Biomedical subjects

J W Savell

Publications and source records attributed to J W Savell.

At least 73 records · Page 4Linked to original sources

PubMed1992

Live and carcass values from different cattle types.

Slaughter steers and heifers (n = 345) were selected representing the following cattle types: English steers and heifers, Exotic steers and heifers, less than 50% Bos indicus steers and heifers, greater than or equal to 50% Bos indicus steers, and Holstein steers. Thirty sides representing 30 carcasses from each cattle type were fabricated into boneless subprimals and trimmed to three fat-trim levels: 2.54, 1.27, and .64 cm. Yields of cuts to each trim level were used to calculate values for each carcass component. Live values were calculated after slaughter and fabrication costs and drop credits were considered. Values were calculated for U.S. Choice and U.S. Select grades and the weighted average value accounting for the Choice/Select mix for each cattle type. At a constant quality level, fatter cattle types were more valuable at the 2.54 cm of fat-trim level. As fat was trimmed, the leaner cattle types became more valuable and the fatter types became less valuable. Cattle types with higher percentages of Choice carcasses were more valuable at the 2.54 cm of fat-trim level, but when subprimals were trimmed to .64 cm, the lower-grading carcasses became closer in value due to cutability advantages.

Adipose Tissue↗

PubMed1992

Yield grade and carcass weight effects on the cutability of lamb carcasses fabricated into innovative style subprimals.

Lamb carcass (n = 100) were selected from USDA yield grades (YG) 2, 3, and 4 and carcass weight (CW) groups 20.4 to 24.9, 25.0 to 29.5, and 29.6 to 34.0 kg. Lamb carcass were fabricated into semiboneless and boneless subprimals and trimmed to three s.c. fat trim levels: .64, .25, and .00 cm of fat remaining. Innovative subprimals were fabricated and yields were calculated for the subprimals and dissectible components (lean, bone, connective tissue, external fat, and seam fat) from each of the various subprimals. Carcass weight as a main effect in a two-way analysis of variance did not account for a significant amount of the variation in yield among trimmed subprimals or the percentage of the dissectible components, but USDA YG was a significant main effect in determining variation in yield for many of the subprimals or dissectible components. Muscle seaming of shoulders and legs and removal of excessive tails on the loin and rack resulted in a majority of the seam fat being removed from these cuts. Dissection data clearly showed that seam fat is a major component of rack and shoulder cuts and with increasing fatness or higher numerical yield grade there are clearly increased amounts of this depot. Increased trimming of external fat magnifies and draws more attention to the amount of seam fat remaining. Production of heavy, lean lambs would be more useful in an innovative type of program because of the larger-sized muscles. Heavy, fat lambs would not be as useful because of their decreased yields and excess seam fat located in cuts that cannot be muscled-seamed because of the loss of retail cut integrity. Seam fat was highly correlated to percentage of kidney and pelvic fat and to external fat thickness and with USDA yield grade but was not strongly correlated to carcass weight.

Adipose Tissue↗

PubMed1992

Development of a quantitative quality grading system for mature cow carcasses.

Data from 400 cow carcasses were used to develop a new quality grading system. First principal component (FPC) values were determined for shear force (SHR) and palatability attributes of tenderness, connective tissue amount, flavor, and juiciness (JUC). Associated eigenvector load values for those traits were -.48, .54, .51, .46, and .05, respectively, and FPC values ranged from -3.20 to 2.18. Linear regression, using FPC as the independent variate, and SHR and palatability attributes (8-point scale, where 8 was highest) as dependent variates explained a significant amount of variation (P less than .001) in all traits, except JUC, and resulted in R2 values of .71, .89, .80, .66, and .01, respectively. A predictive quality-grade equation was developed using FPC as the dependent variate, and overall maturity (OM), lean color, marbling score (MS), lean firmness, lean texture, fat color (FC), and marbling fineness ([marbling texture + marbling distribution]/2; 8-point scale, where 8 was highest) as independent variates. The resulting best-fit prediction equation (FPC = -.052-[.0031 x OM] + [.0013 x MS] + [.31 x FC]) explained a significant amount (P less than .001) of variation in FPC with R2 = .53, Cp = 15.0, and residual standard deviation = .69. A short-cut equation was developed from this prediction equation. Simple correlations for OM, MS, and FC with FPC were -.56, .39, and .64, respectively. Cow carcasses were assigned to one of three quality grades based on FPC values that corresponded with predetermined acceptability levels for each palatability trait. Newly developed grades were quantitative and less variable than existing grades. Future grades for cow carcasses should include fat color to predict palatability.

Adipose Tissue↗

PubMed1992

Development of a multivariate yield grade equation to predict compositional traits in mature cow carcasses.

Data from 68 cow carcasses were used to develop a new yield grading system. First principal component (FPC) values for compositional attributes (LNFT = separable lean weight/[lean+fat weight] x 100, LNBN = separable lean weight/[lean+bone+connective tissue weights] x 100, and BTPR = [defatted lean from the round, loin, rib, and chuck]/side weight x 100) were determined. The first component explained 83.5% of the standardized variance and load values were .63, -.52, and .58, respectively. The resulting FPC values ranged from -1.93 to 1.89. The linear regression of LNFT, LNBN, and BTPR (dependent variables) on FPC (independent variable) explained a significant amount of variation (P less than .001) in each case and resulted in R2-values of .98, .67, and .85, respectively. A best-fit yield grade equation, developed to predict FPC, included adjusted fat thickness (ADF), percentage of kidney, pelvic, and heart fat (KPH), and overall muscling grade (OM). The equation, FPC = 2.04 - (.67 x ADF) - (.21 x KPH) - (.0016 x OM), explained a significant amount (P less than .001) of variation in FPC with R2 = .94 and residual standard deviation = .25. Simple correlations for ADF, KPH, and OM with FPC were -.87, -.71, and -.80, respectively. Cow carcasses were assigned to one of three grades based on FPC values that corresponded with predetermined levels of LNFT, LNBN, and BTPR. These grades generally had smaller CV than existing grades. When used in conjunction with quality grades, proposed grades could be more useful to the cow meat industry.

Abattoirs↗

PubMed1992

Estimates of subprimal yields from beef carcasses as affected by USDA grades, subcutaneous fat trim level, and carcass sex class and type.

One hundred beef carcasses were selected to represent the mix of cattle slaughtered across the United States. Selection criteria included breed type (60% British/continental European, 20% Bos indicus, and 20% dairy carcasses), sex class (beef and Bos indicus: 67% steers, 33% heifers; dairy: 100% steers), USDA quality grade (4% Prime, 53% Choice, and 43% Select), USDA yield grade (10% YG 1, 43% YG 2, 40% YG 3, and 7% YG 4), and carcass weight (steers: 272.2 to 385.6 kg, heifers: 226.8 to 340.2 kg). One side of each carcass was fabricated into boneless subprimals and minor cuts following Institutional Meat Purchase Specifications. After fabrication, subprimals were trimmed progressively of fat in .64-cm increments beginning with a maximum of 2.54 cm and ending with .64 cm. Linear regression models were developed for each individual cut, including fabrication byproduct items (bone, fat trim) to estimate the percentage yield of those cuts reported by USDA Market News. Strip loin, top sirloin butt, and gooseneck rounds from heifers tended to have a higher percentage yield at the same USDA yield grade than the same cuts from steers, possibly resulting from increased fat deposition on heifers. Percentage of fat trimmed from dairy steers was 2 to 3% lower than that from other sex-class/carcass types; however, due to increased percentage of bone and less muscle, dairy steers were lower-yielding. Fat trimmed from carcasses ranged from 7.9 to 15.6% as the maximum trim level decreased from 2.54 to .64 cm.

Adipose Tissue↗

PubMed1992

Beef carcass composition of slaughter cattle differing in frame size, muscle score, and external fatness.

Commercial slaughter steers (n = 329) and heifers (n = 335) were selected to vary in slaughter frame size and muscle thickness score, as well as carcass adjusted 12th-rib fat thickness. After collection of USDA carcass grade data, one side of each carcass was fabricated into boneless primals, subprimals, and minor tissue components. Cuts were trimmed to 2.54, 1.27, and .64 cm of external fat, except for the knuckle, tri-tip, and tenderloin, which were trimmed of all fat. Forced four-variable regression equations were used to predict the percentage (chilled carcass weight basis) yield of boneless subprimals at the three fat trim levels as influenced by sex class, frame size, muscle score, and adjusted 12th-rib fat thickness. Independent variables that had the most influence on percentage yield of primals and boneless subprimals were adjusted 12th-rib fat thickness and sex class. Within the same phenotypic group, percentage of trimmable fat increased by 2.32% as 12th-rib fat thickness increased by .75 cm. Estimated percentage yield of the major subprimals from the loin and round tended to be higher or relatively equal for heifer carcasses at all trim levels compared with those subprimals from steer carcasses. Holding frame size, sex class, and fat thickness constant, there was a higher percentage yield of chuck roll, rib eye roll, and strip loin for carcasses from thick-muscled cattle than for those from average- and thin-muscled cattle. Frame size had little effect on percentage yield of boneless subprimals.

Abattoirs↗

PubMed1992

Development and preparation of lean meat products.

When the effect of food on human lipoprotein levels is tested, or when human consumption of dietary lipids must be controlled or limited, all food needs to be provided under controlled conditions to achieve consistent composition and sensory traits. It is especially important to control the composition of foods, particularly fat and fatty acid content. Because of the inherent biologic variability in the chemical composition of animal tissues (beef in particular), raw materials must be selected carefully and prepared under strict guidelines. In addition, chemical composition should be verified initially and during the production of the product to ensure the accuracy necessary for controlled dietary intake. Furthermore, the meat provided must be easy for the study subject to prepare, be of consistent serving size, and yet be highly palatable to maintain the subject's interest and participation. This article outlines the protocol for developing lean meat products for use in nutrition studies in which fat content must be controlled, especially those studies designed to examine the effect of fat content on human lipoproteins. Preliminary studies, procurement of raw materials, procedures for recipe selection, product preparation, and sampling procedures for verification of chemical composition are described. Our findings indicate that fat intake from beef, chicken, and fish can be controlled for use in nutrition studies.

Animals↗

PubMed1991

Using calcium chloride injection to improve tenderness of beef from mature cows.

The objective of this investigation was to determine the effect of calcium chloride (CaCl2) injection on Warner-Bratzler shear force (WBS), sensory panel ratings, and collagen traits of mature cow beef. Within 30 min of exsanguination, subprimals (top round, TR; top sirloin, TS; strip loin, SL) from alternate sides of the carcass were injected with a .3 M CaCl2 solution (10% of the subprimal weight) and aged for 1, 7, or 14 d. The corresponding cold-boned cuts of the other side served as a control. Injecting CaCl2 eliminated the requirement for extended postmortem storage, as indicated by d 1 WBS. During the 14-d aging period, WBS of noninjected cuts decreased by 2.59 kg, whereas WBS of CaCl2-injected samples decreased by only .35 kg. Compared with control cuts, CaCl2 injection improved (P less than .05) d-14 WBS of steaks from SL, TS, and TR by 41.1, 40.1, and 15.3%, respectively. Additionally, CaCl2-injected subprimals exhibited higher (P less than .05) sensory panel tenderness ratings, lower (P less than .05) amounts of detectable connective tissue, and shorter (P less than .05) sarcomere lengths. No differences (P greater than .05) were observed in any quantitative collagen traits between CaCl2-injected and control cuts. These results indicate that CaCl2 injection improved ultimate tenderness and sensory ratings of meat from mature cow cuts.

Age Factors↗

PubMed1991

Relationships between pork loin palatability traits and physical characteristics of cooked chops.

Pork loins (n = 72) were selected so that marbling scores would range from "practically devoid" to "abundant" in the longissimus muscle. Loin chops were cooked and rated by a trained six-member sensory panel. Physical and chemical characteristics were stratified according to marbling level (divided into 10 subclasses), muscle structure, shear force, overall palatability, and juiciness (each divided into three subclasses). The highest ratings for overall palatability were assigned to chops with high reflectance (685 nm), low moisture (70.1%), high i.m. fat (9.1%; or, high marbling score), low protein (19.4%), and low cooking loss (25.9%). Chops with the highest percentage of cooking loss were high in moisture content (75.59%), low in i.m. fat (1.78%), and high in protein content (21.54%). Differences in muscle structure, shear force, overall palatability, and juiciness were associated with differences in percentages of protein, moisture (whole tissue basis [WTB]) and fat (WTB). Pork loins with marbling between "practically devoid-plus" and "small" had (P less than .05) more protein and less fat (WTB) than loins with marbling scores between "modest" and "abundant." Loins with overall palatability ratings between 4.0 and 6.0 had more moisture and protein (P less than .05) than did loins with palatability ratings of 6.1 to 8.0. Selecting pork loins with "small" or less marbling, extremely open structure, a juicy rating of "slightly juicy," and an overall palatability rating of "like slightly" would identify fresh loins that had lower fat and(or) higher protein content.

Animals↗

PubMed1991

National beef market basket survey.

Beef retail cases in supermarkets in 12 cities across the United States were surveyed for fat thickness measurements, cut representation, package weights and counts, and case space allocation. Randomly selected retail cuts were purchased and transported to Texas A&M University, where they were dissected into separable components. Samples of ground beef were obtained for chemical analysis. Over 42% of the beef retail cuts had no external fat, and approximately 75% of all cuts were boneless. The overall mean fat thickness for all retail cuts in the beef case was .31 cm, and the overall mean fat thickness for steaks and roasts from the major primals - chuck, rib, loin, and round - was .38 cm. The average percentage of separable lean was 79.0%, separable fat was 12.3%, and bone and connective tissue was 8.7%. Retail cuts had more than twice as much separable seam fat as separable external fat. Beef steaks and roasts had 27.4% less separable fat than values from USDA Agriculture Handbook 8-13. Of the ground beef surveyed, 37% was regular, 40% was lean, and over 22% was extra lean. Retail ground beef had approximately 10% less fat than values from USDA Agriculture Handbook 8-13.

Animals↗

PubMed1991

National beef tenderness survey.

To determine the average tenderness and sensory ratings of beef subprimal cuts sold in retail cases across the United States, retail cuts were purchased through typical retail outlets in 14 metropolitan cities and transported to Texas A&M University for sensory and Warner-Bratzler shear analysis. The overall mean shear force for all cuts was 3.65 kg, and the mean shear force values for chuck, rib, loin, and round cuts were 3.72, 3.36, 3.17, and 4.31 kg, respectively. No difference (P greater than .05) in tenderness was detected among the cuts from the rib. Mean palatability ratings and shear force values of top loin steaks were similar to those of rib cuts. Top sirloin steaks were tougher (P less than .05) and received the lowest sensory ratings compared with other loin cuts. Approximately two to three times as many round and chuck steaks had shear force values in excess of 4.6 kg compared with their roast counterparts. In all cases, roasts tended to be more tender than steaks from the same subprimal source. USDA Choice chuck retail cuts, compared to Select and No-roll chuck cuts, had approximately 10% fewer cuts with shear force values in excess of 4.0 kg. More work is needed to improve meat tenderness, primarily for retail cuts from the round and chuck primals. Future research must investigate the interaction of antemortem and postmortem factors associated with variation in beef tenderness.

Animals↗

PubMed1991

Growth, carcass traits, and fatty acid profiles of adipose tissues from steers fed whole cottonseed.

To investigate the impact of dietary whole cottonseed (WCS) level on fatty acid composition, growth, and carcass traits, 45 Hereford steers were assigned to diets containing 0, 15, or 30% dietary WCS. The 15 and 30% WCS contributed an estimated 3.3 and 6.6% additional lipid, respectively, to the diets. After being fed for 54 d, all animals were weighed and slaughtered, and carcass measurements were obtained. There were no differences (P greater than .05) among dietary treatment groups in live weight or ADG for the 54-d feeding period. Control steers had larger (P less than .05) longissimus muscle areas than steers fed 30% WCS, which accounted for the advantage in yield grade (P less than .05) exhibited by the control group. Feeding of 30% WCS resulted in minor increases in linoleic and total polyunsaturated fatty acid content of perinephric fat expressed in both normalized (area percentage) and gravimetric (g/100 g of fresh tissue) formats. There were no significant differences in the monounsaturated or saturated fatty acid content of adipose tissues from animals fed the different diets. Subcutaneous adipose tissue samples were higher (P less than .01) in total unsaturates but had lower (P less than .05) proportions of C18:0 and C18:1 than perinephric samples. Feeding WCS at the levels reported herein only had minor effects on fatty acid composition of beef adipose tissues.

Adipose Tissue↗

PubMed1990

Effect of postmortem treatments on the tenderness of meat from Hereford, Brahman and Brahman-cross beef cattle.

The effect of postmortem aging (7, 14, 21 or 28 d), high-voltage electrical stimulation (stimulated or not stimulated) and blade tenderization (none or once; crossbreds only) on the sensory and cooking properties of meat from four beef breeds or breed-types (purebred Hereford, purebred Brahman, Hereford x Brahman and Brahman x Hereford) was determined. The meat from purebred Brahman cattle that was not electrically stimulated was less tender and more variable in tenderness than that from other breed-types but electrical stimulation reduced these differences in tenderness. The Brahman crossbred steers produced meat that was not different in tenderness or variability in tenderness from that of purebred Hereford steers, although all were only judged "slightly tender." Electrical stimulation reduced the length of postmortem aging needed to reach a given level of tenderness regardless of breed or breed-type. Meat from crossbred animals that was blade-tendernized was not different in tenderness from meat that was electrically stimulated. The results of this investigation indicate that purebred Brahman muscle was inherently less tender, but postmortem tenderization procedures produced meat that was similar tenderness to that of the other breed-types used in this study.

Animals↗

PubMed1990

Yields of by-products from different cattle types.

Slaughter cattle (n = 360), selected and allocated to types according to their phenotypic breed type characteristics, were slaughtered in lots of 15 head at a large commercial packing plant. By-product weights were obtained for these lots of 15 head after plant personnel had separated the by-products according to plant procedures. Percentage of slaughter weight in each by-product was calculated. The trait most influenced by cattle type was the hide; Bos indicus cattle generally had the greatest percentage of their live weights as hide (green, trimmed, fleshed or cured), and Holstein cattle generally had the lowest. For edible by-products, the liver differed significantly among cattle types, with Holstein cattle having the higher percentage of their live weight as liver. Other items studied were not significantly or economically different among cattle types.

Animals↗

PubMed1990

Mechanisms associated with the variation in tenderness of meat from Brahman and Hereford cattle.

To study possible mechanisms for differences in meat tenderness, 10 purebred Hereford and 10 American Grey Brahman steers were fed a typical feedlot diet and slaughtered when ultrasound measurements indicated that they had approximately 1 cm of fat thickness at the 12th rib. Longissimus muscle from Brahman cattle was less (P less than .05) tender after 7, 14, 21, 28 and 35 d postmortem than muscle from Hereford cattle, but muscle from Hereford cattle showed greater improvement in tenderness from 7 to 14 d postmortem than muscle from Brahman cattle (interaction P less than .05). Cathepsin B or cathepsin B+L activities and the myofibrillar response to elevated ionic strength were not different between breeds, but both could be related to the postmortem increase in tenderness of both breeds. Calcium-dependent protease activity, as modulated by calcium-dependent protease inhibitor, seems to play a major role in the inherent tenderness differences between breeds.

Adipose Tissue↗

PubMed1990

Relationships of empty-body composition and fat distribution to live animal and carcass measurements in Bos indicus-Bos taurus crossbred cows.

Empty-body composition and fat distribution were determined for 55 nonpregnant, mature Bos indicus-Bos taurus crossbred cows fed to achieve variation in fatness. Prior to slaughter, cows were condition and frame scored, weighed and measured for hook height, hook width, heart girth and lengths from point of shoulder to pin and hook to pin. Fat thickness at three locations and ribeye area were measured ultrasonically on the live animal and carcass. Quality and yield grades were determined after a 48-h postslaughter chill. Visceral fat was excised at slaughter and weighed. Kidney, heart and pelvic (KHP) fat was excised from one side and the remainder of the side was separated into bone and soft tissue. Soft tissue was subsampled and analyzed for ether extract. Proportions of fat in soft tissue, bone, viscera and KHP were calculated. Variations of percentage of empty-body fat in soft tissue, KHP and bone were explained (R2 greater than .64) by equations involving either live animal or carcass measurements. Both ultrasonic and subjective fat estimates were of importance (P less than .05) in equations predicting fatness, indicating the importance of variation in fat distribution. Factor analysis indicated that fat accretion is a complex entity composed of several distinct distribution patterns (anterior-posterior, internal-external, intramuscular-intermuscular).

Adipose Tissue↗

PubMed1990

The influence of sex-class, USDA yield grade and USDA quality grade on seam fat trim from the primals of beef carcasses.

Beef carcasses (129 steers and 80 heifers) differing in weight, muscling, fatness and marbling score were selected to represent the full spectrum of USDA yield grades; one side was fabricated into boneless primal cuts. Primals were trimmed of all external fat and intermuscular (seam) fat and all components were weighed. Regression equations were developed to predict the percentage of seam fat on an external fat-free primal basis using USDA yield grade (YG), marbling score and a squared function of YG as the independent variables. YG (.77) and marbling score (.67) were highly correlated to seam fat. Heifers tended to have a higher predicted percentage of seam fat than did steers across all YG. Primals from USDA Choice carcasses had approximately 1.0 percentage point more predicted seam fat than did USDA Select primals at the same YG and sex-class. The YG 2.5 heifers had similar proportions of predicted seam fat from primals as YG 3.5 steers, but YG 3.5 heifers tended to have more seam fat than YG 4.5 steers. The same trend was noted between YG 4.5 heifers and YG 5.5 steers, indicating a sex-related deposition of seam fat in fed cattle.

Adipose Tissue↗

PubMed1990

Lean beef: impetus for lipid modifications.

Health-conscious consumers want lean beef. The beef industry has responded by physically removing much of the adipose tissue from retail products and by initiating attempts to produce--genetically and environmentally--cattle with more muscle, less external fat, and less seam fat, without sacrificing the quality dependent on the amount of marbling present. Offering lean beef that is closely or completely trimmed of external fat has improved retail beef sales. Impetus for modification of the lipid composition of bovine muscle and adipose tissue, including marbling, has resulted from the following: (a) diet/health concerns of consumers and demands for leaner beef, (b) research clarifying effects of dietary fatty acids and cholesterol on serum cholesterol levels, (c) dietary guidelines and recommendations from health organizations, and (d) dietary recommendations by physicians and dietitians to reduce beef consumption. Analysis of cholesterol content of marbling dissected from the rib (longissimus dorsi) muscle revealed that marbling contributes little to total cholesterol content. Cholesterol content of marbling was 117 mg/100 gm intramuscular adipose tissue (equivalent to about a 2 mg cholesterol contribution to a 100-gm serving of uncooked meat). The difference in fatty acid composition of lean meat and of adipose tissue is primarily in the percentage of polyunsaturated fatty acids, which is higher in lean meat. The most prevalent fatty acids in adipose tissue including marbling were: palmitic acid (24.1%), stearic acid (13.5%), and oleic acid (37.7%).

Adipose Tissue↗