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.     

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.     

The effects of castration, preslaughter stress and zeranol implants on beef: Part 1-The texture of loin steaks from bovine males

A total of 144 male crossbred calves were allocated to four castration or implant treatments (unimplanted bulls; unimplanted steers; bulls implanted with zeranol at 100 days of age and reimplanted at intervals of 69, 93, and 56 days thereafter; bulls implanted with zeranol at 168 days of age and reimplanted at intervals of 93 and 56 days thereafter) and two preslaughter shipping treatments (minimum preslaughter stress with cattle shipped and slaughtered within 4 h of leaving the feedlot pen; normal preslaughter stress with cattle mixed, trucked 160 km, and slaughtered up to 24 h after leaving the feedlot pen). These cattle were slaughtered and striploins of these steaks were removed after 6 days of post-mortem aging. Evaluations of these steaks were then conducted using both an experienced laboratory taste panel and a highly trained professional texture profile panel. Results indicated that: (1) the differences that existed in palatability between steaks from unimplanted bulls and steers were primarily due to differences in textural properties directly related to tenderness; (2) increases in preslaughter stress levels were detrimental to the eating quality of both intact males and castrates; (3) zeranol implants had little effect on the textural properties of bull steaks when minimum levels of preslaughter stress were applied; (4) zeranol implants in combination with normal levels of preslaughter stress resulted in steaks which readily broke down to a wide range of particle types many of which were inappropriate and detracted from a well balanced beef texture, thereby more than offsetting the beneficial effects observed on textural properties directly related to tenderness, thus, reducing the texture amplitude; and (5) the influence of the combination of zeranol implants and normal preslaughter stress on textural properties may be manifested through the production of 'dark cutting' beef.     

Tenderizing, Ageing, and Thawing Effects on Sensory, Chemical, and Physical Properties of Beef Steaks

The effects of electrical stimulation, tender stretching, ageing, freezing and thawing on beef palatability were assessed by a trained sensory panel and by several objective methods. The overall palatability of both longissimus dorsi (strip loin) and semimembranosus (topside) steaks improved with ageing, irrespective of tenderizing method, but there appeared to be little advantage in extending ageing beyond 10 days. Tender stretched longissimus dorsi steaks were marginally preferred by the taste panel to electrically stimulated steaks subjected to the same ageing. Unfrozen steaks were preferable to frozen and thawed steaks with respect to juiciness, flavor and tenderness. Thawing method had little effect on steak palatability.     

The effects of ante-mortem feed and water withdrawal, ante-mortem electrolyte supplementation, and post-mortem electrical stimulation on the palatability and consumer acceptance of bull beef after ageing (6 days at 1°C)

A total of 120 bulls each weighing approximately 500 kg were used to evaluate the effects of withholding feed and water for various intervals pre-slaughter, ante-mortem supplementation with an electrolyte solution, and post-mortem electrical stimulation on the cooking and palatability attributes and consumer acceptance of boneless rib steaks aged for 6 days at 1°C. The results clearly showed the detrimental effects of withholding feed and water pre-slaughter and the beneficial effects of post-mortem electrical stimulation on the eating quality of bull beef aged for 6 days at 1°C. Taste panel ratings of palatability attributes between electrolyte-treated and untreated animals did not differ significantly. However, consumer evaluations indicated a lower overall palatability rating for electrolyte-treated bulls. The results clearly indicate that feed and water deprivation is detrimental to the palatability attributes and consumer acceptance of aged bull beef.     

Palatability characteristics of loin steaks from Charolais crossbred bulls and steers

Loins from 1/2-blood or 3/4- to 7/8-blood Charolais bulls (n = 60) and steers (n = 64) were obtained at 24 h post mortem from electrically stimulated sides and, at 12 days post mortem, steaks were removed and frozen. Shear force values were higher (P < 0·001) and sensory panel evaluations of tenderness and overall palatability were lower (P < 0·001) for steaks from bulls than from steers. No differences (P > 0·05) in connective tissue amount or off-flavour were detected for steaks from bulls versus steers. Significant correlations between carcass secondary sex characteristics and sensory panel evaluations of tenderness were noted, but the coefficients were not of a magnitude to be considered predictive of tenderness.     

Consumer attitudes towards beef and acceptability of enhanced beef

The objective of this study was to evaluate consumer quality characteristics of enhanced steaks and roasts derived from cattle supplemented with vitamin E during finishing, and to assess the attitudes of these consumers towards beef. Twelve steers were fed either a control (E-) diet or a diet supplemented with dl-alpha tocopheryl acetate (E+). Paired strip loins and rounds were either used as controls (C) or were pumped (P) to 110% of raw weight to contain 0.4% sodium chloride and 0.4% sodium tripolyphosphate in the final product. Consumers (n=103) evaluated roasts and steaks for juiciness, tenderness, saltiness, and overall acceptability on a 9-point hedonic scale. Enhanced steaks and roasts were more acceptable than non-enhanced controls; E+ steaks were less acceptable than E- steaks. A beef quality questionnaire revealed that color, price, visible fat and cut were the most important factors underlying beef steak purchase, while tenderness, flavor and juiciness were weighted most heavily with regard to eating satisfaction.     

Effect of transport time on sensorial aspects of beef meat quality

Forty-eight slaughter bulls were transported by road in groups of eight for approximately 30 min, 3 h and 6 h in two replicates. After slaughter and an ageing time of 7 days, steaks from the longissimus dorsi thoracis were tasted by a trained sensory panel in terms of odour, tenderness, residue, juiciness, flavour intensity, flavour quality, and overall liking. Transport time had a significant effect (P<0.05) on meat tenderness and overall liking. The panel preferred meat from animals given the 3-h journey as opposed to the 30 min or 6-h journey and found it was more tender and had a better overall liking.     

Effect of Duroc content, sex and ageing period on meat and eating quality attributes of pork loin

This study was conducted to determine the effect of percentage Duroc content of entire male and female pigs and ageing period on meat and eating quality attributes of pork loin (M. longissimus thoracis et lumborum). A total of 84 pigs [entire males (n=42) and female (n=42)] of 0% Duroc (100% Large White), 50% Duroc (Duroc×Large White) or 100% Duroc (n=14 pigs per sex×genotype combination) were slaughtered at a liveweight of 100 kg. Steaks from the M. longissimus lumborum of female pigs were aged for either 2 or 7 days post-slaughter and evaluated using a consumer taste panel. Eating quality attributes of tenderness, flavour and overall liking of pork loin steaks from female pigs were not (P>0.05) influenced by Duroc content. Pork from 100% Duroc pigs was juicier (P=0.05) and had a higher (1.84%, P=0.05) intramuscular fat content than pork from 0 and 50% Duroc pigs (1.40 and 1.25%, respectively). Pork from entire male pigs had a lower (P<0.001) intramuscular fat content, was darker (P<0.01) in colour and recorded higher (P<0.01) Warner Bratzler shear force values compared with pork from female carcasses. Ageing pork loin steaks in vacuum bags for 7 days improved tenderness (P<0.01), flavour (P<0.05) and overall liking (P<0.05) compared with steaks aged for 2 days post-slaughter. Ageing of pork steaks for 7 days post-slaughter improved eating quality attributes far more effectively than increasing percentage Duroc content of pigs, which only influenced consumer scores for juiciness.     

FACTORS RELATED TO LONGISSIMUS TENDERNESS AMONG ALTERNATE METHODS OF LEAN BEEF PRODUCTION

A 2³ factorial arrangement of treatments comparing bull versus steer, Angus versus Limousin, and zeranol implanted versus nonimplanted controls was used as a data source for this trial. Bulls had less intramuscular lipid and more total collagen than steers. Limousin had less intramuscular lipid, shorter sarcomere lengths and a higher percentage of fast-twitch glycolytic fibers than Angus cattle. Limousin and implanted cattle had more rapid postmortem temperature declines. Chemical, physical and histological traits as well as yield and quality grade traits were used in correlation procedures to examine their relationship with sensory panel tenderness and Warner-Bratzler shear force values of longissimus muscle steaks. The results of this trial indicate that postmortem muscle temperature decline plays a role in longissimus palatability and must be considered in the production of leaner beef.     

MECHANICAL MEASUREMENTS OF MEAT TENDERNESS USING THE NIP TENDEROMETER

Abstract. A series of evaluations to compare the sensory panel ratings for tenderness with the Warner-Bratzler shear force and the Nip Tenderometer values was conducted using 150 pork chops, 239 lamb chops and 674 beef steaks. The Warner-Bratzler shear force values were more highly correlated with panel tenderness ratings than were the Nip Tenderometer readings for samples of pork, lamb and beef tested after cooling to room temperature (23 °C). Nip Tenderometer determinations on hot samples of beef (75 °C) were more closely related to panel tenderness ratings ( r =— 0.80) than were Nip Tenderometer readings ( r =— 0.58) or shear force values ( r =— 0.63) obtained on cold samples (23 °C). The combined advantages of ease and speed of application, correlation with sensory panel ratings and the demonstrated accuracy in identifying 'tough' vs 'tender' steaks suggest that the Nip Tenderometer has potential as an objective means for evaluating meat tenderness.     

Descriptive Sensory Assessment of Beef Steaks by Category Scaling, Line Scaling and Magnitude Estimation

Eighteen trained panelists evaluated the eating quality of a total of 54 cooked semimembranosus steaks from delay chilled and hot boned treatments using category scaling (CS), line scaling (LS) and magnitude estimation (ME) in different sequences. Treatment F-values showed that CS was most sensitive and LS was least sensitive in detecting differences in steak quality attributes. ME was as sensitive as CS to most treatment differences. For tenderness, correlations between each of the three evaluation techniques were high (r > 0.86). Significant correlations (r > 0.63) between panel tenderness assessments and shear data were also found. CS was most preferred and ME was least preferred by panelists. Panelists found ME the most difficult to use.     

USDA MATURITY INDICES AND PALATABILITY OF BEEF RIB STEAKS1

In a population of 195 beef carcasses, as maturity increased (by whole USDA groups) from A to B, flavor, tenderness and overall palatability ratings for rib steaks decreased (P < .05); further increases in maturity (B vs. E) resulted in subsequent decreases (P < .05) in tenderness and overall palatability. Subdivision of whole maturity groups into thirds and subsequent data analyses supported precepts in USDA grade standards of declining palatability with advancing maturity, but the declines, when they occurred, were nearly linear through the extremes (from A^? to E⁺) and did not support the concept, in USDA grade standards, of a precipitous decline in eating satisfaction at or near the B⁺/C^? maturity line. Among seven carcass maturity indices, all were similarly and singularly related (P < .05) to palatability of rib steaks, with some measure of skeletal maturity (the best of these was color/shape of the rib bones) plus some measure of muscle maturity (the best of these was color of the longissimus muscle) combining (by means of multiple regression analyses) to predict tenderness (panel ratings and shear values) with maximum precision. Neither total pigment concentration (a chemical measure of muscle color), amount of ether-extractable lipid (a chemical measure of intramuscular fatness) nor marbling score (a visual measure of intramuscular fatness) was able to explain more than about 7% of the observed variability in palatability ratings for cooked beef steaks. Data suggest that more attention should be paid to appearance of rib bones in a carcass (to better assess effects of maturity) and that less attention could be paid to differences between SLIGHT, SMALL and MODEST in marbling in the ribeyes, in attempting to predict, via USDA grading, the palatability of beef rib steaks.     

The effects of castration, preslaughter stress and zeranol implants on beef: Part 2-Cooking properties and flavor of loin steaks from bovine males

A total of 144 male crossbred calves were allocated to four castration or implant treatments (unimplanted bulls; unimplanted steers; bulls implanted with zeranol at 100 days of age and reimplanted at intervals of 69, 93 and 56 days thereafter; bulls implanted with zeranol at 168 days of age and reimplanted at intervals of 93 and 56 days thereafter) and two preslaughter shipping treatments (minimum preslaughter stress, with cattle shipped and slaughtered within 4 h of leaving the feedlot pen; normal preslaughter stress, with cattle mixed, trucked 160 km, and slaughtered up to 24 h after leaving the feedlot pen). These cattle were slaughtered and striploin steaks were removed after 6 days of post-mortem aging. Evaluations of these steaks were then conducted using both an experienced laboratory taste panel and a highly trained professional flavor profile panel. Results indicated that: (1) steaks from bulls had higher cooking losses than their counterparts from steers, when minimum preslaughter stress was applied; and required longer cooking times under both preslaughter handling treatments; (2) steaks from unimplanted bulls had greater cooking losses and required longer cooking times than their counterparts from implanted bulls under normal preslaughter stress, but not under minimum preslaughter stress; (3) higher proportions of bull steaks than steer steaks contained inappropriate flavor character notes, under both minimum and normal levels of preslaughter stress; (4) both castration and preslaughter handling affected the intensity and order of appearance of specific flavor character notes; (5) the level of preslaughter stress significantly influenced the detection of specific flavor character notes in steaks from both bulls and steers; (6) steaks from steers under minimum preslaughter stress were rated significantly higher in flavor amplitude than their counterparts from bulls when under normal preslaughter stress, and steaks from steers under minimum preslaughter stress received higher flavor desirability scores than steaks from bulls under both minimum and normal preslaughter stress; (7) zeranol implants influenced the appearance and the order of appearance of specific flavor character notes under both minimum and normal levels of preslaughter stress; (8) both zeranol implants and the length of time animals were implanted appeared to increase the intensity of certain inappropriate character notes, and to decrease the intensity of certain appropriate character notes; (9) steaks from implanted bulls received lower flavor amplitude ratings than their counterparts from unimplanted bulls under normal preslaughter stress, but not under minimum preslaughter stress; (10) the level of preslaughter stress influenced both the appearance and order of appearance of specific flavor character notes in both implanted and unimplanted bull steaks; (11) the intensities of certain flavor character notes were influenced by differences in the level of preslaughter stress in both implanted and unimplanted bull steaks, and higher levels usually resulted in inappropriate character notes being more intense; (12) steaks from bulls in both implant groups received lower flavor amplitude ratings when normal preslaughter stress was applied, clearly indicating the deleterious effect of the combination of zeranol implants and normal preslaughter stress on bull beef flavor; and (13) the deleterious effect of the combination of zeranol implants and normal preslaughter stress on bull beef flavor could not be explaind on the basis of greater production of 'dark cutting' beef.     

Effect of Pre-chill Removal of Kidney Fat on Young Angus Bull Carcass Quality and Longissimus Muscle Tenderness

The effect of pre-chill removal of kidney fat from bull carcasses on Longissimus palatability, histological and enzyme characteristics was studied. To better represent the time flow of product from packer to consumer, steaks were removed from one side of each carcass for evaluation after a 7-day chill. Carcasses having intact kidney fat exhibited firmer and more marbled Longissimus muscle, and this was reflected in slightly higher quality grades: low choice versus high select in carcasses having fat removed. No differences were observed in panel tenderness, shear force value, or histological and lysosomal enzyme characteristics. A slower pH decline was observed in muscle of carcasses with kidney fat removed.     

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.     

Effect of Subprimal Fabrication and Packaging Methods on Palatability and Retail Caselife of Loin Steaks from Lean Beef

Eighty subprimals were fabricated from 20 pairs of beef strip loins from lean (fat thickness, 0.2-0.4 cm) US Standard and US Good carcasses. Three vacuum packaged (VP) and one dry aged treatments were randomly assigned to short loin sections of each carcass. Steaks from VP intact and VP not-reassembled subprimals were rated highest in overall appearance and eating quality. Dry aging reduced retail caselife, produced greater shrinkage and trim losses and lower overall satisfaction ratings by panelists. Precutting subprimals into steaks followed by VP aging tends to decrease retail caselife (especially if steaks are reassembled) and decrease juiciness and tenderness.     

Consumer Assessment of Beef Tenderloin Steaks from Various USDA Quality Grades at 3 Degrees of Doneness

A consumer study was conducted to determine palatability ratings of beef tenderloin steaks from USDA Choice, USDA Select, and USDA Select with marbling scores from Slight 50 to 100 (USDA High Select) cooked to various degrees of doneness. Steaks were randomly assigned to 1 of 3 degree of doneness categories: very‐rare, medium‐rare, or well‐done. Consumers (N = 315) were screened for preference of degree of doneness and fed 4 samples of their preferred doneness (a warm‐up and one from each USDA quality grade treatment in a random order). Consumers evaluated steaks on an 8‐point verbally anchored hedonic scale for tenderness, juiciness, flavor, and overall like as well as rated steaks as acceptable or unacceptable for all palatability traits. Quality grade had no effect (P > 0.05) on consumer ratings for tenderness, juiciness, flavor, and overall like scores, with all traits averaging above a 7 (“like very much”) on the 8‐point scale. In addition, no differences (P > 0.05) were found in the percentage of samples rated as acceptable for all palatability traits, with more than 94% of samples rated acceptable for each trait in all quality grades evaluated. Steaks cooked to well‐done had lower (P < 0.05) juiciness scores than steaks cooked to very‐rare or medium‐rare and were rated lower for tenderness (P < 0.05) than steaks cooked to a very‐rare degree of doneness. Results indicate consumers were not able to detect differences in tenderness, juiciness, flavor, or overall like among beef tenderloin steaks from USDA Choice and Select quality grades.     

Effect of End-point Temperature and Degree of Doneness on Sensory and Instrumental Flavor Profile of Beefsteaks

ABSTRACT: Beef M. longissimus thoracis et lumborum was used to investigate the effects of 6 end-point temperatures on flavor and texture. Steaks cooked to medium temperature were associated with 4-heptanolide, whereas those cooked to higher temperatures were associated with pyrazines and hexanol. These steaks were also associated with flavor attributes, such as roasted, burnt, and beefy. However, consumers did not find differences in flavor liking of steaks (P > 0.05) cooked to 6 end-point temperatures. Although steaks cooked to lower temperatures were liked for their tenderness and juiciness, overall liking scores were not affected by end-point temperature. Thus both flavor and tenderness play an important role in consumer satisfaction.