Effects of lactic and acetic acid salts on quality characteristics of enhanced pork during retail display

The objective of this study was to evaluate the sensory and physical characteristics of pork chops from loins enhanced to 110% of original weight with either (1) potassium lactate, potassium diacetate, phosphate and salt, (2) sodium lactate, phosphate and salt, (3) potassium lactate, phosphate and salt, (4) sodium acetate, phosphate and salt, or (5) phosphate and salt. A trained sensory panel evaluated pork flavor, saltiness, bitterness, soapy flavor, acid flavor, juiciness and tenderness of cooked chops. Visual color of raw chops was also evaluated. After 96 h in display, chops enhanced with lactate/diacetate had significantly lower (P<0.01) aerobic plate counts than control (unpumped) chops, or those pumped with other solutions. Lactate/diacetate-enhanced chops maintained higher a* and b* values during display, and had less visual discoloration after 96 h display. Chops pumped with lactate, acetate or the lactate/diacetate mixture were more tender and juicy, and had more pork flavor than controls or those pumped with phosphate/salt only. There appears to be a significant advantage to using a lactate/diacetate enhancement solution over either lactate or acetate alone.     

ENHANCEMENT SOLUTION EFFECTS ON SHELF-LIFE, COLOR AND SENSORY CHARACTERISTICS OF PORK CHOPS DURING RETAIL DISPLAY

Abstract The objective of this study was to evaluate shelf-life, color and sensory characteristics of pork chops from loin sections (n = 12/treatment) injected (110% original weight) with a potassium lactate/potassium acetate solution (2 %) + phosphate (0.35%)/salt (0.35%), compared with those injected with sodium lactate (3%) + phosphate/salt, or phosphate/salt alone, to control loins. After 96 h of display, aerobic plate counts (CFU/cm²) were significantly lower (P<0.05) for chops enhanced with the lactate + acetate combination than for the other treatments. Hue angle (tan^-1 b*/a*) of lactate + acetate enhanced chops was lower (P<0.05) than all other treatments at 96 h indicating that red color did not deteriorate as rapidly as in control, phosphate + salt- and lactate-injected chops. Sensory data suggest that lactate + acetate and lactate-injected chops were juicier, more tender, and less bitter than the noninjected chops. A difference in enhancement solution retention may partially explain differences in plate counts and sensory characteristics.     

Sensory and Chemical Characteristics of Pork Chops as Affected by Precooking, Curing and Frozen Storage

Four processing procedures were compared as methods of reducing warmed-over flavor (WOF) of pork chops during frozen storage for 84 days, These procedures were (1) oven-broiled chops, (2) chops from loins precooked with no additives, (3) chops from loins cured with 0.5% salt and 40 ppm NaNO2 and precooked, and (4) chops from loins cured with 2% salt and 120 ppm NaNO2 and precooked. Samples were evaluated by the TBA test, Warner-Bratzler shear, hydroxyproline assay and by sensory analysis after frozen storage at -18°C. Chops from the three precooked treatments were more tender than oven-broiled chops. Nitrite inhibited WOF development of precooked chops during frozen storage and 40 ppm nitrite was nearly as effective as 120 ppm.     

Electrical Stimulation, Hot-Boning and Prerigor Cookery Effects on Lamb Longissimus Tenderness

Paired halves of 32 lamb carcasses were either electrically stimulated (ES) or not (NES), then assigned to one of the following treatments: (1) hot-boned, cooked prerigor, frozen and reheated (HEPRC); (2) conventionally chilled and boned, cooked, frozen and reheated (CB-ARC); (3) hot-boned, frozen and cooked (HB); and (4) cold- boned, frozen and cooked (CB). Electrical stimulation lowered (P < 0.05) peak force (PF) of chops from CB-ARC, HB and CB treatments. Nonstimulated HB-PRC chops had a lower (P < 0.05) PF than ES, HB-PRC chops. Lower (P < 0.05) compression values were noted for HEPRC and CB-ARC chops than for HB and CB chops. Electrical stimulation reduced (P < 0.05) PF regardless of cooking method. Chops cooked in the microwave had lower (P < 0.05) work values than chops cooked in the convection oven.     

Cooking method and endpoint temperature effects on sensory and color characteristics of pumped pork loin chops

The objective of this study was to evaluate the effects of pumping, cooking method and endpoint temperature on quality of fresh pork chops. The longissimus was removed from 30 paired pork sides. One side was pumped to 110% of original weight (0.4% phosphate, 0.4% salt+added water). Chops were cut (2.5 cm thick) then fried or grilled to 70 or 80 °C. As endpoint temperature increased from 70 to 80 °C, pork flavor increased (P<0.05) from 95 to 104 (on a 150 point scale) for pumped samples but remained constant in unpumped samples. Juiciness decreased when unpumped samples cooked to 80 °C (62) rather than 70 °C (78). Warner–Bratzler shear values were lower (P<0.05) in pumped chops than in unpumped controls. Pork flavor was higher and off-flavor was lower in fried chops. Pumping loins appears to enhance sensory attributes of chops even when cooked to abusive endpoint temperatures with limited detrimental effects on physical characteristics.     

Effect of carbon monoxide in modified atmosphere packaging, storage time and endpoint cooking temperature on the internal color of enhanced pork

The objective of this research was to evaluate the effects of gas atmosphere, refrigerated storage time, and endpoint temperature on internal cooked color of injection-enhanced pork chops. Enhanced chops were packaged in 0.36% CO/20.34% CO₂ (CO-MAP), 80% O₂/20% CO₂ (HO-MAP), or PVC-overwrapped (PVC-OW; controls), stored at 4 °C for 0, 12, 19 or 26 days, displayed for 2 days then cooked to six endpoint temperatures (54, 60, 63, 71, 77, and 82 °C). L^*, a^*, and b^* values, hue angle and chroma were determined on the internal cut surface of cooked chops. Chops packaged in CO-MAP had the highest a^* values; a^* value began increasing on day 14. The lowest hue angles occurred in chops cooked to lower endpoint temperatures. Chops in CO-MAP had lower hue angles and higher chroma than those in HO-MAP and PVC-OW. Above 71 °C, hue angle and chroma increased. Overall, CO-MAP packaged chops stored for longer time periods then cooked to lower endpoint temperatures appeared reddest. HO-MAP packaged chops were less red, did not change over time, and appeared more well done at lower endpoint temperatures than those in other gas atmospheres. CO-MAP packaged chops retained redness even after cooking at 82 °C.     

Effects of brine ingredients and temperature on cook yields and tenderness of pre-rigor processed roast beef

In semimembranosus (SM) muscles removed pre- and post-rigor and injected 10% (wt/wt) with brines formulated to give 2% salt, 1.5% glucose, 0.3% phosphate, 0.15% calcium chloride or 3% sodium lactate in the finished product and cooked within 1 h of injection, cook yields were not significantly affected by processing pre- or post-rigor. Within treatments, however, brine composition had a significant (P < 0.05) effect on cook yields; highest yields were obtained using salt (although this was not significantly different from the water injected control) and lowest yields with calcium chloride. Adding phosphate resulted in lower peak shear force values, and less energy was required to break the sample. The most tender roasts from pre-rigor meat were produced using salt, phosphate or lactate brines and the least tender using calcium chloride. Brine temperature (0-12 °C) during injection had little effect on cook yields or tenderness of the roast beef manufactured pre-rigor. The results indicate that accelerated processing of roast beef can result in finished product with acceptable yields and tenderness if salt and phosphate brines are used.     

Vacuum-Packaged Precooked Pork from Hogs Fed Supplemental Vitamin E: Chemical, Shelf-Life and Sensory Properties

Precooked longissimus chops and semimembranosus/adductor roasts from pigs (n = 30) given no supplemental vitamin E (CON) or supplemented with 100 mg vitamin E/kg diet (VITE) were evaluated for lipid oxidation, microbial growth, sensory characteristics, cooking/storage losses and reheating losses. Chops and roasts were vacuum packaged, precooked to 60°C and stored at 2°C for 0, 7, 14, 28, or 56 days. Lipid oxidation was lower in VITE chops and roasts than in CON chops and roasts. Off-flavor intensity scores were more acceptable and storage/ cooking losses were lower for VITE roasts than for CON roasts. Supplementation of vitamin E in a swine diet provided added protection against lipid oxidation and precooking pork under vacuum provided a palatable product with a shelf-life of 56 days.     

Chemical, Textural and Sensory Characteristics of Precooked, Restructured Lamb Shoulder Roasts as Influenced by Grinding Method, Salt Level and Vacuum Massage Time

The influence of level of grind (kidney plate only vs kidney plate plus coarse grinding 25% of raw meat weight), salt level (0.5 vs 1.0%) and vacuum massage time (1.0 vs 1.5 hr) on the chemical, textural and sensory characteristics of precooked, restructured lamb shoulder roasts were studied. Grinding method of kidney plate only decreased the fat content of the cooked product, while the higher salt level (SL) resulted in roasts with higher moisture and lower protein. Calories were reduced by 5% when 1.0% SL roasts were vacuum-massaged for 1.5 vs 1.0 hr. Increasing level of grind and SL decreased cooking losses and increased objective chewiness. Flavor differences were detected by sensory analysis due to the addition of coarse ground trimmings to lean ground through a kidney plate only.     

Effects of incubation temperature and salt concentration on plasminogen activators in cheese curd

Plasmin (PL) can play a major role in the proteolysis of dairy products, especially during cheese ripening. The effects of cook temperature and salt concentration on PL in cheese systems have been studied; however, the effects of cheese making conditions on plasminogen activators (PAs) have not. Therefore, the objective of this study was to determine the effect of curd cook temperature and salt concentration on PL, plasminogen (PG), and PAs. PL, PG, and urokinase-type PA activities extracted from cheese curds cooked at 21 °C were significantly ($P⩽0.05$) lower than those extracted from cheese curds cooked at 37 or 55 °C. Activity assays showed that PG was the only component in the PL enzyme system that was significantly affected by salt concentration, with higher PG-derived activity at 0% NaCl than 5% NaCl. Specialized electrophoresis confirmed that PL and PA activities increased with increasing cook temperature, and, unlike the activity assays, indicated that increase in salt concentration (to a certain extent) could increase PL and tissue-type PA activities.     

CHARACTERISTICS OF MICROWAVEABLE PORK CHOPS

Blade tenderized whole muscle cuts and restructured chops were conventionally cooked (CO), microwave cooked (MW), and precooked/microwave reheated (CMW) and stored for 2, 15, and 21 days. Blade tenderization did not affect (P > 0.05) these sensory traits evaluated with the exception of texture. Precooked products had higher (P < 0.05) TBA values than conventionally cooked samples for both whole and restructured chops. TBA values increased (P < 0.05) with storage time for up to 21 days. Whole muscle chops that were conventionally cooked had the lowest (P < 0.05) peak force values and the highest (P < 0.05) texture scores. After 21 days of storage of whole muscle samples, overall flavor scores decreased (P < 0.05) and juiciness scores improved (P < 0.05) when compared to samples held for 2 days. Storage time had a minimal relationship to peak force values and no effect on sensory scores of restructured samples.     

Effect of Calcium Carbonate and Sodium Alginate on the Textural Characteristics, Color and Color Stability of Restructured Pork Chops

The effects of factorial combinations of calcium carbonate (0.00 and 0.26%) and sodium alginate (0.0 and 0.7%) on the initial cooked tensile strength and texture profile analysis and the amount of discoloration during three months frozen storage of restructured pork chops were investigated. Calcium carbonate increased (p < 0.05) and alginate had no effect (p>0.05) on the tensile strength of the chops. Alginate decreased the hardness, cohesiveness, springiness, chewiness and gumminess of the restructured chops (p < 0.05). Chops that contained alginate and/or calcium carbonate had more initial discoloration than those that contained (1) no additives, (2) 0.75% NaCl plus 0.5% sodium tripolyphosphate, and (3) 0.75% NaCl plus 0.26% calcium carbonate but they did not discolor further during frozen storage.     

Effect of carbon monoxide and high oxygen modified atmosphere packaging and phosphate enhanced, case-ready pork chops

The objective of this study was to evaluate the effects of CO-MAP compared to traditional high oxygen MAP (HiOx-MAP) packaging and enhanced with different phosphate on enhanced pork quality. Pork loins were enhanced to 10.5% over initial weight to contain 0.3% salt and 0.4% phosphate (either sodium tripolyphosphate [STP] or a blend of STP and sodium hexametaphosphate) on a finished weight basis. Chops were cut, packaged in atmospheres containing 0.4% CO/30.0% CO₂/69.6% N₂ (CO-MAP) or 80% O₂/20% CO₂ (HiOx-MAP), aged in the dark, then placed in a lighted retail display case for 48 h. Chops packaged in CO-MAP were redder (higher Minolta a^* values) and darker (lower Minolta b^* values) than chops packaged in HiOx-MAP. Based on sensory scores, the CO-MAP chops were pinker than the HiOx chops after cooking. CO-MAP chops also experienced less purge loss than chops in HiOx-MAP. Results indicate that CO-MAP had no effect on flavor or consumer acceptability and only minimal effects on other characteristics.     

SODIUM LACTATE/SODIUM POLYPHOSPHATE EFFECTS ON OXIDATION IN PRECOOKED FROZEN PORK PATTIES

The objective of this study was to evaluate sodium lactate (SL; 0, 1, 2 or 3%) and sodium polyphosphate (SP; 0, 0.1, 0.2 or 0.3%) effects on lipid oxidation and color characteristics of precooked pork patties during frozen storage. Ground pork was mixed with SL and/or SP, stuffed, frozen, sliced and cooked from the frozen state, packaged and held frozen for 14 weeks. Samples containing SP had lower TBARS, regardless of SL content. SL decreased pH, a* and b* values and red color (R630–R580). L* value, hue angle, pork flavor, saltiness, and juiciness increased as SL increased. A moderate correlation occurred between SL and TBARS. SP decreased hue angle, cook loss, and rancid flavor and increased pH, b* value, pork flavor, saltiness, and juiciness. Storage time decreased a* value, red color and juiciness, while saltiness, alkalinity, and rancid flavor scores increased. Based on both physical and sensory characteristics, optimum combinations appear to be 3% SL and 0.2–0.3% SP.     

Palatability and Storage Characteristics of Precooked Pork Roasts

Pairs of boneless pork loins (n=10) were pumped to contain 0.5% tripolyphosphate or water and allotted to three treatments: PVC wrapped, convection oven cookery (CO); vacuum packaged, precooked and reheated in a water bath (PC); and vacuum packaged and cooked in a water bath (VP). Paired loins (n = 30) were injected with tripolyphosphate and allotted to the following treatments and storage (0, 14 or 28 days) conditions: Control (?20°C) [CO]; precooked (?20°C) [PCPR]; precooked (4°C) [PCRF]; vacuum packaged (?20°C) [VPFR]. VP and PC phosphate injected roasts were more tender and had lower cooking losses than CO roasts. After 28 days, all PC roasts had lower microbial counts than other treatments, and PC and VP roasts had improved palatability compared with CO roasts.     

Effects of Internal Temperature and Thickness on Palatability of Pork Loin Chops

Three thicknesses (2.54, 1.90 and 1.27 cm) of pork chops were cutl alternately from 20 paired loins of similar quality. Chops were cooked on Farberware grills or in a convection oven to internal temperatures of 60, 70 and 80°C for sensory and objective evaluations. Juiciness, percent moisture and tenderness decreased and cooking losses increased (P < 0.05) as temperature increased for both cooking methods. Pork flavor intensity increased in oven- prepared chops, while no change was observed in grilled chops at each level of increased temperature. Thickness had no effect (P > 0.05) on tenderness, juiciness or total cooking loss of oven-prepared or grilled chops. The thickest chops received the highest (P < 0.05) pork flavor scores.     

SODIUM LACTATE EFFECTS ON THE STABILITY OF FRESH AND CURED PORK LONGISSIMUS

Boneless pork loins sliced into 1.9 cm fresh chops were dipped to retain 0, 1.5 or 3% sodium lactate (SL) and packaged in polyvinylchloride (PVC) or vacuum-packaged (VP), Color of fresh chops was monitored visually and objectively. Boneless pork loins were cured by injection with 0, 1.5 or 3% SL, or were dipped after slicing to retain 0, 1.5 or 3% SL. Cure for the dipped loins contained no SL. Color and aerobic plate count (APC) of vacuum-packaged chops were evaluated over 70 days of retail storage (4C). Visual color was darker (P < 0.05) and L* values were lower (P < 0.05) for 3% SL-dipped fresh chops. Fresh chops containing 1.5 and 3% SL had higher a* values than controls. Surface discoloration of 3% SL fresh chops was lower (P < 0.05) than control chops. Cured injected chops (3% SL) had lower (P < 0.05) L* values than dipped chops or injected controls. L*, a* and b* values of cured dipped chops (3% SL) were not different (P > 0.05) from controls. No consistent trends were found in APC of cured chops. Injection of SL prior to cooking darkened the color of cured pork loin chops.     

Effect of carbon monoxide and high oxygen modified atmosphere packaging and phosphate enhanced,case-ready pork chops

The objective of this study was to evaluate the effects of CO-MAP compared to traditional high oxygen MAP (HiOx-MAP) packaging and enhanced with different phosphate on enhanced pork quality. Pork loins were enhanced to 10.5% over initial weight to contain 0.3% salt and 0.4% phosphate (either sodium tripolyphosphate [STP] or a blend of STP and sodium hexametaphosphate) on a finished weight basis. Chops were cut, packaged in atmospheres containing 0.4% CO/30.0% CO₂/69.6% N₂ (CO-MAP) or 80% O₂/20% CO₂ (HiOx-MAP), aged in the dark, then placed in a lighted retail display case for 48 h. Chops packaged in CO-MAP were redder (higher Minolta a¹ values) and darker (lower Minolta b¹ values) than chops packaged in HiOx-MAP. Based on sensory scores, the CO-MAP chops were pinker than the HiOx chops after cooking. CO-MAP chops also experienced less purge loss than chops in HiOx-MAP. Results indicate that CO-MAP had no effect on flavor or consumer acceptability and only minimal effects on other characteristics.     

Effect of Heat Treatment and Selected Antimicrobials on the Shelf-life and Safety of Cooked, Vacuum-Packaged, Refrigerated Pork Chops

The shelf-life of refrigerated (2–4°C) pork chops inoculated with Clostridium sporogenes PA3679 and Staphylococcus aureus Z88 was examined in products sliced from loins cooked to 66°C (150°F), dipped in 5% polyphosphate blend, 2.5% potassium sorbate or 2% acetic acid solutions, vacuum-packaged and stored at 2–4°C. The effect of a second in-the-bag cooking step to 66°C (150°F) after vacuum packaging was also studied. Pork chops not reheated after packaging showed incipient spoilage after 15 days at 2–4°C, depending on surface treatment. The second cooking increased the shelf-life of refrigerated product to more than 60 days and reduced counts of inoculated cultures to undetectable levels. However, on exposure of the chops to simulated mishandling (24–25°C), clostridial growth was detected in all samples except those dipped in polyphosphate or acetic acid solutions.     

Effect of carbon monoxide in modified atmosphere packaging,storage time and endpoint cooking temperature on the internal color of enhanced pork

The objective of this research was to evaluate the effects of gas atmosphere, refrigerated storage time, and endpoint temperature on internal cooked color of injection-enhanced pork chops. Enhanced chops were packaged in 0.36% CO/20.34% CO₂ (CO-MAP), 80% O₂/20% CO₂ (HO-MAP), or PVC-overwrapped (PVC-OW; controls), stored at 4 °C for 0, 12, 19 or 26 days, displayed for 2 days then cooked to six endpoint temperatures (54, 60, 63, 71, 77, and 82 °C). L¹, a¹, and b¹ values, hue angle and chroma were determined on the internal cut surface of cooked chops. Chops packaged in CO-MAP had the highest a¹ values; a¹ value began increasing on day 14. The lowest hue angles occurred in chops cooked to lower endpoint temperatures. Chops in CO-MAP had lower hue angles and higher chroma than those in HO-MAP and PVC-OW. Above 71 °C, hue angle and chroma increased. Overall, CO-MAP packaged chops stored for longer time periods then cooked to lower endpoint temperatures appeared reddest. HO-MAP packaged chops were less red, did not change over time, and appeared more well done at lower endpoint temperatures than those in other gas atmospheres. CO-MAP packaged chops retained redness even after cooking at 82 °C.