|dc.description.abstract||A significant portion of fresh beef trimmings are distributed aerobically under refrigeration from large beef fabrication plants to further processors to use as the raw material source for products such as beef patties. Time from fabrication to arrival at further processing facilities may be anywhere from 0 to 5 days, or longer due to inclement weather conditions. This variation impacts the overall condition (color, odor/flavor/spoilage) of these trimmings destined for further processing, i.e, beef pattie manufacture. The economic loss due to meat discoloration was estimated to be 1 billion/year. Most researches utilized single ingredient to address a specific problem, such as myoglobin oxidation, lipid peroxidation, etc. Hence, we proposed to develop a processing aid containing multiple selected ingredients to resolve the myoglobin oxidation, lipid peroxidation, off odor, and microbial spoilage which reduce the shelf life of aerobically stored beef trimmings. Phase 1 and 2 were conducted to investigate the effect of sodium lactate (NaL), potassium lactate (KL), sodium erythorbate (NaE), and sodium bicarbonate (NaB) on fresh beef trimmings for ground beef production within and exceeding federal regulations. For phase 1 and 2, a full factorial design was used to generate treatment combinations containing NaL (0.1 to 1.5 M), NaE (1 mM to 0.6 M), and NaB (0.1 to 1.5 M) with water used as a control in both studies. Based on phase 1 and 2, a 2^3 central composite response surface design (RSM), which generated 15 treatment combinations containing NaL (0.1 to 1.5 M), NaE (0.1 to 0.6 M), and NaB (0.1 to 1.5 M) with water used as a control was used to optimize the concentration level of treatment combinations. All phases used the same the procedure for treatment preparation, sample preparation, treatment application, sample collection and analysis. Beef trimmings fabricated from 14-day-postmortem carcasses were aerobically stored for 6 days at 5 oC. After storage, beef trimmings were coarse ground, treated with various treatments, reground, and formed into beef patties wrapped with oxygen permeable films. The patties were stored under simulated retail conditions: 5°C, cool white fluorescent light (200 to 300 lux) and analyzed at day 0, 3, 6, and 9 of storage to assess the effectiveness of each treatment in preventing further quality deterioration. Objective color (L*, a*, and b*), 2- thiobarbituric acid (TBA) determinations, GC-MS for off-odor assessment and aerobic plate counts (APC) were measured. The treated beef patties with NaB (1.5 M), NaE (0.1 to 0.8 M) and NaL (1 M) had the greatest effect on enhancing the color stability, reducing the lipid peroxidation and controlling the microbial spoilage compared to the control upon storage day 6 for phase 1 and 2, respectively.
Based on these results, we optimized the concentration levels of NaL, NaE, and NaB which were active ingredients using response surface methodology (RSM) to develop a processing aid. The treated beef patties showed improved a* values, MMb formations, TBA values and total ion counts of hexanal compared to the control upon storage day 6 (P < 0.05). Based on the results, a* and TBA values were used to conduct multivariate RSM analyses for day 3 and 6. The predicted value of hexanal was 0 for all treatments. Multivariate RSM was conducted to overlap the contour plots of predicted a* and TBA values at day 3 and 6 to better approximate the optimal ingredient concentrations for a* values. The optimum concentration ranges of solutions based on this analysis were NaL (0.43 to 0.57 M), NaE (0.35 M) and NaB (1 M) with predicted a* values > 11 and TBA values < 0.52. Results of the research suggested that a combination of NaL, NaE and NaB (0.43 to 0.57, 0.35 and 1 M, respectively) could be applied into ground beef patties generated from aerobically 6-days-stored (5 oC) beef trimmings to improve color stability, reduce lipid oxidation and mitigate off-odor upon 6 days storage with retail display condition.||en