PSVI-27 Relationship of volatile compounds and consumer sensory traits from New Zealand grass-fed and American grain-fed beef strip loins varying in marbling level and wet aging time

Cattle diet, marbling and wet aging can affect eating quality and consumer preference of beef. The objective of this study was to assess the relationship of cooked volatile compounds and consumer sensory traits of New Zealand grass-fed strip loin steaks in comparison to US grain-fed strip loin steaks from five different USDA quality grades, wet-aged for 7, 21 and 42 days. Beef strip loins (n = 200; 20 per USDA quality grade/fed cattle type) representing five USDA quality grades (USDA Prime, Top Choice, Low Choice, Select and Standard) and two fed cattle types (New Zealand grass-finished and US grain-finished) were used. Steaks were cooked to a target internal temperature of 71°C and served to consumer panelists (n = 600; 120 per five different cities in the US). Volatile analysis (n = 600) was performed on cooked samples, and quantitation was conducted by an internal standard calibration with authentic standards. Statistical analyses were conducted using the FACTOR procedure of SAS. A principle component analysis (PCA) showed relationships of volatile compounds, treatments, and consumer ratings. PC1 explained 17.17% of the variation and PC2 explained 10.96% of the variation. Consumer flavor liking was most closely associated with ethanol and treatments grass and grain Prime aged 42d. The majority of the alcohols and n-aldehydes were associated with the 7d grain treatments including grain Top Choice, Low Choice and Select. The Maillard derived compounds were grouped together and most associated with grass Top Choice 42d and the consumer attributes. Methional was closest to many grass treatments including grass Top Choice 7d, Low Choice 7d, Standard 7d, Prime 7d and Standard 21d. Although associations were evident between volatile compounds and consumer sensory attributes, they were not strongly related.

A comparison of consumer response using paper and digital ballots for eating quality assessment of beef steaks

A consumer study was conducted to determine if consumers scored beef palatability traits differently on paper vs. digital ballots. Beef subprimals were collected to represent four treatments with inherent variation in eating quality: USDA Select eye round aged 7 d postmortem, USDA Select strip loin aged 7 d postmortem, USDA Choice tenderloin aged 21 d postmortem, and USDA Prime strip loin aged 21 d postmortem. Accessory muscles, external fat, and connective tissue were removed from subprimals. Muscles were fabricated into 2.5 cm steaks and further divided into 2 equal halves for consumer testing. Consumers (n = 360) were served eight samples divided into two blocks representing the two ballot types. Select longissimus lumborum samples were always served in the first and fifth position to start each ballot block, with the remaining three treatments served in a randomized order between the latter three positions within each ballot block. Consumers rated each steak sample for tenderness, juiciness, flavor liking, and overall liking on either a paper or digital ballot, and then rated the paired steak halves on the opposite ballot during the second block of sample testing. Ballot type influenced (P < 0.02) all traits, as consumers scored tenderness, juiciness, flavor liking, and overall liking greater (P < 0.05) on paper ballots compared to digital ballots, regardless of treatment. The smallest margin between paper and digital ballots was observed for tenderness, where scores only differed by 1.8 units. However, juiciness, flavor liking, and overall liking all differed by 3.4 units in favor of paper ballots. Consumers scored palatability traits greater on paper ballots compared to digital ballots, and these findings were consistent across a range of eating quality outcomes. These results should be considered when comparing past consumer testing results using paper balloting systems to those where digital ballots were used.

Palatability of high-quality New Zealand grass-finished and American grain-finished beef strip steaks

The objective of this study was to evaluate palatability of strip loin steaks from grass- and grain-fed beef across five United States Department of Agriculture (USDA) quality grades and three wet aging periods. Beef strip loins (N = 200; 20 per USDA quality grade/fed cattle type) representing five USDA quality grades [USDA Prime, Top Choice (Average and High Choice), Low Choice, Select and Standard] and two fed cattle types [New Zealand grass-finished and United States (U.S.) grain-finished] were used in the study. Each strip loin was equally portioned into thirds and randomly assigned to one of three wet aging periods (7 d, 21 d or 42 d). Consumer panelists (N = 600; 120/location: Texas, California, Florida, Kansas, and Pennsylvania) evaluated eight grilled beef steak samples for palatability traits, acceptability, and eating quality. All palatability traits were impacted by the interaction of diet × quality grade (P < 0.05). Although similar (P > 0.05) to grass-fed Prime steaks for juiciness, tenderness and overall liking, grain-fed Prime steaks rated greater (P < 0.05) than all other grass- and grain-finished treatments for all palatability attributes. Grass-finished Top Choice, Low Choice, and Standard steaks were rated greater (P < 0.05) than the respective grain-finished quality grades for juiciness and tenderness. Grain-finished Standard steaks rated lower (P < 0.05) than all other grass- and grain-finished treatments for juiciness, tenderness, and overall liking; but were similar (P > 0.05) to grass-finished Standard steaks for flavor liking. Our results indicate beef strip loin steaks of similar quality grades from grass-finished New Zealand cattle produce similar eating experiences when compared to those from U.S. grain-finished beef, even following extended post-mortem aging. This indicates improved palatability for consumers based on marbling without respect to grass- or grain-finishing diets. 

Sorting beef subprimals by ribeye area size at the packer level to optimize utility and product uniformity in foodservice and retail

The objectives of the study were to evaluate if sorting beef carcasses at the packer level by loin muscle (LM) area, using instrument grading technology, would increase the consistency of three boxed beef products for the foodservice and retail sectors of the industry. U.S. Department of Agriculture (USDA) Choice beef sides (n = 100) and USDA Select sides (n = 100) were selected and stratified into five LM area categories (±2.9 cm2): 1) 77.4, 2) 83.9, 3) 90.3, 4) 96.8, and 5) 103.2 cm2. Beef lip-on ribeyes and boneless strip loins were obtained from USDA Choice sides and full, partially defatted tenderloins were obtained from USDA Select sides. Subprimals were scanned with a portioner that captured visual images and dimensional analyses of each subprimal, and data were analyzed by the software to determine multiple portioning outcomes for each subprimal. Portioning data were generated for each subprimal based on a variety of targeted portion weights (ribeye and strip loin steaks = 340.2 g; tenderloin steak = 170.1 g), as well as various portion thicknesses (ribeye and strip loin steaks = 31.8 mm; tenderloin steak = 44.5 and 50.8 mm). Subprimal utility varied across targeted portion weights and thicknesses within each LM area category. For the ribeyes and strip loins, optimal portion weight and thickness combinations were observed more frequently in LM area categories 1 and 2 than for the three larger LM area categories. Analysis of data for tenderloins revealed that LM area categories played a lesser role in identifying optimization of steak portion weight and thickness combinations. Findings demonstrate that creating categories of beef subprimals based on LM area as opposed to subprimal weight might provide a unique sorting method that would improve boxed beef product consistency and uniformity for foodservice and retail sectors.

Assessing outcomes of genetic selection panels to predict marbling in crossbred beef cattle

The objective of this study was to evaluate the effectiveness of genetic panel marbling indexes [Igenity (IT) and PredicGEN (PG)] to predict marbling and tenderness of crossbred cattle. Steers (n = 23) were harvested at the University of Idaho Meat Science Laboratory, and blood samples were submitted to Neogen and Zoetis for genetic panel analysis. Forty-eight hours postharvest, one boneless strip loin was collected from each carcass, and six 2.54-cm thick steaks were cut from each strip loin. Steaks were aged for 14 and 21 d and assigned to consumer sensory evaluation or Warner–Bratzler Shear Force (WBSF) analysis. Results were analyzed using the Mixed Model procedure of the Statistical Analysis System (SAS Institute, Inc., Cary, NC). Carcasses were grouped by marbling index score into Low IT (IT indexes 3–6; n = 16; marbling score (MS) = 410), High IT (IT indexes 7–10; n = 7; MS = 496), Low PG (PG index <50; n = 9; MS = 398), or High PG (PG index ≥50; n = 14; MS = 458). Mean MS was observed to be greater in High IT steaks than Low IT (P < 0.01) and greater in High PG steaks than Low PG (P = 0.01). There was a trend observed in WBSF between IT marbling groups (P = 0.06); however, no difference in WBSF was observed between PG marbling groups (P = 0.83). Consumers did not report differences between IT marbling groups in terms of acceptability (P = 0.99) or tenderness (P = 0.24). Additionally, consumers could not detect differences between PG marbling groups in terms of acceptability (P = 0.75) or tenderness (P = 0.40). Consumers consistently preferred Choice steaks over Select steaks in terms of acceptability (P = 0.02) and tenderness (P = 0.02). In conclusion, though consumers were not able to tell the difference between steaks from each of the genetic panels, using genetic panels to predict marbling, in conjunction with proper nutrition and handling practices, could be a beneficial tool to producers making decisions about retaining ownership at the feedlot.

Relationship between heifer carcass maturity and beef quality characteristics

Our objective was to determine the relationship between heifer carcass maturity and beef palatability of the longissimus lumborum (LM) and biceps femoris (BF). Left sides of A (n = 30), B (n = 30), and C (n = 30) maturity heifer carcasses under 30 mo of age by dentition were used. Carcasses were selected to ensure similar marbling scores across maturity groups (Small to Modest). Beef strip loins (LM) and outside rounds (BF) were obtained from these carcasses. Steaks were used to measure color stability, lipid oxidation (thiobarbituric acid reactive substances; TBARS), Warner-Bratzler shear force (WBSF), soluble and insoluble collagen, and consumer sensory perceptions. Heifer carcass maturity did not affect pH, fluid loss, WBSF, or collagen content of LM or BF steaks (P > 0.29). In LM and BF steaks, a maturity × day of retail display interaction occurred for TBARS, in which B maturity steaks had lower levels of lipid oxidation compared with A and C maturity steaks from the fourth day to the end of the retail display (P < 0.01). Nevertheless, LM steaks from B maturity carcasses tended to have lower overall acceptability (P = 0.08) and juiciness (P = 0.09) than steaks from C maturity carcasses, but steaks from B and C maturity carcasses did not differ from LM steaks obtained from A maturity carcasses. No differences in tenderness or flavor were observed due to maturity (P > 0.24). Similarly, maturity had no effect on sensory characteristics of BF steaks (P > 0.30). In conclusion, our results indicate that advanced physiological maturity does not decrease palatability of strip loin or outside round steaks from carcasses of heifers under 30 mo of age.

Effects of Finishing Diet and Packaging on Longissimus Dorsi Color

ObjectivesMeat color is extremely influential in purchasing decisions as consumers associate a bright-red color with freshness. The type of finishing diet can influence beef color. Previous studies have shown that grass-finished cattle have darker muscle color than grain-finished cattle. With the use of modified atmospheric packaging (MAP), beef purveyors are able to vary the gas compositions within a package and enhance beef color. However, limited studies have determined the effects of modified atmospheric packaging on grass-finished beef color. The objective of this study was to determine how finishing diet and packaging type affects the color of the longissimus dorsi (LD) muscle.Materials and MethodsDuring the stocker period, all of the cattle were on a forage diet. Cattle were then randomly assigned to either a conventional grain-based diet or an alfalfa pasture diet for finishing. Both conventionally and pasture-finished cattle were fed for 91 d. Cattle were slaughtered on the same day at a commercial beef processing facility under normal conditions and chilled for approximately 30 h. After grading, one strip loin from each carcass was collected and transported to Oklahoma State University. At 11 d postmortem, one steak (n = 60) from each strip loin was vacuum packaged and randomly assigned to display. Those steaks were then randomly assigned to PVC, HiOx-MAP (80% oxygen and 20% carbon dioxide), or CO-MAP (0.4% carbon monoxide, 69.5% nitrogen, and 30% carbon dioxide) packaging and were displayed under retail conditions for 5 d. Muscle darkening (MD), muscle color (MC), and surface discoloration (SD) were all analyzed by a trained panel (n = 6). MD was evaluated only on d 0 and MC and SD were scored once every 24 h for 0, 1, 2, 3, and 4 d. Lipid oxidation was measured by thiobarbituric acid reactive substances (TBARS) assay on d 4. Data were analyzed using the Mixed Procedure of SAS.ResultsThere was a significant display day by finishing diet by packaging interaction (P < 0.05) for muscle color and surface discoloration. There was also a significant finishing diet by packaging interaction (P < 0.05) for muscle darkening. Steaks packaged in HiOx-MAP remained the most stable in color and the brightest cherry-red colored throughout display time (P < 0.05) compared with other packaging types. PVC was the most discolored (P < 0.05) on d 3 and 4 when compared to HiOx-MAP and CO-MAP with the grain-finished PVC packaged steaks showing the most discoloration on d 4. Pasture-finished steaks packaged in CO-MAP displayed the darkest colored muscle (P < 0.05) on d 0. Steaks packaged in PVC had a higher amount of lipid oxidation (P < 0.05) compared with other packaging types.ConclusionThese results indicate that HiOx-MAP more effectively maintains the desired beef color of bright cherry-red for pasture-finished beef. The results also indicate that the use of appropriate packaging type can minimize the losses due to discoloration of steaks from either grain or grass-finished beef.

Effects of Dry Heat Cookery Method and Quality Grade on the Palatability of Beef Strip Loin Steaks

ObjectivesCooking meat using a clamshell grill has become common in university research settings due to speed, relative low cost, and acceptable repeatability. However, other cooking methods such as charbroiling and salamander grills have also become a popular method in the hotel and restaurant industry. The objective of this experiment was to evaluate the effect of different dry heat cooking methods on beef palatability across a range of USDA quality grades.Materials and MethodsA consumer panel (n = 288) was conducted at Texas Tech University. Strip loin steaks from four different USDA quality grades (Prime, upper 2/3 Choice, lower 1/3 Choice, and Select) were cooked using one of four cooking methods: electric clamshell grill (CLAM), flat top gas grill (FLAT), Charbroiler gas grill (CHAR), or Salamander gas broiler (SAL). After cooking to medium degree of doneness (70–72°C), steaks were cut into cubes (1.3-cm × 1.3-cm × steak thickness), and two cubes were served immediately to 6 predetermined consumers from each steak. Each consumer evaluated 8 samples, representing half of the 16 possible quality grades × cooking method treatment combinations. Consumers scored juiciness, tenderness, flavor liking, and overall liking using electronic ballots with the zero-point anchors labeled as extremely dry, extremely tough, dislike flavor extremely, and dislike overall extremely and the 100-point anchors labeled as extremely juicy, extremely tender, like flavor extremely, and like overall extremely. Also, consumers rated each sample as either acceptable or unacceptable for each palatability trait.ResultsThere were no interactions between the cooking method and quality grade for any of the palatability traits (P > 0.05). Steaks cooked on CHAR had greater (P < 0.05) flavor and overall liking scores, as well as a greater percentage of samples (P < 0.05) that were considered acceptable overall compared to the other cooking methods. Steaks cooked on FLAT were scored lower (P < 0.05) for tenderness and juiciness compared with all other cooking methods. Steaks cooked on CLAM, SAL, and CHAR were scored similarly for tenderness and juiciness (P > 0.05). Steaks cooked on FLAT were scored lower (P > 0.05) than CHAR and SAL for overall liking. Steaks cooked on CLAM had lower (P < 0.05) flavor liking scores than CHAR and SAL. Prime samples had greater scores (P < 0.05) than Low Choice and Select, which were similar (P > 0.05), for tenderness, juiciness, flavor liking, and overall liking, but Prime did not differ from Top Choice (P > 0.05) for any palatability traits.ConclusionThese results indicate cooking method had a significant impact on consumer palatability ratings, and those results were consistent across a range of quality grades. Even though these cooking methods are all classified as dry heat cookery methods, consumers in this study were able to detect differences in tenderness, juiciness, flavor liking, and overall liking. This may be due to increased cooking times or differing types of heat transfer possessed by the various cooking methods. These data suggest cooking steaks by CHAR resulted in the most desirable eating experience, and cooking steaks on FLAT and CLAM were less desirable. However, the low eating satisfaction of FLAT can be linked to low tenderness and juiciness, whereas CLAM liked less due to low flavor liking.