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August 7, 2023 | by Sam Shafer
Consumers often find goose meat low in tenderness, possibly because of conventional commercial methods of chilling carcasses. Goose is a popular dish in Taiwan, where a recent study tested "stepwise" chilling with calcium chloride incubation to improve muscle proteolysis and meat tenderization.
Conventional commercial goose processing involves submerging carcasses in ice-cold water right after harvest, which induces "cold shortening" of sarcomere muscle tissues and increases toughness of the meat. However, early studies with beef and chicken showed that carcasses entering rigor at 12°C to 18°C avoided cold shortening and had improved meat tenderness.
More recently, researchers have developed stepwise beef and poultry chilling procedures -- such as holding carcasses at a rigor temperature of 10°C to 15°C for up to 6 hours prior to storing or aging at 0°C to 4°C -- as well as further refinements in the slow chilling of meat from other species, including pigs, sheep, and ostriches. Their measures of improved meat tenderness include a higher myofibril fragmentation index (MFI) and a lower shear force value.
Other research has shown that incubation with a solution of calcium chloride (CaCl2) -- an FDA-approved food additive for meat and poultry products -- helps accelerate the proteolysis of goose meat through activation of calcium ion-dependent proteases called calpains. Researchers identified calpain-11 in goose muscle as an ortholog of mammalian calpain-11. Other studies found that both calpain-1, present in aged meat of other species, and calpain-11 may be involved in the proteolysis and tenderization of goose meat.
In this study, a researcher with the Department of Animal Science, Chinese Culture University in Taipei, Taiwan obtained 12-week-old male White Roman geese (Anser anser domesticus, n = 30) from a local government-inspected slaughter plant at approximately 10-minutes postmortem, then sealed carcasses individually in zip-lock bags and chilled them immediately in a water bath at 15°C for 1 hour. The study used both sides of the breast muscles (Pectoralis major), incubated in 30 mM CaCl2 or 30 mM ethylenediaminetetraacetic acid (EDTA) at 15°C for 5 hours, then vacuum-packaged individually and stored at 5°C for 72 hours. Control samples (without CaCl2 or EDTA incubation) were directly vacuum-packaged and chilled in a water bath at 15°C for 5 hours and stored at 5°C for 72 hours, thereby mimicking conventional processing.
The study used samples of the left breast muscles at 1 hour of chilling (about 1 hour postmortem) and at 5 hours of incubation at 15°C (about 6 hours postmortem), as well as 24, 48, and 72 hours of aging at 5°C in order to measure calpain-1 and calpain-11 activity and amounts of the 80 kDa calpain-1 subunit and desmin. Desmin is a protein that meat scientists use as a marker for the integrity of skeletal muscle.
To measure shear force value and myofibril fragmentation index (MFI), the study took samples from right breast muscle at 24 hours and 72 hours of 5°C storage.
This study demonstrated that decreases in calpain-1 and calpain-11 activity and decreases in the 80 kDa calpain-1 subunit and desmin contents were more rapid (P < 0.05) in calcium-incubated samples than in control and EDTA-incubated samples. Also, the shear force of the goose breast meat was lower, although the MFI was higher in calcium-incubated samples than in control and EDTA-incubated samples (P < 0.05).
Thus, this study showed that the combined effects of stepwise chilling with calcium chloride incubation at 15°C and thereafter aging at 5°C influenced the calpain-mediated proteolysis and tenderization of postmortem goose muscle.
"Applying this procedure," the lead researcher noted, "commercial slaughter plants may have an alternative way to improve the tenderness of goose meat."
What does this study mean for producers?
The full paper, titled "Effects of stepwise chilling with calcium incubation on proteolysis and tenderization in postmortem goose muscle," can be found in Poultry Science and online here.
Categories: Interpretive Summary