Injection of salt, tripolyphosphate and bicarbonate marinade solutions to improve the yield and tenderness of cooked pork loin

Several marinade solutions were tested for their effects on pork tenderness. Paired loins were removed from eight Large White crossbred pigs. Each pair was cut to give eight pieces and injected to a target of 110% of original weight with one of the following eight solutions (g/100 g water): uninjected (A, control), 5% salt (B), 5% sodium tripolyphosphate (C), 3% sodium bicarbonate (D), 5% salt and 5% sodium tripolyphosphate 5% (E), 5% salt and 3% sodium bicarbonate (F), 5% sodium tripolyphosphate and 3% sodium bicarbonate (G), 5% salt, 5% sodium tripolyphosphate and 3% sodium bicarbonate (H). Samples were left overnight to equilibrate, cooked and assessed for tenderness using a Volodkevich shear force method. Mean pHs for meat injected with phosphate and/or bicarbonate (C–H) ranged from 5.75 to 5.97, compared to 5.45 for the control. All injected loins, had a significantly higher yield than the control (p<0.05), except salt alone which, though higher, did not differ significantly (p>0.05) from the control. Treatment H increased the yield from 70% (control) to 85%. All marinades significantly reduced the shear force (p<0.05), some treatments (D and F) by up to a half compared to the control (5150 g). Individual animal results suggest that marination could be used to good effect even in the toughest samples, whilst improving tender samples still further. Samples treated with bicarbonate had an usual porous structure, probably due to carbon dioxide produced during cooking which may have contributed to the reduced toughness.