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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Formation of Acetaldehyde and Alcohol in Frozen Peas and Their Relation to Off-flavour Development

Moore, R. E. January 1951 (has links)
No description available.
2

Actaldehyde production and utilization by lactic cultures

Keenan, Thomas William 29 September 1965 (has links)
Acetaldehyde is known to be responsible for the green or yogurt-like flavor defect of lactic cultures. This study was undertaken to extend the knowledge of acetaldehyde production and utilization by microorganisms normally found in mixed-strain butter cultures. It is anticipated that the resulting information will contribute to a more thorough understanding of the development of a green flavor defect; hence, to methods of avoiding and overcoming this defect. Acetaldehyde production by single-strain cultures of S. lactis, S. cremoris, and S. diacetilactis was found to parallel the increase in microbial population. S. lactis and S. cremoris were found to remove some of the acetaldehyde produced on continued incubation at 21°C. S. diacetilactis did not remove any of the acetaldehyde produced. The ratio of diacetyl to acetaldehyde in the strains of S. diacetilactis studied was found to be unfavorable for a good culture flavor at all times up to 22-24 hr incubation. All of the cultures studied produced a distinct green flavor when grown in milk media. All of the lactic streptococci studied produced both ethanol and acetone when grown in a boiled milk medium. No evidence of acetone utilization by S. diacetilactis was observed. A tentative mechanism for the formation of acetone from pyruvate via acetoacetate was proposed. Single-strain cultures of Leuconostoc dextranicum and Leuconostoc mesenteroides were shown to be capable of utilizing added acetaldehyde under a variety of culturing conditions. These two organisms, along with L. citrovorum were combined into two-strain mixtures with various lactic streptococci. The production and utilization of acetaldehyde varied widely among different two-strain mixtures. The ratio of different lactic organisms comprising the flora of a desirably flavored commercial mixed-strain butter culture was determined. The microbial shift occurring when this culture developed a green flavor defect was found to be an overgrowth of the homo-fermentative lactic streptococci by the S. diacetilactis population. It was found that the concentration of acetaldehyde in a ripened single-strain lactic culture could be significantly reduced by adding a large inoculum of a culture of L. citrovorum and continuing incubation at 21°C or by cooling and holding the culture at 5°C after the addition of L. citrovorum. / Graduation date: 1966
3

A study of the activation energy and mechanisms of some elementary reactions

Bryan, Mary Leo, January 1953 (has links)
Thesis--Catholic University of America.
4

Reactions of acetaldehyde and ethanol over oxide catalysts under pressures of 1 to 500 atmospheres

Kinsey, Maurice Everett. January 1931 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1931. / Typescript. eContent provider-neutral record in process. Description based on print version record.
5

Vapor-liquid equilibria of the system sulfur dioxide-acetaldehyde-water.

Rabe, Allen Edwin, January 1958 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1958. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 158-162).
6

Biochemical heterogeneity of hepatocytes: alcohol metabolizing enzymes and related systems

Chen, Ling January 1992 (has links)
This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).
7

Unimolecular photodissociation dynamics

Mabbs, Richard January 1995 (has links)
No description available.
8

Ethanol metabolites in alcohol abuse /

Treloar, Tony. January 2004 (has links) (PDF)
Thesis (Ph.D.) - University of Queensland, 2003. / Includes bibliography.
9

Effect of shelf-life and light exposure on acetaldehyde concentration in milk packaged in HDPE and PETE bottles

van Aardt, Marleen 29 February 2000 (has links)
Poly(ethylene terephthalate) (PETE) packaging is becoming an increasingly popular choice of packaging material for milk, but has the disadvantage of releasing odorous acetaldehyde into food matrices. Sensory detection group thresholds for acetaldehyde in whole, low fat and nonfat unflavored milks were 3939, 4020, and 4040 ppb respectively with no significant difference due to fat level. Chocolate flavored milk and spring water showed detection thresholds levels for acetaldehyde of 10048 and 167 ppb respectively. This information assisted in determining if acetaldehyde migration from the package to the product would influence the flavor of the product. Whole milk was packaged in glass, high density polyethylene (HDPE), amber PETE, clear PETE, and clear PETE with UV light block and was exposed to fluorescent light of 1100-1300 lux (100-120 FC) at 4oC for 18 days. Sensory and chemical analysis and was done on milk from all containers over a period of 18 days. Emphasis was on oxidation, acetaldehyde and lacks freshness off-flavors and byproducts. All volatile flavor compounds studied (acetaldehyde, pentanal, dimethyl disulfide, and hexanal) were increased in light-exposed milk samples. Amber PETE showed the least amount of oxidation off-flavor, while clear PETE with UV block showed significantly less oxidation off-flavor than glass, clear PETE or HDPE on day 7 and 18. Acetaldehyde was not detected by sensory analysis in either light-exposed or light-protected samples. Chemical analysis showed relative acetaldehyde levels in glass (2220 ppb), HDPE (1265 ppb), amber PETE (3397 ppb), clear PETE (2930 ppb), and clear PETE with UV light block (1754 ppb) were all below concentrations found for human flavor threshold. / Master of Science
10

Acetaldehyde and neuroamine-derived tetrahydroisoquinoline alkaloids : role in alcohol toxicity and dependence /

O'Neill, Patrick Joseph January 1976 (has links)
No description available.

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