Fresh pork sausages: Effect of non-meat ingredients

The impact of non-meat ingredients (i.e., sodium erythorbate [SE] & lemon juice powder [LJP]) on the colour stability of fresh pork sausage products was assessed over a 10-day storage period. Loss of quality was evident through the discolouration of meat, depletion of endogenous antioxidant activities, proliferation of spoilage microorganisms, and reduction in the meat’s redox potential. Results showed no synergistic colour stabilizing effect (p>0.05) between SE & LJP during storage. Furthermore, the combination of SE & LJP did not affect antioxidant activity, colour, or the microbiological profile. The addition of SE alone, however, had a significant effect (p<0.05) on catalase activity. Catalase was more effective in protecting against oxidation following the addition of SE, resulting in preservation of the redness (i.e., a* value) in fresh pork sausages. Combining SE & LJP did not affect antimicrobial activity, as there was no significant (p>0.05) difference in total microbial counts (i.e., Brochothrix thermosphacta count and lactic acid bacteria). Redox potential measurements from the middle of fresh pork patties indicated that the addition of SE reduced the redox of fresh pork sausage containing 0.05% SE and those containing 0.05% SE with 0.25% LJP. Background Color is a key factor which determines the shelf-life and saleability of fresh port sausages; consumers tend to use meat colour as an indicator of freshness and make a value judgment regarding purchase. A major challenge for the meat industry is to maintain an “acceptable” color in fresh sausages for as long as possible during holding under retail display conditions. Non-meat ingredients are adjuncts included in formulations to obtain a desired effect in the processed product. In this study, SE & LJP, which are often included in Canadian fresh pork sausage formulations, were added as non-meat ingredients. The idea is that SE serves as a primary antioxidant to prolong the meat’s desirable bloomed color (i.e., oxymyoglobin concentrations); however, SE is prone to metal-catalyzed oxidation. Thus, the inclusion of LJP, as a chelator, is expected to increase the stability of SE so that it will be more effective in protecting against meat colour deterioration (i.e., metmyoglobin formation). The objective of this study is to evaluate the interactions of both SE & LJP in preserving fresh pork sausage colour during a distribution period of 7 days and a display period of 10 days. Measurements during these periods included the meat’s redox potential, key endogenous antioxidant enzyme (i.e., catalase [CAT], superoxide dismutase [SOD], glutathione peroxidase [GSHPx]) activities, and the impact of microbial loads. Materials and methods A typical fresh sausage formulation was used to prepare pork patties with targets of 20% (or less) fat and 14-16% protein. The meat utilized was pork picnic shoulder. The non-meat ingredients included water/ice (12%, w/w), sodium chloride (1.5%, w/w), LJP (0.25%, w/w), and SE (0.05%, w/w). Meat and non-meat ingredients were combined in a Hobart mixer for 60s before portioning into ~120-g pork patties. The patties were then placed on Styrofoam trays and over-wrapped with a standard O2-permeable film with a known O2-transmission rate of 30000cm/m/24 h. The patties were stored in the dark for 7 days at -1°C (i.e., to simulate a typical distribution scenario) & then under fluorescent lighting (950 lux) at 4°C for up to 10 days (i.e., to simulate retail display conditions). The effect of SE & LJP in the formulations were analyzed by using a factorial design approach, as indicated in fresh sausage A, (0% SE & 0% LJP); B, (0.05% SE & 0% LJP); C, (0% SE & 0.25% LJP); and D, (0.05% SE & 0.25% LJP). Colour measurements (CIE, L, a, b*) were performed at the surface of meat samples using a HunterLab Miniscan XE colorimeter with illuminant A and 10° standard observer. This unit was also used to determine the % metmyoglobin at the surface of the meat patties; the relative content of metmyoglobin was estimated by calculating the K/S 572/525 ratio, as described by Hunt et al. (1991). The measurement of meat patty redox potential was assessed using microelectrodes connected to a data logger (51x Micrologger,