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Replica-plating and computer analysis for rapid identification of microorganisms in seafoodsCorlett, Donald A. 04 August 1965 (has links)
A method was devised and tested for rapid and quantitative
identification of microbial flora in fresh seafoods. The rapid
identification of large numbers of isolates was made possible by
(1) a simplified identification scheme established by reference
culture studies and from the known reactions of microorganisms
reported in the literature, (2) the multiple transfer of large numbers
of isolates by means of replica-plating, and (3) the use of an
electronic computer to analyze data.
For the identification of microbial isolates, colonies
developing on initial isolation plates were picked by sterile toothpicks
and inoculated on a master-plate in prearranged spacing and
order. Growth on the master-plate was replicated on a series of
solid agar plates containing differential or selective agents. Identifying characteristics consisted of growth responses of the
isolates on media containing penicillin, tylosin, vancomycin,
streptomycin, chloramphenicol, neomycin and colistin; growth responses
on Bacto-SS, Bacto-S-110, Bacto-potato dextrose agar;
and culture pigmentation, cell morphology and the Gram-reaction.
Information was processed by an IBM 1410 digital computer which
sorted and grouped each isolate into one of ten microbial genera or
groups, according to a programmed identification key. The identification
system was tested by analyzing the microbial flora of dover
sole fillets (Microstomas pacificus) and ground beef.
This rapid identification method was employed in an investigation
designed to determine the nature of the microbial flora shifts
in dover sole resulting from irradiation and storage at 6°C. The
relationship between the microorganisms which initially survive irradiation,
and those making up the final spoilage flora, was determined.
A total of 2,723 isolates were examined in this study.
The spoilage of unirradiated control samples during storage
at 6°C was almost entirely due to the growth of Pseudomonas.
This group, which occupied 25 percent of the fresh flora, grew up to
nearly 100 percent in two days storage. In contrast, irradiation
doses of 0.1, 0.2, 0.3, and 0.4 megarad favored the growth of
Achromobacter and yeasts. Micrococcus species, which survived
radiation, did not grow at 6°C. At 0.5 megarad, spoilage of
fish samples at 6°C was due entirely to yeasts. / Graduation date: 1966
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Flavor chemistry of butter cultureLindsay, Robert C. (Robert Clarence), 1936- 14 May 1965 (has links)
Numerous investigations have been made on the contribution of
butter cultures to the flavor of cultured cream butter, but production
of uniform cultured cream butter has not been possible in industry.
Therefore, it was desirable to investigate in detail the qualitative
and quantitative chemistry of the flavor of high quality butter cultures,
and to examine more closely some of the aspects of flavor
production by butter culture organisms.
Volatile flavor components of high quality butter culture and
control heated milk were isolated from intact samples by means of
a specially designed low-temperature, reduced-pressure steam distillation
apparatus. Most of the flavor compounds present in the resulting
distillate fractions were tentatively identified by gas chromatographic
relative retention time data. Flavor concentrates obtained
by ethyl ether extractions of aqueous distillates were also separated by temperature-programmed, capillary column gas chromatography,
and the effluent from the capillary column was analyzed by a fast-
scan mass spectrometer. Many of the flavor compounds in the flavor
concentrates were positively identified by correlation of mass spectral
and gas chromatographic data. In addition, supporting evidence
for the identification of some flavor components was obtained through
the use of qualitative functional group reagents, derivatives and headspace
gas chromatography.
Compounds that were positively identified in butter culture include
ethanol, acetone, ethyl formate, methyl acetate, acetaldehyde,
diacetyl, ethyl acetate, dimethyl sulfide, butanone, 2-butanol,
methyl butyrate, ethyl butyrate, methane, methyl chloride, carbon
dioxide and methanol; also included were 2-pentanone, 2-heptanone,
acetoin, formic acid, acetic acid, lactic acid, 2-furfural, 2-furfurol,
methyl hexanoate, ethyl hexanoate, 2-nonanone, 2-undecanone,
methyl octanoate and ethyl octanoate. Compounds that were tentatively
identified in butter culture include hydrogen sulfide, methyl
mercaptan, n-butanal, n-butanol, 2-hexanone, n-pentanal, n-pentanol,
2-mercaptoethanol, n-butyl formate, n-butyl acetate,
2-methylbutanal, 3-methylbutanal, methylpropanal, methyl heptanoate,
n-octanal, 2-tridecanone, methyl benzoate, methyl nonanoate,
ethyl nonanoate, ethyl decanoate, methyl dodecanoate, ethyl dodecanoate,
delta-octalactone and delta-decalactone.
Compounds that were positively identified in control heated milk
include acetaldehyde, ethyl formate, ethyl acetate, 2-heptanone,
2-furfural, 2-furfurol, 2-nonanone, 2-undecanone, ethyl octanoate
and methyl decanoate. Compounds that were tentatively identified in
control heated milk include dimethyl sulfide, hydrogen sulfide, ammonia,
methyl mercaptan, methyl acetate, acetone, methanol, butanone,
butanal, n-butanol, methyl butyrate, ethyl butyrate, 2-pentanone,
2-hexanone, 2-mercaptoethanol, 2-furfuryl acetate, ethyl
hexanoate, methyl heptanoate, 2-tridecanone, ethyl decanoate, ethyl
dodecanoate, delta-octalactone and delta-decalactone. The data indicated
that the qualitative flavor composition of control heated milk
and butter culture were very similar. Diacetyl, ethanol, 2-butanol
and acetic acid were noted to be consistently absent in the data for
the control heated milk. Other compounds were not observed in the
heated milk fractions, but were also absent from some of the culture
fractions. This was attributed to their presence in low concentrations,
chemical instability or inefficient recovery.
A modified 3-methyl-2-benzothiazolone hydrazone spectrophotometric
procedure was adapted for the determination of acetaldehyde
produced in lactic starter cultures. The procedure was applied in
conjunction with diacetyl measurements in studying single- and
mixed-strain lactic cultures. The diacetyl to acetaldehyde ratio was
found to be approximately 4:1 in desirably flavored mixed-strain butter cultures. When the ratio of the two compounds was lower
than 3:1 a green flavor was observed. Acetaldehyde utilization at
21°C by Leuconostoc citrovorum 91404 was very rapid in both acidified
(pH 4.5) and non-acidified (pH 6.5) milk cultures. The addition
of five p.p.m. of acetaldehyde to non-acidified milk media prior to
inoculation greatly enhanced growth of L. citrovorum 91404 during
incubation at 21°C. Combinations of single-strain organisms demonstrated
that the green flavor defect can result from excess numbers
of Streptococcus lactis or Streptococcus diacetilactis in relation
to the L. citrovorum population.
Diacetyl, dimethyl sulfide, acetaldehyde, acetic acid and carbon
dioxide were found to be "key" compounds in natural butter culture
flavor. Optimum levels of these compounds in butter culture were
ascertained by chemical or flavor panel evaluations. On the basis of
these determinations, a synthetic butter culture prepared with heated
whole milk and delta-gluconolactone (final pH 4.65) was flavored with
2.0 p.p.m. of diacetyl, 0.5 p.p.m. of acetaldehyde, 1250 p.p.m. of
acetic acid, 25.0 p.p.b. of dimethyl sulfide and a small amount of
sodium bicarbonate for production of carbon dioxide. The resulting
synthetic butter culture exhibited the typical aroma, flavor and body
characteristics found in natural high quality butter cultures, except
that the delta-gluconolactone was found to contribute an astringent
flavor. / Graduation date: 1965
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A systems engineering and concurrent engineering framework for the integrated development of complex productsLoureiro, Geilson January 1999 (has links)
No description available.
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The effect of cultural values on consumer choice behaviour in Western Europe and the resulting segmentation of the marketFifield, Paul C. January 1985 (has links)
No description available.
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PURIFICATION AND CHARACTERIZATION OF PROTEIN CONCENTRATES FROM JOJOBA (SIMMONDSIA CHINESIS) PRESSED MEAL.WISEMAN, MEGANNE O. January 1983 (has links)
Jojoba, Simmondsia chinesis, a shrub native to the Sonoran Desert, has seeds with a high percentage of oil. The oil, which has properties similar to sperm whale oil, is expressed with heat and pressure, leaving behind a pressed meal rich in protein and carbohydrate. High concentration of a cyanoglycoside, simmondsin, and polyphenolic compounds in the meal make it unusable for animal or human consumption. Commercial means of protein extraction were improved by washing the protein concentrate with methanol, acetone, and acidic methanol to remove sugars, polyphenolic components and simmondsin. A concentrate with 85% protein, less than 0.3% polyphenolic compounds, and less than 1% simmondsin resulted. The foamability, water absorption, oil absorption, gelation, emulsification and nitrogen solubility were comparable to other plant protein concentrates. Fewer than 15 proteins in the pressed meal and concentrates were detected using PAGE (12.5% T, 2.4% C) in a Laemmli discontinuous system. The proteins were deficient in the sulfur amino acids, and marginal in threonine and lysine. The amino acid imbalance might be partially responsible for poor weight gain and other toxicity symptoms reported previously.
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GLUCOSE ISOMERASE ACTION ON ACID WHEY LACTOSE HYDROLYSATE AND OTHER SUGARS.ABRIL DOMINGUEZ, JESUS RUBEN. January 1984 (has links)
In this work, glucose isomerase (GI) activity was measured with several sugar substrates. Lactase was also used with several carbohydrate substrates to observe its hydrolytic action. In order to observe the enzymes' action, a small batch reactor was designed and used in the entire project. Paper partition chromatography, was the analytical method of choice to measure the reaction end products. It proved to be a valuable technique in combination with other analytical methods for determination of various carbohydrates. GI showed positive activity with glucose, fructose, xylose and L-sorbose but none with mannose, galactose, lactose, maltose, melibiose and cellobiose. Lactase was active on maltose, cellobiose, raffinose, lactose and sucrose but not with maltiol, melibiose or melezitose. Whey proteins were removed either by ultrafiltration or heat precipitation. This deproteinized whey was treated with the two enzymes to produce a syrup composed mainly of galactose, glucose, fructose and small amounts of oligosaccharides. The syrup had a predominantly sweet taste with a slight salty attribute. The proper utilization of whey lactose has potentially valuable features in the production of a sweetening ingredient for foods. This is especially true after the lactose has been hydrolyzed by lactase and then the glucose in the hydrolyzate isomerized to fructose with glucose isomerase.
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Approaches to cyclopentenoid natural products using the Khand reactionKerr, W. J. January 1986 (has links)
No description available.
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Simulation studies of transition metal and actinide oxidesNicoll, Steven January 1995 (has links)
No description available.
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Nucleophilic addition to #pi#-allyl molybdenum complexes : a synthesis of the C1-C9 fragment of salinomycinProcter, Martin James January 1996 (has links)
No description available.
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Characterisation of high temperature molecules by matrix isolation infrared spectroscopy and mass spectrometryDay, Trevor Neil January 1994 (has links)
No description available.
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