The 16th Annual
NC State University
Undergraduate Research Symposium
Biological Sciences:
Applied Sciences
(Crop, Poultry, Animal,
and Horticultural
Sciences)
Abstracts
Abstracts are listed in alphabetical order by the last name of the
corresponding author.
- Biological Sciences abstracts
Applied Sciences (Crop, Poultry, Animal, and
Horticultural Sciences)
Ecology, Environmental, Conservation, Botanical
Molecular, Biochemical, Genetics, Cell Biology
Zoology, Physiology, Behavior, Neurobiology
- Engineering & Technology abstracts
- Humanities, Social Sciences, Psychology abstracts
- Physical and Mathematical Sciences abstracts
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Bilello, Kelly E. |
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Department(s):
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Poultry
Science |
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Research |
James N. Petitte/Poultry Science Paul E. Mozdziak/Poultry Science |
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Title of
Presentation: |
The Effect of
Dietary Protein on the Growth of Transgenic Chickens Expressing High Levels
of Bacterial Beta-Galactosidase |
Recently, a line of transgenic chicken, designated
NCSU Blue-1, has been developed that expresses bacterial beta-galactosidase (LacZ) as a useful
tool for cell lineage analysis. Expression of the transgene
is particularly high in skeletal muscle, the small intestine, and spleen. In
addition, insertion of the transgene disrupted the
expression of CXC3CL1 (Fractalkine). However, the
expression of the LacZ gene and its insertion into
the fractakine gene may influence the general
physiology of the bird that may require changes in animal husbandry. For
example, it was noticed that the growth of NCSU Blue-1 chicks homozygous for LacZ appeared to be slower compared to hemizygous
or wild-type siblings. Therefore, the objective of this study was to examine
the effect of dietary protein on the growth of NCSU Blue-1 transgenic chicks. A
total of 30 chicks for each genotype (wild-type, hemizygous,
homozygous) were fed an 18% or 22% protein ration. Bodyweight and feed
consumption were monitored. Beginning at 6 days of age, a significant
difference (P<0.05) was observed between the two diets regardless of the
genotype of the birds. Chicks of all genotypes had heavier body weights on the
22% protein ration compared to the birds on the 18% protein diet. However, by
36 days of age the hemizygote and homozygote
transgenic birds on the lower protein diet had smaller body weights compared to
the wild-type, non-transgenic birds. While the two diets had an impact on the
growth curve of all genotypes, this study demonstrates a need for an increase
in the level of nutrition for the NCSU Blue-1 line of transgenic chickens.
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Callahan, Brittney S. Beachler, Theresa M. |
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Department(s):
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Animal
Science |
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Research |
William
Flowers/Animal Science |
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Title of
Presentation: |
Reliability
of Semen Extenders 5-Days Post Extending |
Semen extenders are commonly used in semen analysis
labs worldwide. These extenders come in
two varieties, a five-day extender and a three-day extender. Our study used only the five-day extender. Extenders are used to prolong the life of the
spermatozoa so that analyses can be run several days after collection. Spermatozoa are very sensitive to any changes
in their environment. Do these extenders
affect the quality of the semen and skew the analysis results? This question was the main focus of our
study. Samples of normal morphology such as tail abnormalities, proximal and
distal cytoplasmic droplets, and acrosome
defects and head abnormalities were analyzed.
The data with significant differences are Motility (p=.01820), abnormal acrosome (p=.0179) and a very significant difference of
abnormal tails at (p=.0002), significant p values are those that are less than
.05. The ones that show no significant difference, but do suggest trends are
Progressive Motility (p=.0643), normal morphology (p=.0610) and translocated tails (p=.0804). Distal droplets, Proximal
droplets and "heads" show no significance at all between day 1 and
day 5. By comparing the results of same day of collection analysis and analysis
of five days later, we were able to conclude from our data that semen extenders
do not have a profound effect on the quality of the semen. Through several statistical analyses we were
able to compare our results from four days later to Kara Roski’s
same day results and found that the normal morphology rates and acrosome morphologies were not that different. It is an accepted fact that semen quality
will decrease as the length from collection date increases. Semen extenders were created for this reason
and is obviously why that they are used to prolong the life of the sperm for
analyses and insemination properties.
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Carter, Rebecca S. |
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Department(s):
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Biological Sciences |
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Research |
Kimberly Ange-van Heugten/Animal Science |
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Title of
Presentation: |
The Body Condition Scoring of Exotic Felids |
The purpose of this project was to develop a body
condition score (BCS) reference for exotic felids and counteract the declining
trend of existence for many of these felid species. Optimum health and
nutrition is vitally important for the survival of exotic endangered felids.
Because malnourishment can lead to chronic disease, poor reproductive
performance, and even death, it is critically important that endangered exotic felids
in captivity be properly nourished. The BCS of a cat is an overall assessment
of the cat’s health and nutritional status. Currently, the Nestlé Purina Body
Condition System for domestic cats is the primary felid scoring system
available for evaluating the nutritional status of cats, rating them on a scale
from 1 (very emaciated) to 9 (very obese). It can be difficult to rate the body
condition of an exotic felid using only a chart that is designed for domestic
cats. The objective was to make an exotic felid BCS reference by taking
pictures of felids from the
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Compton, Elizabeth C. |
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Department(s):
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Animal
Science |
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Research |
Charlotte E. Farin/Animal Science |
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Title of
Presentation: |
The Role of Transcription
in EGF and FSH Mediated Oocyte Maturation in Vitro |
The transcriptional inhibitor, DRB, prevents germinal
vesicle breakdown (GVBD) in bovine oocytes cultured
with follicle stimulating hormone (FSH). However, it is unclear whether DRB is
effective in blocking maturation induced by epidermal growth factor (EGF).
Therefore, the objective of this study was to examine the role of transcription
in mediating bovine oocyte maturation induced by FSH,
EGF or their combination. Bovine cumulus oocyte
complexes (COC) were cultured in the presence or absence of DRB in cSOF medium supplemented with FSH, EGF or their
combination. After culture, COC were denuded, fixed, and stained to evaluate
stage of meiosis. As expected, 93 ±4% and 85% ±4% of COC cultured without hormone or with FSH,
respectively, underwent GVBD. The addition of DRB did not affect the occurrence
of GVBD in the absence of hormone (90% ±4%). In contrast, DRB blocked GVBD induced by FSH (13%
±4%,
P<0.05). Thus, oocyte maturation in the absence of
hormone does not involve gene transcription, whereas transcription is required
for GVBD induced by FSH. When cultured with EGF, 93±4% of COC underwent GVBD.
If DRB was included with EGF, 73±4% of COC underwent GVBD (P<0.05). Thus,
only a portion of COC cultured with EGF mature using a transcriptional
mechanism whereas the majority do not. When COC were cultured with both FSH and
EGF, 92 ±4% underwent
GVBD. In contrast, only 16 ±4% of COC underwent GVBD when DRB was added
(P<0.05). Thus, it appears that the transcriptional mechanism used by FSH to
induce maturation over-rides that used by EGF in the majority of COC. In
conclusion, in the majority of oocytes matured with
FSH, gene transcription is required for oocyte
maturation. In contrast, in the majority of oocytes
matured with EGF, transcription is not required for maturation. Furthermore,
when both FSH and EGF are present, the transcriptional pathway stimulated by
FSH takes precedence.
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Fernandez, Diana |
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Department(s):
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Biochemistry |
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Research |
Christopher
M. Ashwell/Poultry Science |
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Title of
Presentation: |
Real Time PCR
Analysis of Differential Chicken Gene Expression in Response to Dietary
Phosphorus Restriction |
Dietary manipulation immediately post hatch has long
term effects on the regulation of gene expression in chicken. Experiments with
regard to market weight have suggested that broiler chickens fed a restricted P
diet from hatch to 96 hours of age were better suited to a restricted diet from
22 to 38 days of age than those fed a control diet in the first 96 hours post
hatch. The difference has been further examined by looking at changes in gene
expression between the two treatments by microarray
analysis. These experiments showed genes whose expression are significantly
affected by dietary P restriction including TC219243 (Retinal-g-protein
receptor opsin homolog), TC207130 (Rps3a-prov protein
homolog) and TC186738 (ChlGL VJC Ig
light chain precursor). These array results were verified using Real Time PCR.
Total RNA was extracted from the duodenum of chickens that were fed either a
control or restricted diet (0.5% and 0.25% available P, respectively) from
hatch to 96 hours of age. The RNA was converted to cDNA
and it was used as a template for RT-PCR using specific primers for the 3 genes
specified above. When the RT-PCR data was analyzed these genes were found to
have significant changes in expression between treatments and time.
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Gladden, Patrice J. |
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Department(s):
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Biological
Sciences Nutrition |
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Research |
Carol S.
Mitchell/Wake |
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Title of
Presentation: |
Extension
Education Equips Childcare Providers to End Adolescent Obesity Epidemic |
With more parents working longer hours outside the
home, childcare providers spend over 9 hours a day with children during their
critical years from birth to age 5. As a result, family meals are less common
and kids are less likely to be able to play outside. Healthy eating and
exercise therefore take back seats to fast food and sedentary lifestyles. In
this project, my objective was to provide childcare providers with the tools
and motivation to promote healthy lifestyles in the classroom. From January to
April 2006, over 100 different childcare providers across
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Hughes, Shaya
N. |
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Department(s):
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Animal
Science |
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Research |
Scott C. Whisnant/Animal Science Joe P. Cassady/Animal Science Matt H. Poore/Animal Science Gerald B.
Huntington/Animal Science |
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Title of
Presentation: |
Feed
Efficiency of Beef Bulls and Heifers: Measuring Thyroid Hormones |
In beef cattle, there are some animals that can gain
weight faster than other animals on the same feed. Those animals are more feed
efficient, and efficiency can be measured by residual feed intake. In this
experiment, there were two treatment groups, one of heifers and one of bulls.
The animals were individually fed and their weights were taken every two weeks
for eighty-four days, which is the typical length for a cattle growth trial.
Blood samples were taken at the beginning, middle, and end of the experiment,
and the thyroid hormones T3 (tri-iodothyronine) and
T4 (thyroxine) were measured. Normally, T3 represents
about 5% of the thyroid hormones in blood plasma, mostly from conversion of T4.
Though less abundant, T3 has greater metabolic activity and faster turnover
than T4. The thyroid hormones control metabolic rate and could affect the energy
use in the animals. The blood samples for bulls were taken from September to
December, while the heifer blood samples were taken from October to January.
There was not a noticeable difference in hormone levels between bulls and
heifers. In both groups, the level of T4 increased from the first sample to the
second and then dropped in the third, while the level of T3 increased
throughout the experiment. This could be an age effect or represent a response
to cooler temperatures. The hormone levels were measured with radioactive
iodine (125I) in antibody-coated tubes that bound to the free hormones in the
blood plasma. As part of the feed efficiency trial, we also used ultrasound to
determine the amount of fat and muscle on the animals. Their behavior was also measured
using a chute score, which analyzes how the animals acted while being worked,
and escape velocity from the headgate. The calmer
animals in the trial were the most efficient.
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Lane, Selena L. |
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Department(s):
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Biological
Sciences |
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Research |
Daniel H.
Johnson/Veterinary Medicine |
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Title of
Presentation: |
Effectiveness
of Cryosurgery versus Cold-Steel Surgery for Removal of Skin Tumors in Carassius auratus |
Ornamental fish are economically important to the pet
trade. In fact, pet fish outnumber all other pets in the
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Lannon, Kestrel R. |
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Department(s):
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Horticulture |
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Research |
H.D. Shew/Plant Pathology |
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Title of
Presentation: |
Root-Knot Nematodes
Break Single-Gene Resistance to Phytophthora nicotianae in Flue-Cured Tobacco |
Phytophthora nicotianae is a soilborne plant
pathogen that causes the black shank disease of tobacco. This disease causes
high levels of plant mortality in
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Layfield, Johnathon B. Russell, Chasity
L. Tate, Reginald D. |
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Department(s):
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Food Science |
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Research |
Dana J.
Hanson/Food Science MaryAnne Drake/Food Science Brian E. Farkas/Food Science |
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Title of
Presentation: |
Consumer
Acceptance of Cooked Bacon as Affected by Genetic Line and Feeding Program |
A 2x2 factorial study was conducted on the consumer
acceptance of cooked bacon as affected by genetic line and feed program. Pigs
(n=79) produced by current industry practices were compared to pigs (n=79)
produced from a 1980 genetic sample (GS). Pigs were randomly assigned to a 1980
or 2005 feeding program (FP), and were slaughtered when average pen weight
exceeded 116 kg. Bellies from slaughtered pigs were vacuum packaged and frozen
at –17oC prior to conversion to bacon. Bellies were skinned and pumped with a
brine solution and then cooked (avg. 3.5 hr) to an internal temperature of
59oC. Cooked bellies were then cooled (0oC) and vacuum packaged until slicing.
Packaged samples were sliced to 3 mm thickness for consumer acceptance testing.
Samples were cooked for 4.5 min using an 800-Watt commercial microwave oven,
and presented to consumers (n=84) that evaluated bacon for overall acceptance,
flavor, leanness, fattiness, saltiness, and crispness liking on a 9-point
hedonic scale. Consumer acceptability of
all treatments was high (> 6.3) and no difference was found between overall
liking scores for bacon from pigs fed the 1980 FP and bacon from pigs fed the
2005 FP. The 1980 FP had higher fattiness, leanness, and crispness liking
scores (P<0.05) than the 2005 FP bacon. There was no significant difference
in saltiness or flavor liking scores among all treatments. When consumers were
asked to make a forced choice ranking of the samples, the preferred bacon was
the 2005 GS paired with a 1980 FP. Changes in FP appear to have had the
greatest impact on consumer preference of bacon while changes in genetics had
little or no effect on overall consumer preference. Industry benefits include
higher consumer acceptability of bacon through data on changes in feeding
programs.
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Leksrisompong, Pattarin Thibault, Yvette M. Downer, Andrew P. |
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Department(s):
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Food Science |
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Research |
Brian E. Farkas/Food Science Lynn G.
Turner/Food Science |
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Title of
Presentation: |
Thermovinification of Grape Must by Microwave and Indirect Heating |
Thermovinification is used to enhance red wine color intensity,
although traditional methods using indirect heat may cause some phenolic degradation. In previous studies, phenolic compounds have been shown to be stable when juice
is heated using microwave energy. The goal of this research was to quantify the
differences between microwave (MW) and indirect (ID) heating treatments used
for thermovinification of red globe grape must. The
objectives were to determine the phenolic content,
color intensity, and yeast counts in the juice produced by each method. A
continuous flow MW system operating with an energy output of 5 kW at 915 MHz
and a jacketed kettle with agitator using 100C steam as a heat source were
used. Grape must was heated to 70C, held for 0, 5, 10, 15, and 20 minutes,
cooled to 20oC and pressed. A Folin-Ciocalteu assay
was used to measure the phenolic content. Juice color
intensity was determined by summing the absorbance values found at 420 nm and
520 nm. Yeast counts were obtained by spread plating on Wallerstein
laboratory nutrient agar containing erthythromycin.
Preliminary results suggest a greater phenolic
content and color intensity in grape must heated with the MW. A reduction in
yeast counts from the unheated to all heat treated samples was observed with ID
heating resulting in the lowest counts at each time interval. Greatest color
intensity was achieved at a 15 minute hold time while the highest phenolic content was achieved at a 10 minute hold time.
Based on these results, production of grape must heated using MW energy may be
considered as an alternative to traditional thermovinification
methods but further study is needed.
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Metzler, Tria
M. |
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Department(s):
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Animal
Science |
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Research |
Chris M. Ashwell/Poultry Science |
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Title of
Presentation: |
Corroboration
of Disease Resistance Quantitative Trait Loci (QTL) in Lines of White |
The chicken was the first livestock species to have
its genome sequenced with the initial draft being released in March of 2004.
There have been many Quantitative Trait Loci (QTL) mapping studies performed in
the chicken for different traits including growth, egg quality, body weight,
feed efficiency, survival rate, and disease resistance. For this study we have
compiled a list of QTLs that other researchers have
found to be associated with immune response to various antigens and disease
resistance to several common chicken viruses. From this list of 24 previously
described QTLs we have selected 69 flanking microsatellite markers to analyze in a population of White
Leghorn chickens. These chickens have undergone 32 generations of divergent
selection for high and low immune response to the antigen sheep red blood cells
(SRBCs). Initially these markers will be screened in
the selected lines to determine those which are polymorphic and informative in
this population. Three of the markers that were found to be polymorphic were
then screened in the F2 QTL mapping population and analyzed for association
with antibody response. We will determine if QTLs
found to be associated with immune response and disease resistance in previous
experiments are also present in this population. This data will provide
evidence that these QTLs are consistently associated
with immune response and disease resistance in a large proportion of the
general chicken population and not just a feature of individual laboratory
lines.
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Murray, Haley D. |
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Department(s):
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Animal
Science |
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Research |
Leonard
Bull/Animal Science; Associate Director, Animal and Mark
Rice/Biological and Agricultural Engineering, Extension Specialist |
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Title of
Presentation: |
The Effects
of Weather Parameters on Sludge Levels in Waste Management Lagoons |
The swine industry is one of the most important industries
in
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Nivison, Leslie M. |
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Department(s):
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Animal Science |
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Research |
Detection of Anti-nematode IgE in Horses |
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Title of
Presentation: |
Bruce Hammerberg/Population,
Health, and Pathobiology |
Since the decline of large strongyles,
cyathostominae have risen to be the most pathogenic
nematode found in horses. Population control by the use of anthelmentics
is difficult due to the encapsulation of cyathostomines
in the mucosa of the gut. Emergence of larvae destroys mucosal cells and
involves a severe inflammatory response. Synchronous emergence of encysted
larvae can become particularly pathogenic. The only noninvasive technique
available for quantifying nematode numbers is by coprological
methods which do not detect prepatent infection and
only estimate the number of adult worms. It would be beneficial for clinicians
and equine owners to detect prepatent infections.
Currently, immunodiagnostic techniques seem to have the most potential in
diagnosing mucosal infection. In this study, L4 cyathostome
antigens were used to detect levels of anti-L4 antigen specific IgE in fecal extracts and sera. A modified enzyme-linked immunosorbent assay (ELISA) was used to detect changes in
fecal and serum total IgE and anti-L4 antigen
specific IgE from summer 2006 to winter 2007. A
relationship was observed between anti-L4 antigen specific fecal IgE levels and falling temperatures. Anti-L4 antigen
specific serum and fecal IgE did not seem to be
related, although total serum IgE and anti-L4 antigen
specific serum IgE was observed to have a positive
relationship.
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Roberts, Joseph A. |
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Department(s):
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Biological
Sciences |
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Research |
Lane Tredway/Plant Pathology |
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Title of
Presentation: |
Curvularia, Ubiquitous Organism or Potential Pathogen; A
Study of Various Curvularia
Isolates Involving Molecular Characterization and Effects on Multiple
Cultivars of Zoysiagrass |
Species of Curvularia are known to be ubiquitous and are typically
considered to be secondary pathogens or saprophytes. However, under certain
conditions, Curvularia
spp. can cause blighting of various turfgrass species. Severe blighting of Zoysiagrass,
a common species of turfgrass used for home lawns and
golf courses, was observed in the
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Simmons, Kirsten A. |
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Department(s):
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Animal
Science |
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Research |
Donna K.
Carver/Poultry Science |
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Title of
Presentation: |
Geographic
and Biosecurity Trends Among |
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Stride, Alex A. |
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Department(s):
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Biochemistry |
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Research |
Chris M. Ashwell/Poultry Science |
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Title of
Presentation: |
Regulation of
Genes by Hypoxia in Chicken |
Hypoxia is when tissue is unable to get sufficient
oxygen supply. A low iron diet can induce hypoxia and leads to hardening of
arteries. In this study phenylhydrazine was used to
inhibit heme production to induce hypoxia. In this
study the expression of 5 different genes were investigated using quantitative
real-time PCR (qPCR). The genes being investigated
were ferritin, hypoxia inducing factor (HIF), hypoxia
up-regulated 1 (HYOU1), heme oxygenase
1 (HMOX1) and vascular endothelial growth factor (VEGF). The two housekeeping
genes GAPDH and 18s were used as internal controls to determine changes in gene
expression. The tissue being studied was taken from 16 chicks fed on a control
diet or one containing phenylhydrazine. From each
treatment 8 samples were taken of heart, aorta, lung, and liver, the RNA
extracted, cDNA made and qPCR
ran. The results showed that in the liver all genes were unaffected by
treatment with phenylhydrazine, the lung showed down
regulation of ferritin, HYOU1 and VEGF, the heart
down regulated all genes apart from ferritin and the
aorta showed down regulation of all genes.
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Thompson, Lisa M. |
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Department(s):
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Animal
Science |
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Research |
Billy L.
Flowers/Animal Science |
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Title of
Presentation: |
The Effect of
Spatial Memory Performance on a Pig's Ability to Locate a New Food Source |
The objective of this study was to determine the
effect of a pig’s spatial memory on its ability to locate a food source when
placed in a novel environment. Eight, 3-minute trials on a wooden, 3-armed maze
were used to assess the spatial memory of eight pigs between 1 and 3 weeks of
age. Trials 1 and 2 determined whether pigs had any innate preferences for a
particular arm of the maze. The arm of the maze for which each pig had the
lowest preference was “baited” on trials 3 and 4 using a heat lamp stimulus and
on trials 5 and 6 using the noise of a litter mate. Trials 7 and 8 tested
whether the pig’s innate pattern had changed by determining whether the pigs
entered the “baited” arm in trials 3 through 6 in the absence of an actual
stimulus. Pigs entering the baited arm with the fewest mistakes and shortest
time intervals were viewed as having good spatial memory. At 5 weeks of age the
pigs were subjected to a nursery trial where their feeders were placed in a
novel orientation and their actual order of discovery of the feeder noted.
There were no correlations between the pigs’ spatial memory rankings and their
ability to locate feeders in the nursery (r=-0.07; p=0.87). However, it was
found that the incidence of baited arm visits on the preference alteration test
(trials 7 and 8) correlated most to the cumulative incidence of baited arm
visits (r=.80; p=.0165) and that the time to first find the noise stimulus was
closely correlated to the cumulative times of pigs to find the baited arms
(r=.92; p=.001) for each pig. In conclusion, spatial memory was not found to be
a factor in a pig’s ability to find a new feeder.
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Tilley, Amanda |
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Department(s):
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Biological
Sciences |
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Research |
Jonathon
Allen/Nutrition Science Jennifer
Boardman/Nutrition Science Amanda
Stephens/Nutrition Science Savitri Mullapudi/Nutrition
Science Kimberly
Hoffman/Nutrition Science |
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Title of
Presentation: |
Evaluation of
Cholesterol Levels in Athletic and Non-athletic Collegiate Students Who
Consume High Amounts of Fast Food |
Diets high in calories, saturated fats, and
cholesterol are linked to increased blood triglycerides and total cholesterol,
which increase risk for developing cardiovascular disease. Fast foods usually
have these characteristics. Individuals who consume large quantities of fast
foods in their diets tend to exhibit signs of increased risk for cardiovascular
disease. Conversely, individuals who exercise regularly are shown to have lower
total cholesterol to HDL ratios and therefore a lower cardiovascular disease
risk when compared to sedentary individuals. Our study investigates the effect
of consuming fast foods on blood lipid values: total cholesterol (TC),
triglycerides (TG), high density lipoproteins (HDLs),
low density lipoproteins (LDLs) and TC:HDL ratio. We
tested 40 individuals aged 18-26, of whom 20 were athletes and 20 non-athletes.
All participants were required to routinely consume fast food at a minimum of 3
times per week. We analyzed surveys to determine their exercise and dietary
patterns. Participants were considered athletes if they work-out at a high
intensity more than 3 times a week, and considered non-athletes if they
work-out less than 2 times a week. Participants were required to fast starting
at midnight the day prior to testing. For cholesterol measurement purposes, we
utilized a finger-stick cholesterol screening test and recorded TC, LDL, TG,
HDL, TC:HDL using the Cholestech LDX. We hypothesize
that those athletes aged 18-26 who consumed diets of fast food will demonstrate
normal levels of cholesterol offset by their high levels of activity. On the
converse, those with low levels of activity and high consumption of fast food
will exhibit higher levels of cholesterol. At this time, results are showing a
small difference between the two groups, but extensive analysis is still
needed. This research aims to demonstrate the increased need to study the
impact physical activity may have to balance poor dietary choices.
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Treasure, Emrys
A. |
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Department(s):
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Forestry and
Environmental Resources |
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Research |
Daniel J. Robison/Forestry
and Environmental Resources Matthew H. Gocke/Forestry and Environmental Resources |
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Title of
Presentation: |
Characterization
of Root System Symmetry for Two-year-old Rooted Stem Cuttings of Cherrybark Oak (Quercus pagoda
Rafinesque) |
Hardwood tree species are an integral component of
most forest ecosystems and have special commercial, as well as, intrinsic
value. Cherrybark oak (Quercus pagoda Rafinesque), a bottomland species native to
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Watson, Drew M. Tarkington,
Benjamin E. Whitson,
Megan E. |
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Department(s):
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Food Science |
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Research |
Lynn G.
Turner/Food Science Brian E. Farkas/Food Science |
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Title of
Presentation: |
Effect of Air
Incorporation and post-process Hold Time on Incidence of Cracking in
Chocolate Milk |
“Cracking” is a visual defect in chocolate milk observed
by the dairy industry over the past three to five years. This visual defect is
characterized by the appearance of cracks or folds in the product one to five
days after processing. Cracked product is viewed by the consumer as
undesirable, and results in costly product recall by the industry. The goal of
this research was to determine the cause of cracking. Industry contacts
suggested that air incorporation into chocolate milk during processing
increased incidence of cracking, while post-processing hold time decreased
cracking. Research objectives were to force cracking in an effort to understand
the effects of hold time and air incorporation on the incidence and intensity
of cracking. The design involved small-scale production of chocolate milk. Chocolate
milk was produced on three days; each day, excessive air was incorporated via
funnel mixer into a chocolate milk blend. Chocolate milk samples were subjected
to a post-processing hold time of 0 min, 20 min, 40 min, or 60 min, which was
hypothesized to reduce the incidence of visual defect by allowing air to escape
the mixture. The design was replicated three times. Our data indicated that, in
general, increasing post-process hold time resulted in a reduction of the
incidence and intensity of visual defects in samples. Increased quantities of
air incorporation into chocolate milk during mixing showed an increase in the
intensity of visual defects in chocolate milk. Further research is being
conducted to determine the mechanism by which air affects cracking in chocolate
milk.
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Whitley, Andrea N. |
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Department(s):
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Food Science |
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Research |
Leon
Boyd/Food Science Ruth
Watkins/Food Science Rong Reynolds/Food Science |
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Title of
Presentation: |
The Effects
of Location and Cultivar on the Antioxidant Activity of North Carolina Muscadine Grapes |
Rationale: Muscadine grapes
are known to have high levels of antioxidants, which are believed to reduce
risk factors associated with several degenerative diseases. Objectives: This study was conducted to
determine the effects of location, cultural practices and differences in
cultivar on the levels of antioxidants present in muscadine
grapes. Methods: Fresh grapes were obtained from the NCSU research farm and a
commercial grower. Grapes were macerated, juice collected with the skin and
seeds and freeze dried. Two different assays were used to determine the
antioxidant activity. The Folin-Ciocalteau assay was used to measure total phenols as
gallic acid milliquivalents
(meq) whereas the DPPH (1,
1-diphenyl-2-picrylhydrazyl) assay measures the ability of antioxidants to
quench free radicals generated by DPPH.
Results: Phenol values of the juice ranged from 129.7 to 515.3 meq/L of
solution. Skin values ranged from 14.12
to 49.52 meq/g of skin whereas the seeds ranged from
29.84 to 109.17 meq/g. The DPPH values showed a similar trend to
that of the total phenol assay in that seeds contained the highest antioxidant
activity followed by skin and juice.
Grapes obtained from the commercial grower had higher antioxidant
activity than samples obtained from the research farm. Conclusion: Muscadine seeds had the most antioxidant activity, followed
by the skins and juices. Grapes obtained
from the commercial grower appeared to have a higher level of antioxidants than
samples obtained from the NCSU research farm.
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Last modified Februrary 2007 by Sharon E. Hunt, WordHunting