Internal Endpoint Temperature Research Articles

The effect of sealing process on the textural and sensory properties and protein profile of cooked meat

SummaryThis work aimed to determine the effect of sealing process at different internal temperatures on the cooking loss, lipid oxidation, textural, and sensory properties, as well as the protein profile of cooked meat. For this aim, four different groups were formed. The control group was not sealed, while the other three groups were sealed until their internal temperature reached 20, 30, and 40 °C. Then, all samples were baked until their internal endpoint temperature reached 71 °C to ensure food safety. The lowest cooking loss (11.57%) was detected in the control group, and increased sealing core temperature resulted in an increase in cooking loss. The sealing did not show a significant effect (P > 0.05) on the TBARS value. On the other hand, myofibrillar and sarcoplasmic protein profile were influenced by sealing. Myofibrillar protein profile showed that protein denaturation rate was higher in groups sealed at the internal temperature of 30 and 40 °C. The sealing process affected only the hardness value among the textural properties examined. With the sealing process, the hardness value of the meat significantly (P < 0.05) reduced and the lowest hardness value was determined in the sample sealed at the internal temperature of 20 °C. Sealing positively affected the overall acceptability score of the samples, and the samples sealed until their internal temperatures reached 30 and 40 °C had higher overall acceptability scores.

Internal endpoint temperature (level of cooking doneness) effects on the fatty acid and mineral profiles of grilled lamb m. longissimus lumborum

This study compared the fatty acid and mineral concentrations of lamb meat that was prepared to different levels of cooking doneness. Ten m. longissimus lumborum were each sectioned into 4 slices that were randomly assigned to be uncooked or grilled to an internal end-point temperature of 60 °C (rare), 71 °C (medium), or 77 °C (well done). It was found that cooking loss increased as the level of cooking doneness increased. The proportion of most major fatty acids were not altered by cooking. However, when adjusted for cooking loss (i.e., mg/135 g serve of lamb as-is equivalent prepared to each level of cooking doneness), the concentration of most major fatty acids, including C16:0, C18:0, C18:1n-9, and many conjugated linoleic acids, were lowered after grilling to any level of cooking doneness and compared to the uncooked samples. The omega-6 to omega-3 ratio was lowest for the uncooked samples and highest for those prepared to a well done level of cooking doneness. Conversely, the concentration of health claimable omega-3 fatty acids in the uncooked meat was retained upon cooking and across all the different internal endpoint temperatures. Calcium, magnesium, phosphorous, potassium, and sodium were reduced with preparation of lamb meat to any level of cooking doneness, compared with uncooked meat. Zinc, iron, and selenium were retained within the cooked samples. These findings show that consumer preference for a level of cooking doneness will have only minor effects on the concentration of minerals and fatty acids in lamb meat.

Effects of increasing internal end-point temperatures on physicochemical and sensory properties of meat: A review.

Although many efforts have been made to improve and control the eating quality of meat, there is still high variability in palatability, which may ultimately result in customer dissatisfaction. Beef meat is especially intricate to study since consumers have specific preferences for degrees of doneness. The degrees of doneness in beef is known to affect its physicochemical properties and have a subsequent effect on palatability. Nevertheless, an in-depth investigation into the exact changes that occur with increasing internal end-point temperatures of meat is yet to be explored. With researchers implementing various cooking methods and cooking conditions (i.e., sample preparation and internal end-point temperatures), the results of studies are often impossible to compare. This review provides an overview of the various benefits and drawbacks of the cooking methods commonly used at home, in commercial enterprises, and research on meat. Furthermore, the physicochemical changes in meat with increasing degrees of doneness are discussed in detail with considerations of the subsequent changes in the sensory properties of meat.

Characteristics of Pork Muscles Cooked to Varying End-Point Temperatures.

M. biceps femoris (BF), m. semimembranosus (SM) and m. semitendinosus (ST) from fresh pork ham were evaluated for characteristics of quality after cooking to an internal endpoint temperature of 62 °C or 73 °C. Fresh ham muscles from the left side (N = 68) were cut into 2.54 cm thick chops and allocated to cooking loss, Warner–Bratzler shear force (WBSF), pH and instrumental cooked color analysis. Cooking losses were greater (p < 0.0001) for SM and chops cooked to an internal temperature of 73 °C (p < 0.0001), whereas WBSF did not differ (p = 0.2509) among the three muscles, but was greater (p < 0.0001) in chops cooked to 73 °C. Fresh muscle’s pH was greater (p < 0.05) in ST than BF or SM. Lastly, the interactive effect (p < 0.05) of muscle × endpoint temperature for ST chops cooked to 73 °C was lighter (L*), but, when cooked to 62 °C, they were more red (a*), more yellow (b*) and incurred less color change from red to brown than BF or SM. The current results suggest it is plausible for BF, SM and ST to be considered for alternative uses instead of traditional value-added manufacturing.

Sarcoplasmic Proteome Profile and Internal Color of Beef Longissimus Lumborum Steaks Cooked to Different Endpoint Temperatures

The complex relationship between endpoint temperature, sarcoplasmic proteome, and internal color in cooked steaks is yet to be examined. The objective of the present study was to characterize the changes in sarcoplasmic proteome and their influence on the internal color of beef longissimus lumborum (LL) steaks cooked to different endpoint temperatures. Two 2.5-cm-thick LL steaks were fabricated from 9 beef strip loins and were cooked to an internal endpoint temperature of either 60°C (C-60) or 71°C (C-71). Cooked steaks were cooled and sliced parallel to the grilled surface, and internal color was evaluated instrumentally. Sarcoplasmic proteome from the interiors of the cooked steaks was analyzed using two-dimensional electrophoresis, and the gel images were digitally analyzed. The protein spots exhibiting more than 2-fold intensity differences (P &amp;lt; 0.05) were subjected to in-gel tryptic digestion and were identified by tandem mass spectrometry. The C-60 steaks demonstrated greater (P &amp;lt; 0.05) redness and color stability than the C-71 ones. Eleven differentially abundant protein spots were identified, and they belonged to 6 functional groups (transport proteins, enzymes in energy metabolism, chaperones, antioxidant proteins, enzymes in amino acid metabolism, and glycolytic enzymes). While 10 spots were overabundant (P &amp;lt; 0.05) in C-60 steaks, 1 spot was overabundant (P &amp;lt; 0.05) in C-71 steaks. The spot overabundant in C-71 samples was identified as myoglobin, suggesting the possible role of post-translational modifications in the heme protein’s thermal stability. The results indicated that the endpoint cooking temperature influenced sarcoplasmic proteome profile and internal color of cooked beef LL steaks. The overabundant proteins in steaks cooked to 60°C may be exploited as potential biomarkers for undercooked beef, which is a source for foodborne infections.

Endpoint Temperature Influences Sarcoplasmic Proteome Profile of Cooked Beef Longissimus Lumborum

ObjectivesCooking ensures safety and enhances the palatability attributes of meat. Denaturation of myoglobin results in the dull-brown color of cooked meats. The denaturation of sarcoplasmic proteins is influenced by the degree of heat treatment, and their solubility is decreased with an increase in the endpoint cooking temperature. While previous studies examined the relationship between myoglobin denaturation, cooked color, and internal temperature in beef, investigations are yet to be undertaken to characterize the association between endpoint temperature, sarcoplasmic proteome, and color attributes in cooked steaks. Therefore, the objective of the present study was to examine the influence of endpoint cooking temperature (60 and 71°C) on sarcoplasmic proteome and internal color of beef longissimus lumborum (LL) steaks.Materials and MethodsEight (n = 8) beef LL muscles (14 d postmortem; USDA Choice) were obtained from a commercial packing plant. Two 2.5-cm thick steaks were fabricated from the center of the muscles and were cooked to internal endpoint temperature of 60°C (C-60) or 71°C (C-71) in a clam-shell grill. Cooked steaks were immediately cooled in slushed ice, sliced parallel to the grilled surface, and internal redness (a* value) and color stability (R630/580) were evaluated instrumentally. Sarcoplasmic proteome from the interiors of the cooked steaks was analyzed using 2-dimensional electrophoresis, and the gel images were digitally analyzed. The protein spots exhibiting more than 2.5-fold intensity differences (P &lt; 0.05) between C-60 and C-71 were subjected to in-gel tryptic digestion and were identified by tandem mass spectrometry.ResultsThe C-60 steaks demonstrated greater (P &lt; 0.05) a* and R630/580 than their C-71 counterparts. Seven differentially abundant proteins were identified and were over-abundant (P &lt; 0.05) in C-60 compared to C-71. The differentially abundant proteins belong to 6 functional groups, i.e., transport proteins (serum albumin and hemoglobin), energy metabolism (adenylate kinase isoenzyme 1), chaperones (heat shock protein β-1), antioxidant (thioredoxin-dependent peroxide reductase), glycolytic enzymes (fructose-bisphosphate aldolase B), and protease (cytosol aminopeptidase).ConclusionThe findings indicated that the endpoint cooking temperature influences the internal cooked color and the sarcoplasmic proteome profile of beef LL steaks. The overabundant proteins in steaks cooked to 60°C may be utilized as potential biomarkers for undercooked beef, which is a source for foodborne infections.

Endpoint Temperature Influences Sarcoplasmic Proteome Profile of Cooked Beef Longissimus Lumborum

ObjectivesCooking ensures safety and enhances the palatability attributes of meat. Denaturation of myoglobin results in the dull-brown color of cooked meats. The denaturation of sarcoplasmic proteins is influenced by the degree of heat treatment, and their solubility is decreased with an increase in the endpoint cooking temperature. While previous studies examined the relationship between myoglobin denaturation, cooked color, and internal temperature in beef, investigations are yet to be undertaken to characterize the association between endpoint temperature, sarcoplasmic proteome, and color attributes in cooked steaks. Therefore, the objective of the present study was to examine the influence of endpoint cooking temperature (60 and 71°C) on sarcoplasmic proteome and internal color of beef longissimus lumborum (LL) steaks.Materials and MethodsEight (n = 8) beef LL muscles (14 d postmortem; USDA Choice) were obtained from a commercial packing plant. Two 2.5-cm thick steaks were fabricated from the center of the muscles and were cooked to internal endpoint temperature of 60°C (C-60) or 71°C (C-71) in a clam-shell grill. Cooked steaks were immediately cooled in slushed ice, sliced parallel to the grilled surface, and internal redness (a* value) and color stability (R630/580) were evaluated instrumentally. Sarcoplasmic proteome from the interiors of the cooked steaks was analyzed using 2-dimensional electrophoresis, and the gel images were digitally analyzed. The protein spots exhibiting more than 2.5-fold intensity differences (P < 0.05) between C-60 and C-71 were subjected to in-gel tryptic digestion and were identified by tandem mass spectrometry.ResultsThe C-60 steaks demonstrated greater (P < 0.05) a* and R630/580 than their C-71 counterparts. Seven differentially abundant proteins were identified and were over-abundant (P < 0.05) in C-60 compared to C-71. The differentially abundant proteins belong to 6 functional groups, i.e., transport proteins (serum albumin and hemoglobin), energy metabolism (adenylate kinase isoenzyme 1), chaperones (heat shock protein β-1), antioxidant (thioredoxin-dependent peroxide reductase), glycolytic enzymes (fructose-bisphosphate aldolase B), and protease (cytosol aminopeptidase).ConclusionThe findings indicated that the endpoint cooking temperature influences the internal cooked color and the sarcoplasmic proteome profile of beef LL steaks. The overabundant proteins in steaks cooked to 60°C may be utilized as potential biomarkers for undercooked beef, which is a source for foodborne infections.

The effects of ultimate pH and color on sensory traits of pork loin chops cooked to a medium-rare degree of doneness.

The objective was to determine the effects of pH and color on sensory characteristics of boneless pork loin chops cooked to an internal endpoint temperature of 63 °C. Center cut loins (296 total) from barrows and gilts, 5 different sire lines, and a range in pH of 5.36 through 6.23 were used. Previously, ultimate pH was correlated with sensory characteristics of chops cooked to a medium (71 °C) degree of doneness. Additionally, increasing ultimate pH improved sensory tenderness and juiciness of loin chops cooked to a medium degree of doneness. However, in 2011, the United States Department of Agriculture Food Safety and Inspection Service reduced the recommended final internal cooking temperature of pork chops from 71 to 63 °C (followed by a 3-min rest). The effects of ultimate pH on sensory traits of pork chops cooked to a medium-rare (63 °C) degree of doneness are not known. Therefore, loins were categorized using historical categories based on ultimate pH: >5.95, n = 22; 5.80 to 5.95, n = 75; 5.65 to 5.80, n = 102; 5.50 to 5.65, n = 91; <5.50, n= 6. On 1-d postmortem, loins were evaluated for CIE instrumental L*, a*, b*, visual color, marbling, and subjective firmness. Then, loins were aged in vacuum packages at 4 °C until 16-d postmortem. After aging, loins were cut into 2.54-cm thick chops, vacuum-packaged, and frozen until sensory or instrumental tenderness analysis. One chop was also used to determine extractable lipid. Chops were weighed, cooked to 63 °C, cooled to approximately 23 °C, weighed again to determine cook loss, and then evaluated for Warner-Bratzler shear force. Another chop was cooked to 63 °C internal temperature and served warm to trained panelists to determine sensory traits. Coefficients of determination (R2) were calculated to determine the predictability of ultimate pH and instrumental color on sensory tenderness, juiciness, and flavor. A 1-way ANOVA and means separation test were used to determine specific differences among pH categories. Ultimate pH explained less than 5% of the variation in tenderness and less than 1% of the variation in juiciness or flavor. Furthermore, sensory tenderness did not differ (P > 0.05) among pH categories, except for chops with an ultimate pH > 5.95. Chops with a pH > 5.95 were at least 9.1% more tender (P < 0.05) than chops with a pH < 5.95. Visual and instrumental color were not predictive (R2 ≤ 0.03) of any sensory traits. Overall, pH does not influence sensory traits of pork chops cooked to medium-rare degree of doneness unless pH is at least 5.95.

Fresh Ham Chop Characteristics Cooked to Various Internal Endpoint Temperatures

Fresh Ham Chop Characteristics Cooked to Various Internal Endpoint Temperatures

Grilling Temperature Effects on Trained Sensory Panel and Warner Bratzler Shear Force of USDA Select Beef Striploin Steaks

ObjectivesThe objective of this study was to evaluate the trained sensory panel and Warner-Bratzler shear force (WBSF) responses to 5 different grilling temperatures on USDA Select strip steaks.Materials and MethodsThirty USDA Select strip loins were collected from a major packing plant where carcass data was collected, then aged for 14 d. After aging, 10 steaks were cut 2.54 cm thick from each loin, randomized among 1 of 5 treatment grill surface temperatures (149°C, 177°C, 204°C, 232°C, or 260°C), and given a WBSF or trained sensory panel designation. Steaks were individually vacuum-packaged and placed in frozen storage until analyses were performed. Individual steaks were thawed in refrigerated storage (4°C) for 12 to 24 h prior to cooking. Steaks were cooked on a commercial flat top grill, preheated to the designated grill surface temperature treatment. All steaks were cooked to an internal end point temperature of 71°C, turning once at 35°C. Six, 1.3 cm diameter core samples were collected from each WBSF steak after being refrigerated (4°C) overnight. Steaks designated for trained panel were cut into 1.3cm cubes and served, warm, to an expert trained beef flavor descriptive panel. Each steak was evaluated on a 16-point intensity scale for 18 flavor attributes, tenderness, and juiciness. Data were analyzed using the GLM procedure in SAS with significance set at an ɑ value < 0.05, where grilling temperature served as the main effect and loin, panelists, day, and serving order served as covariates. The LSMeans procedure in SAS (SAS Inst. Inc., Cary, NC) was used to separate significant means (P < 0.05).ResultsWarner-Bratzler shear force values were not affected (P > 0.05) by grill temperature and were generally low (mean WBSF = 3.1779 kg). At lower grill temperatures, beef identity, brown, roasted, burnt, and bitter were lower (P < 0.05) and bloody/serumy, sour, and juiciness were higher (P < 0.05). As grill temperatures increased, bloody/serumy, sour, and juiciness were lower (P < 0.05) and beef identity, brown, roasted, burnt, and bitter were higher (P < 0.05).ConclusionGrill surface temperature can be used to change beef flavor trained sensory panel scores, but has no impact on tenderness.

Thermal inactivation of Salmonella spp. in pork burger patties

Predictive models, to estimate the reduction in Escherichia coli O157:H7 concentration in beef burgers, have been developed to inform risk management decisions; no analogous model exists for Salmonella spp. in pork burgers. In this study, “Extra Lean” and “Regular” fat pork minces were inoculated with Salmonella spp. (Salmonella 4,[5],12,i:-, Salmonella Senftenberg and Salmonella Typhimurium) and formed into pork burger patties. Patties were cooked on an electric skillet (to imitate home cooking) to one of seven internal temperatures (46, 49, 52, 55, 58, 61, 64°C) and Salmonella enumerated. A generalised linear logistic regression model was used to develop a predictive model for the Salmonella concentration based on the internal endpoint temperature. It was estimated that in pork mince with a fat content of 6.1%, Salmonella survival will be decreased by −0.2407log10 CFU/g for a 1°C increase in internal endpoint temperature, with a 5-log10 reduction in Salmonella concentration estimated to occur when the geometric centre temperature reaches 63°C. The fat content influenced the rate of Salmonella inactivation (P=0.043), with Salmonella survival increasing as fat content increased, though this effect became negligible as the temperature approached 62°C. Fat content increased the time required for patties to achieve a specified internal temperature (P=0.0106 and 0.0309 for linear and quadratic terms respectively), indicating that reduced fat pork mince may reduce the risk of salmonellosis from consumption of pork burgers. Salmonella serovar did not significantly affect the model intercepts (P=0.86) or slopes (P=0.10) of the fitted logistic curve. This predictive model can be applied to estimate the reduction in Salmonella in pork burgers after cooking to a specific endpoint temperature and hence to assess food safety risk.

Effects of different cooking regimes on the microstructure and tenderness of duck breast muscle

Cooking has a great influence on meat tenderness, and we assumed that changes of tenderness in this process resulted from the liberation of actin and associated structural changes. Therefore, in this study, we investigated changes in the microstructure and tenderness when duck breast muscle were cooked to different internal endpoint temperatures (70, 80, 90, 95 °C) by three cooking regimes (conventional cooking, two-stage cooking and three-stage cooking). When duck breast muscle was cooked to an internal endpoint temperature of 70 °C, the three-stage cooking significantly decreased the Meullenet-Owens razor shear force (MORSF) value (P<0.05) and resulted in a longer sarcomere length (P<0.05) compared with the conventional cooking. However, further improvement of the tenderness and an increase in sarcomere length did not occur at higher internal endpoint temperatures. The two-stage cooking regime, with a much longer cooking time below 55 °C, also resulted in a lower MORSF value (P>0.05) and increased sarcomere length (P<0.05) at an internal endpoint temperature of 70 °C compared with the conventional cooking. Significant liberation of actin was also observed in duck meat cooked between 50 and 60 °C. The two- and three-stage cooking regimes with initial temperatures of 50-60 °C and endpoint temperature of 70 °C could improve tenderness of duck breast meat, which might be related to the liberation of actin. Three-stage cooking had the great advantages of improving meat tenderness and reducing cooking loss; therefore, this is to be recommended for further application and research.

Textural properties and water-holding capacity of broiler breast meat cooked to various internal endpoint temperatures

A total of 100 broiler breast meat was cooked at 176°C to internal temperatures of either 71, 73, 75, 77, or 79°C. Tenderness significantly decreased as internal temperatures increased. The decrease was most pronounced at 79°C with a 26.4% increase in Meullenet-Owens-Razor-Shear (MORS) energy compared to that at 71°C. The toughness-temperature coefficient (TTC, change in tenderness/1°C increase) was calculated to be 4.48% across the temperature ranges. Cooking loss increased constantly with the increase of internal temperatures and ranged from 15 to 27% across the range of endpoint temperatures. Poultry breast meat cooked to a higher internal temperature was in average less tender and also more variable in tenderness.

Inactivation of Shiga toxin-producing O157:H7 and non-O157:H7 Shiga toxin-producing Escherichia coli in brine-injected, gas-grilled steaks.

We quantified translocation of Escherichia coli O157:H7 (ECOH) and non-O157:H7 verocytotoxigenic E. coli (STEC) into beef subprimals after brine injection and subsequently monitored their viability after cooking steaks cut therefrom. Beef subprimals were inoculated on the lean side with ca. 6.0 log CFU/g of a five-strain cocktail of rifampin-resistant ECOH or kanamycin-resistant STEC, and then passed once through an automatic brine-injector tenderizer, with the lean side facing upward. Brine solutions (9.9% ± 0.3% over fresh weight) consisted of 3.3% (wt/vol) of sodium tripolyphosphate and 3.3% (wt/vol) of sodium chloride, prepared both with (Lac(+), pH = 6.76) and without (Lac(-), pH = 8.02) a 25% (vol/vol) solution of a 60% potassium lactate-sodium diacetate syrup. For all samples injected with Lac(-) or Lac(+) brine, levels of ECOH or STEC recovered from the topmost 1 cm (i.e., segment 1) of a core sample obtained from tenderized subprimals ranged from ca. 4.7 to 6.3 log CFU/g; however, it was possible to recover ECOH or STEC from all six segments of all cores tested. Next, brine-injected steaks from tenderized subprimals were cooked on a commercial open-flame gas grill to internal endpoint temperatures of either 37.8 °C (100 °F), 48.8 °C (120 °F), 60 °C (140 °F), or 71.1 °C (160 °F). Regardless of brine formulation or temperature, cooking achieved reductions (expressed as log CFU per gram) of 0.3 to 4.1 of ECOH and 0.5 to 3.6 of STEC. However, fortuitous survivors were recovered even at 71.1 °C (160 °F) for ECOH and for STEC. Thus, ECOH and STEC behaved similarly, relative to translocation and thermal destruction: Tenderization via brine injection transferred both pathogens throughout subprimals and cooking highly contaminated, brine-injected steaks on a commercial gas grill at 71.1 °C (160 °F) did not kill all cells due, primarily, to nonuniform heating (i.e., cold spots) within the meat.

Chitosan inhibits premature browning in ground beef

Our objective was to evaluate the effect of chitosan on premature browning in refrigerated ground beef patties stored in different packaging systems. Ground beef patties (15% fat) with chitosan (1% w/w) or without chitosan (control) were individually packaged either in vacuum (VP), aerobic packaging (AP), carbon monoxide modified atmosphere packaging (LO-OX; 0.4% CO+19.6% CO2+80% N2), or high-oxygen modified atmosphere packaging (HI-OX; 80% O2+20% CO2), and stored for 0, 1, or 3days at 1°C. At the conclusion of storage, raw surface redness was evaluated, patties were cooked to internal end-point temperatures of either 66°C or 71°C, and internal cooked color was measured. The incorporation of chitosan increased (P<0.05) the interior redness of patties stored in AP, VP, and LO-OX, but not in HI-OX. The results of the present study suggest that the incorporation of 1% chitosan minimizes premature browning in ground beef patties stored under AP, VP, and LO-OX.

A COMPARISON OF HEAT‐INDUCED CHANGES OF INTRAMUSCULAR CONNECTIVE TISSUE AND COLLAGEN OF BEEF SEMITENDINOSUS MUSCLE DURING WATER BATH AND MICROWAVE HEATING

ABSTRACTThe main objective of this study was to characterize the thermal properties of intramuscular connective tissue (IMCT) and collagen in beef semitendinosus (ST) muscle from Chinese yellow bulls during water bath and microwave heating. Beef ST muscle was heated to internal endpoint temperature of 40, 50, 60, 70, 80 and 90C by water bath and microwave oven, respectively. The results indicated that insoluble collagen contents of microwave‐heated meat were higher than water bath heated except for 90C, and showed significant differences at 80 and 90C (P &lt; 0.05). Mechanical strength of IMCT showed significant difference (P &lt; 0.05) at 60C between water bath‐ and microwave‐heated meat. Perimysial portion content of microwave‐heated meat was significantly higher than water bath heated at 60, 70, 80 (P &lt; 0.05) and 90°C (P &lt; 0.01), and endomysial portion content showed a gradual decrease during heating. A heating temperature of 60C was critical, and affects the maximum shrinkage temperatures (Tmax) of IMCT for both heated meat. With the increase in heating temperature, granulation changes of IMCT and disorderly changes of collagenous fibers arrangement have resulted.PRACTICAL APPLICATIONSIt is well known that the characteristics of intramuscular connective tissue (IMCT) and collagen are related to meat quality, especially for the meat tenderness. Besides, heating is an important step for the conversion of inedible (raw) meat to edible meat, and can make remarkable effects on the eating quality of meat. Based on those viewpoints, we reported the comparative research of water bath and microwave heating on the effects of meat quality and thermal characteristics of IMCT and collagen. Results reported in this article would be useful either for the science community or for the food industry of beef production. Moreover, our study can provide the reference for the systematic researches for Chinese yellow bulls in the future.

Effect of muscle source on premature browning in ground beef

Premature browning (PMB) describes cooked beef that may appear done before reaching 71 °C. Ground beef from paired Longissimus lumborum (LL) and Psoas major (PM) muscles was formed into patties. Patties were cooked immediately, and after 48 and 96 h storage at 4 °C. Total reducing activity (TRA) and external color were measured immediately prior to cooking. Patties were cooked to internal end point temperatures of 60, 66, 71 or 77 °C and internal cooked color ( L *, a * and b * values) was measured. Raw PM patties had greater L * values and lesser a * values than those from LL ( P<0.05). For LL and PM, raw a * and b * values decreased with storage from 0 h to 96 h ( P<0.05). At 0 and 48 h storage, cooked patties prepared from PM had greater a * values than those prepared from LL at all internal endpoint temperatures ( P<0.05). Internal cooked a * values of patties from PM decreased with storage of raw patties, whereas it was stable for LL patties ( P<0.05).

Unheated Water in the First Tank of a Three-Tank Broiler Scalder

Scalding with unheated water in the first tank of a simulated three-tank scalder was tested to determine whether carcass bacteria, efficiency of feather removal, and cooked breast meat tenderness are affected as compared with carcasses scalded at the same temperature (57 C) in all tanks. This experiment was performed on 3 d using 6-wk-old broilers. On each day, eight birds per treatment were processed. During the first 40-s scalding period, one carcass was placed in approximately 24 C water. The other carcass was placed simultaneously in a scalder unit containing approximately 2,050 L of water at 57 C. Carcasses were then held out of the water for 15 s, after which both were placed for 40 s in opposite ends of the scalder containing water at 57 C. After the second scalding period, both carcasses were again removed from the water for 15 s, followed by another 40 s in the 57 C water. Total scald time was 2 min for each treatment. After picking, carcasses were rinsed with 200 mL of sterile 0.1% peptone water for 1 min. Aerobic bacteria and Escherichia coli were enumerated and incidence of salmonella was determined by standard methods. After rinsing, carcasses were eviscerated by hand and chilled for 30 min in ice slush. All carcasses were scored for the presence of feathers, and the appearance and condition of the skin were noted. Four hours postmortem, breast fillets were removed from carcasses and chilled overnight at 2 C. The next morning, breast fillets were cooked to an internal endpoint temperature of 75 to 80 C. Warner-Bratzler shear values were measured to determine tenderness. No differences were found in numbers of aerobic bacteria and E. coli, incidence of salmonellae, tenderness of cooked breast meat, or number of feathers left on carcasses.

Effect of erythorbic acid on cooked color in ground beef

Consumers often use the color of cooked ground beef as an indicator of doneness. For safety reasons, it is recommended that the center of ground beef products be heated to 71°C. In some instances beef may appear done before reaching 71°C, a condition termed premature browning (PMB). Ground beef (15% fat), with added erythorbic acid (ERY) at 0.04 and 0.06% was formed into patties, wrapped in oxygen permeable film, and stored in the dark at 4°C. Patties were stored for either 10 h or 58 h and then cooked to internal end point temperatures of 60, 66, 71 or 77°C. Internal cooked color L ∗, a ∗ and b ∗ values were measured. For beef patties stored 10 h, there was no effect of ERY on internal cooked color. After 58 h storage, ground beef with 0.04 and 0.06% ERY had higher a ∗ values than controls at 60°C ( P<0.05). Beef with 0.04% ERY cooked to an internal temperature of 66°C had higher a ∗ values than 0.06% ERY and controls ( P<0.05). There was no effect of ERY on color of beef patties cooked to 71 or 77°C. The presence of 0.04% ERY in ground beef patties stored 58 h appeared to maintain red color at internal temperatures of 60 and 66°C.

CONSUMER ACCEPTANCE OF HONEY MARINATED CHICKEN

ABSTRACT Chicken bone‐in breast quarters marinated through injection with lemon‐pepper poultry marinade containing 20 or 30% honey were compared to that marinated without honey and commercial marinated chicken. The objectives were to determine (1) consumer acceptance and willingness to buy and the amount to pay for marinated chicken and (2) the effect of honey on instrumental measurements of color and texture. Chicken was roasted at 177C for 1 h to an internal endpoint temperature of 80C and evaluated for acceptance by 67 untrained consumers. All experimental test products had similar hedonic ratings for appearance, color, flavor, taste, tenderness, juiciness, and overall liking. All samples, both experimental and commercial, were acceptable, and most consumers would be willing to buy chicken marinated with the formulations used in this study for the same price that they were paying for similar products.