Leg Chops Research Articles

PSV-31 Influence of Hempseed Meal Supplementation on Fresh and Cooked Characteristics of Boer Cross Goats

Abstract Hempseed meal is byproduct of hemp oil production and is relatively high in fiber, fat, and protein, making it a potential feedstuff for ruminants. However, the impact this new byproduct could have on meat characteristics is unknown. The objective of the current study was to evaluate the impact of HSM on fresh and cooked characteristics of Spanish meat goat retail cuts. Forty Boer crossbred castrated male goats were randomly allocated to one of four diets (n = 10; 0, 10, 20 or 30%) containing HSM which originated from the manufacturing industry of hemp oil. Goats were provided 2 kg of diet daily that contained varying levels of HSM in addition to ad-libitum access to water throughout the study. Following a 60-day feeding period goats were harvested at the Lambert-Powell Meats Laboratory located at Auburn University. After chilling for 12 h at 0°C, carcass measurements were collected prior to carcass fabrication. Goat carcasses were fabricated into wholesale cuts of the shoulder, rack, loin and leg. Paired loins and legs were sliced into 2.54-cm-thick chops, vacuum packaged, and assigned to cook yield, instrumental fresh color, and instrumental tenderness and frozen at -23°C until all laboratory analysis could be completed. The use of HSM did not alter cooking yield in either the goat loin or leg chop (P > 0.05) regardless of inclusion percentage within the diet. Furthermore, Warner-Bratzler shear force (WBSF) did not differ (P > 0.05) with increasing inclusion rates of HSM for either the loin or leg chops. Instrumental color for lightness (L*) or yellowness (b*) did not differ (P > 0.05) across diet treatments for either the loin or leg chops. These findings suggest that the inclusion of HSM within the diet of Boer cross goats did not alter fresh or cooked meat characteristics in either the loin or leg chops.

Volatile Compounds of Lamb Longissimus and Semimembranosus from Australia, New Zealand, and the United States

ObjectivesDifferences in production practices based on country of origin create distinct differences in palatability of lamb from both the loin and the leg. The objective of this study was to identify volatile compounds which influence flavor across lamb leg and loin chops sourced from three countries of origin.Materials and MethodsLamb loins (IMPS #232 1 × 1; n = 30/treatment) and legs (IMPS #233A; n = 60/treatment) were sourced from Australia (AUS), New Zealand (NZ), and the United States (US). Product was fabricated to isolate the longissimus lumborum (LL) from the loins and the semimembranosus (SM) with adductor from the legs. Muscles were trimmed of external fat and connective tissue and fabricated into 2.54-cm thick chops, vacuum packaged individually, and frozen. A subset of samples (n = 15/treatment) for volatile compound analysis were thawed at 2–4°C for 24 h, cooked to a medium degree of doneness, frozen, and powdered. Volatile compounds were extracted via SPME from powdered samples and analyzed using GC–MS. Data were analyzed as a 2 × 3 factorial design with muscle, country of origin (COO), and their interaction as fixed effects with a significance level of α = 0.05.ResultsDifferences in volatile compounds of all classes were largely related to COO. Of the 36 lipid-derived compounds, 18 were affected by COO (P < 0.05) and 11 were affected by the interaction of muscle and COO (P < 0.05). Where the interaction was significant, US LL and SM samples generally produced greater concentrations of volatile compounds than other treatments (P < 0.05), especially in compound classes including alcohols, n-aldehydes, and ketones. Of the alkanes evaluated, only pentane was greater in US samples compared to other samples (P < 0.05) and was more than double the concentration produced in NZ and AUS samples. Alkenes did not follow the general trend of being increased in US samples. P-xylene was elevated in SM samples compared to LL samples (P < 0.01), and toluene was greater in NZ samples than US and AUS samples (P < 0.05). D-limonene was decreased in AUS samples compared to US and NZ samples. Of the 18 Maillard-derived compounds identified, 13 were affected by COO (P < 0.05), 3 were affected by muscle (P < 0.01), and 3 were affected by the interaction of COO and muscle (P < 0.05). Of the Strecker aldehydes, 3-methylbutanal and 2-methylbutanal were both affected by both COO (P < 0.01) and muscle (P < 0.05). US samples produced the greatest concentration of these compounds (P < 0.05) and AUS samples produced the least (P < 0.05). Samples from LL produced more of these compounds than SM samples (P < 0.05). Ketones including acetoin and 2,3-butanedione, which contribute positively to flavor in meat, were highly elevated in US samples compared to AUS and NZ (P < 0.05). Sulfur-containing compounds were generally greater in non-domestic product than US samples, except for dimethyl sulfide, which was greatest in US SM samples and least in NZ LL and AUS SM samples (P < 0.05). Pyrazines were generally elevated in NZ samples compared to AUS samples (P < 0.05), with US samples intermediate (P > 0.05).ConclusionCountry of origin is a strong influencer of flavor compounds in lamb. This is likely attributable to global differences in production system including, but not limited to, diet, genetics, sex, and postmortem handling and will influence the perception of flavor by consumers.

Consumer visual appraisal and shelf life of leg chops from suckling kids raised with natural milk or milk replacer.

The use of milk replacers to feed suckling kids could affect the shelf life and appearance of the meat. Leg chops were evaluated by consumers and the instrumental color was measured. A machine learning algorithm was used to relate them. The aim of this experiment was to study the shelf life of the meat of kids reared with dam's milk or milk replacers and to ascertain which illuminant and instrumental color variables are used by consumers as criteria to evaluate that visual appraisal. Meat from kids reared with milk replacers was more valuable and had a longer shelf life than meat from kids reared with natural milk. Consumers used the color of the whole surface of the leg chop to assess the appearance of meat. Lightness and hue angle were the prime cues used to evaluate the appearance of meat. Illuminant D65 was more useful for relating the visual appraisal with the instrumental color using a machine learning algorithm. The machine learning algorithms showed that the underlying rules used by consumers to evaluate the appearance of suckling kid meat are not at all linear and can be computationally schematized into a simple algorithm. © 2017 Society of Chemical Industry.

Consumer Assessment of Lamb Loin and Leg from Australia, New Zealand, and United States

Lamb was sourced from 3 countries [Australia (AUS), New Zealand (NZ), and United States (US)] representing 2 muscle types (semimembranosus and longissimus lumborum) to evaluate the palatability of lamb loin and leg chops according to US consumers (n = 360). For tenderness, flavor, and overall liking, there was an interaction detected between source country and muscle (P < 0.05). Overall, US loin chops had the highest (P < 0.05) consumer sensory scores, were rated the most acceptable (P < 0.05), and were placed in better than everyday quality or premium quality categories more often than all other treatments. Leg samples sourced from AUS and NZ were rated the lowest (P < 0.05) for consumer sensory scores for tenderness, flavor liking and overall liking, as well as being the least acceptable (P < 0.05) for flavor liking and overall liking. Both source country and muscle impacted (P < 0.01) juiciness scores, as well as tenderness and juiciness acceptability. US chops were juicier and more acceptable for tenderness and juiciness than chops sourced from AUS or NZ, regardless of muscle; consumers rated loin chops juicier and more acceptable for tenderness and juiciness than legs chops, regardless of source country (P < 0.05). Overall, consumers detected differences in palatability between muscle type and the source country. Loin chops were preferred over leg chops for all palatability traits. US consumers preferred the domestically sourced lamb over the lamb sourced from AUS and NZ; however, complete animal background (diet, gender, and age) and knowledge of potential differences in slaughter and chilling conditions, as well as control over postmortem aging, is needed to help differentiate if differences in flavor were due to diet, genetics, or other environmental factors.

Effect of dietary vitamin E on physicochemical and fatty acid stability of fresh and thawed lamb

This study evaluated the effect of dietary vitamin E supplementation (1000mg of DL-α-tocopheryl acetate/kg of basal diet) on physicochemical and fatty acid stability of fresh and thawed lamb leg chops, frozen stored for 3, 6 and 9months. Legs were chopped, modified atmosphere packaged (70%O2/30%CO2) and maintained under retail conditions (4±0.5°C, with 14h fluorescent light) for 9days. Muscle α-tocopherol concentration was over 3.5-fold higher in supplemented samples than in control lambs. The effect of dietary vitamin E was independent of frozen storage, so these effects were analysed separately. Vitamin E supplementation reduced lipid oxidation (P≤0.001) and decreased metmyoglobin formation, leading to a more attractive colour of meat. Moreover, supplementation led to a higher percentage of polyunsaturated fatty acids. Therefore, vitamin E supplementation could be recommended for preserving either fresh or thawed lamb.

Effect of borage and green tea aqueous extracts on the quality of lamb leg chops displayed under retail conditions

Different concentrations of two aqueous extracts from green tea leaves and borage seeds with potential antioxidant activity were evaluated in lamb leg chops. Chops were sprayed with 0.005, 0.05, 0.5, 5% (p/v) green tea extracts (T) and 0.5, 5 and 10% (p/v) borage seed extracts (B) and displayed under retail conditions for 13days. Total polyphenols, TBARS, colour, microbial and sensory analyses were performed. The extracts showed a concentration-dependent action; the minimum concentration of polyphenols which significantly reduced lipid oxidation was 2.08mgGAE/100cm2 of meat. Both 0.5% T and 10% B limited colour deterioration, reducing also metmyoglobin formation. The extracts showed no antimicrobial effect, exceeding microbial counts of 7logCFU/cm2 at 13days of display. Sensory analyses determined that none of the extracts added herb odours or flavours to lamb. In conclusion, 0.5% T or 10% B extracts extended lamb shelf life from 8 to 11days, so both would be recommended for lamb chops preservation.

US Consumer Assessment of Lamb Loin and Leg Chops From Australia, New Zealand, and United States

ObjectivesAlthough lamb is consumed in low volumes in the U.S., especially when compared to high lamb consumption countries such as Australia (AUS) and New Zealand (NZ), U.S. consumers have 3 main options when choosing lamb in the U.S.: domestic, imported from AUS, or imported from NZ. Based on previous research with beef, palatability differences in lamb are expected when comparing country origins and muscle types. The objective of this study was to evaluate the effects of country-of-origin and muscle type on palatability of lamb loin and leg chops as determined by U.S. consumers.Materials and MethodsThe U.S. lamb (n = 70 carcasses) was obtained from a commercial lamb processor in Colorado; full lamb loins (IMPS 232; 1 × 1) and paired lamb legs (IMPS 233A) were retained from those carcasses, vacuum packaged and shipped to Texas. Full lamb loins and lamb legs from AUS and NZ were procured from food distributors. Loins were fabricated to obtain only the longissimus lumborum, by removing tenderloins, bone, flank and all other secondary muscles. Legs were fabricated to obtain the semimembranosus with adductor. Loins and legs were trimmed of any visible external fat and connective tissue, manually fabricated into 2.5 cm thick chops, vacuum packaged, stored at 2°C, and frozen at 21d postmortem. Untrained consumers (n = 360) from Lubbock, TX; State College, PA; Gainesville, FL; Fort Collins, CO; and Fresno, CA rated tenderness, juiciness, flavor liking and overall liking on 100 mm line scales. Data for sensory attributes were analyzed as a 2 × 3 factorial design using the GLIMMIX procedure SAS (Version 9.4; SAS Inst. Inc., Cary, NC) with fixed effects of country, muscle and their interaction. Location and consumer within testing night were included as random effects. Treatment least squares means were separated with the PDIFF option of SAS at a significance level of P < 0.05.ResultsThe interaction between country and muscle was detected for tenderness, flavor, and overall liking (P < 0.05). U.S. loins were more tender (P < 0.05) than all other treatments, followed by AUS and NZ loins, which did not differ (P > 0.05). Next, U.S. legs were more tender than legs from AUS or NZ, which did not differ (P > 0.05). Consumers preferred the flavor of U.S. loins more (P < 0.05) than all other treatments. Next, U.S. legs and AUS loins were similarly liked more than NZ loins, but consumers liked the flavor of legs from NZ and AUS less than any other treatment. Overall liking followed the exact same trend as flavor liking. Both country and muscle impacted (P < 0.01) juiciness scores. U.S. loin chops were juicier than AUS or NZ loin chops, regardless of muscle, and consumers rated loin chops juicier than legs chops, regardless of country (P < 0.05).ConclusionConsumers found palatability differences in lamb between country origins and muscle types. U.S. consumers prefer domestically sourced lamb over AUS and NZ when comparing tenderness, juiciness, flavor and overall liking. Loin chops were preferred over leg chops for all palatability traits. It is recommended that U.S. consumers purchase U.S. lamb and lamb loin for a better eating experience.

Sensory quality of lamb following long-term frozen storage

The study analysed the effect of frozen storage duration (FSD) on lamb sensory quality. Trained panel evaluated Longissimus lumborum aged for 1d in unfrozen carcass plus 3d in modified atmosphere packaging on thawed (1, 9, 15 or 21month FSD) or refrigerated (0month FSD) meat. Consumer acceptability test was performed on leg chops (Semimembranosus) kept in the same conditions but those chops for the visual test were retail displayed up to 10d from packaging. FSD differed on texture variables and fresh meat showed intermediate values among thawed meats for trained evaluators. Consumers gave the lowest acceptability to 21months FSD and preferred 1month FSD, being all meats ‘acceptable’. A third of the population scored fresh meat with the lowest acceptance after consumption, although its visual score remained ‘acceptable’ 3d longer than most of thawed meats. As thawed and fresh meats were equally preferred at short display, consumer concerns about thawed meat might be reconsidered.

Characterization and consumer acceptance of three muscles from Hampshire × Rambouillet cross sheep expressing the callipyge phenotype1

Eight Hampshire x Rambouillet crossbred wethers expressing the callipyge phenotype and eight Hampshire x Rambouillet half-sibling wethers with a normal phenotype were slaughtered when they reached 59 kg. The supraspinatus (SPM), longissimus (LM), and semitendinosus (STM) muscles were analyzed to determine callipyge effects on calpain and calpastatin activities, sarcomere length, percentage of muscle fiber types, and muscle fiber areas. After 14 d of aging, chops were frozen until analyses for trained sensory panel evaluations, Warner-Bratzler shear force values, and consumer perceptions of tenderness, flavor, juiciness, and overall satisfaction of chops were conducted. Calpastatin activity was 57% greater (P < 0.05) and m-calpain activity was 33% greater (P < 0.05) in muscles from carcasses of callipyge than normal sheep. Sarcomeres were shorter (P < 0.001) in the LM than the SPM or STM, regardless of phenotype. Muscle fiber area was 76% larger (P < 0.05) in the LM of callipyge than normal sheep, but muscle fiber area was not affected (P > 0.05) by phenotype in the SPM or STM. Phenotype had no effect (P = 0.12) on the percentage of slow-twitch, oxidative fiber types in any of the three muscles. In STM and LM from callipyge lambs, the percentage of fast-twitch, oxidative/glycolytic fibers was lower (P < 0.05) and that of fast-twitch-glycolytic fibers was higher (P < 0.05) than in their normal counterparts. Phenotype did not affect (P = 0.90) the fiber type percentage in the SPM. Callipyge LM were less tender and normal LM were more tender than other chops (P < 0.05). Callipyge loin chops had higher Warner-Bratzler shear force values than other chops (P < 0.001). Consumers rated fewer (P < 0.05) callipyge loin and shoulder chops acceptable in juiciness, tenderness, and overall acceptability than normal chops, but phenotype did not affect (P > 0.05) consumer acceptability of leg chops. These results indicate that LM from Hampshire x Rambouillet sheep displaying the callipyge phenotype had higher calpastatin activity and were less tender than the LM from normal sheep. In addition, consumer perceptions indicated that only one in 10 leg chops, one in five shoulder chops, and one in four loin chops from callipyge sheep were unacceptable.

Effect of the callipyge phenotype and cooking method on tenderness of several major lamb muscles.

We conducted three experiments to determine the effects of the callipyge phenotype on the tenderness of several major lamb muscles and to determine the effect of method of cookery on the tenderness of callipyge lamb at 7 d postmortem. In Exp. 1, chops from normal (n = 23) and callipyge (n = 16) carcasses were open-hearth-broiled. Warner-Bratzler shear force values of longissimus, gluteus medius, semimembranosus, biceps femoris, semitendinosus, adductor, and quadriceps femoris were 123, 44, 28, 26, 19, 16, and 13% greater, respectively, for callipyge (P < .05). In Exp. 2, muscles from normal (n = 18) and callipyge (n = 18) carcasses were oven-roasted. Shear force of triceps brachii was 11% greater for callipyge (P < .001); however, phenotype did not affect shear force of supraspinatus (P = .87) or psoas major (P = .64). In Exp. 3, a trained sensory panel evaluated leg roasts and open-hearth-broiled leg chops from normal (n = 60) and callipyge lamb carcasses (n = 60). Callipyge chops were less tender than normal chops (P < .05). Regardless of callipyge phenotype, muscles were more (P < .05) tender when roasted; however, the effect of method of cookery on tenderness scores was greater for callipyge muscles than for normal muscles. Callipyge roasts and normal roasts had similar tenderness (P = .58), and callipyge roasts were more tender than normal chops (P < .05). Regardless of cooking method, callipyge samples were less juicy than normal samples (P < .05). These data demonstrate that the callipyge phenotype will likely reduce consumer satisfaction due to reduced tenderness and juiciness; however, reduced tenderness in callipyge leg muscles could be prevented by ovenroasting.