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Heat induced compounds in milkScanlan, Richard A., 1937- 02 November 1967 (has links)
Milk, preheated at 82°C for 30 minutes, was heated to 146°C
for four seconds (UHT-treated) and cooled to 5°C in a tubular heat
exchanger. Immediately after heat treatment, 20 gallons of heated
milk were vacuum distilled at 30°C in a semi-continuous, reduced
pressure glass apparatus. Twenty gallons of non-heated milk were
distilled in a similar manner to serve as a control. Continuous
liquid-liquid ethyl ether extractions were employed to recover the
compounds from the aqueous distillates.
Gas chromatography, mass spectrometry, infrared spectrophotometry
and odor confirmation were used to characterize the
compounds in the flavor concentrates. A technique for collecting
and transferring packed column gas chromatographic fractions to
capillary columns for mass spectral analysis was developed.
The following compounds were identified in UHT-treated milk (the underlined compounds appeared to result from the heat treatment):
the C₃, ₄, ₅, ₇, ₈, ₉, ₁₀, ₁₁, ₁₃ n-methyl ketones, the C₈, ₁₀, ₁₂
delta-lactones, acetaldehyde, hexanal, benzaldehyde, furfural,
phenylactaldehyde, vanillin, the C₆, ₈, ₁₀ n-alkanoic acids, ethanol,
oct-1-en-3-ol, n-heptanol, 2-butoxyethanol, diacetyl, maltol,
acetophenone, ethyl acetate, benzothiazole, toluene, naphthalene,
a dichlorobenzene, a trichlorobenzene, methyl iodide, benzonitrile
and chloroform.
The following compounds were identified in non-heated milk:
C₃, ₄, ₅, ₇, ₉ n-methyl ketones, C₁₀, ₁₂ delta-lactones, hexanal,
benzaldehyde, C₆, ₈, ₁₀ n-alkanoic acids, ethanol, diacetyl,
ethyl acetate, methyl palmitate, diethyl phthalate, a dichlorobenzene,
a trichlorobenze and methyl iodide.
The concentration of diacetyl in UHT-treated and non-heated
milk was determined by a modified gas entrainment, on-column
trapping GLC technique. The amount of diacetyl in non-heated milk
was 3 ppb while the amount in the UHT-treated was 38 ppb. The
diacetyl concentration of UHT-treated milk decreased approximately
40% over 16 days storage at 4°C. The average flavor threshold for
diacetyl in milk was found to be 12 ppb. It seems therefore that the
UHT-treatment increased the diacetyl concentration from a subthreshold
level to above the average flavor threshold. It is suggested
that diacetyl contributes to the "rich", "heated" note in the flavor of
heated milk. / Graduation date: 1968
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Calcium analysis in seawater by an ion sensitive electrodeBradford, Wesley L. 09 May 1968 (has links)
A newly developed calcium sensitive liquid-liquid membrane
electrode is used to analyse seawater off the Oregon coast in waters
fed by the Columbia River runoff. For the analysis, an application of
the method of standard additions is used requiring the assumption that
the seawater is of so high a salt concentration that a small change in
the overall ionic strength is insufficient to disturb the electrode response
to calcium.
Two equations describing the behavior of the electrode are
treated and one is found applicable for use in seawater.
Analyses by electrode are compared with analyses of the same
water by atomic absorption spectroscopy with a degree of scatter in
the correlation which is largely accounted for by 10% of calcium accuracy
in the electrode readout device. Overall laboratory precision
of the electrode and readout was 3% of calcium per standard deviation.
The electrode appears to be much better for analytical purposes than
± 10% of calcium concentration. / Graduation date: 1968
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The nature of the flavors of filbert nuts (Corylus avellana)Aref, Moustafa 22 June 1954 (has links)
Graduation date: 1955
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Flavor chemistry of roasted filberts (Corylus avellana)Sheldon, Ross Mark 14 August 1969 (has links)
Graduation date: 1970
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Lactone precursor in milk fatWyatt, Carolyn Jane 04 April 1966 (has links)
Graduation date: 1966
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Floristic composition of a tropical rain forest in Indonesian BorneoSUKARDJO, Sukristijono, HAGIHARA, Akio, 萩原, 秋男, YAMAKURA, Takuo, 山倉, 拓夫, OGAWA, Husato, 小川, 房人 03 1900 (has links) (PDF)
農林水産研究情報センターで作成したPDFファイルを使用している。
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Marine algal chemistryWoolard, Frank January 1977 (has links)
Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1977. / Includes bibliographies. / I. Halogenated constituents of Chondrococcus hornemanni (Mertens) Schmitz.--II. Halogenated constituents of Asparagopsis taxiformis (Delile) trev.--III. Studies on the biogenesis of the dictyopterene hydrocarbons and sulfur compounds. / Microfiche.
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Organic constituents of the deep-sea precious corals Gerardia and Corallium spp.Schwartz, Robert Eugene January 1980 (has links)
Typescript (photocopy) / Thesis (Ph. D.)--University of Hawaii at Manoa, 1980. / Bibliography: leaves 162-166. / Microfiche. / xxi, 166 leaves, bound ill. 29 cm
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Constituents of marine invertebrates : chemical and pharmacological propertiesIchiba, Toshio January 1994 (has links)
Thesis (Ph. D.)--University of Hawaii at Manoa, 1994. / Includes bibliographical references (leaves 97-105). / Microfiche. / xiv, 105 leaves, bound ill. 29 cm
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Vegetation community development eight years after harvesting in small streams buffers at the Malcolm Knapp Research ForestMiquelajauregui, Yosune 05 1900 (has links)
Riparian areas connect terrestrial and aquatic environments. The objectives of this research were to compare the vegetation community composition and structure eight years after harvesting and to explore successional trends among buffer widths at year eight after disturbance and in a chronosequence. A series of small clearcuts were harvested in 1998 in a 70 year old second growth stand at the Malcolm Knapp Research Forest and 0m, 10m and 30m reserve zones were established adjacent to the streams. Each treatment was replicated 3 times and 3 unharvested streams were identified as controls. Overstory and understory vegetation was measured annually from the year of harvest. Canopy density was measured using a densiometer. For comparative purposes, four vegetation plots were added in riparian areas within an 1868 and an old-growth stand during the summer of 2006. Eight years after harvesting, understory vegetation development is affected by buffer width due to higher light levels, and species richness in the 10m and 0m buffers is higher than in the 30m buffer and control. Shrubs and deciduous trees dominate the 0m and 10m buffer treatments. Proximity to the stream does not affect the composition and abundance of species with the exception of herbs and mosses. In the 10m and 30m buffer treatments, up to 15% overstory trees were windthrown in the first 2 years after harvest producing large canopy gaps. Consequently, the understory development in the 10m and 30m buffers is more like that in the 1868 and old-growth stands than in the controls, but these treatments still lack the very large trees and microsite heterogeneity of the older stands. In the unharvested controls, self-thinning continues and there has been 30% mortality of mostly smaller trees over the past 8 years. However, overstory density remains high. The 0m buffer was quickly colonized by shrubs and ferns and within the last 2 years has become dominated by juvenile deciduous trees. Overall, the 10m buffer balances timber production with the maintenance of overstory and understory structure dynamics. The combined effect of light from the edge and partial windthrow is accelerating succession towards a more mature or ‘old-growth’ condition.
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