Search

Sensory and consumer sciences seek to comprehend the influences of sensory perception on consumer behaviors such as product liking and purchase. The food industry assesses product liking through hedonic testing but often does not capture affectual response as it pertains to product-generated (PG) and product-associated (PA) emotions. This research sought to assess the application of PA and PG emotion methodology to better understand consumer experiences. A systematic review of the existing literature was performed that focused on the Facial Action Coding System (FACS) and its use to investigate consumer affect and characterize human emotional response to product-based stimuli, which revealed inconsistencies in how FACS is carried out as well as how emotional response is inferred from Action Unit (AU) activation. Automatic Facial Expression Analysis (AFEA), which automates FACS and translates the facial muscular positioning into the basic universal emotions, was then used in a two-part study. In the first study (n=50 participants), AFEA, a Check-All-That-Apply (CATA) emotions questionnaire, and a Single-Target Implicit Association Test (ST-IAT) were used to characterize the relationship between PA as well as PG emotions and consumer behavior (acceptability, purchase intent) towards milk in various types of packaging (k=6). The ST-IAT did not yield significant PA emotions for packaged milk (p>0.05), but correspondence analysis of CATA data produced PA emotion insights including term selection based on arousal and underlying approach/withdrawal motivation related to packaging pigmentation. Time series statistical analysis of AFEA data provided increased insights on significant emotion expression, but the lack of difference (p>0.05) between certain expressed emotions that maintain no related AUs, such as happy and disgust, indicates that AFEA software may not be identifying AUs and determining emotion-based inferences in agreement with FACS. In the second study, AFEA data from the sensory evaluation (n=48 participants) of light-exposed milk stimuli (k=4) stored in packaging with various light-blocking properties) underwent time series statistical analysis to determine if the sensory-engaging nature of control stimuli could impact time series statistical analysis of AFEA data. When compared against the limited sensory engaging (blank screen) control, contempt, happy, and angry were expressed more intensely (p0.05), CATA data produced illustrated term selection based on motivation to approach and/or withdrawal from milk based on packaging color. Additionally, the lack of difference (p>0.05) between emotions that do not produce similar facial muscle activations, such as happy and disgust, indicates that AFEA software may not be determining emotions as outlined in the established FACS procedures. In the second study, AFEA data from the sensory evaluation (n=48 participants) of light-exposed milk stimuli (k=4) stored in packaging with various light blocking properties underwent time series statistical analysis to determine if the nature of the control stimulus itself could impact the analysis of AFEA data. When compared against the limited sensory engaging control (a blank screen), contempt, happy, and angry were expressed more intensely (p

Fluorescent light exposure has well documented negative effects on fluid milk through oxidation reactions. A shift to light-emitting diode (LED) lights in retail dairy cases has occurred due to increased energy efficiency, but the effects of LED light on fluid milk are not known. The objective was to study the interaction of light protective additives (LPA) with a high oxygen barrier package under fluorescent and LED lighting conditions simulating a retail refrigerated dairy case. The extent of oxidation in 2% milk packaged in polyethylene terephthalate (PET) packages with different light interference properties (UV barrier, 2.1% titanium dioxide (TiO2) LPA, 4.0% TiO2 LPA, 6.6% TiO2 LPA) under light exposure up to 72h was compared to control packages (light-exposed, light-protected). Chemical measures of oxidation included dissolved oxygen content, formation of secondary lipid oxidation products, riboflavin degradation, and volatile analysis by electronic nose. Changes in dissolved oxygen content were associated closely with oxidation changes in milk over 72h. PET with 6.6% TiO2 was the most successful package, based on triangle test methodology, protecting milk sensory quality similar to light-protected milk through 8h LED light exposure. Based on a 9-point hedonic scale, (1=dislike extremely, 9=like extremely), consumers liked milk stored under LED light more (α=0.05; 6.59 ± 1.60) than milk stored under fluorescent light (5.87 ± 1.93). LED light is less detrimental to milk quality than fluorescent light and PET with high levels of TiO2 can protect milk quality for short periods of time under typical retail storage conditions. Master of Science in Life Sciences

Energy regulations have shifted commercial retail cases from fluorescent to light emitting-diode lights (LED), however the effect of LED light on milk quality (flavor and nutritional content) has not been thoroughly studied. Packaging efficacy of light protecting additives (LPA) in high-density polyethylene (HDPE) was studied for protection against light-induced oxidation of high-temperature short-time (HTST) 2% milk under fluorescent (1882±993 lux) and LED light (915±150 lux). Milk quality measures included oxidation level, riboflavin (Rb) retention, headspace volatiles, and sensory evaluation were analyzed to determine the interaction between light source, packaging material, and storage time. HDPE packaging included translucent package (0% TiO2) serving as control (light-exposed, light-protected: foil and plastic overwrap) and three LPA packages (low (1.3% TiO2), high (4.9% TiO2), yellow). Rb concentration decreased among all packages (40%-60%) after 72h for both lights. Volatile aldehydes (TBARS), increased in all packages (23%-82%) during storage over 72h at 4C. Sensory evaluation (triangle test) revealed detectable flavor changes at a TBARS value of 0.11 mg/L; LPA packages saw this change starting at 4h and continued through 72h. The high package protected milk flavor effectively at 4h under fluorescent light; yellow package was effective for 4h under LED light. Despite detectable sensory differences, acceptability scores (9-point hedonic scale) were significantly greater for milk exposed to LED light in light-protected and high packages (p

Emotional responses, whether approach or withdrawal motivated, are fundamental factors in all food-related experiences. In this research project four experiments were completed with the goal of contributing to the growing body of research related to food and emotions. Implicit (unstated) measures of attention, emotional expression, and motivational behavior tendencies were assessed as additional supportive information for explicit (cognitive) measures of acceptability and emotional response to food and attributes of food with quality and safety concerns. Differences in explicit responses were evaluated using a 9-point hedonic scale, check-all-that-apply (CATA) emotion term questionnaire, and a six basic emotion intensity ratings scale. Implicit responses of emotion, attention and motivational behaviors were measured using automated facial expression analysis (AFEA), eye-tracking technology, electrocardiography (ECG) and electroencephalography (EEG). An initial study on light-induced milk oxidation flavor quality indicated reliable explicit measures of emotion and consumer acceptability, while AFEA showed a wide range of facial expression. In a following study, five different control breakfast meal videos were created; three were matched with a nearly identical video that contained one of three food concerns, food spoilage quality, hygiene quality and safety. Explicit measures provided solid support for the expected explicit response differences between food concerning and control breakfast meal types. Implicit measures of heart rate, facial motor expressions and frontal cortex asymmetries (brain activity) were only minimally informative across each measure or conclusive across meal types. The use of time series statistical analyses illustrated temporal changes in emotions when compared to a control condition, which was not evident using traditional analysis of variance approaches. A visual attention study investigated use of eye tracking as an indicator of the emotional responses elicited. Eye tracking technologies, as well as the other implicit measures (ECG, EEG, and AFEA), encountered similar limitations pertaining to participant variability due to personal preferences and characteristics, as well as a need for standard methodologies with food as stimuli and appropriate control conditions. With further research in this area of study, implicit measures of emotion, attention and motivational behaviors may provide additional valuable information to more traditional explicit affective methodologies for a greater understanding of the overall consumer food experience. Ph. D.

Sensory and consumer sciences aim to understand the influences of product acceptability and purchase decisions. The food industry measures product acceptability through hedonic testing but often does not assess implicit or qualitative response. Incorporation of qualitative research and automated facial expression analysis (AFEA) may supplement hedonic acceptability testing to provide product insights. The purpose of this research was to assess the application of AFEA and qualitative analysis to understand consumer experience and response. In two studies, AFEA was applied to elucidate consumers emotional response to dairy (n=42) and water (n=46) beverages. For dairy, unflavored milk (x=6.6±1.8) and vanilla syrup flavored milk (x=5.9±2.2) (p>0.05) were acceptably rated (1=dislike extremely; 9=like extremely) while salty flavored milk (x=2.3±1.3) was least acceptable (p0.05). However, the exterior of water fountains were microbially (8.8 CFU/cm^2) and visually cleaner than filling stations (10.4x10^3 CFU/cm^2) (p

Emotions are thought to play a crucial role in food behavior. Non-rational emotional decision making may be credited as the reason why consumers select what, how, and when they choose to interact with a food product. In this research, three experiments were completed for the overall goal of understanding the usefulness and validity of selected emotional measurement tools, specifically emotion questionnaire ballots and facial expression analysis, as compared to conventional sensory methods in developing a holistic view of product interest and engagement. Emotional response to 1% low-fat unflavored and chocolate-flavored milk was evaluated by using an emotion-based questionnaire as well as facial expression analysis software, to measure post-experience cognitive and in-the-moment intrinsic (implicit) emotional response, respectively. The software correlated facial movements of participants to associated basic emotions to estimate with what degree consumers were expressing these measured emotions upon presentation of each sample. Finally, the adapted facial expression method was compared to expected measurements from previous studies by measuring emotional facial response to four (sweet, salt, sour, and bitter) basic tastes. The cognitive emotion ballot and implicit facial analysis were able to differentiate between milk samples and offer a greater understanding of the consumer experience. Validity of the facial expression method was lacking for reasons including high individual taste variability, social context, intensities of stimuli, quality of video data capture, calibration settings, sample size number, analysis duration, and software sensitivity limitations. To better validate automatic facial expression methodology, further study is needed to investigate and minimize method limitations. Master of Science in Life Sciences

Implications of water chemistry on milk synthesis are not well described yet water is an important nutrient for dairy cattle. High mineral concentrations (>0.3 mg/kg Fe and others) may be associated with natural levels in ground water, contaminating sources, drought conditions, or storage systems. This study evaluated effects of added iron in bovine drinking water on milk composition (Ca, Cu, Fe, P) measured by inductively coupled plasma mass spectrometry and oxidative stability measured by thiobarbituric acid reactive substances assay for malondialdehyde (MDA), volatile chemistry and sensory analysis (triangle test). Prepared ferrous lactate treatments, corresponding to 0, 2, 5, and 12.5 mg/kg drinking water levels were given abomasally (10 L/d) to 4 lactating dairy cows over 4 periods (1 wk infusion/period) in a Latin square design. Milk was collected (d6 of infusion), processed (homogenized, pasteurized), and analyzed within 72 h of processing and 7 d of refrigerated storage. No differences in MDA (1.46�0.04 mg/kg) or iron (0.22�0.01 mg/kg) were observed in processed milk. Cross effects analysis (treatment*cow) showed significant differences in calcium, copper and iron (P < 0.05). Sensory differences (P < 0.05), in treatment vs. control, suggested iron from water sources contributes to milk flavor changes. A case study with high and low (0.99; 0.014 mg/kg) iron treatments revealed no significant differences (P > 0.05) in mineral composition (0.23�0.06 mg/kg Fe) or MDA (0.77�0.03 mg/kg) of raw milk. Iron added to milk causes changes in oxidation; high levels of iron in bovine drinking water may not have observed effects. Master of Science in Life Sciences

Milk is often packaged in translucent containers providing little protection against flavor degradation from light. The effectiveness of TiO2 modifications of high density polyethylene (HDPE) packaging in affecting light-induced oxidation of extended shelf-life milk (2% total fat) and omega-3 fatty acid enriched milk (2% total fat) was studied. Packaging effectiveness was determined by assessing product quality, including changes in flavor, measuring changes in volatile compounds, thiobarbituric reactive substances and riboflavin concentrations. Products were evaluated over a 35-day shelf-life when stored under fluorescent light (2200 lux) at 4"C. HDPE packaging included clear (no TiO2) serving as control (light exposed: no light barrier, light protected (foil overwrap) and three different TiO2 levels (low, medium, high) for the experimental treatments (total of five packaging treatments). TBARS was a good predictor of the perception of changes in sensory characteristics in 2% milk.. Under the experimental conditions used, a TBARS value of 1.3 mg/L could be considered the limiting sensory threshold for oxidized milk. Riboflavin concentration decreased by 10.5% in the light-protected control over 36 days and 28.5% in the high TiO2 packaged 2% milk, but losses were greater than 40% for all other packages. In omega-3 enriched milk, the high TiO2-HDPE package provided greater protection of sensory quality and riboflavin than clear, low and medium TiO2 packaging. However riboflavin decreased by 28% even in the light protected control which is a higher loss than observed in 2% fluid milk without omega-3 lipids. TBARS was greater than 4 mg/L in all products, including the light-protected control within three days, suggesting that oxidative stability was low. Omega-3 milk packaged in clear HDPE package exceeded MDA of 3 mg/L by day 7, suggesting the milk would have changes in sensory quality related to oxidation. The high TiO2 package protected riboflavin concentration from degradation and controlled MDA concentration the best of the TiO2 treatments through the test period in both fish oil enriched and non-enriched products. Master of Science in Life Sciences

The effectiveness of titanium dioxide (TiO?) in polyethylene films at preventing the photooxidation of riboflavin in a model solution was evaluated. Five different TiO? loads (0.5-8.0 wt%), each at 3 different thicknesses (50-100 um) were evaluated. A photochemical reactor, equipped with a 350W mercury lamp, provided full spectrum light or narrow bandwidth wavelength exposure, using filters allowing transmission at 25 nm wavebands at maximum peak height at 450, 550, or 650 nm. Riboflavin concentration was measured by HPLC over 8 hours of exposure. Increased TiO? load and thickness significantly affected riboflavin photooxidation (p0.05). Master of Science in Life Sciences

Milk is often packaged in translucent containers providing little protection against flavor degradation from light. Addition of omega-3 fatty acid sources into milk increases the risk of light-initiated degradation of nutrients and sensory quality. The effectiveness of iridescent film materials in reducing light-induced oxidation of extended shelf-life omega-3 fatty acid enriched milk (2% total fat) was studied. Film selections were targeted to provide product visibility and control product exposure at targeted riboflavin excitation wavelength regions. Effectiveness was determined by sensory evaluation and measuring changes in volatile compounds on days 1, 7, 14, and 21 when stored under fluorescent light at 4°C. Five packaging treatments (films overwrapped on glass bottles) were evaluated: 446nm block, 570 nm block, broad spectrum block with 4% transmission (BS4T), light-protected (foil overwrap) control, and light-exposed (no overwrap) control. Experienced panelists (n=12) rated oxidized flavor intensity (0-9; 9=extreme) for milk samples. Light-protected milk was lower in oxidized flavor (mean score less than 3) throughout the storage period. Oxidized flavor in milk with BS4T film overwraps was not different compared to light-protected milk (p>.05) at the later stage (21 days), suggesting some level of protection to milk flavor. Milk without fish oil (milk fat only) shows relatively larger peak areas for 2-butanone on day 14, compared to other milk samples, suggesting antioxidants in the fish oil can prevent light oxidation. Overall, packaging that provides a complete light block is still the best way to prevent light-oxidized flavor in milk. Master of Science in Life Sciences

Gas chromatography (GC) and gas chromatography olfactometry (GCO) was used to determine the effect of specific light wavelengths on light oxidation in milk. The most damaging wavelengths to milk quality appear to be the UV (200-400 and 395 nm) and short visible (463 nm) wavelengths. However, exposure to 610 nm also appears to be damaging. GC and GCO were also used to look at the efficacy of film over-wraps made from iridescent films. Single-layer over-wraps were not as effective in reducing light oxidation as multi-layer film over-wraps. Single-layer over-wrap treatments had higher numbers of odor-active compounds than multi-layer over-wrap treatments with a number of odor-active compounds detected consistently in single-layer over-wrap treatments but not in the multi-layer over-wrap treatments. Concentrations of volatile compounds were slightly lower in the multilayer treatments. Multi-layer film over-wrap treatments were tested for light oxidation flavor intensity with a balanced incomplete block multi-sample difference test using a ranking system and a trained panel. Packaging over-wraps limited the production of light oxidation flavor in milk over time but not to the same degree as the complete light block. Blocking all visible riboflavin excitation wavelengths was better at reducing light oxidation flavor than blocking only a single visible excitation wavelength. A method to determine light oxidation in oil using Fourier Transform Infrared (FTIR) spectroscopy was established and preliminary data is presented. Ph. D.

Residual value is defined as the price for which a used piece of equipment can be sold in the market at a particular time. It is an important element of the owning costs of equipment and needs to be estimated by equipment managers for making investment decisions. The purpose of this study is to gain insights into the residual value of selected groups of heavy construction equipment and to develop a mathematical model for its prediction. Auction sales data were collected from two online databases. Manufacturer publications and an online source provided size parameters and manufacturers suggested retail prices matching the auction records. Macroeconomic indicator values were collected from a variety of sources, including government agencies. The data were brought into the same electronic format and were matched by model name and calendar date, respectively. Data from auctions in the U.S. and in Canada were considered for this study. Equipment from four principal manufacturers of up to 15 years of age at the time of sale was included. A total of 35,542 entries were grouped into 11 different equipment types and 28 categories by size as measured by horse power, standard operating weight, or bucket volume. Equipment types considered were track and wheel excavators, wheel and track loaders, backhoe loaders, integrated toolcarriers, rigid frame and articulated trucks, track dozers, motor graders, and wheel tractor scrapers. Multiple linear regression analyses of the 28 datasets were carried out after outliers had been deleted. Explanatory variables for the regression model were age in years, the indicator variables manufacturer, condition rating, and geographic region, and selected macroeconomic indicators. The response variable was residual value percent, defined as auction price divided by manufacturers suggested retail price. Different first, second, and third-order polynomial models and exponential and logarithmic models of age were examined. A second-order polynomial was selected from these functional forms based on the adjusted coefficient of determination. Coefficients for the 28 models and related statistics were tabulated. A spreadsheet tool incorporating the final regression model and its coefficients was developed. It allows performing the residual value prediction in an interactive and intuitive manner. Ph. D.

Odor detection thresholds of hexanal, 2-heptenal, 2-pentanone, and 2,4-nonadienal were determined in spring water, high temperature short time (HTST) 2% fat milk, and extended shelf life soymilk. The efficacy of odor scavenger's beta-cyclodextrin, D-sorbitol, and nylon 6 in removing these odors was also determined. The odor thresholds of the different odor and media combinations were as follows: hexanal in spring water, milk, and soymilk were 585, 339, and 536 ppb respectively; 2-heptenal in spring water, milk, and soymilk were 2,092, 2,322, and 3,184 ppb respectively; 2-pentanone in spring water, milk and soymilk were 24,925, 29,255 and 33,271 ppb respectively; and 2,4-nonadienal in spring water, milk, and soymilk were 164, 326, and 243 ppb respectively. These amounts reference the initial spiked concentration that was added directly to the media. Both hexanal and 2,4-nonadienal had lower thresholds than 2-heptenal and 2-pentanone in all of the media. The odor detection thresholds of 2-heptenal, 2-pentanone, and 2,4-nonadienal did show a significant difference between soymilk and water, but not for milk. The efficacy of the odor scavengers were determined by use of solid phase micro-extraction gas chromatography (SPME-GC) and sensory evaluation. Hexanal, 2-heptenal, 2-pentanone, and 2,4-nonadienal were spiked at 1,000, 3,000, 30,000, and 300 ppb respectively in all three media. Beta-cyclodextrin, D-sorbitol, and nylon 6 were added at a level of 0.1% w/v and 1.0% w/v. In all of the media, beta-cyclodextrin was found to significantly reduce hexanal, 2-pentanone, 2-heptenal, and 2,4-nonadienal at both 0.1% w/v and 1.0% w/v. Nylon 6 was not found beneficial. Master of Science