Examination of protein and lipid oxidation revealed that the stability
of the matrix components of different retail pork products is affected
differently by a MAP environment that becomes increasingly oxidative.
TBARS increases during cold storage even in anoxic conditions, but the
presence of oxygen induced lipid oxidation at a rate that is independent
of product type and initial oxidative status.
Oxidative changes in the protein fraction are product specific and
more affected by the oxygen concentration levels. LTL steaks; a product
with intact myofibrils, low lipid and myoglobin content, are stable; and
the use of high oxygenMAP during seven days of storage does not affect
considerably their oxidative stability. In contrast, protein and lipid oxidation
were observed as early as two days during storage of minced
pork; a product with disrupted structure, high fat and myoglobin content,
and high prevalence of oxidative type I fibres. The use of low
(20%) and intermediate (50%) O2 in the porkmince MAP resulted in improved
oxidative stability, while it had little effect on the LTL steaks.
Therefore, real benefits may lie in the specific optimisation of the MAP
gas composition for different retail pork products and may result in
improved quality of pork mince.
Based on the above discussion, we propose that different retail pork
products should be considered on an individual basis when selecting
the MAP gas composition, and that the muscle fibre composition and
physiology should be concurrently considered.