Gathering food from the oceans repr

Gathering food from the oceans represents the last major hunting effort of humans. As has happened in other fields, however, our technological abilities have
outstripped our capacity to deal with the social, cultural, and economic consequences of these technologies. Where national and international regulations, exhortations, and pleas have failed, the common property status of sea resources
had led to overexploitation, which has reduced the number of animals available
to be used as foods. This decline has been accompanied by an increase in human
populations and, more importantly, rising expectations for improved diets in
newly developing areas of the world. These factors have increased demands on
fish and shellfish stocks and increased strains on the ability of the fish and shellfish to maintain their numbers. Quite naturally, this has had the most impact on
those species that have the greatest attraction as food for humans.
Traditionally, the fisheries have been a wasteful industry, in that often no
more than 50% of the flesh of even desirable species is converted to high-value
human food, and often much high-value seafood protein and lipid is dumped
back, unused, into the oceans. No one denies the great need to utilize our aquatic
resources more efficiently. It not only makes economic sense, but on a planet
with limited resources, there is a moral imperative not to needlessly destroy
valuable raw materials. First, we must use traditional commercial species to the
fullest extent. This means adding value by utilizing processing byproducts to
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produce high-value materials (e.g., enzymes) and developing techniques to recover all the flesh and use it for human food.
Approximately half of all the species caught in the world today go into
the production of fish meal and oil. Development of procedures that will make
these resources directly available for human food would greatly improve their
efficiency of use. The chemical instability of both the protein and lipid fractions, the presence of high concentrations of unstable dark muscle, seasonal
fluctuations in catch, unfavorable sizes and shapes, strong flavors, and skeletal
structure that does not permit easy removal of bones are all factors limiting the
use of these species. Advances in our knowledge of the chemistry and biochemistry of the unstable components and improvement in processing procedures
will be necessary to adapt these species for human food. We must face and accept this challenge.
A thorough understanding of the nature of the critical components of
seafood tissues and how they respond to processing, storage, and handling
procedures is an absolute necessity to achieve these goals. No class of components of seafood tissues is more important than their enzymic systems. The
number of books or reviews devoted exclusively to seafoods is small compared to those dealing with the muscle tissue of land animals. Indeed, in many
cases land animals or birds have been used as models to discuss fishery problems. Although there are many similarities between the muscles of fish and
land animals, some important considerations for specific seafoods are often
overlooked or downplayed. One point often overlooked in discussions of
enzymes in foods is that most of the important commercial species are caught
in cold water. In fact, 95% of the ocean has a temperature of less that 5ºC
year-round, leading to species with lipids that contain a large percentage of
the highly unsaturated fatty acids eicosapentaenoic and docosahexaenoic
acids (which maintain fluidity of the lipids at low temperature). This makes
the lipid fraction susceptible to oxidation. Likewise, proteins (enzymes) of
seafoods must have a greater inherent flexibility to be able to function at low
temperatures—a flexibility that also makes them less stable. Thus, seafood
enzymes function well at low temperatures and refrigeration might not have
the same inhibitory effect on postmortem changes that it would for warmblooded land animals.
Seafood Enzymescovers a myriad of topics on how enzymes are important to improve uses of seafood raw materials. These topics include the nature
of the enzymes themselves and biological factors that affect them; the role of
native enzymes in postmortem effects on quality attributes such as texture,
flavor, and color; the use of products of enzymic breakdown as quality indices; control of enzymic activity by modification of environmental conditions, processing, or use of inhibitors; and the use of enzymes isolated from
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fish processing byproducts as processing aids. These discussions of the special roles of seafood enzymes in postmortem fish metabolism and the quality
changes they effect are critical pieces of knowledge in achieving the goal of
obtaining maximum value from the available species. We have a strong obligation to use seafood resources wisely and responsibly so future generations
may also enjoy their benefits.
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