of the flour has to be related to a specific treatment.

Doctor of Philosophy / Food Science Institute / Finlay I. MacRitchie / Ozonation was studied as an alternative to chlorination for cake flour. Ozone treatment in a wooden tumbler at room temperature was conducted. Unchlorinated flour was treated with ozone at the rate of 0.06 L/min for 10 and 36 min using 5 lb of flour. Ozonation of cake flour decreased pH and increased the lightness (L value) of flour. Baking studies using a high-ratio white layer cake formulation showed that the volume of cakes significantly increased (p< 0.05) as ozonation time increased and cakes were softer than those made with chlorinated or control flours. The cell brightness and number of cells measured by image analysis (C-Cell) of cakes from ozone treated flour for 36 min exhibited similar values to those from chlorinated flour. Cakes made from flours after lipid extraction and after lipid extraction plus ozonation had low volume, indicating that lipids play a role in cake performance. Identification of volatile compounds that contribute to the odor of ozone treated flour was conducted. Volatile compounds of chlorinated, unchlorinated, defatted control, and ozonated defatted flours were analyzed using a purge and trap instrument and GC-MS. Aldehydes, alcohols, hydrocarbons and other compounds were found in unchlorinated and chlorinated flours while the volatile compounds present in ozone treated flours were mainly aldehydes and ketones. A rapid reduction in volatile compounds was detected when ozone treated flours were stored uncovered in a fume hood. Ozonation of defatted soft wheat flour produced less volatile aldehydes than ozone treated whole flour. The optimum temperature and time for ozone treatment in a metal tumbler using a response surface methodology design was studied. Time (5, 15, and 25 min) and temperature (25, 35 and 45 [degrees]C) was used with three response parameters. The optimum ozonation time was about 8 to 11 min with the temperature range between 36 and 46 [degrees]C. Ozone treatment for 5 to 25 min at room temperature showed an increase in unextractable polymeric protein, indicating a shift of protein to a higher molecular weight. Increase in Mixograph peak time, peak viscosity, and water retention capacity were observed as ozonation time increased. The ozone treatment did not affect the transition temperature and enthalpy change of the flour samples.

Doctor of Philosophy / Department of Hotel, Restaurant, Institution Management and Dietetics / Elizabeth B. Barrett / This study examined the relationships among restaurant managers' attitudes, subjective norms, and perceived behavioral controls, using the Theory of Planned Behavior, that cause them to support or not support food safety training for their employees. The goal of this study was to investigate the facts that affect restaurant managers' willingness to support food safety training for their employees. Based on the results of the elicitation study, a pilot test focus group, and a pilot study, an 85 question instrument, that measured eight constructs and demographic information was developed. The instrument was administered via telephone, but response data was input using an online format. Data was entered electronically as it was collected. A total of 266 managers responded, but due to incomplete and missing data, 237 responses were usable. The final overall response rate was 17.9%. Results determined that overall intention to offer food safety training to employees was high. Restaurant managers had a positive attitude about food safety, placed importance on the beliefs of individuals they consider important, and felt they were in control about offering food safety training to their employees. Certified managers had more positive attitudes about offering food safety training and placed more emphasis on those individuals whom they considered to be important in their lives (subjective norms), but also perceived they had less control about offering food safety training to their employees. Most importantly, those managers who were certified had a higher intention to train employees than managers who did not have food safety certification. When comparing behavioral, normative, and control beliefs between chain and independent restaurant managers, only behavioral (specific attitudes) and normative beliefs (specific individuals whom they considered important) differed. In the multiple regression analysis exploring the prediction of behavior based on the respondents attitudes, subjective norms, and perceived behavioral controls, the model was significant (F=139.932, p [equal to or less than] .000) (Table 5.2). The significant independent variables in the model were the attitude mean composite score (Beta=-0.106, p [equal to or less than] .038) and the subjective mean composite score (Beta=0.727, p [equal to or less than] .000). Perception of control was not significant. Three multiple regression models were used to examine the relationships between the attitudes, subjective norms, and perceived behavioral controls as dependent variables and the factors for their indirect measures as independent variables. Of the three simple linear regression models, only two were significant. The regression of the behavioral belief factors on attitude composite score (Hypothesis 4) (F=16.714, p [equal to or less than] .000) and the regression of normative belief factors on the subjective norm composite score (F=11.896, p [equal to or less than] .000) were significant. The regression of control beliefs on perceived behavioral control showed no significance.

Master of Science / Food Science Institute / Fadi M. Aramouni / Ohmic heating for the food industry consists of using electrical energy to heat foods as a method of preservation, which can in turn be used for microbial inactivation or several other processes such as pasteurization, extraction, dehydration, blanching or thawing. Few studies have been conducted on the usefulness of this environmentally friendly processing technique. Due to the lack of sufficient information on research into ohmic heating for the food industry, a few of the published studies are discussed here in detail. This report also focuses on self-conducted research using ohmic heating to determine its effect on Lactobacillus acidophilus inactivation versus conventional heating. Lactobacillus acidophilus was inoculated into MRS broth and incubated for 24 hours. The sample was then inoculated into sterile buffer at a dilution rate of 1:100. Samples of the diluted culture were subjected to either low voltage (18 V) or conventional heating (300°C) over a hotplate stirrer. Temperature was monitored on test and control samples to achieve an endpoint of 90°C. Samples were taken at regular intervals, plated onto MRS agar and incubated for 72 hours at 35°C to compare plate count expressed as colony forming units per milliliter (cfu/mL). Temperature was uniform throughout the ohmically heated sample and reached the endpoint more quickly than the conventionally heated sample, which also had cold spots. The total plate count at the end of the experiment was less for the ohmically heated sample versus the conventionally heated sample. Ohmic heating was more effective in inactivation of Lactobacillus acidophilus than conventional heating, most likely due to the more rapid and uniform heating of the sample, and possible electroporation of the cells.

Noroviruses (NoV) and Hepatitis A viruses (HAV) are the most commonly implicated viruses in foodborne disease. Their transmission is mainly via the fecal-oral route and distribution of contaminated foods has lead to large outbreaks. Thus, it is crucial that contaminated foods be identified promptly. Detection by cell culture is not possible for these viruses so that researchers rely on the reverse transcription polymerase chain reaction (RT-PCR). Prior to detection, however, viruses must be isolated from foods and, as of yet, no one method has been found applicable to a large variety of food matrices. Problems with existing methods include, but are not limited to, the co-extraction of inhibitory molecules and lack of sensitivity. In addition, they are labour-intensive and time consuming. Therefore, the aims of this research project were to develop a novel methodology for the rapid and sensitive isolation and detection of NoV and HAV from select food matrices. In the first part of these studies, TRIzolRTM reagent and the RT-PCR were used to isolate and detect feline calicivirus (FCV) (a norovirus surrogate) from select artificially-inoculated foods. However, the co-extraction of PCR inhibitors resulted in false-negative results. RNA purification methods were then compared prior to detection and Oligo d (T) beads provided for the best sensitivity. However, virus capture was not sufficiently sensitive to be applied to outbreak situations. In the second part of this thesis, the Pathatrix(TM) system was applied to the isolation of HAV and NoV from a variety of foods with the use of positively-charged (cationic) magnetic beads. The use of the Pathatrix(TM) machinery has led to success in detecting a wide range of bacteria from various food matrices, and we were the first to report on its use for the concentration of viruses. When combined with the RT-PCR for detection, the Pathatrix(TM) system was able to detect HAV from inoculated foods at levels typically found in outbreak situations. Though results were not as sensitive with NoV-inoculated foods, the methodology was successful at detecting NoV in outbreak food samples. Furthermore, the cationic beads used in the Pathatrix(TM) system were able to simultaneously isolate two contaminating viruses from food samples. Therefore, the Pathatrix(TM) methodology reported herein is a very sensitive and rapid method that holds promise for the isolation and detection of HAV and NoV in outbreak situations.

Liver off-flavor is a sporadic problem that limits the consumer acceptance of several beef chuck muscles, including the infraspinatus (flat iron steak). Residual blood hemoglobin is known to contribute to liver off-flavor development. This study was conducted to evaluate factors affecting development of liver off-flavor after cooking of beef chuck (shoulder) muscles. The study was conducted in three parts. The objective of part 1 was to determine effects of muscle (infraspinatus, longissimus dorsi, serratus ventralis, supraspinatus, teres major) and processing (with or w/o carcass electrical stimulation) on residual blood hemoglobin content and total pigment content of raw muscle and sensory characteristics after cooking to 71 or 82?C. The objective of part 2 was to evaluate the effect of antioxidant treatment and anaerobic packaging to possibly reduce the incidence of liver and other off-flavors of beef infraspinatus (IF) steaks. The objective of part 3 was to determine the effect of animal age (commercial grade; >42 months, compared to select grade; <30>months), antioxidant treatment, and anaerobic packaging on sensory characteristics of beef IF steaks. Among beef chuck muscles, the infraspinatus had highest mean liver flavor score of 2.08±1.00 where 2=slightly intense liver flavor. Other muscles (longissimus dorsi, serratus ventralis, supraspinatus, teres major) had mean liver flavor scores less than 2. Liver flavor score, myoglobin, hemoglobin, and total pigment content were higher (p<0.05) for infraspinatus muscle from older animals. Among select grade muscles, carcass electrical stimulation had no significant effect on liver flavor score. Rancid flavor scores were significantly increased from 1.34±0.65 to 1.58±0.84 as internal cook temperature increased from 71 to 82°C but mean TBA values as a measure of rancidity (0.25±0.15 and 0.29±0.13, respectively) were not affected by cook temperature. Antioxidant treatment significantly reduced TBA values, rancid, and liver flavor scores for aerobically packaged steaks (PVC or 80% O2-MAP) but had little effect on scores of steaks in anaerobic packaging (0.4% CO-MAP). Results of this study indicate that infraspinatus steaks from older animals are most likely to have objectionable liver, sour/grassy, or rancid flavors. Objectionable flavor scores were lower in steaks receiving antioxidant injection or packaged anaerobically in 0.4% CO-MAP.

Master of Science / Department of Grain Science and Industry / Jon M. Faubion / Endosperm texture is an important characteristic in determining wheat processing and end-use. The presence of puroindoline proteins on the starch surface is the biochemical marker for wheat hardness. Near-isogenic samples over expressing puroindolines have been used to assess the effect of wheat hardness on final product characteristics. The objective of this study was to determine differences among starch isolated from near-isogenic samples and to investigate the role starch surface components play in pasting. The use of near-isogenic samples over expressing puroindolines combined with the use of two methods of starch isolation (batter and dough) was an effective means to create samples with varied amounts of surface components. Starch thermal properties were characterized and surface proteins and lipids were quantified. Starch isolated from hard wheat cultivars presented more similarities with starch isolated from its soft near-isogenic line when a dough method was used than when a batter method was used. Starch from soft experimental lines isolated using a batter method showed increased MVA peak viscosity, breakdown and swelling power. Increased levels of LysoPC in starch isolated from hard wheat cultivars or soft experimental lines by dough method could have complexed with amylose and restricted granule swelling. Thereby, decreasing peak viscosity, breakdown and swelling power.

Doctor of Philosophy / Department of Human Nutrition / Edgar Chambers IV / Companies introduce new products with the goal of achieving success. However, many products fail. The overall objective of this research was to design processes for determining sensory and market characteristics of food products that could predict success. The first sub-objective was to determine if success could be predicted using information known before launch. The second sub-objective was to describe a process for determining specific sensory characteristics that promote success. Most methods chosen for this research are commonly used. However, previous research has identified a relationship between consumers liking and salivation, without defining a method. Thus, three salivation methods were selected for initial testing: spit, cotton rolls and sensory scale. These were tested on foods with different textures. Although all methods gave similar results, the spit method was chosen for further testing of flavor differences. Differences in salivation measurements were found for snacks where flavors were different but texture was unchanged. Next, flavored snack products from 15 countries were selected that were successful or had failed. Questionnaires were completed for each product and included questions related to authenticity, familiarity, current trends, packaging and marketplace issues such as product competition and pricing, all of which would be known before launch. A discriminant function was developed that correctly identified 75.8% of the successful flavored snack products as successful and 66.7% of the unsuccessful products as unsuccessful. Stepwise comparisons were used to determine that four variables are necessary to correctly categorize these products. The products then were clustered into three groups to select 34 products from 11 countries for further sensory testing. Information from extensive sensory descriptive methods were evaluated individually and in various combinations through stepwise regression and discriminant analysis. The final sensory model correctly predicted all successful and unsuccessful products, had an R-square of 0.84 and included nine regression factors: seven flavor attributes and two flavor attribute ratios. Many of the attributes were base flavor notes necessary for this flavored snack category. A process for selecting key attributes for success was described. For this snack category, creating products with flavors that interact well with base flavor notes can lead to a successful product.