Texture, a critical property of Asian wheat noodles, is normally assessed by sensory evaluation. However, sensory evaluation may be impractical for wheat breeders and noodle researchers who need to evaluate a large number of samples and have limited sample. Instrumental Texture Profile Analysis (TPA) has been widely employed to evaluate Asian wheat noodle texture. Nevertheless, a standardized method for performing TPA on these products has not been established. A series of studies were conducted to develop a testing method to best relate TPA results to sensory texture characteristics of Asian wheat noodles. First, the optimum TPA testing conditions (crosshead speed and degree of deformation) were determined for each noodle category (alkaline, instant fried, salted flat, and salted round), and were defined as the conditions which best related their results to the sensory data. Partial Least Squares (PLS2) was used to examine relationships between sensory first-chew characteristics (hardness, cohesiveness, springiness, denseness, starch between teeth, and toothpull) and TPA output (peak areas and heights). Response Surface Methodology determined the optimum TPA conditions (crosshead speed and % deformation) as follow: 1 mm/s and 85 % for alkaline, 1 mm/s and 70% for instant fried and salted round, and 5 mm/s and 65 % for salted flat noodles. Second, the effects of two sample cooking factors: noodle weights (20, 50, 100 g) and noodle to water ratios (1:10, 1:20) and three holding factors: media (with, without water), temperatures (25, 55 °C), and times (2, 15, 30 min), on the TPA results were investigated. Cooking factors did not significantly affect the TPA results but higher holding temperatures, the use of water as a holding media, and longer holding time significantly decreased most TPA parameters' values. Third, relationships between TPA and sensory first-chew parameters were examined for each noodle category. Predictive models of each sensory first-chew attribute were developed using linear and nonlinear (Fechner and Stevens) models, with single and multiple parameters. Hardness could be satisfactorily predicted by a single TPA parameter (area 1 or area 2), but other attributes required multiple parameters in the models to be satisfactorily predicted. Different model types were selected for each sensory attribute and noodle category. TPA peak area 1 and 2 were the best predictors for first-chew characteristics of cooked Asian wheat noodles. / Graduation date: 1998

A lexicon describing the sensory perception of carbonated water was developed. Temporal aspects and differing ingestion conditions were investigated for Bite and Burn sensation using time-intensity (T-I). Four CO₂ levels (0, 1.7, 2.8, and 4.6 volumes) at 3°C and 10°C were tested. Trained panelists used a 16-pt category scale for evaluation in the first study. One swallow (15 ml) and four continuous swallows were evaluated by trained subjects using T-I in the subsequent studies. Lexicon included: salty, sour, bitter, cooling, astringency, bubbly, bubble size, bubble sound, gas expansion feeling, bite, burn, and numbing. Descriptor ratings, except cooling, increased as CO₂ level increased. Bubble size and bubble sound were rated higher for 10°C. Cooling, bite, burn, and numbing were rated higher for 3°C . Descriptors were divided into cooling, taste (salty, sour, bitter, astringency), trigeminal (bite, burn, and numbing), and mechanoreception descriptors (bubbly, bubble size, bubble sound, gas expansion feeling) based on PCA. Average temporal curves for Bite and Burn demonstrated that Burn sensation (steep linear rise and long-lived exponential decay slope) was similar to previously investigated irritants while Bite (steep linear rise and decay slopes, and relatively short duration) was unlike other irritants. Sensations were qualitatively and quantitatively different. Intensity and duration of Bite and Burn were concentration dependent. Cold temperature enhanced perception. Possible psychological habituation or desensitization was observed. Most T-I parameters were correlated for both Bite and Burn. These included CO₂ level dependent and CO₂ level independent parameters. Considerable subject variability was found. Increased exposure to CO₂ solution and increased cooling with ingestion of four continuous swallows was compared to one swallow. T-I curves for Bite (four swallows) were of higher intensity, longer duration, and developed maximum intensity plateaus. Those for Burn exhibited higher maximum intensities. At four swallows, T-I parameter correlations were strengthened, subject variability reduced and replication reproducibility improved by ease of rating afforded subjects by higher intensity sensations. Increased oral CO₂ perception with higher CO₂ levels and enhancement by cold temperature was reconfirmed. Beginnings of maximum intensity, Duration, and reaction time perceptual terminal thresholds were seen for the highest 3°C, CO₂ level. High CO₂ concentration, cold temperature, and exposure time induced these effects. / Graduation date: 1993

Call number: LD2668 .T4 1986 S37 / Master of Science

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Typescript. / Digitized by Kansas Correctional Industries

Very little research has been conducted on the development of taste perception in humans. Therefore there is a lack of knowledge, first, about how children perceive taste, especially when compared to what is known about how adults experience taste, and second, about the functioning and development of the gustatory system, including when the system is fully mature and functioning in an adult-like manner. The aims of this thesis were (i) to investigate the growth pattern of the tongue throughout childhood / adolescence, and (ii) to determine the state of maturity of some of the aspects of the sense of taste in mid-childhood. Overall, the data in this thesis indicate that children respond similarly to adults with regard to single-point measures of sensitivity and perceived intensity, but there are some differences in the overall temporal experience of taste, from onset of perception through to extinction, and the way in which it is perceived by adults and 8-9 year old children. The latter / Master of Science (Hons)

Both consumer and descriptive analyses were used to study the shelf-life of packaged, roasted and ground coffee in order to evaluate the utility of using sensory data in a shelf life model, and to examine the ability of consumers to detect a difference between treated and control samples. Two types of coffee, which differed in bean roast, blend and origin, were evaluated and were referred to as moderate roast and high roast. Samples were packaged under <2%, 9%, or 21% oxygen in airtight laminated foil packages. Over the course of 84 days, the samples were stored in 20��C, 30��C, or 40��C conditions and samples for all treatments were removed throughout the storage. The control samples were packaged at <2% oxygen and stored at -35��C for the duration of the study. Descriptive results illustrated a time trend in the moderate roast coffee along Factor 1, characterized by changes in the attributes of paper aroma, paper flavor, paper aftertaste, wood flavor, body, and oily mouthfeel. This trend resulted in significant differences between the control and the 40��C high oxygen 7 day stored samples in paper aroma (p=0.000) and paper flavor (p=0.000), as well as significant differences between the control and the 40��C high oxygen 49 day stored samples in paper aroma (p=0.002), paper flavor (p=0.000), paper aftertaste (p=0.000), body (p=0.000), and wood flavor (p=0.002). Factor I data from the 40��C high oxygen, moderate roast coffee were utilized in an Arrhenius shelf-life model. A second order model was fit to the data, indicating curvature in relationship for the rate of change over temperature for Factor 1 attributes. The model successfully generated a predictive curve for storage at 40��C. Consumers evaluated 30��C stored samples packaged under high oxygen and stored for either 4 or 7 days, and packaged under low oxygen and stored for 42 and 84 days. Consumer results indicated that it was difficult for consumers to detect differences between the moderate roast coffees. Consumers were readily able to tell significant differences between the high roast coffee treatments and the control sample (p<0.05). / Graduation date: 2000

This work set out to examine the methodologies of dry hopping, compare different hop materials, and look at the extraction behavior of different types of hop compounds. This work consists of two discrete studies, where the first study informed the design of the second. The first study measured the concentrations of hop aroma compounds extracted from Cascade hops during dry hopping using a model beer system devoid of malt, yeast aromas, and hops. Cascade hops pelletized by four different processors yielded different particle size distributions and pellet densities. These pellets were dosed into a degassed medium (water, 6% v/v ethanol, pH 4.2) and the hop aroma extraction was measured periodically over a one week period. Solid phase micro-extraction (SPME) followed by gas chromatography (GC-FID) was used to analyze the levels of aroma compounds in the extraction medium. Variation in the hop pellet physical properties did not significantly impact the extraction rate of hop volatiles such as linalool, geraniol, limonene and myrcene with one exception. One treatment showed an increased absolute concentration of geraniol. Separately, dry hop aroma extraction was measured over a short time (1 day) at room temperature in an unhopped beer using small-scale (1L), stirred vessels. Irrespective of the hop form (whole or pellet), the concentrations of hydrocarbon terpenes peaked between 3 and 6 hours and subsequently declined, while the concentrations of terpene alcohols continued to increase throughout the 24 hour dry hop extraction. The rate of hop aroma extraction did not appear to be significantly influenced by hop pellet properties and occurred rather rapidly regardless of the hop form. The second study examined the extraction of hop aroma compounds during a pilot brewery scale (~4hL) dry hop treatment. Dry hop treatments consisted of whole cone hops and pellet hops (Cascade cultivar, 2011 harvest) which were dosed into cylindroconical vessels which were either stirred with a pump or left quiescent. Samples were taken for GC-FID and HPLC analysis as well as sensory evaluation at various time points between 30 minutes and 12 days. Polyphenol and alpha acid extraction was highest in a stirred system dosed with pellets. Hop aroma compound extraction was also the highest in the stirred system utilizing pellet hops. The sensory panel rated the stirred pellet samples as having the highest hop aroma, bitterness, and astringency. The results showed that hop flavor from dry hopping can be readily achieved with much shorter contact time than the current 4-12 day industry practice. / Graduation date: 2013

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 261-219). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 261-219). Also available on the Internet.