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Characteristics of frozen peaches as affected by various pre-freezing treatmentsBlack, Verna Mae 10 June 1960 (has links)
Graduation date: 1961
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Objective quality tests in evaluating frozen strawberriesRasulpuri, Muhammad Latif 03 January 1961 (has links)
Graduation date: 1961
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Effect of maturity on the physical, chemical and sensory properties of frozen peasOlaeta-Coscorroza, Jose A. 02 July 1980 (has links)
Peas (Pisum sativum) are an important constituent in the diet
of many people. Peas may be cooked and eaten as green peas shortly
after harvest, stored for short periods in the pods, or, after suitable
treatment, stored for long periods before consumption. Many factors
influence the yield and quality of frozen peas but maturity
requires careful consideration because of the relation of maturity
to color, flavor, and texture.
The objectives of this thesis were to determine the effect of the
maturity stage on the quality of the frozen peas during processing and
storage and to correlate the interactions between the sensory evaluation
panel with the physical and chemical quality factors measured.
Venus pea variety grown under commercial conditions at the
Sublimity area east of Salem, Oregon, were used in this study. The
trials were randomized, for three stages of maturity with three replications
per each stage of maturity. Each of the three maturity stages
was harvested; vined; blanched by steaming at 98.8°C (210°F) for
30 sec for the immature peas, 60 sec for the mature peas, and 90 sec
for the overmature peas; frozen at -37.2°C (-35°F) for 24 hr in an air
blast freezer and stored at -23.3°C (-10°F) for 4 and 8 month. During
processing and. storage the following factors were determined:
tenderometer value, total solids, alcohol insoluble solids, peroxidase
activity, ascorbic acid., total sugars and sensory evaluation. In the
sensory evaluation analysis starchiness, sweetness and tenderness
intensity, as well as texture, flavor and overall desirability were
measured. Analysis of variance and least significant difference were
used to compare the effect of pea maturity during processing and
storage on the different quality factors measured. Correlation coefficients
were used to determine the relationship between these factors.
Immature peas had lower tenderometer value than overmature
peas. Tenderometer value of peas decreased, during processing. The
highest total solids content was observed, in the overmature peas and
the lowest total solids content in the immature peas. This behavior
was also observed in the alcohol insoluble solids content.
Raw peas in the three maturity stages had the same initial
peroxidase activity and the significant effect of the maturity level
found in the residual peroxidase was affected by the different blanching
time applied at each maturity stage. The ascorbic acid content
was significantly affected, by the maturity level and was reduced
during the blanching treatment. Total soluble sugar content was
higher in immature peas and lower in overmature peas.
All the sensory evaluation parameters measured were affected
by the maturity. In general, the taste panel found higher flavor desirability
on the mature peas but when texture and overall desirability
were measured immature and mature peas were equally preferred.
Significant correlations were found between physical, chemical,
and sensory parameters analyzed, some of them are tenderometer
value and alcohol insoluble solids; total solids and alcohol insoluble
solids; alcohol insoluble solids and overall desirability. / Graduation date: 1981
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Effect of initial quality on the frozen shelf-life of Pacific shrimp (Pandalus jordani)Madero, Carlos F. 02 December 1977 (has links)
The effect of round shrimp post-catch age on the frozen shelf-life
characteristics of processed cooked meat was evaluated. Refrigerated
shrimp, one, three, and five days post-catch, were cooked,
mechanically peeled, frozen at -29°C and held for a period of twelve
months at -18°C. At three month intervals, samples were subjected to
chemical and sensory evaluation. Levels of trimethylamine oxide
(TMAO), trimethylamine (TMA), dimethylamine (DMA), formaldehyde
(FA), inosine monophosphate (IMP) and hypoxanthine (Hx) were determined.
Sensory evaluations included judgements for texture, juiciness,
flavor, and overall desirability.
The degradation of frozen cooked meat quality was directly
related to round shrimp age. Flavor panel scores for meat from one
day old shrimp decreased in a linear manner with regard to texture
(r= -.933, P .005), juiciness (r= -.795, P .005), flavor (r= -.861,
P .005) and overall desirability (r= -.919, P .005). The change in
the quality of the meat from three and five day old shrimp with
respect to storage time was largely non-linear and after an initial
quality reduction during the first three months flavor panel scores
were relatively stable. Scores for frozen meat during the first six
months were equal, but the more rapid deterioration of meat from
one day old shrimp yielded scores inferior to those for meat derived
from three and five day old shrimp after twelve months.
Initial levels of TMAO, TMA, IMP and Hx in cooked meat reflected
the age of round shrimp. Differences in levels were related to chemical
decomposition, drip loss and/or bacterial out growth. DMA and FA
levels were low and not related to round shrimp age. No Hx was detected
in meat from one day old shrimp and only low levels were detected
in meat from three and five day old shrimp.
TMAO decomposed during storage to yield DMA and FA. TMAO levels
decreased in a roughly linear manner. DMA formation was neglegible
during the first six months, but increased during the latter six
months of storage in a manner inversely related to round shrimp age.
The rates of DMA formation did not show a direct inverse proportionality.
Formaldehyde was formed during the first three months of
storage, but determined levels between three and twelve months were
constant, probably reflecting its high reactivity with protein.
Determined IMP and Hx levels were relatively constant. Levels
of TMA were stable for the first nine months, but decreased during
the last three months, concurrent with the rapid formation of DMA.
The degree of quality deterioration during storage was
closely associated with the decomposition of TMAO.
. The regression of TMAO and DMA levels on scores for meat from
one day old shrimp yielded significant positive and negative correlations,
respectively. Levels in meat from three and five day old
shrimp were not correlative with the observed non-linear quality
degradation. Initial levels of TMAO, while not correlative with
initial panel scores, did correlate with scores after twelve months.
The regression of initial TMAO levels in meat from one, three and
five day old shrimp on scores yielded significant negative correlations for texture (r= -.936, P [greater than or equal to] .005), juiciness (r= -.825,P [greater than or equal to] .01) and flavor (r= -.752, P [greater than or equal to] .025). Similarly, texture (r= -.910,
P [greater than or equal to] .005), juiciness (r= -.815, P [greater than or equal to] .01), flavor (r= -.670, P [greater than or equal to] .05) and
overall desirability (r= -.783, P [greater than or equal to] .025) scores correlated in a
significant manner with DMA levels determined for meat stored twelve
months.
The findings of this investigation support the involvement
of TMAO and its decomposition products in mediating the frozen
shelf-life of Pacific shrimp. / Graduation date: 1978
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The texture and appearance of dual blanched frozen green beansFarrier, Ray Wesley 02 November 1962 (has links)
A quality problem that frequently occurs with frozen green beans
is the sloughing of the skin (epidermal tissues) of the cooked, ready-to-
serve bean pods. It was found that by giving the beans a pre-blanch
(relatively mild heat treatment) prior to the blanch treatment normally
used for frozen green beans, on cooking, sloughing was markedly
reduced, and furthermore, the bean pods were firmer.
As an additional heat treatment was involved, over and above what
is now used for commercial packs of frozen green beans, it was of
interest to know the extent to which the color of the beans was affected.
Also of interest was the effect of storage at 0°F for four months on
the color of the beans.
The color changes in the dual and single blanched green beans
were evaluated by two methods: (1) a physical analysis of the light
reflected from the beans (Hunter Color and Color Difference Meter) and, (2) a physical analysis of the light absorbing properties of the
pigments extracted from the beans and subsequent calculation of the
per cent conversion of chlorophyll to pheophytin. Texture (firmness),
as indicated by resistance to shear, was measured by a modified
Kramer Shear Press. A mechanical device was used to determine the
amount of sloughing of the skins of the bean pods.
After a statistical analysis of the data collected in the experiment,
the following conclusions were drawn:
1. The firmness of the cooked, dual and single blanched, frozen
green beans, as measured by the shear press, was found to be highly
significantly negatively correlated with sloughing of the skins.
2. There was no change in lightness or darkness of the color of
single or dual blanched beans over storage at 0°F for four months.
The Hunter "-a [subscript L]/b [subscript L]" index of color noted a significant change in hue
from green towards yellow of the single and dual blanched beans. The
conversion of chlorophyll to pheophytin was not significant over
storage.
3. The color of those beans receiving the 200°F - 150 second
final blanch (single blanch) was the same as the color of those beans
receiving the 210°F - 105 second final blanch (single blanch).
4. As the time and temperature of the pre-blanch increased,
there was a corresponding increase in the amount of chlorophyll
converted to pheophytin, and a change in the visual color of the beans from green towards yellow. The effect of variations of time of preblanch
was much greater on the color of the dual blanched beans than
the effect of variations of temperature of pre-blanch.
5. As the time and temperature of the pre-blanch increased, the
texture (firmness) of the cooked dual blanched beans increased. The
200°F - 150 second final blanch resulted in beans that were firmer
than beans receiving the 210°F - 105 second final blanch,
6. A pre-blanch at 170°F for 30 seconds followed by a final
blanch at 200°F for 150 seconds was found to result in beans that
were similar in color, yet firmer in texture (less sloughing of the
skins) than the single blanched beans. / Graduation date: 1963
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Studies on defrosting methods for frozen beef.Bedirian, Papken January 1977 (has links)
No description available.
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The effect of freezing on microscopic structure and palatability of French-fried potatoesLyman, Shirley Catherine Marie 02 May 1960 (has links)
Graduation date: 1960
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Simulation of temperature history and estimation of thermal properties of food materials during freezing /Saad, Zoubeir, January 1994 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 154-161). Also available via the Internet.
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Changes in food tissues at high subfreezing temperaturesGkinis, Asterios Michael, January 1976 (has links)
Thesis--Wisconsin. / Vita. Includes bibliographical references (leaves 193-212).
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The Permafrost regime in the Mackenzie Delta-Beaufort Sea region, N.W.T. and its paleoclimatic implications.Allen, Diana M. (Diana Margaret), Carleton University. Dissertation. Geology. January 1988 (has links)
Thesis (M. Sc.)--Carleton University, 1988. / Also available in electronic format on the Internet.
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