Scanning electron microscopy is a useful tool for understanding food contamination and directing product development
of food and industrial products. The current trend in food research is to produce foods that are fast to prepare and/or
ready to eat. At the same time, these processed foods must be safe, high quality and maintain all or most of the
nutritional value of the original whole foods. Minimally processed foods, is the phrase used to characterize these "new"
foods. New techniques are needed which take advantage of minimal processing or processing which enhances the fresh
properties and characteristics of whole foods while spending less time on food preparation. The added benefit coupled to
less cooking time in an individual kitchen translates to an overall energy savings and reduces the carbon emissions to the
environment. Food processing changes the microstructure, and therefore, the quality, texture and flavor, of the resulting
food product. Additionally, there is the need to reduce waste, transportation costs and product loss during transportation
and storage. Unlike food processing, structural changes are desirable in co-products as function follows form for food
packaging films and boxes as well as for building materials and other industrial products. Thus, the standard materials
testing procedures are coupled with SEM to provide direction in the development of products from agricultural residues
or what would otherwise be considered waste materials. The use of agricultural residues reduces waste and adds value to
a currently underutilized or unutilized product. The product might be biodegradable or compostable, thus reducing
landfill requirements. Manufacturing industrial and packaging products from biological materials also reduces the
amount of petroleum products currently standard in the industry.
High temperatures during wheat grain fill decrease starch and protein levels, adversely affecting wheat yield and flour
quality. To determine the effect of high temperature on starchy endosperm cell development, grain (Triticum aestivum
L. 'Butte 86') was produced under a 24/17°C or 37/28°C day/night regimen imposed from flowering to maturity and
starch and protein deposition examined using scanning electron microscopy. The high temperature regimen shortened
the duration of grain fill from 40 to 18 days. Under the 37/28°C regimen, A- and B-type starch granules decreased in
size. A-type starch granules also exhibited pitting, suggesting enhanced action of starch degradative enzymes. Under
both temperature regimens, protein bodies originated early in development and coalesced during mid to late
development to form a continuous protein matrix surrounding the starch granules. Under the 37/28°C regimen, the
proportion of protein matrix increased in endosperm cells of mature grain. Taken together, the changes in starch granule
number and size and in protein matrix amount provide clues for understanding how high temperature during grain fill
can affect end use properties of wheat flour.
Structure and histochemistry of mature seeds of <i>Desmanthus illinoensis</i> (Illinois bundle flower) show that the seed has
typical legume structure. The seed can be separated into two major fractions including the seed coat/endosperm and the
embryo. The seed coat consists of a cuticle, palisade sclereids, hour glass cells and mesophyll. Endosperm is attached to
the inner portion of the seed coat and is thicker beneath the pleurogram in the center of the seed. The embryo consists
mostly of two large cotyledons, the major storage structures of the seed. The cotyledons are high in protein which occurs
in protein bodies. Protein bodies in the cotyledons include those without inclusions, those with phytin inclusions and
those with calcium-rich crystals. The phytin inclusions are spherical and have high phosphorus and magnesium contents.
The calcium-rich crystals are also included inside protein bodies and are druse-type crystals.
Fresh-cut produce has a huge following in today's supermarkets. The trend follows the need to decrease preparation time
as well as the desire to follow the current health guidelines for consumption of more whole "heart-healthy" foods.
Additionally, consumers are able to enjoy a variety of fresh produce regardless of the local season because produce is
now shipped world-wide. However, most fruits decompose rapidly once their natural packaging has been disrupted by
cutting. In addition, some intact fruits have limited shelf-life which, in turn, limits shipping and storage. Therefore, a
basic understanding of how produce microstructure relates to texture and how microstructure changes as quality
deteriorates is needed to ensure the best quality in the both the fresh-cut and the fresh produce markets. Similarities
between different types of produce include desiccation intolerance which produces wrinkling of the outer layers,
cracking of the cuticle and increased susceptibility to pathogen invasion. Specific examples of fresh produce and their
corresponding ripening and storage issues, and degradation are shown in scanning electron micrographs.
Conference Committee Involvement (2)
Scanning Microscopies 2011: Advanced Microscopy Technologies for Defense, Homeland Security, Forensic, Life, Environmental, and Industrial Sciences