Using untargeted metabolomics and volatile aroma compounds to predict expert sensory descriptors and consumer liking of beef loin steaks varying in quality grade, aging time, and degree of doneness.

Precursors to flavor are important to its development, yet little is known about the intrinsic products of metabolism that influence flavor. Our objective was to use untargeted metabolomics and volatile aroma compounds to predict expert and consumer sensory traits. USDA Select and upper 2/3 Choice beef strip loins were wet aged for 10 or 20 d and then cut into steaks, vacuum-packaged, and frozen. Steaks were cooked to 63 °C, 71 °C, or 80 °C end-point internal steak temperature. USDA Choice steaks had more intense beef flavor identity, brown, roasted, fat-like, salty, sweet, sour, umami, buttery, and overall sweet flavors compared to USDA Select steaks (P < 0.05). Steaks cooked to 80 °C had more intense beef identity, brown, roasted, and umami flavors than steaks cooked to a lower degree of doneness. Steaks cooked to either 63 °C or 71 °C had more intense bloody, metallic, and sour flavors and were juicier, more tender, and had less connective tissue than steaks cooked to a higher degree of doneness. Volatile aroma compounds increased (P < 0.05) in Choice steaks aged for 20 d, while cooking steaks to 80 increased aldehydes, ketones, and pyrazines. Raw steaks had 69 small-molecule metabolomic compounds shared across all four quality grade x aging combinations, and discriminant analysis correctly categorized (P < 0.05) these metabolites. Metabolites and volatiles can be used to predict (r2 > 0.85) expert and consumer sensory panel descriptors and liking.

Replacing cottonseed meal and sorghum grain with corn dried distillers' grains with solubles in lamb feedlot diets: carcass, trained sensory panel, and volatile aroma compounds traits.

In a randomized design study, lambs were individually fed with ad libitum access to 70.9% concentrate diets for 56 d in individual pens. The positive control diet (CNTL) contained cottonseed meal (CSM), sorghum grain, and cottonseed hulls, but no dried distillers' grains with solubles (DDGS). Four treatment diets were similar to CNTL but did not contain CSM. Corn DDGS replaced 0% (0DDGS), 33% (33DDGS), 66% (66DDGS), or 100% (100DDGS) of the sorghum grain in the treatment diets. At 48-h postmortem, the longissimus muscle (LM) was removed from the carcass, cut into chops, frozen, thawed, cooked, and evaluated by a trained sensory panel. Lambs fed CNTL were compared with 0DDGS using contrasts and linear and quadratic effects were evaluated among the four DDGS diets. Lambs fed CNTL had greater (P ≤ 0.03) hot carcass weight (HCW) and LM area than lambs fed 0DDGS. As DDGS incrementally replaced sorghum grain, marbling linearly decreased (P = 0.03), LM area tended to linearly increase (P = 0.06), and skeletal maturity tended to linearly decrease (P = 0.06). As DDGS incrementally replaced sorghum grain, flavor attributes quadratically increased to 33DDGS then decreased (brown, roasted, umami; P ≤ 0.03), quadratically decreased to 33DDGS then increased (metallic; P = 0.004), or linearly decreased (lamb flavor identity; P = 0.03). Volatile aroma compounds 2-(hexyloxy)-ethanol decreased and 2,3-octanedione and methyl pyrazine increased quadratically with an increase in DDGS (P < 0.05). Additionally, 2-heptenal, heptanal, and 2-pentyl furan increased linearly, while 2-butanone decreased linearly as DDGS increased in the diet (P < 0.05). Results indicate that carcass and sensory characteristics and volatile aroma compounds are not negatively affected, in fact brown, roasted, and umami flavors are enhanced, when 33% DDGS replaces CSM and sorghum grain in Dorper lamb feedlot diets.

Effects of feeding juniper as a roughage on feedlot performance, carcass measurements, meat sensory attributes, and volatile aroma compounds of yearling Rambouillet wethers1,2.

The majority of U.S. lambs are born during late winter or early spring, which can create downstream variability in carcass quality if commercial lamb harvest is to be relatively constant throughout the year. Flavor is an important quality determining characteristic of sheep meat and is influenced, in part, by animal age at harvest. However, management practices to mitigate the risk of objectionable flavors in meat from old crop lambs or yearlings are not well known. Yearling (16.8 ± 0.14 mo) Rambouillet wethers were assigned to 1 of 3 treatment groups, which consisted of feeding a 20% ground sorghum-sudangrass hay diet for 40 d (JUN0; n = 10), a 20% ground juniper diet for 40 d (JUN40; n = 10), or a 20% ground hay diet for 20 d followed by a 20% ground juniper diet for 20 d (JUN20; n = 10). Wethers were harvested on day 41 and a whole bone-in loin and a boneless inside leg roast were fabricated from one side each of carcass. After grilling (loin chop) or convection air roasting (leg roast), trained sensory panel evaluation and measurement of aroma volatiles by gas chromatography/mass spectrometry were performed. Treatment diet did not affect (P ≥ 0.17) wether feedlot performance, dressing percentage, or loin eye area. However, wethers fed JUN0 tended (P = 0.06) to have greater back fat depth than wethers fed JUN20 or JUN40. No trained sensory panel trait of loin chop samples was affected (P > 0.10) by treatment. Leg roasts from JUN0 and JUN20 wethers had greater (P = 0.01) lamb identification sensory score than JUN40. Benzaldehyde, 1-heptanol, and 1-octanol concentrations were greater (P < 0.05) and decanal and nonenal concentrations were less (P < 0.05) in loin chops from JUN0 compared with JUN40 wethers. Additionally, the terpenes cedr-8-ene, gamma muurolene, and widdrene tended to be greater (P < 0.07) in loin chops from JUN20 and JUN40 than JUN0 wethers. The 2-pentyl-furan concentrations were greatest (P = 0.03) in leg roasts from JUN40 wethers. Like the loin chops, cedr-8-ene, gamma-muurolene, toluene, and widdrene were greater (P < 0.05) in leg roasts from wethers fed either of the juniper diets compared with JUN0. Yearling wethers can be finished on a feedlot diet containing 20% juniper for up to 40 d prior to harvest with no impact on feedlot performance, carcass characteristics, nor negative impact on sensory attributes or volatile compounds of either grilled loin chops or roasted legs.

Grilling temperature effects on tenderness, juiciness, flavor and volatile aroma compounds of aged ribeye, strip loin, and top sirloin steaks.

Ribeye, top loin, and top sirloin steaks were assigned a grilling temperature setting (177°C, 205°C, or 232°C) and consumer panel, Warner-Bratzler shear force, trained sensory panel, and GC/MS - olfactory analyses were performed. No differences (P > 0.05) in consumer overall, tenderness, juiciness, appearance, and flavor liking were detected among steak type or grill temperature. Grill surface temperature had no effect (P > 0.05) on trained panel tenderness scores. Of the volatiles present during an aroma event, pyrazine compounds were most influenced by grill surface temperature. The tenderness and juiciness of steaks grilled at differing temperatures were not perceived to be different by consumers; however, grilling temperature impacted the flavor of the final product by generating more pyrazine compounds. Steaks in this study likely were too tender to have a grilling effect on tenderness, but selecting different grilling temperatures can be used to vary the amount of browning of steaks and/or to modify aroma volatile compounds.

Substituting ground woody plants for cottonseed hulls in lamb feedlot diets: carcass characteristics, adipose tissue fatty acid composition, and sensory panel traits.

Effects of using ground woody plants in Rambouillet wether lamb (n = 48) feedlot diets on carcass characteristics, adipose tissue fatty acid composition, and sensory panel traits were evaluated. In a randomized design study with two feeding periods (period 1 = fed a 70% concentrate diet from days 0 to 27; period 2 = fed an 86% concentrate diet from days 28 to 57), lambs were individually fed six diets that differed only by roughage source (n = 8 animals/treatment; initial BW = 32.9 ± 3.2 kg): cottonseed hulls (CSH; control) or ground wood consisting of either redberry (RED), blueberry (BLUE), one-seed (ONE), or eastern red cedar (ERC) Juniperus spp., or Prosopis glandulosa (MESQ). After 57 d, the lambs were humanely harvested and after chilling (2 ± 1 oC) 24 h, carcasses were evaluated for carcass traits. At 48 h postmortem, the longissimus thoracis (LT) was removed from the left side of the carcass, and after freezing for no more than 3 mo, were thawed for 24 h, cooked, and evaluated by a trained sensory panel. Additionally, volatile aroma chemicals on the LT were determined by gas chromatograph/mass spectrometer/olfactory (GC/MS/OF, respectively) analyses. Lamb HCW was greater (P = 0.01) for lambs fed CSH compared with all other diets, but lambs had similar (P > 0.08) LM area, back fat thickness, leg circumference, and body wall. Neither adipose tissue fatty acid composition (P > 0.08) nor trained sensory panel evaluation (P > 0.18) was affected by finishing diet roughage source. Of the 81 volatile aroma compounds found in the grilled lamb chops, only seven were affected (P < 0.05) by dietary roughage source and included 1-pentanol (a sweet, pleasant aroma), heptenal (a fishy aroma), pentanal (fermented, bready aroma description), 1-(1H-pyrol-2yl)-ethanone (caramel-like), 2-heptanone (cheesy, banana, fruity aromatic), 6,7-dodecanedione (unknown aroma), and butanoic acid (a sweaty, rancid aroma). The addition of any of four species of juniper or mesquite may be substituted for CSH without negatively affecting carcass fat and muscling, fatty acid, or sensory traits.

Escherichia albertii Inactivation following l-Lactic Acid Exposure or Cooking in Ground Beef.

Escherichia albertii is an emerging foodborne pathogen recovered from young children and adults exhibiting symptoms of gastroenteritis via pathogenesis factors including attaching and effacing lesions, cytolethal distending toxin, and Shiga toxin variants. Study objectives were to determine E. albertii survival following (i) exposure to lactic acid as a function of solution pH and incubation period and (ii) cooking ground beef patties to different endpoint temperatures. E. albertii was incubated in phosphate buffer containing 3.0% l-lactic acid adjusted to pH 3.0, 4.0, 5.0, or 7.0; survivors were determined every 30 min for 150 min. Ground beef patties (80% lean) were cooked to temperature endpoints simulating undercooking (62°C), the minimum temperature for safe cooking (71.1°C), and cooking to well done (76°C). Maximal pathogen reduction was observed after a 30-min exposure to pH 3.0 l-lactic acid. Reductions of 3.9, 4.4, and 4.9 log CFU/g were obtained following cooking ground beef patties to 62, 71.1, and 76°C, respectively, but the reductions did not differ as a function of the endpoint cooking temperature (P ≥ 0.05). E. albertii may be controlled on beef through the proper application of antimicrobial interventions and cooking.