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Historically, consumer acceptance of beef was determined by tenderness. Developments in genetics and management over the last couple of decades have improved tenderness to the point that it is secondary to other factors in beef's taste. Flavor, however, is an extraordinarily complex taste attribute dependent on biological sensors in the mouth, sinus cavity, and jaws. The culinary industry has recently focused on innovative ways to give consumers new products satisfying their curiosity about different foods, especially proteins. Competition from plant-based, cell-based, and even other animal-based proteins provides diversity in consumers' ability to select a protein that satisfies their desire to include unique products in their diet. Consequently, the beef industry has focused on flavor for the last 10 to 15 years to determine whether it can provide the guardrails for beef consumption in the future. The U.S. beef industry formed a Flavor Working Group in 2012 composed of the authors listed here to investigate new and innovative ways to manage and measure beef flavor. The results of this working group have resulted in dozens of papers, presentations, abstracts, and symposia. The objective of this manuscript is to summarize the research developed by this working group and by others worldwide that have investigated methodologies that measure beef flavor. This paper will describe the strengths of the research in beef flavor measurement and point out future needs that might be identified as technology advances., Competing Interests: Declaration of competing interest None., (Copyright © 2024. Published by Elsevier Ltd.)

Beef flavor continues to be one of the largest drivers of beef demand and a differentiation point of beef from other competing proteins. Tenderness has long been identified as the most important palatability trait for consumer satisfaction. However, as technological advancements and industry practices evolve and improve in response to tenderness management, flavor has emerged as a key driver of consumer satisfaction. In response, the beef industry has recently invested in research focused on beef flavor development, measurement, and management to better understand the factors impacting flavor and help beef maintain this advantage. The current review paper is the second of two such papers focused on summarizing the present knowledge and identifying knowledge gaps. While the other review focuses on current practices related to beef flavor measurement, this review will cover research findings related to beef flavor management. Numerous production and product management factors influence beef flavor. Pre-harvest factors including marbling level, animal genetics/cattle type, diet, and animal age, can influence beef flavor. Moreover, numerous post-harvest product management factors, including product type, aging length and conditions, cookery methods, product enhancement, muscle-specific factors, packaging, retail display factors, and antimicrobial interventions, have all been evaluated for their impact on beef flavor characteristics. Results from numerous studies evaluating many of these factors will be outlined within this review in order to present management and production chain factors that can influence beef flavor., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Our objective was to investigate possible differences in muscle fiber characteristics of beef longissimus lumborum (LL) steaks varying in tenderness (very tender vs. intermediate tender). Therefore, the relative abundance of myosin heavy chain (MHC) isoforms and activity/abundance of several glycolytic and oxidative enzymes were compared between the two steak groups. Greater (P < 0.05) content of MHC type IIa (MHC-IIa) and activities of phosphofructokinase (PFK) and glycogen phosphorylase (GP) were observed in the very tender steaks. Conversely, intermediate tender steaks had greater (P < 0.05) contents of MHC type I (MHC-I) and succinate dehydrogenase (SDH) and greater citrate synthase (CS) activity. Increased tenderness in the very tender steaks was associated with greater (P < 0.05) proteolysis as evaluated by desmin and troponin-T degradation. Further, mitochondrial calcium uniporter (MCU) was lower (P < 0.05) in the very tender steaks than steaks of intermediate tenderness. Collectively, shifting muscle characteristics toward a more glycolytic type appears to positively impact postmortem proteolysis and tenderization., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The objective of this study was to evaluate the influence of metabolizable protein (MP) restriction in mid- and/or late-gestation on meat quality characteristics of progeny. Heifers were assigned to 2 levels of dietary protein (control [CON], 102% of MP requirements; or restricted [RES], 80% of MP requirements) at 2 stages of gestation (mid-gestation [MID] and late-gestation [LATE]) in a Balaam's Design crossover treatment structure resulting in 4 treatment combinations (CON-CON, CON-RES, RES-CON, RES-RES). A carryover effect of MID MP treatment on LATE CON indicated CON-CON steaks were more tender (P < .001) than RES CON. Mid-gestation restriction resulted in progeny with increased (P < .05) carcass water, soft tissue moisture, and decreased soft tissue fat percentage compared with progeny from dams receiving MID CON. Reduced maternal MP also differentially influenced the fatty acid profiles of progeny. Results suggest it is possible for progeny to overcome a moderate gestational MP restriction with minimal impacts on carcass composition or meat characteristics., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The objective of the current study was to determine the effects of three USDA quality grades and cooking on the water-soluble flavor precursors of beef Longissimus lumborum. Raw and cooked steaks from beef strip loins of USDA Prime (PR; n = 8), Low-Choice (LC; n = 8), and Standard (ST; n = 8) were analyzed for extractable free amino acids, reducing sugars, and other nitrogenous organic compounds (NOCs). Overall, two-way quality grade × cooking interactions were found for the contents of most water-soluble precursors (P quality grade × cooking  < 0.05), which were greater in raw LC and ST and were changed more in ST and LC steaks by cooking. The magnitude of those changes suggested that cystine, a dimer of cysteine, glucose, and glucose 6-phosphate might play more important roles in beef flavor development than previously thought., (Published by Elsevier Ltd.)

The objective of this study was to evaluate the effect of dry-aging on meat quality and microbiological properties of grass-fed beef loins. At 7 d postmortem, eighteen bone-in loins (M. longissimus lumborum) from 9 beef carcasses (USDA Select) were obtained. Each loin was cut in half yielding a total of 36 sections, which were assigned to three aging methods: wet-aging (WA); dry-aging (DA); and dry-aging in a water permeable bag (DW). DA resulted in greater shrink and trim loss compared to WA (P < 0.05). However, DW minimized moisture and trim loss resulting in an increase in total saleable yield up to 4%. DA samples were lowest in both aerobic/anaerobic bacteria (P < 0.05). DA steaks had significantly higher flavor and tenderness preferences compared to WA counterparts. Consumers determined DW to have greater juiciness compared with WA (P < 0.05). Our findings indicate that dry-aging could improve eating quality attributes of low marbled grass-fed beef without adversely affecting microbial characteristics., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The palatability of USDA graded beef strip loins of seven treatments [High Enhanced (HE: 112% of raw weight) Select, Low Enhanced (LE: 107% of raw weight) Select, Prime, upper 2/3 Choice (Top Choice), lower 1/3 Choice (Low Choice), Select, and Standard] cooked to three degrees of doneness [DOD; rare (60°C), medium (71°C), or well-done (77°C)] was evaluated by consumer and trained sensory panelists. For consumers, Select HE steaks rated higher (P<0.05) for juiciness, tenderness, flavor identity, flavor liking, and overall liking than all non-enhanced treatments other than Prime. No differences (P>0.05) were observed between Select LE and Prime samples for most traits evaluated. The effect of USDA grade and enhancement on trained panel palatability scores was independent of DOD for all traits other than juiciness, with the role of marbling in juiciness increasing as DOD increased from rare to well-done. These results indicate enhancement as an effective method to improve the palatability of lower grading beef., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Fatty acids (FA) in neutral and polar lipids (NL and PL) and volatile compounds were determined in Gluteus medius (GM), Longissimus lumborum (LL), Serratus ventralis (SV), and Semimembranosus (SM) muscles from upper 2/3 USDA Choice and Select quality grades (QG). Concentrations of NL FA (mg/g) were influenced by intramuscular fat (IMF) content being greater in upper 2/3 Choice compared with Select. The SV contained greater concentrations of NL FA; meanwhile, the SM contained the lowest quantities of NL FA. Percentages (g/100g of total FA) of NL SFA and MUFA were increased in beef with greater IMF content. Concentrations and percentages of PL FA had muscle specific differences between QG. Volatile compounds were primarily affected by muscle. Increases in SFA and MUFA were related with consumer liking, regardless of lipid fraction. Overall the influence of QG on SFA and MUFA was muscle specific. Therefore, each muscle may require specific considerations when considering FA, volatile compounds, and ultimately consumer liking., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Sensory analysis of ground LL samples representing 12 beef product categories was conducted in 3 different regions of the U.S. to identify flavor preferences of beef consumers. Treatments characterized production-related flavor differences associated with USDA grade, cattle type, finishing diet, growth enhancement, and postmortem aging method. Consumers (N=307) rated cooked samples for 12 flavors and overall flavor desirability. Samples were analyzed to determine fatty acid content. Volatile compounds produced by cooking were extracted and quantified. Overall, consumers preferred beef that rated high for beefy/brothy, buttery/beef fat, and sweet flavors and disliked beef with fishy, livery, gamey, and sour flavors. Flavor attributes of samples higher in intramuscular fat with greater amounts of monounsaturated fatty acids and lesser proportions of saturated, odd-chain, omega-3, and trans fatty acids were preferred by consumers. Of the volatiles identified, diacetyl and acetoin were most closely correlated with desirable ratings for overall flavor and dimethyl sulfide was associated with an undesirable sour flavor., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Consumer palatability scores, sensory descriptive attributes, and volatile compounds were assessed for beef Longissimus lumborum steaks of USDA Prime, Low Choice, and Standard grades. Overall and flavor liking was greater (P<0.05) for Prime and Low Choice. Initial flavor impact and fat-like attributes were greater (P<0.05) among Prime and Low Choice. Prime had greater (P<0.05) brown/roasted, beef identity, overall sweetness, and umami. Cardboard was greater (P<0.05) in Standard. Volatile compounds representing flavor development pathways were varied with quality grade. Standard had greater (P<0.05) abundances of n-aldehydes. Phenylacetaldehyde was greater (P<0.05) in Prime and Low Choice. Both 2,3-butanedione and 3-hydroxy-2-butanone were greatest (P<0.05) in Prime. Overall liking was positively correlated with many descriptive attributes, 3-hydroxy-2-butanone, and phenylacetaldehyde, and negatively correlated with cardboard, green, and n-aldehydes. While the measured attributes and volatiles may not be causative of flavor, this data indicates potential for prediction of flavor through their measurement., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The effects of USDA beef quality grade (QG; Prime, Low Choice, and Standard; n=8) and cooking (RC) on fatty acid (FA) concentrations (mg/g dry matter) and percentages of neutral and polar lipid fractions (NL and PL, respectively)from strip steaks were explored. An increase in QG led to an accumulation of most FA, especially in the NL fraction (P < 0.001). Common effects on FA percentages were two-way interactions of either QG or RC with LF (P ≤ 0.019). Fatty acids were affected differently by QG and RC depending on their originating LF. Monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) percentages of the PL were dependent on QG (P ≤ 0.014). Cooking and QG had minimal impact on FA percentages of the NL, however, greatly influenced PL MUFA and PUFA percentages (P b 0.001). There was evidence indicating that dry heat cookery affected not only PUFA, as generally thought, but also the MUFA of PL fraction.

Proximate data, consumer palatability scores and volatile compounds were investigated for four beef muscles (Longissimus lumborum, Psoas major, Semimembranosus and Gluteus medius) and five USDA quality grades(Prime, Upper 2/3 Choice, Low Choice, Select, and Standard). Quality grade did not directly affect consumer scores or volatiles but interactions (P < 0.05) between muscle and grade were determined. Consumer scores and volatiles differed (P < 0.05) between muscles. Consumers scored Psoas major highest for tenderness, juiciness, flavor liking and overall liking, followed by Longissimus lumborum, Gluteus medius, and Semimembranosus (P < 0.05). Principal component analysis revealed clustering of compound classes, formed by related mechanisms. Volatile n-aldehydes were inversely related to percent fat. Increases in lipid oxidation compounds were associated with Gluteus medius and Semimembranosus, while greater quantities of sulfur-containing compounds were associated with Psoas major. Relationships between palatability scores and volatile compound classes suggest that differences in the pattern of volatile compounds may play a valuable role in explaining consumer liking.

The palatability of tender [Warner-Bratzler shear force values <33.34N (3.4kg)] beef strip loins of 10 different treatments [USDA Prime, High Choice (upper 1/3 Choice), Low Choice (lower 1/3 Choice), Select, Standard, Australian Wagyu, American Wagyu, Holstein Select, Holstein Top Choice (upper 2/3 Choice) and Grass-finished] was evaluated by consumers and a trained flavor panel. In general, tenderness, juiciness, flavor, and overall liking ratings as well as acceptability percentage for each trait, increased with increased fat levels. Moreover, overall liking was highly correlated (P<0.01) with flavor liking (r=0.96) as well as fat percentage (r=0.79). Beef flavor scores were positively associated (P<0.01) with fat-like (r=0.67) and umami (r=0.59) flavors. Fat level was the primary driver of beef flavor acceptability in all samples when no undesirable off-flavors were present., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

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., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The effect of storage length and temperature on the shelf life of three ground beef formulations (lean:fat: 73:27, 81:19 and 91:9) was investigated. Coarsely ground beef was stored at -1.7 or 2.3°C for up to 28d. Traditional overwrap packages were produced every 7d prior to retail display for 24h. Lipid oxidation (TBARS), subjective color, instrumental color, and aerobic bacteria were evaluated after 0 and 24h of display. Formulation influenced initial L* and subjective color values (P<0.05). Storage temperature did not affect initial color, but product stored at 2.3°C was more discolored after 24h (P<0.05). Aerobic bacteria increased as storage d and temperature increased (P<0.05). Initial TBARS increased through d 21, but were lower after 28d. Overall, initial characteristics depended on formulation; however, ground beef shelf-life and stability were largely influenced by storage length and storage temperature., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Beef nutrition is important to the worldwide beef industry. The objective of this study was to analyze proximate composition of eight beef rib and plate cuts to update the USDA National Nutrient Database for Standard Reference (SR). Furthermore, this study aimed to determine the influence of USDA Quality Grade on the separable components and proximate composition of the examined retail cuts. Carcasses (n=72) representing a composite of Yield Grade, Quality Grade, gender and genetic type were identified from six regions across the U.S. Beef plates and ribs (IMPS #109 and 121C and D) were collected from the selected carcasses and shipped to three university meat laboratories for storage, retail fabrication, cooking, and dissection and analysis of proximate composition. These data provide updated information regarding the nutrient content of beef and emphasize the influence of common classification systems (Yield Grade and Quality Grade) on the separable components, cooking yield, and proximate composition of retail beef cuts., (Copyright © 2013 Elsevier Ltd. All rights reserved.)