Prediction of beef palatability from colour,marbling and surface texture features of longissimus dorsi

The palatability of beef has been investigated with digital imaging systems on numerous previous occasions. In the current study, a novel approach was applied using high magnification imaging to develop surface texture features and an alternative colour space greyscale to express muscle surface texture. An automatic segmentation method was applied to develop colour and marbling features and best regression model subsets were selected automatically with genetic algorithms. Results indicated that accurate modelling of beef acceptability with regression models was possible with r² up to 0.95. Modelling of acceptability using high magnification images proved more successful than modelling with low magnification images. Linear models performed well compared to non-linear models. Other sensory measurements particularly TPA hardness were more difficult to model, although an accurate model of juiciness was developed. Addition of non-linear terms did not give large improvements except for juiciness.     

Prediction of beef eating quality from colour, marbling and wavelet texture features

Beef longissimus dorsi colour, marbling fat and surface texture are long established properties that are used in some countries by expert graders to classify beef carcasses, with subjective and inconsistent decision. As a computer vision system can deliver objective and consistent decisions rapidly and is capable of handling a greater variety of image features, attempts have been made to develop computerised predictions of eating quality based on these and other properties but have failed to adequately model the variation in eating quality. Therefore, in this study, examination of the ribeye at high magnification and consideration of a broad range of colour and marbling fat features was used to attempt to provide better information on beef eating quality. Wavelets were used to describe the image texture of the beef surface at high magnification rather than classical methods such as run lengths, difference histograms and co-occurrence matrices. Sensory panel and Instron analyses were performed on duplicate steaks to measure the quality of the beef. Using the classical statistical method of partial least squares regression (PLSR) it was possible to model a very high proportion of the variation in eating quality (r² = 0.88 for sensory overall acceptability and r² = 0.85 for 7-day WBS). Addition of non-linear texture terms to the models gave some improvements.     

Comparison of various wavelet texture features to predict beef palatability

The wavelet transform can be used to characterise the surface texture of beef images in a more efficient manner than classical algorithms such as co-occurrence and run lengths. Features extracted from wavelet decompositions have been used to develop predictive models of important palatability attributes. A variety of common wavelet transforms were considered (biorthogonal, reverse biorthogonal, discrete Meyer, Daubechie, symmetric modified Daubechie and Coifman modified Daubechie) to search for the most useful texture features. A classic run length and co-occurrence algorithm was used for comparison. Using the same data analysis methods for each wavelet type, predictive models of beef acceptability, tenderness, juiciness, flavour and hardness were developed. Genetic algorithms succeeded in finding more accurate models than stepwise and manual elimination except for hardness. An accurate model of flavour (r² = 0.84) was computed. A good model of overall acceptability (r² = 0.79) was computed that fell just short of an important benchmark of accuracy. An encouraging model of juiciness (r² = 0.71) was computed showing that with additional palatability information juiciness might be accurately modelled. Tenderness proved difficult to model with only the classic model satisfying stability criteria and a poorer result (r² = 0.64) meaning substantial additional palatability information is required for accurate modelling. Hardness was particularly difficult to model. The biorthogonal wavelet produced the best model for three palatability measurements but the symmetric modified Daubechie wavelet produced the best model of overall acceptability and thus must be viewed as the most useful wavelet type.     

Relationship between beef consumer tenderness perception and Warner-Bratzler shear force

The aim of this study was to determine consumer ability to discern different levels of beef tenderness established by Warner-Bratzler shear (WBs). A panel of 220 people evaluated 60 samples of longissimus thoracis using a 5-point intensity scale (1: very tough; 5: very tender). Samples differed for commercial category, breed of animals and ageing length of meat. Shear force was measured by Instron equipped with a Warner-Bratzler device on 1.27cm diameter cores. Correlation coefficient of WBs measurements with tenderness sensory ratings was -0.72. WBs value corresponding to class 3 of the sensory tenderness was 47.77N. From this value, the range of WBs (22.96-72.59N) was split into five categories to which connect the five classes of sensory tenderness. The results suggest consumers' difficulty in discriminating category 1 (WBs>62.59N) from category 2 (WBs: 52.78-62.59N) and a greater inclination to distinguish category 5 (WBs<32.96N). As WBs category boundaries were probably too restrictive for the panel's selective ability, WBs scale was reduced to 3 categories by joining the two extreme categories (i.e. category 2 with 1 and category 4 with 5). In this case, 55.6% of consumers significantly discriminated tough from intermediate and tender meat and 62.3% distinguished tender from intermediate and tough meat (P<0.01). Hence, WBs values >52.68N and <42.87N allow classification of tough and tender beef in a sufficiently reliable way.     

The effect of dietary poultry litter supplementation on beef chemical, cooking, and palatability properties and consumer acceptance

Twenty Holstein steers were randomly and equally allocated to two groups (treatment and control) at a mean weight of 334.3 kg and were backgrounded for 133 days and fed a finishing diet for 99 days under commercial conditions. Control animals received 97.1% corn silage, 2.6% canola meal, and 0.3% mineral mix during backgrounding and 72.6% corn silage, 3.9% canola meat, 23% barley and 0.2% mineral mix during finishing. Treated animals received 95.3% corn silage, 4.4% poultry litter, and 0.3% mineral mix during backgrounding and 62.1% corn silage, 5.6% poultry litter, 22% barley, and 0.2% mineral mix during finishing. The poultry litter was provided as a pelleted. At the end of the finishing period, all animals were harvested. After 144 h at 2 °C, the boneless longissimus thoracis et lumborum muscles were removed, cut into steaks (1.9 cm thick) and roasts, vacuum packaged, and frozen. A steak adjacent to the 13th thoracis vertebra of alternate carcass sides was displayed under simulated retail conditions for 4 days and then analyzed for moisture and fat content. A steak immediately posterior to the 13th thoracis vertebra of alternate carcass sides was evaluated by an experienced trained six-member laboratory panel for palatability attributes. The steak immediately posterior to the steak used for sensory evaluation was used for shear force evaluation. A roast constituting the reminder of the longissimus lumborum muscle was used to obtain complete flavour and texture profiles. Total cooking losses were determined and cooking times were recorded for both steaks and roasts. All remaining steaks (1180) were distributed at random to households to determine consumer acceptance. Treated samples were essentially indistinguishable from control samples in both palatability and consumer acceptance, indicating poultry litter supplements can be utilized in feedlot rations for cattle without compromising either palatability or consumer acceptance.     

Comparison of the predictive power of beef surface wavelet texture features at high and low magnification

Beef longissimus dorsi surface texture is an indicator used in predicting beef palatability by expert graders. Computer vision systems have previously used imaging at normal view to develop surface texture features with some success. Good models of beef overall acceptability using imaging at high magnification have been recently developed. As a comparison the same surface texture features were computed from the corresponding images at normal view and used to model overall acceptability. Both sets of texture features were also combined with muscle colour and marbling features and used to model overall acceptability. Models using texture features alone were more successful at normal modality. However colour and marbling features combined much better with texture features at high modality to yield the most accurate model of overall acceptability (r² = 0.93). Accurate Partial Least Squares Regression (PLSR) models were computed at both modalities with and without inclusion of colour and marbling features. Addition of squared terms to the models failed to improve accuracy.     

Automatic segmentation of beef longissimus dorsi muscle and marbling by an adaptable algorithm

An algorithm for automatic segmentation of beef longissimus dorsi (LD) muscle and marbling has been developed. The algorithm used simple thresholding to remove the background and then used clustering and thresholding with contrast enhancement via a customised greyscale to remove marbling. It was possible to attain lean muscle free of obvious marbling or background pixels where specular reflection could be effectively mitigated. Features of the automatically derived LD muscle and marbling images were compared to corresponding features of LD muscle and marbling images derived with a segmentation method requiring manual completion. Very strong correlations (up to r = 1) were found between the colour features of both sets of LD muscle images. Strong correlations (up to r = 0.96) were found between the features of both sets of marbling images. The automatic segmentation method has shown its good ability to approximate colour and marbling features. The algorithm has adaptable parameters and can be retailored to suit different image acquisition environments.     

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.     

Tenderization and fragmentation of myofibrillar proteins in bovine longissimus dorsi muscle using proteolytic extract from Sarcodon aspratus

The objective of this study was to examine the Sarcodon aspratus extract including protease how to affect tenderness of the bovine longissimus dorsi muscle. In addition, we investigated myofibrillar protein fragmentation, particularly in myosin, and its influence on meat tenderness. Beef loin chunks were marinated with 0.5 g/100 g, 1 g/100 g, and 2 g/100 g powdered S. aspratus extract, 0.2 g/100 mL papain, and distilled water (control), respectively. Although tenderness of meat is increased by adding S. aspratus extract, differences in meat quality traits, such as muscle pH and meat color, were small and not considered to have practical importance between the control and enzyme-treated samples. Furthermore, the S. aspratus extract influenced the myofibril fragmentation index (MFI) as well as protein solubility. The changes in MFI and protein solubility were due to the myofibrillar protein degradation. Through Western blotting, we found that the S. aspratus extract, as well as papain, caused fragmentation of the myosin heavy chain, but the mushroom extract induced more fragmentations of myofibrillar proteins, and caused more tender meat.     

Differences in phosphorylation of phosphoglucomutase 1 in beef steaks from the longissimus dorsi with high or low star probe values

The objective of this study was to use proteomics to identify alterations of proteins that are related to tenderness. The longissimus dorsi (LD) were removed from ten beef carcasses at 24 h postmortem, and the two with the highest (HSP; average kg of force = 6.57) and lowest star probe values (LSP; average kg of force = 3.75) at 14 days postmortem were identified. Two-dimensional PAGE was used to compare the sarcoplasmic fraction of the LD from HSP and LSP steaks. A series of spots identified as phosphoglucomutase 1 (PGM1) were identified. Only the most alkaline isoform was identified as being unphosphorylated. The least phosphorylated isoform (isoform 5) had a greater density of the total protein (P < 0.05) and phosphorylated protein (P < 0.05) in the samples from HSP steaks compared to the samples from LSP steaks. This study illustrates the importance of identifying posttranslational modifications of proteins in the search for biomarkers.     

Assessment of meat quality properties and development of a palatability prediction model for Korean Hanwoo steer beef

Effects of the Korean carcass-grading system on carcass traits and meat quality parameters for the longissimus dorsi (LD) and semimembranosus (SM) muscles were investigated for Hanwoo steer beef. High quality grade beef cuts had significantly higher intramuscular fat content than those of low quality grade beef cuts. To establish a guaranteed system of eating quality for Hanwoo steer beef, a palatability prediction model was developed. The model development approach used canonical discriminant analysis and multivariate regression to assess effects of muscle type, cooking method, and aging treatment on Hanwoo beef quality grade. The palatability prediction model can provide Korean consumers with detailed information about expected eating quality for an individual cut, as well as provide critical information to the industry for maintaining high-quality beef production. The model is a significant advance in grading compared with the traditional carcass grading system, which applies a single quality grade to an entire carcass.     

Prediction of beef eating quality from colour,marbling and wavelet texture features

Beef longissimus dorsi colour, marbling fat and surface texture are long established properties that are used in some countries by expert graders to classify beef carcasses, with subjective and inconsistent decision. As a computer vision system can deliver objective and consistent decisions rapidly and is capable of handling a greater variety of image features, attempts have been made to develop computerised predictions of eating quality based on these and other properties but have failed to adequately model the variation in eating quality. Therefore, in this study, examination of the ribeye at high magnification and consideration of a broad range of colour and marbling fat features was used to attempt to provide better information on beef eating quality. Wavelets were used to describe the image texture of the beef surface at high magnification rather than classical methods such as run lengths, difference histograms and co-occurrence matrices. Sensory panel and Instron analyses were performed on duplicate steaks to measure the quality of the beef. Using the classical statistical method of partial least squares regression (PLSR) it was possible to model a very high proportion of the variation in eating quality (r² = 0.88 for sensory overall acceptability and r² = 0.85 for 7-day WBS). Addition of non-linear texture terms to the models gave some improvements.     

Consumer assessment of beef palatability from four beef muscles from USDA Choice and Select graded carcasses

Consumer sensory analysis was conducted to determine differences in beef palatability between two quality grade categories [Upper 2/3 (Top) Choice and Select] and four muscles [longissimus lumborum (LL), gluteus medius (GM), serratus ventralis (SV), and semimembranosus (SM)]. Generally, tenderness, flavor, and overall liking scores were more desirable for Top Choice compared to Select, regardless of muscle. Consumers rated LL as more tender (P < 0.05) than SV and SM, but similar to GM (P = 0.52). Overall and flavor acceptability were similar (P > 0.05) between LL, GM, and SV, regardless of quality grade. Consumer overall liking was most highly correlated with flavor liking (r = 0.85). When tenderness was acceptable, flavor and juiciness played a major role in determining overall acceptability. Overall liking of GM and SV from Top Choice carcasses was superior to LL from Select carcasses and comparable to LL from Top Choice carcasses.     

Physical and sensory characterization and consumer preference of corn and barley-fed beef

Steaks from corn-fed and barley-fed beef were characterized by a trained panel, which rated corn-fed beef higher (p<0.05) for tenderness attributes and overall flavor intensity. Canadian consumers preferred (p<0.01) cooked and raw steaks from barley-fed beef, while Mexican consumers showed no preference (p>0.05) for either type of finished beef. Japanese consumers showed a preference (p<0.05) for the appearance of raw barley-fed steaks but a preference for cooked corn-fed steaks (p<0.05). No differences (p>0.05) were observed for Warner-Bratzler shear, marbling scores, cooking losses or Hunter colorimeter values. There was a trend for higher concentrations (p<0.08) of the saturated fatty acids in the barley treatment, but no differences (p>0.10) in mono or polyunsaturated fatty acids.     

Classification of pre-sliced pork and Turkey ham qualities based on image colour and textural features and their relationships with consumer responses

Images of three qualities of pre-sliced pork and Turkey hams were evaluated for colour and textural features to characterize and classify them, and to model the ham appearance grading and preference responses of a group of consumers. A total of 26 colour features and 40 textural features were extracted for analysis. Using Mahalanobis distance and feature inter-correlation analyses, two best colour [mean of S (saturation in HSV colour space), std. deviation of b∗, which indicates blue to yellow in L∗a∗b∗ colour space] and three textural features [entropy of b∗, contrast of H (hue of HSV colour space), entropy of R (red of RGB colour space)] for pork, and three colour (mean of R, mean of H, std. deviation of a∗, which indicates green to red in L∗a∗b∗ colour space) and two textural features [contrast of B, contrast of L∗ (luminance or lightness in L∗a∗b∗ colour space)] for Turkey hams were selected as features with the highest discriminant power. High classification performances were reached for both types of hams (>99.5% for pork and >90.5% for Turkey) using the best selected features or combinations of them. In spite of the poor/fair agreement among ham consumers as determined by Kappa analysis (Kappa-value < 0.4) for sensory grading (surface colour, colour uniformity, bitonality, texture appearance and acceptability), a dichotomous logistic regression model using the best image features was able to explain the variability of consumers’ responses for all sensorial attributes with accuracies higher than 74.1% for pork hams and 83.3% for Turkey hams.     

Dry versus wet aging of beef: Retail cutting yields and consumer palatability evaluations of steaks from US Choice and US Select short loins

Paired beef short loins from US Choice (n=48) and US Select (n=48) carcasses were assigned to be dry or wet aged for 14, 21, 28 or 35d. After aging, short loins were processed to determine retail yields and processing times. Upon completion of cutting tests, steaks were served to consumers to assess palatability characteristics. Retail cutting tests showed that dry-aged short loins had reduced yields and increased cutting times when compared to wet-aged short loins. Consumers were unable to determine differences between dry- and wet-aged steaks and for aging periods; however, USDA quality grade had a significant impact on consumer perception of palatability attributes.     

Meat quality,microbiological status and consumer preference of beef gluteus medius aged in a dry ageing bag or vacuum

This study investigated meat quality and consumer preference after ageing beef gluteus medius in a water vapour-permeable dry-ageing bag or in vacuum for 14 days. Higher ageing and trim losses but lower thawing loss, cooking loss and water content were found in samples aged in dry ageing bags compared to those aged in vacuum. Samples aged in dry ageing bags had higher total bacteria and yeast counts but lower lactic acid bacteria counts than those aged in vacuum, both before and after trimming. Meat aged in dry ageing bag was more tender and juicier and overall preferred by consumers compared with samples aged in vacuum. Female participants outperformed the males in detecting differences in palatability. No differences were found in pH, smell, shear force, colour, Enterobacteriaceae, and mould counts. Thus, by using a dry ageing bag, it is possible to produce dry-aged meat in a more controlled condition without negative effects on sensory or other quality attributes.     

A comparison of needle-free and needle-injection methods and solutions for enhancement of beef longissimus lumborum muscles

In Experiment 1, beef strip loins (n = 15) were halved and assigned to needle (N) or needle-free (NF) injection enhancement with a phosphate plus salt solution (PS) to determine effects on color, water-binding, and palatability. Pump yields tended (P = 0.08) to be higher for NF injection. Needle-injected steaks were darker (P < 0.05) on day 1 only. The NF treatment had greater instrumental tenderness and intensity of off-flavors but less cooking loss and beef flavor (both P < 0.05). In Experiment 2, strip loins (n = 28) were halved and assigned to one of four treatments: (1) N, or (2) NF injection with PS; (3) N, or (4) NF injection with a calcium lactate solution (CL) to determine effects on water-binding and palatability. Needle-free injection resulted in a greater incidence (P < 0.05) of off-flavors and abnormal texture. The PS solution resulted in greater (P < 0.05) instrumental, myofibrillar, and overall tenderness; greater juiciness; greater incidence of off-flavors and abnormal texture; and less (P < 0.05) connective tissue and cooking losses than CL. The PS and NF combination had the highest pumped yields and least cooking losses (both P < 0.05). Enhancing beef strip loins with PS and NF injection has potential to improve yield, tenderness, and juiciness but harm texture and flavor.     

Influence of blade tenderization,moisture enhancement and pancreatin enzyme treatment on the processing characteristics and tenderness of beef semitendinosus muscle

The combined effect of blade tenderization (BT), moisture enhancement and enzymatic tenderization on drip loss, cook loss, Warner–Bratzler shear force (WBSF) and sensory characteristics of beef semitendinosus (ST) steaks from cattle under 30 months of age was investigated.