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Call number: LD2668 .T4 1984 W33 / Master of Science

Response Surface Methodology (RSM) was used to study the effect of two variables, sugar level (12-16 °Brix) and acid level (0.3-0.7 % T.A.) on sensory qualities and desirability of blackberry juice drinks. Three blackberry juice levels (10%, 15%, and 20%) were used to study the influence of juice flavor on sensory qualities and desirability of the juice drinks. A trained panel evaluated three attributes, blackberry flavor, sweetness, and sourness intensities, of the juice drinks. The consumer panel gave desirability and three attributes just-right ratings. A Balanced Complete Block Design was used. Blackberry flavor intensity was enhanced by sugar level. Blackberry flavor intensity was enhanced by acid level to a point about 0.5% T.A., and then decreased. Blackberry flavor intensity was not related to °Brix:acid ratio and was only related to the sweetness:sourness ratio at the 20% juice level. Sweetness and sourness intensities increased with increasing sugar and acid levels. There was a suppression effect of sugar and acid on each other in the juice drink. The relationships of sweetness, sourness, and sweetness:sourness ratios to °Brix:acid ratios were all linear. Desirability rating was related to °Brix:acid and sweetness:sourness ratios for the 10% and 20% juice levels, for 15% juice level no association was found. The formula which received the closest to "just right" ratings and highest overall desirability rating had in a °Brix of 15.4 and a % titratable acidity of 0.64, resulting in a °Brix:acid ratio of 24 and a corresponding sweetness:sourness ratio of slightly less than 1.0. In general, the 15% juice level was the best because of its sugar and acid tolerance and high desirability. / Graduation date: 1989

The primary purpose of this study was to continue the search for a suitable liquid phase which could be utilized in a gas chromatographic study of actinomycetic tastes and odors. Of equal importance were the attempts to characterize the compounds found in the odor water.

Call number: LD2668 .T4 1951 B45 / Master of Science

Call number: LD2668 .T4 1958 C67 / Master of Science

Honey bees mark artificial flowers with scents that advertise about the previous history of the flower to subsequent foragers. Unrewarding flowers are marked with a scent, after a single visit, that makes the flower less attractive to subsequent foragers. Previously rewarding flowers are initially less attractive than unvisited flowers but become more and more attractive with each rewarding visit. Flowers that have rewarded bees four times are more attractive than unvisited flowers. This attractant is applied by the bees in response to the presence of nectar and is not, as has been suggested by other researchers, inadvertently applied to anything on which the bee lands. Similar scent-markings are applied to a real flower, Lotus corniculatus. One visit was enough to make a flower less attractive to subsequent foragers but flowers that consistently offered high amounts of nectar became more attractive than unvisited flowers. Repellents may be used by bees to avoid revisiting recently emptied flowers while attractants may be applied to flowers within a patch that consistently offer high rewards. The possible selective pressures responsible for the evolution of scent-marking was investigated by doing an energetic analysis. The presence of scent-markings in a patch results in a 33% increase, over an unmarked patch, in the amount of sugar obtained per time. The attractive scent-marking was extracted from a glass flower and maintained its biological activity when applied to a clean glass flower. The extract was chemically analyzed using gas chromatography-mass spectrometry. Four chemicals were identified; none of the chemicals has previously been found in honey bees. Mandibular glands were analyzed as a possible source of the attractant. Although none of the components was found in the gland extracts, two previously unidentified chemicals were found. / Graduation date: 1994

The capacity to form olfactory images has received less attention than the formation of visual and auditory images. The evidence in favor of such ability is also inconsistent. This thesis explored some of the characteristics of olfactory imagery through three empirical studies. Study I investigated the effects of blocking spontaneous sniffing during olfactory imagery. The results indicated that the prevention of spontaneous sniffing reduced olfactory but not visual imagery capacity. Study II studied the relation between olfactory awareness (as indexed by olfactory dreams, olfactory imagery, and olfactory interest) and olfactory functions (i.e., odor threshold, episodic odor memory, and odor identification). The main findings were that compared to low, high olfactory awareness was associated with better episodic odor memory and identification, but not with higher olfactory sensitivity. Study III investigated the neural correlates of odor evoked autobiographical memories (OEAMs) as (a) a function of cue modality (i.e., odors and their verbal referents), and (b) a function of memory remoteness. The results from Study III showed that OEAMs activated regions generally associated with autobiographical memory. In addition, verbally cued OEAMs were associated with activity linked to olfactory imagery. Odor cues activated the limbic and temporal polar regions more than verbal cues; a result that may explain the phenomenological differences found between the cued memories. Moreover, OEAMs from the first decade of life were associated with higher activity in the secondary olfactory cortex, whereas memories from young adulthood were related to areas linked to semantic memory processing. Taken together these studies favor the notion of a human capacity to form olfactory images.

Kitchen waste compositing plants emit odorous gas streams with sulfur-, nitrogen-, and oxygen-containing compounds and other hydrocarbons. A pilot-scale biotrickling filter with a space of 0.3 m square and 1.0 m height packed with fern chips was used for removing the odorous components from the kitchen waste compositing gas. An average weight ratio of ¡§kitchen waste: bulking material: seeding compost¡¨ of 90:4.5:5.5 was used to prepare the compositing material for producing the odorous gas for test. The kitchen waste was composed of residual material from food preparation and meal wastes. The bulking material was either wood trimmings or dried leaves and the seeding material was a blend of manure and bird feather compost. Experiments indicate that the composting material could develop to 32-55 oC during a composting period of 6 weeks and the vented gas contained ammonia, amines, mercaptans, and hydrogen sulfide to maximum values of 700, 1,000, 53, and 1.0 ppm, respectively. A maximum odor concentration of 23,000 was obtained and the odor intensity was closely related to mercaptans in the vented gas. Results indicate that by using the bio-treated effluent of the school-owned domestic wastewater treatment plant as a supplemental water and nutrition sources for the biotrickling filter, 0.5-5 and 1-15 ppm of ammonia and amines, respectively, in the introduced odorous gas could completely be removed at conditions of empty-bed-retention-times (EBRT) of 15 s and liquid/gas flow ratio (L/G) of 0.003 m3/m3. Particularly, with an EBRT of 7 s at a fixed L/G of 0.002, 99.7% of odor intensity (dilution to the threshold ratio, DT) in the influent gas with a DT of 5,500 could be removed. Instead of effluent wastewater, by supplementing tap water with 25 mg/L of milk powder to the biotrickling filter, results indicate that with an EBRT of 7 s at a fixed L/G of 0.002, 99.7% of odor intensity in the influent gas with a DT of 13,000 could be removed. Milk powder supplementation gave better performance than the effluent wastewater one.

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