| Currently, the Chinese meat industry is in the third stage of development, which is devoting to improve meat quality and ensure the safety of meat products in the mean time. Vacuum package has long been widely used in the meat industry because of its good promise in product safety. For instance, it can help inhibit the growth of microorganisms and minimize the oxidation of meat products. However, the drawback is vacuum-package has detrimental effect to meat color quality. Brine injection-enhancement is a widely used production process to improve meat eating quality (palatability), but the problem is it certainly transfers bacteria to the interior of meat products during the process, causing potential safety hazards.In this research, regarding the above two problems, the following two experiments about vacuum-packed beef color improvement technology and injection-enhanced beef antimicrobial technology were done on beef steaks:1. Nitrite spraying treatment to promote the red color stability of vacuum-packed beef steaks. The aim was to determine the optimum level of sodium nitrite in the spray solution, which should be sufficient to develop a bright red color to vacuum packaged beef steaks and have no noticeable pink, ham-like color of cooked steaks. In the study, beef rib and round steaks were sprayed with low levels of nitrite solution (100mg/kg-350mg/kg) and vacuum packed separately. During storage (1℃), Hunter color measurements and visual color evaluations were conducted on raw and cooked steak samples, sensory traits were also evaluated.Results showed that250-350mg/kg nitrite solutions were optimum for raw steak color promotion during21days storage at1°C (P<0.05)(Hunter color a*>10, Chroma C*>16). Sprayed steaks had3.0g-3.6g weight gain and a calculated level of3.5-5.3mg/kg nitrite added. Residual nitrites of250mg/kg-350mg/kg nitrite spray treatments (0.5-0.9mg/kg) were lower than the limitation of natural nitrite concentration in fresh meat (LOQ4.5mg/kg). Raw steak redness was less stable in round than rib during storage. Visual color scores for pinkness after cooking were low, indicating that cooked color of even the highest nitrite treatment (350 mg/kg) was acceptable. Thus, nitrite spraying would be a practical and cheap method to develop a bright red color to vacuum packaged beef steaks.2. Evaluating the effects of sodium levulinate on microbial growth, color stability and sensory attributes of brine-injection enhanced beef rib steaks. Objectives were to compare the use of sodium levulinate and lactate, and optimize sodium levulinate levels for sufficient antimicrobial effect and color promotion. In the study, primal ribs were injected with brine solutions to add0.25%-2.5%sodium levulinate or1.5-2.5%sodium lactate,0.3%salt and0.3%sodium tripolyphosphate into primal ribs. After48hrs equilibration, primal ribs were cut into steaks and tray packed, stored at4℃from0-9days and10℃from9-12days. Aerobic plate counts, Hunter color values, visual color scores and sensory qualities were evaluated during storage.Results showed1.5%sodium levulinate had greater antimicrobial effects than1.5%sodium lactate (P<0.05), and1.5%sodium levulinate was as effective as2.5%sodium lactate (P>0.05).0.25%to2.5%levulinate inhibited microbial growth significantly (P<0.05). At day12, the lowest level of sodium levulinate (0.25%) inhibited microbial growth by1.9log CFU/cm3. Moreover,0.25%sodium levulinate had significant benefit to increase both lightness and redness of rib steaks (P<0.05), which scored highest in visual color evaluation (P<0.05). Also, injection with0.25%-1.5%sodium levuliante did not have detrimental effects on steak lipid oxidation and overall flavor (P>0.05); moreover,0.25%-1.5%sodium levuliante increased beef steak tenderness and juiciness. Thus, sodium levuliante is at least as effective as sodium lactate in bacteria inhibition.0.25%sodium levulinate has potential to become an antimicrobial and color stabilizer for enhanced beef steaks. |
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