Endpoint Temperature Research Articles

Evaluation of the changes in composition of pork chops during cooking.

The objective was to determine the change in extractable lipid concentration during cooking of boneless pork chops to different endpoint temperatures. Pork loins (152 total) were used and three consecutive chops were cut from each loin. Chop 1 was evaluated raw (not cooked) for intramuscular fat (IMF) percentage. Raw IMF percentages were used to categorize the remaining two chops, from each loin, into low, average, and high marbling bins. The low bin included ≤3% IMF, the average bin included 3–4% IMF, and the high bin included ≥4% IMF. Chop 2 was cooked to 63 °C and chop 3 was cooked to 71 °C to evaluate cook loss, Warner–Bratzler shear force (WBSF), and IMF percentage. When cooked to either 63 or 71 °C, high IMF chops maintained greater (P < 0.001) IMF percentage than average and low IMF chops. Additionally, average IMF chops maintained greater (P < 0.001) IMF percentage than low chops, regardless of endpoint cooking temperature. The three marbling categories did not differ in cook loss (P = 0.28) or WBSF (P = 0.23) when chops were cooked to either 63 or 71 °C. However, both WBSF (2.76 kg) and cook loss (18.72%) were decreased (P < 0.001) in chops cooked to 63 °C compared with chops cooked to 71 °C (3.08 kg, 23.45%). Overall, differences in IMF percentages persisted even after cooking. Furthermore, IMF percentage of pork chops did not affect tenderness.

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.

A new model of overall heat transfer coefficient of hot wax oil pipeline based on dimensionless experimental analysis

Aimed at biggish prediction error of the overall heat transfer coefficient caused by running parameters fluctuations, analyze the correlations between various elements including outlet oil temperature, oil physical properties, flow rate, environmental temperature, wax deposition rate as well as running time after pigging and the overall heat transfer coefficient. And four dimensionless number determining the laws of overall heat transfer coefficient was put forward. Simplified model came in the use of collinearity diagnosis theory and dimensionless experimental analysis, followed by determining the optimal functional form of prediction model and physical meaning for each dimensionless numbers, then establish a new prediction model. Prediction of the overall heat transfer coefficient for several pipelines came after applying Ten-fold Cross Validation to solve the model. The results showed that, compared with back calculation, the error of overall heat transfer coefficient reduces by 3.62%, and average relative error of end-point temperature lowers by 2.88%. The model is of good steadiness and generalization, and better characterization on heat transfer mechanism of overall heat transfer coefficient, to some degree, solving the biggish prediction error led by running parameters fluctuations.

Texture of Fermented Summer Sausage With Differing pH, Endpoint Temperature, and High Pressure Processing Times

The objective was to evaluate the quality and texture of all-beef summer sausages produced with varying degrees of fermentation, endpoint cooking temperatures, and high pressure processing (HPP) hold times. Across 3 replications, sausages were fermented and (Process A) cooked to pH 4.6 and thermally processed to 54.4°C with smokehouse chilling, (Process B) cooked to pH 5.0 and thermally processed to 54.4°C with smokehouse chilling, (Process C) cooked to pH 5.0 and thermally processed to 54.4°C with rapid ice bath chilling, (Process D) cooked to pH 5.0 and thermally processed to 48.9°C with rapid ice bath chilling, and (Process E) cooked to pH 5.0 and thermally processed to 43.3°C with rapid ice bath chilling. After chilling, the sausages were sliced, layered, vacuum packaged, and subjected to HPP at 586 MPa for 0, 1, 150, or 300 s. Post HPP, the sausages were evaluated for objective color (n = 9), lipid oxidation (n = 9), water activity (n = 9), texture profile analysis (TPA; n = 15), sensory analysis (n = 9), and proximate analysis (n = 9). Neither process (combination of pH and endpoint temperature) nor HPP affected lipid oxidation (P = 0.45 and P = 0.69, respectively). Process A resulted in a lighter color (P &amp;lt; 0.01) compared to the other process treatments. Additionally, Process A was less red (P &amp;lt; 0.01) than all other process treatments, and Processes D and E were the reddest (P &amp;lt; 0.01). TPA and trained sensory analysis indicated that, as endpoint temperature increased, so did sample hardness (P &amp;lt; 0.05). Springiness, cohesiveness, and gumminess decreased (P &amp;lt; 0.05) as the endpoint temperature decreased. Although springiness and gumminess increased (P &amp;lt; 0.05) with longer HPP hold times, the panelists were unable to detect differences among samples with longer hold times. The use of HPP at 586 MPa for up to 300 s may be incorporated into manufacturing processes for semidry beef summer sausages with limited impacts on color and texture.

Rapid inspection method for investigating the heat processing conditions employed for chicken meat using Raman spectroscopy

In Japan, the imports of meat products have been increasing every year. Heat processing of meat is the current standard method for ensuring domestic animal health, particularly in case of meat products from areas where infectious diseases are known to have occurred in domestic animals. The Animal Quarantine Service needs to establish a method that detects the temperature at which the meat has been heat-processed (endpoint temperature) to ensure that the standard protocol is followed at the production location. Here, we developed a Raman spectroscopy and multivariate statistics (viz. multivariate curve resolution (MCR))-based simple and rapid method for accurately estimating the end point temperature. We showed that the temperature-dependent secondary structure modification of proteins can serve as an accurate indicator of the temperature of heat processing. This methodology can be easily automated for effective utilization by someone who is not an expert in spectroscopy. We envisage a wider application of this method in food analysis, although the present research investigated the application of this method in chicken meat heat processing analysis.

Pork meat prepared by different cooking methods. A microstructural, sensorial and physicochemical approach

The influences of four different cooking methods—pan, ohmic, vacuum and sous vide—were studied with regard to the microstructural, sensorial and physicochemical characteristics of pork meat. The end point temperature to all cooking methods was 70 °C. Pan cooking resulted in a softer meat with higher overall liking by the consumers, and ohmic cooking produced firmer (p < .05) meats and myofibrils, with higher alignment compared to the pan-cooked meat as well as a golden colour. Sous vide-cooked meats were perceived as insipid, while vacuum-cooked meats showed loss of structure and were perceived as drier (p < .01) and paler (p < .01). No statistically significant differences were found for cooking loss and water-holding capacity (p > .05). The results suggest that consumers preferred pan-cooking, as they described these samples as juicy, tender and tasty. Ohmic-cooked meat, which required shorter cooking times, showed similar characteristics to pan-cooked meat and could be used as alternative to pan cooking in the catering industry.

Cost-effective FTIR and 1H NMR spectrometry used to screen valuable molecules extracted from selected West African trees by a sustainable biochar process

This study focused on wood extractives by a slow pyrolysis thermal extraction technique and screening of potentially valuable compounds from three African trees: Lophira lanceolata Tiegh. ex Keay., Dialium guineense Willd. and Afzelia africana Sm. The primary objective of the thermal treatment was biochar production but also liquids were collected and analyzed. Raw materials were cut into sizes of about 25 cm in length and then processed with slow pyrolysis from 20 °C up to 400 °C; the slow pyrolysis process included two stages, drying and pyrolysis. Five end-point temperatures were used in the range of 250 °C–400 °C. Raw distillates were collected at three temperatures (120 °C, 60 °C and 25 °C) and their composition screened by either cost-effective FTIR or benchtop 80 MHz 1H NMR methods. HR-NMR and 2D GC–MS were used to confirm some findings. Results from the drying stage indicated that all distillates contained mostly water >90%, acetic acid, methanol and some other compounds at very low levels. The percentages of acetic acid were 3.5% for L. lanceolate, 2.8% for D. guineensis and 3.8% for A. africana (% with respect to the identified peaks). Results from the pyrolysis stage revealed the presence of bioactive compounds such as ketones, methanol, hydrocarbons, acetic acid, esters, alkenes and phenolic compounds at higher quantities than in the drying stage. The quantity of phenols in certain runs and distillate fractions using NMR was 1%–20% for L. lanceolata, 7–17% for D. guineensis and 10%–17% for A. africana (% with respect to the composition of the identified peaks). The percentage of hydrocarbons was 1%–48% for L. lanceolata, 1%–34% for D. guineensis and 2%–33% for A. africana. The percentage of ketones was 7%–19% for L. lanceolate, 4%–27% for D. guineensis and 19%–22% for A. africana. In general, the results indicated the presence of potential valuable compounds at relatively high concentrations. By optimizing the slow pyrolysis process parameters, it is possible to collect distillates with high concentrations of valuable biomolecules.

Ohmic heating effect on enzyme assisted aqueous extraction of rice bran oil

This study explored the improvement of oil recovery from rice bran by pre-treatment of ohmic heating prior to enzyme assisted aqueous oil extraction process (EAEP). A full factorial design was utilized to investigate the effect of electric field strength (OH450V, OH550V and OH650V), end point temperature (75, 85 and 95°C) and holding time (0, 5 and 10 min.). Incremental oil recovery through combined EAEP and ohmic heating ranged from 3.5% to 15.5% over EAEP alone. The electric field strength of OH650V at 95°C for 10 min holding time yielded maximum oil recovery (82%) for combined ohmic and EAEP treatment. The extracted oil was comparatively darker in colour than examined market edible rice bran oil. Pre-treatment of ohmic heating with EAEP on rice bran slightly increased the FFA in oil (1.89–2.24%) compared to market edible rice bran oil.

End-point dynamic control of basic oxygen furnace steelmaking based on improved unconstrained twin support vector regression

In order to improve the end-point hit rate of basic oxygen furnace steelmaking, a novel dynamic control model was proposed based on an improved twin support vector regression algorithm. The controlled objects were the end-point carbon content and temperature. The proposed control model was established by using the low carbon steel samples collected from a steel plant, which consists of two prediction models, a preprocess model, two regulation units, a controller and a basic oxygen furnace. The test results of 100 heats show that the prediction models can achieve a double hit rate of 90% within the error bound of 0.005 wt.% C and 15 °C. The preprocess model was used to predict an initial end-blow oxygen volume. However, the double hit rate of the carbon content and temperature only achieves 65%. Then, the oxygen volume and coolant additions were adjusted by the regulation units to improve the hit rate. Finally, the double hit rate after the regulation is reached up to 90%. The results indicate that the proposed dynamic control model is efficient to guide the real production for low carbon steel, and the modeling method is also suitable for the applications of other steel grades.

Chef and Consumer Evaluation of the Degree of Doneness of Beef Strop Loin Steaks Cooked to Six Endpoint Temperatures

ObjectivesThe objective of this study was to assess if visual degrees of doneness (DOD) are in-line with current published cooking temperatures and to assess differences in perceptions between consumers and chefs.Materials and MethodsTwenty-four paired beef strip loins (IMPS #180) representing four quality grades [Prime, Top Choice, Low Choice, Select] and an additional 12 enhanced Select strip loins were fabricated into 2.54 cm thick steaks and used in the study. Steaks were randomly assigned to one of six DOD: very rare (55°C), rare (60°C), medium-rare (63°C), medium (71°C), well done (77°C), or very well done (82°C). Following cooking, a photograph of the cut steak surface was taken immediately using a digital camera (Canon PowerShot SX620 HS). A digital survey for chefs and consumers was created for the electronic evaluation of the pictures of the internal surface of the cooked steaks. Chefs (n = 83) and consumers (n = 1134) were asked to assess the DOD of digital steak pictures representing multiple DOD and quality grades. Participants were also asked several questions related to how they determine DOD when cooking steaks, about their use of thermometers, and the temperatures they associate with each DOD.ResultsThere were no quality treatment effects (P &gt; 0.05) for any DOD for the images evaluated. Between 14 to 44% of chefs categorized the steak images as the DOD to which it was cooked. For all DOD, 9 to 48% of chefs classified the steak images as 2 or more DOD from the DOD to which the steak was cooked. Of the 1134 consumers, 27 to 35% of consumers categorized steaks as the appropriate DOD. For all DOD, 16 to 36% of consumers identified steaks as 2 or more DOD higher or lower than the DOD that the steak was cooked. When chefs were asked how they determined DOD when cooking beef steaks, 66% of chefs reported using feel or firmness, whereas 28% stated they use a thermometer. Within the chefs that reported use of thermometers, 15% indicated the specific temperature they used was pull-off the heat temperature and 13% used carry-over cooking temperature. To assess DOD when cooking beef at home, 54% of consumers reported they used color, 16% used feel or firmness, and 10% used time. Additionally, 3% of consumers responded that they do not determine DOD. Only 16% of consumers reported using temperature or food thermometer for determining the correct DOD when cooking beef. Consumers that answered to using a food thermometer were then prompted to state the temperature they utilize, being either pull off the heat temperature (69%) or temperature following the post-cooking temperature rise (31%). However, 48 to 61% of consumers that stated they use a thermometer then reported they did not know the temperatures that correspond with each DOD. Additionally, only 14 to 32% of consumers that utilized peak temperatures matched the NCBA temperatures.ConclusionAlthough consumers do not have a good understanding of beef cooking temperatures, they are able to identify DOD of steaks cooked to specified endpoint temperatures. Additionally, chefs do not consistently use the same method when determining DOD and are unable to accurately identify DOD of steaks cooked to specified endpoint temperatures. This lack of uniformity between chefs and consumers on DOD determination can create challenges for foodservice establishments to successfully meet consumer DOD expectations.

Evaluation of the Changes in Composition of Pork Chops During Cooking

ObjectivesThe objective was to determine the change in extractable lipid concentration during cooking of boneless pork chops to different endpoint temperatures. Intramuscular fat (IMF) concentration of pork chops changes during the cooking process when chops are cooked to 63°C, water is lost thereby concentrating extractable lipid. When chops are cooked to 71°C, water is lost, but it was hypothesized that lipid is lost as well. This would result in less variability in IMF of cooked chops compared with raw chops. This reduction in variability may explain the lack of sensory perception differences between chops with substantial marbling and chops with little marbling. This is important because consumers use marbling to make purchasing decisions. The hypothesis was that the range in IMF would be lessened after cooking due to moisture loss and potentially lipid loss at higher cooking temperatures. Ultimately, the variation in IMF in cooked pork chops would be less than that of fresh pork chops.Materials and MethodsPork loins (152 total) were used by cutting 3 consecutive chops from each loin. Chop 1 was evaluated raw (not cooked), chop 2 was cooked to 63°C, and chop 3 was cooked to 71°C before evaluation for IMF. These chops were divided into 3 separate bins based on raw IMF percentages. The low group consisted of chops with an IMF percentage equal to or less than 3%, the average group consisted of IMF percentages between 3 and 4% and the high IMF group consisted of chops with an IMF greater than 4%. Moisture and IMF were determined using duplicate 10-g samples from each chop. Samples were dried and IMF was determined with the chloroform-methanol solvent method. Cook loss was calculated by weighing chops before and after cooking. Warner-Bratzler Shear Force (WBSF) was determined by shearing 5 cores from each chop. Data were analyzed using a one-way ANOVA with the fixed effect of IMF level. Means were separated using a probability of difference statement and considered significantly different at P &lt; 0.05.ResultsRaw high IMF chops (4.94%) had greater (P &lt; 0.0001) IMF than average IMF chops (3.51%). Raw average IMF chops (3.51%) had greater (P &lt; 0.0001) IMF than low IMF chops (2.47%). High IMF chops cooked to 63°C (5.59%) had greater (P &lt; 0.0001) IMF than average IMF chops cooked to 63°C (4.17%). Average IMF chops cooked to 63°C (4.17%) had greater (P &lt; 0.0001) IMF than low IMF chops cooked to 63°C (3.39%). High IMF chops cooked to 71°C (6.12%) had greater (P &lt; 0.0001) IMF than average IMF chops cooked to 71°C (4.55%). Average IMF chops cooked to 71°C (4.55%) had greater (P &lt; 0.0001) IMF than low IMF chops cooked to 71°C (3.88%). Additionally, WBSF was not different (P ≥ 0.32) among high, average or low groups when cooked to 63°C or 71°C. Cook loss was not different (P ≥ 0.31) among high, average, or low groups when cooked to 63°C or 71°C. However, WBSF (2.77 kg) and cook loss (18.70%) was less in chops cooked to 63°C than when cooked to 71°C (3.10 kg, 23.37%).ConclusionThe hypothesis was that the range and variability in IMF would be lessened after cooking due to moisture loss and potentially lipid loss at higher cooking temperatures. This was not the case and the differences in IMF percentages persisted even after cooking. Furthermore, WBSF and cook loss did not differ among chops categorized as high, average, and low IMF categories. Ultimately, IMF percentage of raw or cooked chops did not affect tenderness.

Post-Exsanguination Vascular Rinsing of Market Hogs and Cull Dairy Cows on Meat Quality

ObjectivesThe objectives from two separate studies were to determine the meat quality effects of Rinse &amp; Chill® (RC) on market hogs slaughtered under less than ideal harvest conditions (heat stress, warm harvest area, limited cooler air movement) and the impact of RC on commercially harvested cull dairy cows having different body condition scores (BCS).Materials and MethodsImmediately after bleeding, market hogs were conventionally chilled (C, n = 12) or RC processed (RC, n = 13; MPSC Inc.) at the University of Wisconsin harvest facility. RC carcasses were vascularly rinsed (10% of live weight) with an isotonic chilled solution (3°C; 98.5% water; balance: glucose, polyphosphates, maltose). Carcasses were scalded rather than skinned. Carcass temperature (0–24h), carcass cooler shrink, and pH (0.5, 1, 2, 4, 6, 24h) were recorded. At 24 h postmortem (PM), muscles (picnic shoulder, PS;M. Longissimus et lumborum, LL)were further processed (PS: chops, ground pork; LL: chops, ground pork), packaged (polyvinyl chloride, PVC; vacuum, VAC) and displayed continuously (3°C, 1615 lux; 1, 4, 7d PM). Color measurements (CIE L*a*b*, chemical states of myoglobin) along with pH, moisture fat free (MFF), water holding capacity (WHC), oxygen consumption, total pigment, TBARS and hexanal content were determined. Warner-Bratzler shear force on chops aged 4d PM (2°C) were cooked (71°C, endpoint temperature) according to AMSA guidelines.Carcasses from cull dairy cows with two different BCS (Lean, LE; Light, LI) were conventionally chilled (n = 10 each BCS) or RC processed (n = 12 each BCS). Muscles (M. Longissimus et lumborum, LL; M. Triceps brachii, TB) were ground (19mm, 3mm plates), packaged (PVC, VAC) and displayed or stored in the dark. Color, chemical states of myoglobin, pH, temperature, fat content and total pigments were determined. Data were analyzed using PROC MIXED procedures (SAS Institute).ResultsRC resulted in a lower (P &lt; 0.05) pH during the first 4h compared to C.RC ground picnic shoulder was redder (CIE a*), lighter (CIE L*), had greater deoxymyoglobin and less metmyoglobin compared to C (P &lt; 0.05). However, the RC ground loin had less (P &lt; 0.05) oxymyoglobin than C. RC chops (LL) were lighter (CIE L*) and had less deoxymyoglobin compared to C (P &lt; 0.05). RC ground pork had greater (P &lt; 0.05) oxygen consumption. RC pork had lower (P &lt; 0.05) TBARS and hexanal values compared to C. RC did not (P &gt; 0.05) affect cooler shrink, moisture content when assessed on an MFF basis, WHC, purge, cook loss, total pigment and WBS force.RC resulted in a lower (P &lt; 0.05) pH at each time PM than C. C (LE) had a lower pH than C (LI), however pH was not affected by BCS for RC. Generally, RC resulted in lower temperatures during chilling (24h). In LE and LIcows, RC produced greater redness (CIE a*, P &lt; 0.05) associated with blooming and display times. RC LE beef resulted in greater (P &lt; 0.05) oxymyoglobin during all display times, however, RC LI had higher (P &lt; 0.05) deoxymyoglobin on 7d. No differences were found in total pigments.ConclusionFor pork packing facilities that harvest during heat stress times and have less than ideal carcass cooler conditions, RC has the potential to improve color in certain cuts and reduce lipid oxidation. RC on lower quality BCS cull dairy cows has the opportunity to improve color and potentially decrease the incidence of dark cutting beef.

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.

Do Published Cooking Temperatures Correspond with Consumer and Chef Perceptions of Steak Degrees of Doneness?

The objective of this study was to assess consumer and chef perceptions and knowledge of beef degrees of doneness (DOD) as well as to measure the changes in cooked color over time related to DOD. Steaks from strip loins (M. longissimus lumborum) from each of 5 quality treatments were used for this study. Steaks were cooked to an endpoint temperature of either very-rare (54°C), rare (60°C), medium-rare (63°C), medium (71°C), well-done (77°C), or very well-done (82°C). L*, a*, and b* were evaluated at 0, 1, 2, 3, 6, 9, and 12 min post-cutting and digital pictures were taken immediately on an internal surface of the steak. Digital surveys for the evaluation of the images of the cooked steaks were created for consumers and chefs. There were time × DOD interactions (P &lt; 0.05) for L*, a*, and b* values. For very-rare, rare, medium-rare, and medium, a* values increased (P &lt; 0.05) over time. For L*, well-done and very well-done steaks became darker (P &lt; 0.05) and very-rare, rare, and medium-rare steaks became lighter (P &lt; 0.05) over time. Surveys indicated consumers determine DOD when cooking beef in their home primarily by using color, whereas chefs primarily use touch to determine DOD. There were no quality grade effects (P &gt; 0.05) for DOD responses for steak pictures evaluated by consumers or chefs. Consumers identified the DOD of cooked steaks as the DOD that corresponds to published end-point temperatures 27 to 35% of the time. Chefs typically identified the DOD as 1 DOD higher than which the steaks were cooked for steaks cooked to medium or less and 1 DOD lower for steaks cooked to well-done and higher. This indicates differences exist in the perceptions of DOD between culinary professionals and consumers, and may contribute to decreased consumer satisfaction when ordering steaks in a restaurant.

Detection of Differences in Cook Loss and Tenderness of Aged Pork Chops Cooked to Differing Degrees of Doneness Using Sous-Vide

ObjectivesThe objective was to determine the ability to detect differences in cook loss and Warner-Bratzler shear force (WBSF) value between chops aged for differing time periods and cooked to varying degrees of doneness in a sous-vide style cooker.Materials and MethodsLoins (n = 68) from pigs humanely slaughtered at the University of Illinois Meat Science Laboratory were separated between the 10th and 11th rib into anterior and posterior sections. The posterior section was cut into 6 separate 2.54 cm thick chops. The middle 4 chops were randomly designated for aging of 3 d and cooked to 63°C, aged 7 d and cooked to 63°C, aged 14 d and cooked to 63°C, or aged 14 d and cooked to 71°C. Chops (n = 272) were cooked by placing them in a water bath with an immersion circulator set to the desired end-point temperature for 90 min. Cook loss was calculated for each chop by measuring initial and final weight, and accounting for packaging weight. Four cores measuring 1.25 cm in diameter were cut parallel to the muscle fibers from each chop and analyzed for WBSF. Data were analyzed using a 1-way ANOVA. Least squares means were separated using the probability of difference (PDIFF) option in the MIXED procedure of SAS.ResultsCook loss increased as aging period or degree of doneness increased. Among chops cooked to 63°C, chops aged 3 d had 1.14% units less (P &lt; 0.01) cook loss than those aged 7 d, and chops aged 7 d had 1.13% units less (P &lt; 0.01) cook loss than those aged 14 d. Among chops aged for 14 d, chops cooked to 71°C had 10.06% units greater (P &lt; 0.001) cook loss than chops cooked to 63°C. Differences in tenderness were also detected between aging periods. Among chops cooked to 63°C, chops aged 3 d required 0.27 kg more (P = 0.02) force to shear than those aged 7 d, but chops aged 7 d did not differ (P = 0.15) from those aged 14 d. End-point cooking temperature had a greater effect on tenderness, with chops aged 14 d and cooked to 71°C requiring 0.83 (P &lt; 0.001) kg more force than those aged 14 d and cooked to 63°C. Previous studies have reported a decrease in Warner-Bratzler shear force between 7.10–21.29% when comparing early (1–3 d) and mid (7 or 9 d) aging and decreased between 3.53–15.38% when comparing mid and late (14–21 d) aging. In the present study, Warner-Bratzler shear force decreased 9.00% from early-to-mid aging and 5.86% from mid-to-late aging.ConclusionOverall, these data indicate sous-vide is an acceptable cooking method for use in experiments as expected differences in cook loss and WBSF were detected in chops aged to differing time points or cooked to differed degrees of doneness.

Effects of temperature non‐uniformity and effective viscosity on pyrometric cone deformation

AbstractPyrometric cone deformation is used to measure heat work or the combined effect of temperature and time during ceramic firing. Finite‐element analysis shows that stationary‐state temperature non‐uniformity in a pyrometric cone during constant‐rate heating can account for differences in observed endpoint temperatures at different heating rates. Thermophysical modeling provides evidence that two‐phase viscous flow plays an important role in pyrometric cone deformation. The Einstein‐Roscoe equation is used to calculate the effective viscosity of partially molten pyrometric cones during viscous flow deformation, with the solid phase volume fraction determined through thermophysical modeling and the molten phase viscosity estimated with the Modified Quasichemical Model. A correlation was found between the endpoint deformation temperatures of pyrometric cones and corresponding Littleton softening point temperatures; however, the approach fails when viscous flow is not the principal deformation mechanism and when the initial glass fraction exceeds the equilibrium molten phase fraction predicted by thermophysical modeling.

Role of Solvent Properties in the High-Pressure Phase Behavior of (Ethylene + Comonomer + n-Hexane + LLDPE) Systems

The lower critical end point temperatures of [ethylene + comonomer + n-hexane + linear low-density polyethylene (LLDPE)] systems are shown to be strongly correlated with solvent average molecular mass and mole fraction-averaged carbon number, but not solvent density or critical temperature. A synthetic-visual method is used to measure vapor–liquid, vapor–liquid–liquid, and liquid–liquid phase boundaries for quasiquaternary (ethylene + comonomer + n-hexane + LLDPE) systems for the 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, and 1-decene comonomers, and for quasiternary (ethane/n-decane/4-methyl-1-pentene + n-hexane + LLDPE) systems. The reported data span temperatures of T = (375–465) K and pressures of P = (0.5–15) MPa. In all systems, the mass fraction of the LLDPE (Mw = 199 kg·mol–1; Mw/Mn = 2.62; 2.56 mol % 1-hexene) was kept at 3 wt % and solvent compositions were chosen to represent conditions found in the solution polymerization process. The modified Sanchez–Lacombe equation of state can pr...

Understanding Dephosphorization in Basic Oxygen Furnaces (BOFs) Using Data Driven Modeling Techniques

Owing to the continuous deterioration in the quality of iron ore and scrap, there is an increasing focus on improving the Basic Oxygen Furnace (BOF) process to utilize lower grade input materials. The present paper discusses dephosphorization in BOF steelmaking from a data science perspective, which thus enables steelmakers to produce medium and low phosphorus steel grades. In the present study, data from two steel mills (Plant I and Plant II) were collected and various statistical methods were employed to analyze the data. While most operators in steel plants use spreadsheet-based techniques and linear regression to analyze data, this paper discusses on the suitability of selecting various statistical methods, and benchmarking tests to analyze such dephosphorization data sets. The data contains a wide range of operating conditions, both low and high phosphorus input loads, different slag basicity’s, different slag chemistries, and different end point temperatures, etc. The predicted phosphorus partition from various statistical models is compared against plant data and verified against previously published research.

Predicting molten steel endpoint temperature using a feature-weighted model optimized by mutual learning cuckoo search

A feature-weighted neural network model for the prediction of the endpoint temperature of molten steel (MSET) in a ladle furnace (LF) is proposed in this paper. Accurate prediction of MSET is essential for promoting product quality, reducing production costs and enhancing productivity. Considering that different features have different impacts on the MSET during the process of LF refining, a weight is applied to each feature before feeding the feature to neural networks. A mutual learning cuckoo search (MLCS) algorithm is proposed to simultaneously determine the feature weights and network parameters of the proposed prediction model. The search of each cuckoo in the basic cuckoo search algorithm and many of its variants is performed independently, which may decrease the algorithms’ performance. The proposed MLCS algorithm introduces two new search strategies, the mutual learning-based search strategy and the bottom reinforcement learning-based search strategy. The superior performance of MLCS is first confirmed with 20 benchmark optimization problems. Then, MLCS is applied to optimize the feature weights and network parameters in the feature-weighted MSET prediction model. Application to modeling the production data from a 300 t LF in an iron & steel plant in China demonstrates the effectiveness of the proposed feature-weighted neural network model.

The associations between proteomic biomarkers and beef tenderness depend on the end-point cooking temperature, the country origin of the panelists and breed

Steaks of 74 animals from 3 young bull breeds (Aberdeen Angus, Limousin and Blond d'Aquitaine) were cooked at two end-point cooking temperatures (55 and 74 °C) and evaluated for tenderness by trained panelists from France (FR) and the United Kingdom (UK). Using principal component regressions, the tenderness scores of each breed, country origin of the panelists and cooking temperature were linked with the abundances of 21 protein biomarkers belonging to five biological pathways. Twelve regression equations were built and explained 68 to 95% of tenderness variability. A high dissimilarity in the retained biomarkers was observed among the equations and differences exist among breeds, cooking temperatures and country origin of the panelists. Among the 21 biomarkers, 6 proteins including structural (MyHC-I, MyHC-IIa, MyHC-IIx), oxidative stress (DJ-1, PRDX6) and proteolysis (CAPN1) were retained robustly in positive or negative directions in the tenderization process of Longissimus thoracis, regardless the breed, the end-point cooking temperature or the country origin of the panelist.