Effect of different electrical stimulation systems on beef quality and palatability: Constant current compared to constant voltage

This study examined the effects of constant current electrical stimulation (CCES) compared to constant voltage electrical stimulation (CVES), when applied within the same beef carcass (n = 79), on longissimus thoracis et lumborum (LTL) quality and palatability. There was a stimulation method × time interaction for pH, with CCES reducing the 3 h post-mortem pH, but increasing the 72 h post-mortem pH compared to CVES (P < 0.001). The CCES decreased the meat subjective Japanese Meat Grading Agency (JMGA) colour scores (P < 0.05) and increased the objective L⁎ (P < 0.01), a⁎ (P < 0.05) and b⁎ (P < 0.05) colour values at 3 d post-mortem and L⁎ and b⁎ values (P < 0.05) during retail display compared to CVES, although the objective values from both stimulation methods were above established consumer acceptability thresholds. Additionally, CCES reduced the purge (P < 0.05) and drip (P < 0.01) losses, and tended to reduce shear force values (P = 0.089) compared to CVES, although these did not translate into differences in juiciness or tenderness evaluated by trained panelists (P > 0.1). Regarding flavour, the CCES meat had greater bloody/serumy flavour (P < 0.05) and corn aroma (P < 0.05), less unidentified aroma (P < 0.05), and tended to have greater corn flavour (P = 0.077) and less barnyard aroma (P = 0.079) than CVES meat. There were also increased concentrations of flavour-related volatile compounds including 2-methyl-butanal, 3-methyl-butanal and 2-5-dimethyl pyrazine levels (P < 0.05) with CCES. Overall, the CCES system slightly improved meat quality and flavour compared to CVES when applied to the same beef carcasses. Further consumer studies would be warranted to determine whether these differences translate into more acceptable meat.

Freezing/thawing as an accelerating process of wet- and dry-aged Nellore beef

This study aimed to evaluate the use of freezing/thawing as a way of accelerating the aging processes of beef from Nellore animals. Non-frozen (NF) or freezing/thawing (FT) strip loins were aged (for 14 and 28 days) using two systems: bone-in dry-aging (DA); boneless wet-aging (WA). FT-treated samples had greater weight losses (P < 0.05) during aging than NF-treated samples, especially using the DA process. However, the weight loss of the FT 14-days DA beef samples was comparable to that of NF 28-days DA. FT beef had lower fragmentation index and shear force values (P < 0.05), as well as its maximum sensorial tenderness was achieved earlier (P < 0.05) than the NF counterpart. With 28 days of aging, DA beef showed higher (P < 0.05) tenderness and juiciness scores and lower lightness values than WA beef. The FT process decreased the reducing capacity of meat samples, generating more metmyoglobin and lower amounts of chroma than NF. The expected volatile profile of DA beef was achieved faster in FT-treated samples, but the freezing treatments did not compromise the microbial count for either aging system. Our findings indicate that accelerated DA by the FT process could improve the palatability of Nellore beef, allowing the desired tenderness and flavor profile to be achieved in a shorter time, without increasing costs with weight losses or adversely affecting physicochemical, chemical, and microbial characteristics.

A current review of U.S. beef flavor I: Measuring beef flavor

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.

A current review of U.S. beef flavor II: Managing beef flavor

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.

Effects of in-the-bag dry-ageing on meat quality, palatability and volatile compounds of low-value beef cuts

This study evaluated the effects of in-the-bag dry-ageing (BDA) (21 and 42 d) on meat quality, palatability, and volatile compounds of clod heart, brisket, and flat iron cuts from steers. In all cuts, BDA increased moisture losses (P < 0.05), but this did not reduce the juiciness of 21 d BDA versus wet-aged (WA) steaks. In clod heart, BDA increased overall tenderness at 21 d compared to 21 d WA (P < 0.01). Regardless of ageing period, BDA of clod heart increased beef flavour and salty taste and decreased sour-dairy and stale/cardboard flavours and concentrations of volatile compounds derived from lipid oxidation compared to WA (P < 0.05). In brisket, BDA increased salty taste and fatty aroma and reduced bloody/serumy flavour, whereas decreased beef and buttery flavours and intensified some unpleasant aromas/flavours (P < 0.05) for both ageing periods. The BDA of flat iron increased several undesirable aromas/flavours and decreased sweet taste and beef and buttery flavours (P < 0.05), regardless of ageing period. Overall, BDA for 42 d decreased meat quality and palatability and increased concentrations of volatile compounds from lipid oxidation, especially in flat iron cuts. Value could be recovered by customizing BDA periods by cut.

Flavor, Tenderness, and Related Chemical Changes of Aged Beef Strip Loins

Varying aging times and methods were evaluated for their effect on flavor, tenderness, and related changes involatile compounds and flavor precursors. Strip loin sections from USDA Choice beef carcasses (n = 38) were randomly assigned to treatments: (1) 3 d wet-aged, (2) 14 d wet-aged, (3) 28 d wet-aged, (4) 35 d wet-aged, (5) 49 d wet-aged, (6) 63 d wet-aged, (7) 21 d dry-aged, and (8) 14 d wet-aged followed by 21 d dry-aged. Samples were analyzed for trained sensory attributes, shear force, volatile compounds, and flavor precursors (fatty acids, free amino acids, and sugars). Discriminant function analysis was used to identify sensory attributes contributing the greatest to treatment differences. Flavor notes were not differentiated in beef aged up to 35 d, regardless of aging method. A shift in flavor occurred between 35 d and 49 d of wet-aging time that was characterized by more intense sour and musty/earthy notes. Both shear force assessment and trained panelists agreed that tenderness was not affected (P &gt; 0.05) by additional aging beyond 28 d. Volatile compound production and liberation of amino acids and sugars increased (P &lt; 0.01) during the progression of aging time, with no change (P &gt; 0.05) in fatty acid composition, which may be a result of metabolic processes like microbial metabolism. Chemical properties shared strong positive relationships (r &gt; 0.50, P &lt; 0.001) with sour, musty/earthy, and overall tenderness. These results substantiate the deteriorative effect of extended aging times of 49 d or greater on flavor of beef strip loins without tenderness improvement.

Comparison of meat quality, fatty acid composition and aroma volatiles of dry-aged beef from Hanwoo cows slaughtered at 60 or 80 months old

OBJECTIVE

The objective of this study was to compare the quality of dry-aged beef from cull Hanwoo cows slaughtered at 60 or 80 months old.

METHODS

A total of eight cull Hanwoo carcasses with a quality grade of 3 (low-grade) were selected and divided into two age groups: 63.5±2.5 months old (n = 4) and 87.8±4.5 months old (n = 4). Whole longissimus thoracis et lumborum from the 11th rib to the last lumbar vertebrae, including the back fat, was removed from the carcass at 24 h postmortem and aged for 50 days in darkness at a temperature of 2°C±1°C, a relative humidity of 85% and an air flow of 2 m/s. The sampling was performed aseptically after 0, 20, 24, 40, and 50 days of aging.

RESULTS

Regardless of the aging period, aging increased the lightness (p<0.05), redness (p<0.05) and yellowness (p<0.05) at initial blooming (90 min after slicing) and the overall acceptance (p<0.05). No further tenderization effect was found after 20 days of aging, but aging for 50 days significantly increased the lipid oxidation (p<0.05). The generation of aroma volatiles in the roast steak from aged samples was higher (p<0.05) than that of non-aged samples. No significant effect of age at slaughter was found on the color, pH, water-holding capacity, cooking loss, shear force value, bacterial counts, volatile basic nitrogen, consumer acceptance, lipid oxidation, fatty acid composition or aroma volatiles.

CONCLUSION

The quality of dry-aged beef obtained from cull Hanwoo cows slaughtered at either 60 or 80 months old with similar quality grade was comparable and extending dry aging for more than 40 days is not recommended considering the costs and further lipid oxidation.