Changes in lightness of porcine lean meat batters during processing

The pattern of changes of lightness (L(∗)) for porcine lean meat batters (PLMBs) with time was divided in two phases: chopping process (Phase 1) resulting in a sharp increase of L(∗), and the subsequent storage of the batters for 24 h at 15°C (Phase 2). During Phase 2, L(∗)-values decreased with time approximating a plateau. The subjects of study were effects on the course of L(∗) of: (1) added sodium chloride and phosphate in Phase 2, (2) the fate of air bubbles embedded in the batters in Phases 1 and 2, and (3) changes in light absorption by the pigment myoglobin in Phase 2. (1) Sodium chloride and phosphate appeared to have very little impact on the changes in L(∗) during storage of the PLMBs at 15°C, although microstructural changes were distinct. (2) Continuous entrapment of air during the chopping process had a major effect on the increase of L(∗) in Phase 1, air bubbles being scattering elements in the PLMB. Disproportionation caused a decrease in the number of small air bubbles, resulting in a decrease of L(∗) during the early stage of Phase 2 (about 35 min), immediately after the chopping stage was finished. (3) Strong evidence was obtained that shifts in the absorption traits of pigments (red nitric oxide myoglobin was formed at the cost of grey met-myoglobin) during the period from 1 to 5 h, caused a marked decrease in the pattern of L(∗) during Phase 2.