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research
Currently our soft
materials research group's is interests include:
*
Relationship
between physiochemical properties of fats and emulsions and sensory
characteristics
*
Crystallization Kinetics of Fats
* Microstructure of fats
* In-line real-time ultrasonics for
measuring solid fat content in fats and emulsions
Why we value our research
Trends in cancer related to obesity
U.S. Obesity Trends
Analytical Facilities
Questions?
Relationship
between physiochemical properties of fats and emulsions and sensory
characteristics
As food companies strive to improve taste
and nutrition of products while maximizing revenue they are confronted by
numerous technical challenges. We hope that our basic research will
ultimately lead to new knowledge that enhances the experience of eating food
while contributing to healthy diets. Certainly there is significant
opportunity for food scientist to improve nutritional value of fat containing
foods. Some of these opportunities to include:
- eliminating trans fats
- substituting saturated fats with
healthier unsaturated fats
- adding ingredients with high
nutritional and nutraceutical qualities
- using healthier functional food
oils (e.g. polyunsaturated and monounsaturated fatty acids, fish oils,
etc.)
At present we focus on food emulsions such
as spreads, margarines, shortenings, dressings, and toppings. We
investigate the basic mechanisms that contribute to the physical and sensory
stability of emulsions and determine how various ingredients and processing
conditions impact stability.
In addition to a research laboratory well equipped for work in
this area we are fortunate to have a superb sensory evaluation facility
provides much needed data that describes the sensory experience of the materials
we are investigating.
Crystallization Kinetics of Fats
The functional performance and textural
quality of fats, and fat-containing products are determined mainly by the
balance between the solid and liquid phases and the crystal structures of the
solid fats. Fats can crystallize in different forms in a phenomenon called
polymorphism. It is known that polymorphism of fats greatly affects the
consistency, plasticity, graininess and other physical properties of many
products such as butter, lard, margarine, hydrogenated vegetable shortening, and
cocoa butter. During storage, there is a tendency for the fat to be transformed
into the most stable crystal form, which may or may not be desirable. Therefore,
much effort is given to designing the processing, tempering or storage
conditions so as to achieve and maintain the desirable crystal forms.
Control of crystallization in foods is an
important aspect of food quality. Crystallization may be employed as a
separation process (i.e., Sugar refining, fat fractionation, etc.) or to provide
a certain texture within a food itself (i.e., ice cream. Fondant, chocolate,
etc). The nature of the crystalline dispersion in these products helps to define
their organoleptic properties. Furthermore, crystallization may be used for
preservation purposes, for example, during freezing of foods. One of the most
difficult aspects of controlling crystallization related to shelf stability. In
some foods, (i.e., ice in ice cream and frozen foods, chocolate, etc.) the
crystalline dispersion may change its nature during storage to further minimize
free energy. These changes can have severe repercussions on the quality of these
products. In other foods, the desired product is crystal free, but the
thermodynamic driving forces during storage lead to eventual crystallization.
Thus, shelf life is limited by the onset of crystallization in these products
(i.e., lactose in ice cream, hard candies, un-grained caramels, etc.)
In our lab we are interested in
understanding which are the factors that control lipid crystallization in
different food systems. The objective of this area of research is to be able to
tailor a food product for a specific application by controlling the
crystallization process in the food. To achieve this goal, several variables can
be controlled such as:
- crystallization temperature
- cooling rate
- agitation rate
- additives addition
- crystallization induction or inhibition, etc.
Microstructure of fats
When fats crystallize they do so by
forming a network of solid fat in a "sea" of liquid oil.
The small structures of fat are interconnected among them resulting in different
types of "crystal shapes" or microstructures that give information about the
3-dimensional arrangement of the crystals in the network. Depending on the
crystallization procedures different microstructures can be obtained, and
specific fat networks can be tailored in order to obtain a specific
functionality for a certain food product. An important concept about
microstructure of fats is that it is highly correlated with the macroscopic
properties of a food system such as texture, mouth-feel and appearance. For this
reason, the microscopic characteristic of this network is very important when
evaluating the factors that control product quality and sensory acceptance.
Our interest in the microstructure of lipid systems is very
closely related to the crystallization one. Different microstructures result
from different crystallization procedures and again, microstructure as
crystallization properties can be related to a food product functionality. Our
lab seeks to understand the factors that affect the microstructure of these
systems and correlate their behavior with product development and stability.
In-line real-time ultrasonics for
measuring solid fat content in fats and emulsions
New ultrasonic technology shows great
promise as a tool that will help food manufactures optimize production
processes. Traditionally off-line techniques such as p-NMR have been used
to evaluate solid fat content (SFC) in foods. Ultrasonic transducers are
easily mounted on pipes in production lines. An ultrasound generator,
receiver, and processor provides real-time measurements of SFC.
We aim to understand how to apply this
technique in more difficult systems such as emulsions and systems containing air
(e.g. whipped toppings).
Analytical Facilities
Our laboratory relies on a range of
specialized analytical equipment to gather the data and information we need to
conduct our research program. This equipment includes:
- Polarized light
microcopy (PLM)
- Differential Scanning Calorimeter (DSC)
- Rheometer
- Turbiscan
- X-ray diffraction
spectrometer
- Ultrasound spectrometer
- Texture analyzer
- Gas chromatograph
- Low resolution pulsed
nuclear magnetic resonance spectrometer (p-NMR)
- Processing Equipment
If you have any questions
about our
research program please don't hesitate to call:
Silvana Martini Ph.D.
Assistant Professor
Utah State University
Department of Nutrition and Food
Sciences
750 North 1200 East
Logan, Utah USA
84322-8700
Telephone: 435-797-8136
Email: smartini@cc.usu.edu
Website: http://cc.usu.edu/~smartini/index.htm
Why we value our research
We strongly believe that our research plays an important roles
in addressing some important contemporary health issues that we face today.
We believe our research will lead to discoveries that can result in higher
quality of life and lower the demands on our medical systems. Below is
some helpful information pulled from various internet sites:
Overweight and obesity has reached epidemic proportions in the United States,
as well as worldwide.(3) Data collected by the National Center for Health
Statistics indicate that the prevalence of obesity, defined as a body mass index
>30 kg/m² has increased from 12.8% in 1976-1980 to 22.5% in 1988-1994 and 30% in
1999-2000. 4) Roughly 31% of American adults meet the criterion for obesity -
about 59 million American adults. More than 64% of the US adult population have
a BMI >=25 kg/m².(4) In an effort to increase public awareness of the epidemic
proportion of obesity, the Surgeon General has issued a call to action to
prevent and treat overweight and obesity and their associated health
complications.
US Department of Health and Human Services. The Surgeon General's call to
action to prevent and decrease overweight and obesity. [Rockville, MD] US
Department of Health and Human Services, Public Health Service, Office of the
Surgeon General (2001).
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Over seventeen million Americans (6.2% of the population) have
diabetes. Almost 6 million Americans are unaware they have the
disease. There are two main types of diabetes. Both types are caused
by problems in how a hormone called insulin (that helps regulate
blood sugar) works. Type 1 diabetes most often appears in childhood
or adolescence and causes high blood sugar when your body can't make
enough insulin. Over 90% of all diabetes cases are what we call type
2 diabetes. Type 2 diabetes is usually diagnosed after age forty;
however it is now being found in all ages including children and
adolescents. Type 2 diabetes is linked to obesity and physical
inactivity. In this form of diabetes your body makes insulin but
can't use its insulin properly. At first, your body overproduces
insulin to keep blood sugar normal, but over time this causes your
body to lose its ability to produce enough insulin to keep blood
sugar levels in the normal healthy range. The result is sugar rises
in your blood to high levels. Over a long period of time, high blood
sugar levels and diabetes can cause heart disease, stroke,
blindness, kidney failure, leg and foot amputations, and pregnancy
complications. Diabetes can be a deadly disease: over 200,000 people
die each year of diabetes related complications. |
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Considerable evidence suggests that obesity and overweight play an
important role in cancer. Obesity and overweight have been clearly
associated with increased risks for kidney cancer in both men and
women (two-fold increased relative risk), and in women, endometrial
cancer (one and a half-fold relative risk) and postmenopausal breast
cancer (two-fold relative risk). Building evidence suggests that
obesity and overweight also are associated with an increase risk of
colorectal cancer, gall bladder cancer, and perhaps more modestly,
the risk of thyroid cancer in women. For colorectal cancer, the
effect of obesity and overweight on risk may be due in part to low
physical activity, as consistent evidence exists for a strong
protective effect of physical activity against developing colorectal
cancer. Recent studies suggest that obesity and overweight may also
play a role in the increasing incidence of some types of esophageal
cancer, possibly through obesity's association with gastric reflux.
For prostate cancer risk, inconsistent findings from studies
evaluating obesity may result from limitations in the measurement of
obesity, as more consistent results have come from recent studies of
biological factors that are more directly associated with specific
aspects of body composition (e.g., total fat). For other types of
cancer, in general, too few studies have been conducted to draw
conclusions about the relationship between obesity and risk of
disease development. However, strong experimental research in animal
models of cancer development and disease progression have shown that
maintenance of adequate and not overweight body size can delay
development of cancer. Whether this can be achieved in humans has
not been evaluated in prospective randomized trials. |
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Trends in cancer related to obesity:
Like obesity, cancer is a major health problem in the United
States and in other countries as well. Based on the American Cancer
Society's 2002 estimates for cancer incidence, cancers linked to
obesity among women comprise approximately 51% of all new cancers
diagnosed among women in 2002: 2% thyroid cancers (15,800 new
cases), 6% uterine cancers (39,300 new cases), 12% colorectal
cancers (75,700 new cases), and 31% breast cancers (203,500 new
cases). Among men, cancers linked to obesity comprise approximately
14% of new cancers: 3% kidney cancers (19,100 new cases) and 11%
colorectal cancers (72,600 new cases). In terms of mortality, for
women, obesity-related cancers are estimated to comprise 28% of
cancer-related deaths in 2002: 15% breast cancers (39,600 deaths),
2% uterine cancers (6,600 deaths), and 11% colorectal cancers
(28,800 deaths). Among men, obesity-related cancers are estimated to
comprise 13% of cancer-related deaths in 2002: 10% colorectal
cancers (27,800 deaths) and 3% kidney cancers (7,200 deaths).
Overall, while the mechanisms underlying the
obesity-carcinogenesis relationship are not fully understood,
sufficient evidence exists to support recommendations that adults
and children maintain reasonable weight for their height and ages
for multiple health benefits, including decreasing their risk of
cancer.
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U.S. Obesity Trends
During the past 20 years there has been a dramatic increase in
obesity in the United States.
Currently, more than 64% of US adults are either overweight or
obese, according to results from the 1999-2000 National Health and
Nutrition Examination Survey (NHANES). This figure represents a 14%
increase in the prevalence rate from NHANES III (1988-94) and a 36%
increase from NHANES II (1976 -80). (Prevalence is the percentage of
the population that falls into the designated category.)
The greatest increase took place in the obese group (Body Mass
Index > 30), where the prevalence doubled from NHANES II (1976-80).
Roughly 59 million American adults are in this group, which is at
the greatest health risk. (Please note that NHANES data are based on
weights and heights as actually measured by trained health
professionals using standardized measuring equipment.)
Source:
http://www.cdc.gov/nchs/products/pubs/pubd/hestats/obese/obse99.htm
The maps below graphically depict this trend over a 16-year span.
It is important to note that these figures are based on telephone
interviews where weight and height are self-reported. Self reported
data tend to underestimate weight and over-report height. Therefore,
the prevalence rates are actually under-estimates compared to the
NHANES data which originate from actual measurements.
to view the entire presentation go to:
http://www.cdc.gov/nccdphp/dnpa/obesity/trend/maps/index.htm |
Obesity Statistics
Estimated Adult Obesity-attributable Percentages and Expenditures
by State (BRFSS 1998 to 2000)
|
State |
Total population
(%) |
(Millions $) |
Medicare population
(%) |
(Millions $) |
Medicaid population
(%) |
(Millions $) |
|
Alabama |
6.3 |
$1320 |
7.7 |
$341 |
9.9 |
$269 |
|
Alaska |
6.7 |
$195 |
7.7 |
$17 |
8.2 |
$29 |
|
Arizona |
4.0 |
$752 |
3.9 |
$154 |
13.5* |
$242 |
|
Arkansas |
6.0 |
$663 |
7.0 |
$171 |
11.5 |
$180 |
|
California |
5.5 |
$7675 |
6.1 |
$1738 |
10.0 |
$1713 |
|
Colorado |
5.1 |
$874 |
5.1 |
$139 |
8.7 |
$158 |
|
Connecticut |
4.3 |
$856 |
6.5 |
$246 |
11.0 |
$419 |
|
Delaware |
5.1 |
$207 |
9.8 |
$57 |
13.8 |
$66 |
|
District of Columbia |
6.7 |
$372 |
6.5 |
$64 |
12.5 |
$114 |
|
Florida |
5.1 |
$3987 |
6.1 |
$1290 |
11.6 |
$900 |
|
Georgia |
6.0 |
$2133 |
7.1 |
$405 |
10.1 |
$385 |
|
Hawaii |
4.9 |
$290 |
4.8 |
$30 |
11.2 |
$90 |
|
Idaho |
5.3 |
$227 |
5.6 |
$40 |
12.0 |
$69 |
|
Illinois |
6.1 |
$3439 |
7.8 |
$805 |
12.3 |
$1045 |
|
Indiana |
6.0 |
$1637 |
7.2 |
$379 |
15.7 |
$522 |
|
Iowa |
6.0 |
$783 |
7.5 |
$165 |
9.4 |
$198 |
|
Kansas |
5.5 |
$657 |
6.4 |
$138 |
10.2* |
$143 |
|
Kentucky |
6.2 |
$1163 |
7.5 |
$270 |
11.4 |
$340 |
|
Louisiana |
6.4 |
$1373 |
7.4 |
$402 |
12.9 |
$525 |
|
Maine |
5.6 |
$357 |
5.7 |
$66 |
10.7 |
$137 |
|
Maryland |
6.0 |
$1533 |
7.7 |
$368 |
12.9 |
$391 |
|
Massachusetts |
4.7 |
$1822 |
5.6 |
$446 |
7.8 |
$618 |
|
Michigan |
6.5 |
$2931 |
7.8 |
$748 |
13.2 |
$882 |
|
Minnesota |
5.0 |
$1307 |
6.6 |
$227 |
8.6 |
$325 |
|
Mississippi |
6.5 |
$757 |
8.1 |
$223 |
11.6 |
$221 |
|
Missouri |
6.1 |
$1636 |
7.1 |
$413 |
11.9 |
$454 |
|
Montana |
4.9 |
$175 |
6.2 |
$41 |
9.8 |
$48 |
|
Nebraska |
5.8 |
$454 |
7.0 |
$94 |
10.3 |
$114 |
|
Nevada |
4.8 |
$337 |
5.0 |
$74 |
10.1* |
$56 |
|
New Hampshire |
5.0 |
$302 |
5.4 |
$46 |
8.6* |
$79 |
|
New Jersey |
5.5 |
$2342 |
7.1 |
$591 |
9.8 |
$630 |
|
New Mexico |
4.8 |
$324 |
4.6 |
$51 |
8.5 |
$84 |
|
New York |
5.5 |
$6080 |
6.7 |
$1391 |
9.5 |
$3539 |
|
North Carolina |
6.0 |
$2138 |
7.0 |
$448 |
11.5 |
$662 |
|
North Dakota |
6.1 |
$209 |
7.7 |
$45 |
11.7 |
$55 |
|
Oklahoma |
6.0 |
$854 |
7.0 |
$227 |
9.9 |
$163 |
|
Ohio |
6.1 |
$3304 |
7.7 |
$839 |
10.3 |
$914 |
|
Oregon |
5.7 |
$781 |
6.0 |
$145 |
8.8 |
$180 |
|
Pennsylvania |
6.2 |
$4138 |
7.4 |
$1187 |
11.6 |
$1219 |
|
Puerto Rico |
7.4 |
|
8.1 |
|
10.1 |
|
|
Rhode Island |
5.2 |
$305 |
6.5 |
$83 |
7.7 |
$89 |
|
South Carolina |
6.2 |
$1060 |
7.7 |
$242 |
10.6 |
$285 |
|
South Dakota |
5.3 |
$195 |
5.9 |
$36 |
9.9 |
$45 |
|
Tennessee |
6.4 |
$1840 |
7.6 |
$433 |
10.5 |
$488 |
|
Texas |
6.1 |
$5340 |
6.8 |
$1209 |
11.8 |
$1177 |
|
Utah |
5.2 |
$393 |
5.8 |
$62 |
9.0 |
$71 |
|
Vermont |
5.3 |
$141 |
6.9 |
$29 |
8.6 |
$40 |
|
Virginia |
5.7 |
$1641 |
6.7 |
$320 |
13.1 |
$374 |
|
Washington |
5.4 |
$1330 |
6.0 |
$236 |
9.9 |
$365 |
|
West Virginia |
6.4 |
$588 |
7.3 |
$140 |
11.4 |
$187 |
|
Wisconsin |
5.8 |
$1486 |
7.7 |
$306 |
9.1 |
$320 |
|
Wyoming |
4.9 |
$87 |
5.9 |
$15 |
8.5 |
$23 |
|
Total |
5.7 |
$75,051 |
6.8 |
$17,701 |
10.6 |
$21,329 |
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*Estimates based on fewer than 20 observations.
Source: Obesity Research, Vol. 12, No. 1, January 2004
Finkelstein, et al, pages 22-23
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