Biomedical Engineering Reference
In-Depth Information
transport, storage, and marketing.
111
Nussinovitch and Kampf
111
used 1 to 2% alg-
inate-coated mushrooms in order to extend the shelf life and conserve the texture
of these mushrooms.
111
The treated mushrooms showed better color and appearance
than uncoated controls. The strength and integrity of coated mushrooms were main-
tained for longer periods of time than those of the uncoated controls, and the former
therefore more closely resembled fresh, intact mushrooms.
Irradiation
Low-dose gamma-irradiation has been reported to be a very effective method of
controlling deterioriation and improving quality and shelf life of fresh mushrooms.
The irradiation, usually from a cobalt-60 source, is most effective when applied to
the mushrooms shortly after harvest. Mushrooms exposed to 100 krad, a USFDA
approved dose, showed reduced bacterial counts and a slower rate of senescence.
Sensory data comparing irradiated mushrooms with unirradiated controls showed
equal or superior flavor and texture scores for both raw and cooked samples.
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TECHNOLOGICAL PROCEDURES RELATED
TO SHELF LIFE
T
RADITIONAL
A
PPROACHES
Table 10.7
shows the traditional methodologies that have been used by humans in
order to extend the shelf life of foods and their basic preservation principles.
2,125-127
Freezing, canning, and drying are the three principal food preservation techniques
used nowadays. The baking of bread, manufacture of ice cream, production of fruit
jams, fermentation of yogurt, smoking of sausage, and many other processes result
in foods with prolonged shelf life. These techniques, however, are more properly
classified as manufacturing since their principal goal is the creation of a new food
product. Freezing, drying, and canning are used to protect all foods (raw agricultural
produce as well as manufactured food items) from microbial, chemical, or physical
spoilage for many months.
125
N
OVEL
T
ECHNOLOGIES
Biotechnology has been defined as a collection of technologies that employ living
systems, or compounds derived from these systems, for the production of industrial
goods and services.
128
Biotechnology is not new to the agricultural and food sector,
as people have been utilizing living systems for the production, processing, and
preservation of food for centuries. Classical breeding and selection techniques have
been applied to develop superior varieties and species of plants and animals. Muta-
tion and selection techniques have been applied to improve strains of bacteria and
yeast used to produce fermented foods, such as cheese, sausage, bread, and wine.
What distinguishes “modern” biotechnology from the more traditional examples
cited above is the emergence within the last 20 years of recombinant DNA technol-
ogy or genetic engineering. DNA, the universal code of life, is structurally and
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