Effects of enhancement with differing phosphate types, concentrations, and pump rates, without sodium chloride, on beef biceps femoris instrumental color characteristics

Enhancement of beef biceps femoris muscles (n = 45) with solutions comprising sodium hexametaphosphate (SHMP), sodium tripolyphosphate (STPP), or tetrasodium pyrophosphate (TSPP) at either 0.2% or 0.4% of product weight, with the exclusion of sodium chloride, was performed to observe the independent phosphate effects on instrumental color during simulated retail display. All solutions were injected into muscle samples at either 112% (12% pump) or 118% (18% pump) of raw product weight. All three phosphate types maintained higher (P < 0.05) L* values than untreated steaks (CNT) through 5 days-of-display, and SHMP had higher (P < 0.05) L* values than STPP and TSPP through 7 days-of-display. Additionally, steaks with 0.2% phosphate inclusion were lighter (L*; P < 0.05) than CNT throughout display, and were lighter (P < 0.05) than steaks enhanced with 0.4% phosphates through 7 days of display. Steaks enhanced with TSPP had higher (P < 0.05) a* values than CNT on days 5 and 7 of display, whereas SHMP- or STPP-enhanced steaks generally had similar (P > 0.05) a* values as CNT after 3 d of display. Direct comparison of phosphate concentrations revealed no differences (P > 0.05) in a* values. Only steaks enhanced with TSPP were more vivid (P < 0.05) and had higher (P < 0.05) proportions of oxymyoglobin than CNT on days 5 and 7 of display. However, direct comparison of phosphate types indicated that TSPP- and STPP-enhanced steaks had similar (P > 0.05) oxymyoglobin proportions during display. Phosphate inclusion at 0.4% maintained higher (P < 0.05) oxymyoglobin proportions than 0.2% phosphate inclusion through 5 days-of-display. These results indicate that while 0.2% phosphate concentrations maintain lighter color, 0.4% concentrations can more effectively retain oxymyoglobin during display. Additionally, only steaks enhanced with TSPP were redder, more vivid, and had higher oxymyoglobin proportions than untreated steaks during the latter stages of display.