Predicting beef tenderness using color and multispectral image texture features

The objective of this study was to investigate the usefulness of raw meat surface characteristics (texture) in predicting cooked beef tenderness. Color and multispectral texture features, including 4 different wavelengths and 217 image texture features, were extracted from 2 laboratory-based multispectral camera imaging systems. Steaks were segregated into tough and tender classification groups based on Warner–Bratzler shear force. The texture features were submitted to STEPWISE multiple regression and support vector machine (SVM) analyses to establish prediction models for beef tenderness. A subsample (80%) of tender or tough classified steaks were used to train models which were then validated on the remaining (20%) test steaks. For color images, the SVM model correctly identified tender steaks with 100% accurately while the STEPWISE equation identified 94.9% of the tender steaks correctly. For multispectral images, the SVM model predicted 91% and STEPWISE predicted 87% average accuracy of beef tender.     

Classification of tough and tender beef by image texture analysis

Texture features of fresh-beef images were extracted and used to classify steaks into tough and tender groups in terms of cooked-beef tenderness. Crossbred steers varying in quality were processed in a commercial plant and two short loin steaks were sampled from each carcass. One sample was used for imaging and the other was broiled for sensory evaluation of tenderness by a trained panel. The samples were segregated into tough and tender groups according to the sensory scores. A wavelet-based decomposition method was used to extract texture features of fresh-beef images. The texture feature data for 90 sample images were used to train and test sample calssifiers in a rotational leave-one-out scheme. A correct classification rate of 83.3% was obtained in cross validations. While texture features alone may not be sufficient to segregate beef products into many levels of tenderness, they can be significant members in a set of indicators that will lead to adequate tenderness prediction.     

Prediction of color, texture, and sensory characteristics of beef steaks by visible and near infrared reflectance spectroscopy. A feasibility study

Color, instrumental texture, and sensory attributes of steaks from 24 beef carcasses at 2, 4, 8, 14, and 21 days post mortem were predicted by visible/near infrared (visible/NIR) reflectance spectroscopy in 400-1080 nm region. Predicting the Hunter a, b, and E* yielded the coefficient of determination (R(2)) in calibration to be 0.78-0.90, and R(2) was between 0.49 and 0.55 for tenderness, Hunter L, sensory chewiness and juiciness. The prediction R(2) for tenderness was in the range of 0.22-0.72 when the samples were segregated according to the aging days. Based on partial least square (PLS) model predicted tenderness, beef samples were classified into tender and tough classes with a correct classification of 83%. Soft independent modeling of class analogy of principal component analysis (SIMCA/PCA) model of measured tenderness showed great promise in the classification of tender and tough meats with over 96% success.     

Partial least squares analysis of near-infrared hyperspectral images for beef tenderness prediction

Tenderness is a primary determinant of consumer satisfaction of beef steaks. The objective of this study was to implement and test near-infrared (NIR) hyperspectral imaging to forecast 14-day aged, cooked beef tenderness from the hyperspectral images of fresh ribeye steaks (n = 319) acquired at 3–5 day post-mortem. A pushbroom hyperspectral imaging system (wavelength range: 900–1700 nm) with a diffuse-flood lighting system was developed. After imaging, steaks were vacuum-packaged and aged until 14 days postmortem. After aging, the samples were cooked and slice shear force (SSF) values were collected as a tenderness reference. After reflectance calibration, a Region-of-Interest (ROI) of 150 × 300 pixels at the center of longissimus muscle was selected. Partial least squares regression (PLSR) was carried out on each ROI image to reduce the dimension along the spectral axis. Gray-level textural co-occurrence matrix analysis with two quantization levels (64 and 256) was conducted on the PLSR bands to extract second-order statistical textural features. These features were then used in a canonical discriminant model to predict three beef tenderness categories, namely tender (SSF ≤ 205.80 N), intermediate (205.80 N < SSF < 254.80 N), and tough (SSF ≥ 254.80 N). The model with a quantization level of 256 performed better than the one with a quantization level of 64. This model correctly classified 242 out of 314 samples with an overall accuracy of 77.0%. Fat, protein, and water absorption bands were identified between 900 and 1700 nm. Our results show that NIR hyperspectral imaging holds promise as an instrument for forecasting beef tenderness.     

Image texture features as indicators of beef tenderness

Image processing techniques were developed to predict cooked-beef tenderness from fresh-beef image characteristics. Cattle from different finishing treatments were processed in a commercial plant. Two short loin steaks were sampled from each carcass; one used for sensory evaluation and the other for imaging. The samples varied significantly in both US quality grades and sensory tenderness scores. Color, marbling and texture features were extracted from the beef images. Statistical and neural network analyses were performed to relate the image features to sensory tenderness scores. Image texture features were found to be useful indicators of beef tenderness. Partial least squares and neural network models were able to predict beef tenderness from color, marbling and image texture features to R(2)-values up to 0.70.     

Establishing tenderness thresholds of Venezuelan beef steaks using consumer and trained sensory panels

The tenderness thresholds for ribeye steaks at 2 d postmortem were found by using sensory trained (n = 734 steaks) and consumers panel data (55 ribeye steaks and 296 consumers). Also, consumers’ perceptions of sensory attributes of beef steaks were assessed to establish their relationships and to determine acceptability levels. The tenderness threshold obtained by regression analysis from trained panelists was 37.98 N (3.87 kg). Customer satisfaction of 81% was obtained when beef steaks had Warner-Bratzler shear force values (WBSF) less than 40.13 N (4.09 kg), suggesting that 40.13 N could be considered as a tenderness threshold to segregate tough from tender steaks, for Venezuelan beef consumers. According to correlation and regression analyses, consumers focused on flavor to assign their overall liking score. Results suggest that consumers are able to detect changes in tenderness of steaks with different WBSF and that flavor drives customer satisfaction when the beef tenderness is acceptable.     

On-line classification of US Select beef carcasses for longissimus tenderness using visible and near-infrared reflectance spectroscopy

The current experiment was conducted to evaluate the on-line application of visible and near-infrared spectroscopy (VISNIR) to US Select carcasses during commercial beef carcass grading procedures to predict tenderness of longissimus steaks after 14 days of refrigerated storage. A regression model was calibrated using 146 carcasses and tested against an additional 146 carcasses. Carcasses were segregated into VISNIR-based tenderness classes based on whether their VISNIR-predicted slice shear force value was less than (tender) or greater than (tough) the median predicted slice shear force value. Carcasses classified as tender by VISNIR had a lower mean SSF value, were less likely to have slice shear force values greater than 245 N, had higher trained sensory panel tenderness ratings, and were less likely to have trained sensory panel tenderness ratings below slightly tender than were carcasses classified as tough (P<0.001). This technology might be useful for identification of US Select carcasses that excel in longissimus tenderness.     

Effects of Hot-Boning and Particle Thickness on Restructured Beef Steaks

Restructured steaks were made using hot-boned or aged beef made from sliced particles (2.5 mm or 5.0 mm thick). Beef slices were formed to make restructured steaks. The steaks were evaluated for cooking characteristics, textural properties and sensory attributes. Restructured steaks made from hot-boned beef were generally considered less tender and received lower texture desirability, flavor desirability and overall palatability ratings as compared to steaks made from aged beef. Restructured steaks made from larger meat slices (5.0 mm) were less tender and received lower texture desirability ratings than restructured steaks made with thinner slices (2.5 mm).     

INCREASING THE TENDERNESS OF BULLOCK BEEF BY USE OF ANTEMORTEM ENZYME INJECTION

Steaks from 58 beef carcasses were used to determine the effects of antemortem injections of proteolytic enzyme in increasing tenderness and/or in reducing tenderness variability among bullock carcasses. Sensory panel ratings indicated that steaks from the carcasses of treated bullocks did not differ significantly from steaks from treated steer carcasses in tenderness or overall satisfaction, but were significantly more tender and satisfactory overall than steaks from untreated bullocks. Variation in tenderness scores within the group of steaks from treated bullocks was reduced to a level more nearly comparable to that of steaks from treated steers. Since antemortem injections of papain increased tenderness and reduced the variability in tenderness among steaks from bullock carcasses, such treatment could be used to more effectively merchandise beef from young bulls.     

Reducing Postmortem Aging Time of Beef with Electrical Stimulation

Two studies (Study 1 = 23 forage-fed steers; Study 2 = 20 grain-fed steers and heifers) were conducted to determine relationships of electrical stimulation (ES) and/or postmortem aging (PA) to tenderness of beef. For Study 1, steaks from ES sides had lower (P < 0.05) Warner-Bratzler shear (WBS) values than steaks from not-ES sides for each PA period. In addition, the percentage reduction in WBS values was greater for the steaks from the ES-Day 2 group (–29.5%) than for steaks from even the longest PA period (14 days) from the not-ES group (–25.8%). For Study 2, during the fist three PA periods (1, 2 and 5 days), ES resulted in more desirable (P < 0.05) flavor ratings (Day l), higher (P < 0.05) tenderness ratings and lower (P < 0.05) WBS values (Day 1, 2, 5) and more desirable (P < 0.05) overall palatability ratings (Day 1, 2). During the last three PA periods (8, 11 and 14 days), ES resulted in higher (P < 0.05) tenderness ratings (Day 8), lower (P < 0.05) juiciness ratings (Day 11, 14) and lower (P < 0.05) WBS values (Day 8). Based on these results, ES had the greatest impact on beef palatability if the period of aging was 8 days or less; with additional aging time, ES effects on palatability were negated. When each treatment (ES, not-ES) was divided into two groups based on median tenderness ratings for the not-ES group, ES had the greatest impact on those carcasses in the “tough” group while ES had little impact on those carcasses in the “tender” group. ES will accelerate the postmortem aging of beef but the aging time reduction and extent of ultimate tenderization appears to be affected by the inherent tenderness of the beef.     

Effects of cooking beef muscles from frozen or thawed states on cooking traits and palatability

Biceps femoris and longissimus lumborum steaks were cooked from either a frozen or thawed state on an electric belt grill (TBG-60 MagiKitch'n Inc., Quakertown, PA) at 93?°C to the endpoint temperature of 70?°C. Cooking loss, cooking time, Warner-Bratzler shear force (WBSF), and color (Illuminant A, L(?), a(?), b(?)) were evaluated. Trained panelists (n=6) evaluated palatability attributes on an eight-point scale for myofibrillar tenderness, juiciness, flavor, overall tenderness, and connective tissue amount (1=extremely tough, dry, bland, tough, and abundant; 8=extremely tender, juicy, intense, tender, and none). L(?), a(?), WBSF, juiciness, flavor, connective tissue amount, and overall tenderness did not differ (P>0.05) between steaks cooked from frozen and thawed states. However, thawed steaks cooked faster and had lower cooking losses than frozen steaks. The biceps femoris had higher WBSF values than the longissimus lumborum and was rated less tender by trained panelists. L(?), a(?), or b(?) values did not differ (P>0.05) between muscles. The biceps femoris needed more time to cook and had greater cooking losses than longissimus lumborum. Dimensional changes of steaks cooked to either 60 or 70?°C were studied. The width of biceps femoris steaks decreased 12.2%, and width of longissimus lumborum decreased 6.3%. Longissimus lumborum steaks became shorter (P<0.01) than biceps femoris steaks. Thickness of biceps femoris steaks decreased 25.6%, and thickness of longissimus lumborum steaks decreased 23.3%. Muscle type had a more pronounced effect on dimensional changes of steaks than endpoint temperature.     

THE MEASUREMENT OF SHEAR FORCE BY CORE LOCATION IN LONGISSIMUS DORSI BEEF STEAKS FROM FOUR TENDERNESS GROUPS1

Sixty-four longissimus muscle steaks obtained from carcasses of Bos indicus or Bos taurus cattle were used to evaluate shear force requirements from the dorsal to lateral portion of the steak. Steaks were assigned to one of four tenderness groups based on preliminary analysis of shear force requirements of adjacent steaks used in the study. Six dorsal to lateral core positions were incorporated into the test procedures. Shear force requirements of cores of steaks in very tender and tender groups tended (P>0.05) to decrease from the dorsal to lateral position. The increase in shear values from dorsal to lateral was dramatic (P<0.01) in the tough and very tough groups. It appears that overall shear value influences the variation in shear values within the muscle. Location effects of tenderness within the longissimus muscle could be useful in future studies of the physical/biochemical effectors of tenderness.     

Evaluation of the Tenderness of Beef Top Sirloin Steaks

Top sirloin butts and strip loins were obtained from both sides of 20 U.S. Choice beef carcasses and cut into six steaks (2.54 cm thick). These steaks were assigned randomly to one of six aging treatments (0, 7, 14, 21, 28 or 35 days). Top sirloin steaks were less tender and more variable in tenderness than top loin steaks. This difference in tenderness appeared to be due to higher amounts of collagen in top sirloin steaks and a tendency toward lower collagen solubility, shorter sarcomere length and higher (less tender) fragmentation index.     

The Paradox of Toughening During the Aging of Tender Steaks

ABSTRACT:  Aging is the practice of holding meat at low temperatures to improve tenderness that is the most important sensory attribute affecting consumer acceptability of beef. Because of the inconsistencies in measured tenderness changes during aging, we attempted to look at the relationship between aging and initial tenderness irrespective of animal age, genetics, or nutritional status. Cattle were selected to represent a full range of quality grades from Utility to Prime. Steaks from these cattle were aged in vacuum bags for 0, 7, or 14 d and tenderness characteristics were assessed. Steaks were cut from the frozen loin sections, thawed, and cooked on open hearth grills to 70 °C. Sensory evaluation was completed by a 6-member trained sensory evaluation panel and Warner-Bratzler shear was determined. The average shear values decreased with aging time across most grade categories; however, improvement was not uniform. Steaks from Utility grade cattle improved the most while steaks of other grades improved less. Shear values overlapped a great deal across all grades and to gain a better understanding of changes with aging, steaks were grouped based on initial shear value differences of 1 kg. Shear value of the toughest steaks decreased the most during aging (−36%), while those with the lowest shear values increased (16%). The same pattern emerged when steaks were grouped by initial tenderness. These results suggest that initially tough steaks will benefit from aging while very tender steaks may be adversely affected.     

IDENTIFICATION OF THRESHOLD LEVELS FOR WARNER-BRATZLER SHEAR FORCE IN BEEF TOP LOIN STEAKS

Threshold Warner-Bratzler shear (WBS) values were determined by regression analysis of WBS force values and trained sensory panel overall tenderness ratings of beef top loin steaks from A- and B-maturity carcasses (n = 678). Guidelines for retail and foodservice beef were based on 50 and 68% confidence levels, respectively, for overall tenderness ratings of "slightly tender." Due to the extreme variation in tenderness that exists in the current U.S. beef population, more stringent confidence levels were not practical. Threshold WBS values for retail and foodservice beef were 4.6 and 3.9 kg, respectively. When these values were tested against the population of beef in the National Consumer Retail Beef Study, the 4.6 kg value was 88.6% accurate at determining whether or not a steak would be rated less than "slightly tender"by consumers.     

Optical scattering with hyperspectral imaging to classify longissimus dorsi muscle based on beef tenderness using multivariate modeling

The objective of this study was to develop a non-destructive method for classifying cooked-beef tenderness using hyperspectral imaging of optical scattering on fresh beef muscle tissue. A hyperspectral imaging system (λ = 922–1739 nm) was used to collect hyperspectral scattering images of the longissimus dorsi muscle (n = 472). A modified Lorentzian function was used to fit optical scattering profiles at each wavelength. After removing highly correlated parameters extracted from the Lorentzian function, principal component analysis was performed. Four principal component scores were used in a linear discriminant model to classify beef tenderness. In a validation data set (n = 118 samples), the model was able to successfully classify tough and tender samples with 83.3% and 75.0% accuracies, respectively. Presence of fat flecks did not have a significant effect on beef tenderness classification accuracy. The results demonstrate that hyperspectral imaging of optical scattering is a viable technology for beef tenderness classification.     

CONSUMER EVALUATION OF THE PALATABILITY OF USDA SELECT,USDA CHOICE AND CERTIFIED ANGUS BEEF STRIP LOIN STEAKS FROM RETAIL MARKETS IN LUBBOCK,TEXAS, U.S.A.

ABSTRACT

Select, Choice and Certified Angus Beef (CAB) strip loin steaks were sold in Lubbock, TX to determine consumer acceptability. A home survey was attached to each package of steaks (return = 191 steak evaluations). Consumers did not detect differences in tenderness or flavor, but rated CAB steaks juicier (P < 0.05) than Select or Choice. However, 68% of CAB consumers rated steaks as extremely or very tender, but less than half rated Choice and Select steaks the same way. Consumer tenderness and flavor scores for Select steaks were more variable, but consumer satisfaction and tenderness acceptability did not differ (P > 0.05) between grades. Trained sensory panelists rated CAB steaks higher (P < 0.05) than Choice or Select for all palatability traits except flavor intensity. Shear force decreased (P < 0.05) by quality grade as CAB steaks sheared with the least resistance. These results showed marbling influenced objective palatability measures and decreased the variation in both objective and consumer measures of palatability.

PRACTICAL APPLICATIONS

Quality grades were established to predict beef palatability, but marbling can be an unreliable predictor of tenderness. Branded beef programs, such as Certified Angus Beef (CAB), have been developed to distinguish higher palatability products and provide more consistent products for consumers. Consumers can distinguish between levels beef tenderness and are willing to pay a premium for tender beef. Moreover, consumers find product consistency is moderately important when purchasing fresh beef. Therefore, the purpose of this study was to determine consumer acceptability based on in‐home evaluations of strip loin steaks from United States Department of Agriculture Select and Choice grades and CAB purchased from a retail supermarket environment.

     

Effect of Muscle Type and Mixing Time on Sectioned and Formed Beef Steaks

Sectioned and formed beef steaks were manufactured from Standard beef rounds, Choice beef plates and Choice, Yield Grade 3, Meat Buyers Guide (126) 3-piece chucks. Replicates were established by slaughter day. A trained sensory panel evaluated juiciness, flavor, tenderness, and connective tissue residue. Color scores were assigned to steaks from each treatment. Instron Kramer shear was used to evaluate tenderness and thiobarbituric acid (TBA) was used to measure rancidity. Reflectance spectrophotometry indicated oxymyoglobin and metmyoglobin content. Mixing improved tenderness (P < 0.01) by 20% after 18 min. An 8% improvement occurred after 6 min. Mixing increased sensory juiciness (P < 0.01) and flavor (P < 0.05). Subjective and objective measures indicated that steaks processed from chuck were less tender (P < 0.01). Cooking yields improved linearly (P < 0.01) due to mixing. The TBA values were low and did not change due to treatment or after 90 days storage at –30°C. Subjective and objective color analyses indicated highly desirable color for fresh beef. Steaks processed from chuck meat were higher in percent metmyoglobin.     

Consumer Acceptability of Beef Steak Tenderness in the Home and Restaurant

Acceptability of beef steak tenderness in home and restaurant environments was evaluated by 62 consumers. Steaks (loin, ribeye, or bottom and top round) were consumed by each panelist in their home and in a fine dining restaurant. Each consumer rated steaks for tenderness and overall acceptability in the home (over a 2-mo period) and one steak per week (over a 7-wk period) in the restaurant. Acceptability for steaks consumed at home and in the restaurant ranked between 3 (moderately tough) and 4 (slightly tough) on an 8-point scale. The Warner-Bratzler Shear force transition level for beef tenderness acceptability in the home was between 4.6 and 5.0 kg and in the restaurant between 4.3 and 5.2 kg. The unacceptable level of beef steak tenderness was ≤4.3 kg. Results suggested that consumers were more critical of beef tenderness in the home than in restaurants. Consumer responses may have been influenced by receiving free meals in the home or restaurant, as well as by the dining environment.     

Non-destructive assessment of instrumental and sensory tenderness of lamb meat using NIR hyperspectral imaging

The purpose of this study was to develop and test a hyperspectral imaging system (900–1700 nm) to predict instrumental and sensory tenderness of lamb meat. Warner–Bratzler shear force (WBSF) values and sensory scores by trained panellists were collected as the indicator of instrumental and sensory tenderness, respectively. Partial least squares regression models were developed for predicting instrumental and sensory tenderness with reasonable accuracy (R_cv = 0.84 for WBSF and 0.69 for sensory tenderness). Overall, the results confirmed that the spectral data could become an interesting screening tool to quickly categorise lamb steaks in good (i.e. tender) and bad (i.e. tough) based on WBSF values and sensory scores with overall accuracy of about 94.51% and 91%, respectively. Successive projections algorithm (SPA) was used to select the most important wavelengths for WBSF prediction. Additionally, textural features from Gray Level Co-occurrence Matrix (GLCM) were extracted to determine the correlation between textural features and WBSF values.