Food Lipids: Chemistry, Nutrition, and Biotechnology

Hot boning (prerigor excision of muscle or muscle systems from animals) and
further processing of prerigor meat have economic advantages represented by reductions
in refrigeration costs, space requirements, processing delays, and product
turnover time. Studies generally have found that product was less susceptible to
oxidation when ground prerigor than postrigor, a result that was attributed to the
higher ultimate pH in prerigor ground meat [295,296]. In a case of prerigor meat
that was more unstable than postrigor meat, the increased initiation reactions in the
prerigor meat may have been due to higher product temperature during grinding
[297].
E. Salting
Salt (sodium chloride) is added to muscle foods for a variety of reasons, such as
adding flavor and inhibiting microbial growth. Nevertheless, an accelerating effect
on lipid oxidation has been found with salt in a variety of meats, including beef,
pork, chicken, and fish [297–300]. Although Ellis et al. [362] did not attribute the
prooxidative effect of salt to the chloride ion, Osinchak et al. [363] identified chloride
as the active component of salt in a liposomal model system and suggested that it
may operate through release of iron from ferritin or modification in bilayer organization.
Concentration of the chloride anion in the system also appears to affect the
response, with low concentrations elevating and high levels inhibiting lipid oxidation.
Another factor that influences the response to the chloride anion is the associated
cation in the salt. Divalent cations were more stimulatory than monovalent cations
at equivalent concentrations of chloride up to 0.22 M chloride [363]. Wettasinghe
and Shahidi [364] concluded that mediation in response to anions by cations is
through their ability to participate in ion pairing interactions with anion counterparts.
F. Application of Curing Mixtures
1. Nitrite-Based Curing Agents
Meat preservation by means of curing is typically obtained by application of mixtures
containing nitrite as the key ingredient. Other ingredients in the curing mixture include
sodium chloride, sugars, ascorbate, polyphosphates, and spices. Nitrite imparts
multiple functional roles to cured products, inhibiting spore germination of Clostridium
botulinum when added in combination with sodium chloride, producing the
characteristic cured meat color, contributing to the characteristic cured meat flavor,
and inhibiting the development of warmed-over flavor in cooked cured meats. Mechanisms
proposed for the antioxidative activity of nitrite include formation of a strong
complex with heme pigments (thereby preventing the release of nonheme iron and
its subsequent catalysis of lipid oxidation), complexation of nonheme iron (which is
catalytically less active than noncomplexed iron), and reaction with membrane-unsaturated
lipids (which stabilizes the lipids) [301–303].
2. Nitrite-Free Curing Agents
A particular concern with the use of nitrite for the curing of meat has been the
formation of N-nitrosamines, which are known carcinogens. Given the unlikelihood
of finding a single compound that could perform all the functions of sodium nitrite,
research directed to the elimination of the use of nitrites focused on formulation of
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.