Evaluation of sample preparation methods for water activity determination in jerky and kippered beef: A research note

Commercially available packaged whole muscle beef jerky, chopped and formed beef jerky, and kippered beef steak were obtained from retail stores to determine the effect of two sample preparation methods on water activity (a_w). Intact samples were prepared by cutting product into a hexagonal shape with a 3.2 cm diameter. Diced samples were prepared by cutting the product into 0.4 × 0.4 cm squares. Whole muscle jerky a_w was higher (0.016 units; P < 0.001) using the intact method compared to the diced method. There was no difference (P > 0.05) in a_w levels between the two preparation methods for chopped and formed jerky or kippered beef steak. An intact sample preparation method is recommended for a_w determination of whole muscle jerky to obtain a more conservative value, especially if a_w is near the margin of safety.     

EVALUATION OF THE PHYSICAL,CHEMICAL AND SENSORY PROPERTIES OF JERKY PROCESSED FROM EMU,BEEF, AND TURKEY1

Three jerky formulations were prepared from beef top round, turkey breast, and various emu cuts (inner mid drum, inner outside drum, oyster, and fan fillet). The meat sources were sliced, cured, smoked, and dried. All treatments were evaluated for palatability traits, shear force and chemical properties. No significant difference was found in the sodium or ash levels among the three treatments. Beef jerky had the highest percentage fat followed by emu, and then turkey (p < 0.05). Emu jerky was the toughest, chewiest, and most desirable as evaluated by a trained and consumer sensory panels. The production of emu jerky may be of particular interest to the emu industry to increase profits by utilizing less desirable cuts and opening a new market for the meat obtained from the emu. The information provided by this study can be utilized by emu producers and product marketers for the advancement of the emu industry.     

The physicochemical and microbiological characteristics of pork jerky in comparison to beef jerky

This study was carried out to compare the physicochemical and microbiological characteristics of beef and pork jerky, prepared from whole muscle of beef semimembranosus (BSM), pork semimembranosus (PSM), pork longissimus dorsi (PLD), and pork psoas major (PPM). The BSM and PSM jerky had higher moisture content, and PPM jerky had lower water activity than other jerky samples during 30 days of storage at 25 °C (P < 0.05). Pork jerky samples had higher lightness value than beef jerky, while PSM jerky had higher pH value than other jerky samples (P < 0.05). The shear force and TBARS values of PPM jerky were higher than those of other jerky samples (P < 0.05). Saturated fatty acid (SFA, %) was significantly higher in the BSM jerky than others, while unsaturated fatty acid (UFA, %) was significantly higher in the PSM and PLD than BSM and PPM jerky samples (P < 0.05). The PPM jerky showed a significant increase in UFA (%) during storage, and a significantly decrease in microbial count after storage of 30 days (P < 0.05).     

Development of a method to manufacture uncured,no-nitrate/nitrite-added whole muscle jerky

“Natural curing” is accomplished by use of vegetable juice/powder high in naturally occurring nitrates combined with a nitrate reducing starter culture to result in indirectly “cured” products. Since the starter culture used is not water soluble, making “naturally cured” whole muscle jerky with current manufacturing techniques has been found ineffective. The objective was to investigate processes for whole muscle beef jerky that might provide cured meat characteristics similar to those of a nitrite-added control. Treatments where jerky was placed in a barrier bag during incubation were found to be the least similar to the nitrite-added control. Jerky placed in a 40.6 °C smokehouse during incubation resulted in significantly more (P < 0.05) converted cured pigment than the barrier bag treatments but less (P < 0.05) than the control. The processing methods investigated to manufacture “naturally cured” whole muscle jerky in this study were ineffective in resulting in products similar to those cured with sodium nitrite.     

The initial freezing point temperature of beef rises with the rise in pH: A short communication

This study tested the hypothesis that the initial freezing point temperature of meat is affected by pH. Sixty four bovine M. longissimus thoracis et lumborum were classified into two ultimate pH groups: low (< 5.8) and high pH (> 6.2) and their cooling and freezing point temperatures were determined. The initial freezing temperatures for beef ranged from − 0.9 to − 1.5 °C (? = 0.6 °C) with the higher and lower temperatures associated with high and low ultimate pH respectively. There was a significant correlation (r = + 0.73, P < 0.01) between beef pH and freezing point temperature in the present study. The outcome of this study has implications for the meat industry where evidence of freezing (ice formation) in a shipment as a result of high pH meat could result in a container load of valuable chilled product being downgraded to a lower value frozen product.     

Fatty acid profile,carcass and meat quality traits of young Nellore bulls fed crude glycerin replacing energy sources in the concentrate

Carcass and meat quality traits of 60 Nellore young bulls fed diets without crude glycerin (CG); with CG replacing corn (CGc; 10% of dry matter — DM) in the concentrate; and with CG replacing soybean hull (CGsh; 10% of DM) in the concentrate were evaluated. Diets were evaluated at two concentrate levels (CLs). The CL did not affect cold carcass weight (CCW; P = 0.6074), cold carcass dressing (CCD; P = 0.9636), rib fat thickness (RFT; P = 0.8696) and longissimus muscle area (LMA; P = 0.7524). Animals fed diets with CGc or CGsh showed meat with greater deposition of monounsaturated fatty acid (MUFA; P = 0.0022) and CLA (18:2 cis-9, trans-11) contents (P = 0.0001) than animals fed diets without CG. The inclusion of 10% of CG in diets CGc or CGsh does not affect the carcass and meat quality traits; however, it increases the MUFA and CLA contents in beef, although these changes are very small in nutritional terms.     

One technology does not fit all: Profiling consumers of tender and tenderised beef steaks

New production technologies can help the beef sector to improve eating quality, in particular the tenderness, of low-value meat cuts. This paper aims at profiling potential consumers for unprocessed tenderloin M. Psoas major, muscle profiled M. Infraspinatus and marinated by injection M. Semitendinosus in Belgium (n = 108) and Norway (n = 110). Consumers' hedonic expectations for the three beef cuts, along with their general attitudes towards beef and food technology, were collected in central location tests. Results show that tenderloin triggers the highest hedonic expectations and best appeals to consumers profiled with high beef involvement in both countries. Consumers' expectations for steaks from novel technologies vary with consumers' attitudes towards beef, food technology and food risks and their country of residence, resulting in three additional consumer profiles. Furthermore, general attitudinal profiles of beef consumers also differ between the two countries. The results are useful for the positioning of novel beef products within the two national markets.     

不同部位西门塔尔杂交黄牛肉干品质差异分析

为研究不同部位牛肉品质的差异,选取西门塔尔杂交黄牛的臀肉、肩肉、黄瓜条、米龙、霖肉5 个部位, 通过测定出品率、嫩度、风味、色泽和感官品质等指标,探讨部位对黄牛肉干品质的影响规律。结果表明：以米龙 制备的黄牛肉干出品率、水分含量和水分活度均显著高于其他部位黄牛肉干（P＜0.05）,且核磁共振信号强度较 大;黄牛肉干的亮度值表现为肩肉＞黄瓜条＞米龙＞霖肉＞臀肉,以米龙制备的黄牛肉干的红度值（5.76）和黄度 值（10.23）均为最大;以黄瓜条和米龙制备的黄牛肉干挥发性风味差异较小,以肩肉制备的黄牛肉干挥发性风味 与其他4 个部位黄牛肉干差异较大;根据主成分分析和聚类分析得出各指标权重,出品率权重较大,以米龙制备的 黄牛肉干出品率最高,因此米龙较适合加工成牛肉干。     

Eating quality of beef from biotypes included in the PGI “Ternera Asturiana” showing distinct physicochemical characteristics and tenderization pattern

Different biotypes of the Protected Geographical Indication (PGI) “Ternera Asturiana” were studied to determine if their differences in physicochemical characteristics and tenderization pattern during maturation (3 to 21 days) had an effect on the consumer evaluation of beef palatability. Biotype affected significantly pH, water holding capacity, chemical composition (P < 0.001) and meat lightness (P < 0.05). Ageing time affected significantly (P < 0.05) colour, meat toughness and sensory attributes in a different way within each biotype. Multivariate analysis showed two different meat groups: 1) meat from mh-genotypes, characterized by high juice losses, lightness (L*), protein content and high sensory acceptability at intermediate (7 and 14 days) ageing times; 2) meat from rustic (AM) breed and biotypes free of myostatin mutation (AV (+/+) and AV × AM), showing higher intramuscular fat, myoglobin content, and instrumental toughness and requiring longer storage times (21 days). This should be taken into account for the proper post-mortem management and commercialization of each product to achieve its best sensory quality.     

The influence of latitude on the concentration of vitamin D3 and 25-hydroxy-vitamin D3 in Australian red meat

There is little information on the vitamin D content of Australian red meat or on the possible influence of latitude on this content. To determine the content of vitamin D₃ and 25-hydroxy-vitamin D₃ (25OHD₃), lamb and beef were analysed from 34° S with LC–IT-MS. To investigate the possible influence of latitude on vitamin D in meat, the lean meat and fat from five cuts of beef were analysed from 17° S and 41° S. Lamb contained 0.10 μg vitamin D₃/100 g and 0.20 μg 25OHD₃/100 g lean meat, while beef contained 0.12 μg vitamin D₃ and 0.27 μg 25OHD₃/100 g (lean meat). Latitude had no effect on the vitamin D₃ (P = 0.21) or 25OHD₃ (P = 0.29) content of lean beef, but fat from cattle in the 17° S latitude group contained significantly higher (P < 0.01) concentrations of vitamin D₃ than fat from the 41° S group of cattle.     

The influence of product attributes, consumer attitudes and characteristics on the acceptance of: (1) Novel bread and milk, and dietary supplements and (2) fish and novel meats as dietary vehicles of long chain omega 3 fatty acids

Two conjoint studies were undertaken in the USA on relative preferences for sources and food vehicles for long chain omega-3 fatty acids (LCO3FA). Study 1 (n = 202) investigated consumer acceptance of the source of LCO3FA (fish oil, algal oil and novel oilseed) in the most popular, well established vehicle foods (bread, milk and supplements). Study 2 (n = 211) investigated consumer acceptance of the source of LCO3FA (fishmeal, novel oilseed and fish oil) used to enrich the diet of animals for meat production (beef, chicken, pork and fish). Product concepts were varied by base product (vehicle); source of LCO3FA; information source; health claim and additional cost.These samples of US consumers reported preferences for novel (genetically modified, GM) oilseed incorporated into enriched foods (i.e., bread, milk and supplements) and also for meats above fish and fish oil as sources of LCO3FA and vehicles for consumption. Overall conjoint analysis revealed a general positive relative utility (worth or value) for novel oilseeds which were related to neutral or positive attitudes towards GM.Generally, the acceptance of enriched foods was dependent on the type of the base food and the cost of fish, with bread preferred over milk and supplements. Similarly, for meat, base (vehicle) product was significantly the most important driver of preference, with about 80% of the sample expressing highest preferences for chicken, fed oilseed (as a source of LCO3FA). However, cost was not an important driver of acceptance of meat alternatives.Further, knowledge that the novel oilseed was derived from a GM source did not impact on the acceptance of food alternatives. Thus, incorporating GM oilseeds rich in LCO3FA into animal feed, particularly for chicken and beef, and for enriching bread was found to be acceptable amongst the majority. These two studies suggest the existence of a potential demand for novel ‘non-fish’ source of LCO3FA, providing potential health benefits not currently realised.     

Radio-frequency heating of heterogeneous food - Meat lasagna

This research studied feasibility of using radio-frequency (RF) energy to thermally process highly heterogeneous foods in large containers as shelf-stable products. Meat lasagna was selected as the food for the study. Dielectric properties of beef, mozzarella cheese, noodles, and sauce were determined between 1 and 1800 MHz and from 20 to 121 °C. A 6-kW 27-MHz RF system was used to sterilize packaged meat lasagna in large polymeric containers (295 × 253 × 42 mm) during which the temperature of different components were monitored. Computer simulations were also conducted to evaluate the influence of the dielectric properties of each food component on the electric field distribution and heating pattern during RF heating. The measurements indicated small temperature differences in beef meatballs, mozzarella cheese and sauce when they were properly distributed between layers of noodles. Simulation results suggested that in spite of large differences in electric field intensities in different food components, adequate heat transfer reduced differential heating. Thus, RF heating can be used to process pre-packaged heterogeneous foods and retain product quality.     

Effect of varying the gas headspace to meat ratio on the quality and shelf-life of beef steaks packaged in high oxygen modified atmosphere packs

Beef steaks (M. longissimus dorsi) were stored in modified atmosphere packs (MAP) (80% O₂:20% CO₂) with gas headspace to meat ratios of 2:1, 1:1 and 0.5:1 for 14 days at 4 °C. The pH, surface colour, texture and microbiology of beef steaks were unaffected (P > 0.05) by varying the gas headspace to meat ratio. APLSR (ANOVA-partial least squares regression) and jack-knife uncertainty testing indicated that lipid oxidation (TBARS) was significantly positively correlated with days 10 (P < 0.05) and 14 (P < 0.001) of storage. Chemical and sensory detection of lipid oxidation in beef steaks were in agreement on day 14 of storage. The sensory quality and acceptability of beef steaks were similar in gas headspace to meat ratios of 2:1 or 1:1 and unacceptable in 0.5:1. Results indicate that pack size and gas volume can be reduced without negatively affecting fresh beef quality and shelf-life.     

Mass spectrometric characterization and thermostability of turkey myoglobin

Pink color defect (PCD) is a major quality problem in the turkey industry leading to pink appearance of pre-cooked, uncured turkey. The present study determined the molecular mass of turkey myoglobin (Mb) using mass spectrometry and characterized the thermostability of turkey Mb, in comparison with beef Mb, to elucidate the molecular basis of PCD. Purified turkey and beef myoglobins were analyzed using Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry. The thermostability of turkey and beef oxymyoglobins was examined at pH and Mb concentrations (pH 6.2 and 0.04 mmol/L for turkey; pH 5.6 and 0.15 mmol/L for beef) reflecting inherent conditions in these meats. Turkey and beef oxymyoglobins were incubated at 71, 75, and 80 °C and percentage myoglobin denaturation (PMD) was determined. Molecular mass of turkey Mb (17,295 Da) was 346 Da greater than beef Mb (16,949 Da) and was approximately 300-350 Da greater than those of other red meat myoglobins, suggesting its unique primary structure. PMD was lower (P < 0.05) in turkey Mb than in beef Mb during incubation at 71, 75 and 80 °C, indicating that in-situ turkey Mb is less susceptible to heat-induced denaturation than beef Mb at typical meat cooking conditions. The observed greater thermostability of turkey Mb compared to beef Mb could be, partially, due to inherent greater pH in turkey than in beef. Possible unique primary structure of turkey Mb could have contributed to its greater thermostability, which is one of the reasons for PCD.     

Aroma development in high pressure treated beef and chicken meat compared to raw and heat treated

Chicken breast and beef muscle were treated at 400 and 600 MPa for 15 min at 5 °C and compared to raw meat and a heated sample (100 °C for 15 min). Vacuum-packed beef meat with a smaller fraction of unsaturated fatty acids showed better oxidative stability during 14 days of cold storage, as shown by a low steady-state level of hydroperoxide values, than vacuum-packed chicken meat. Accordingly, the critical pressures of 400 MPa and 600 MPa for chicken breast and beef sirloin, respectively, were established. Volatiles released after opening of the meat bags or during storage of open meat bags, simulating consumer behaviour, were measured under conditions mimicking eating. Quantitative and olfactory analysis of pressurised meat gave a total of 46 flavour volatiles, mainly alcohols (11), aldehydes (15), and ketones (11), but all in low abundance after 14 days of storage. Overall, beef meat contained less volatiles and in lower abundance (factor of 5) compared to chicken meat. The most important odour active volatiles (GC-O) were well below the detection thresholds necessary to impart a perceivable off-flavour. Lipid oxidation was significantly accelerated during 24 h of cold storage in both cooked chicken and beef when exposed to oxygen, while the pressurised and oxygen-exposed chicken and beef meat remained stable. Pressure treatment of beef and chicken did not induce severe changes of their raw aroma profiles.     

Occurrence of heterocyclic amines in cooked meat products

Heterocyclic amines (HCAs), potent mutagens and a risk factor for human cancers, are produced in meats cooked at high temperature. The aim of this study was to determine the HCA content in cooked meat products (beef, chicken, pork, fish) prepared by various cooking methods (pan frying, oven broiling, and oven baking at 170 to 230 °C) that are preferred by U.S. meat consumers. The primary HCAs in these samples were PhIP (2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine) (1.49-10.89 ng/g), MeIQx (2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline) (not detected-4.0 ng/g), and DiMeIQx (2-amino-3,4,8-trimethyl-imidazo [4,5-f]quinoxaline) (not detected-3.57 ng/g). Type and content of HCAs in cooked meat samples were highly dependent on cooking conditions. The total HCA content in well-done meat was 3.5 times higher than that of medium-rare meat. Fried pork (13.91 ng/g) had higher levels of total HCAs than fried beef (8.92 ng/g) and fried chicken (7.00 ng/g). Among the samples, fried bacon contained the highest total HCA content (17.59 ng/g).     

Beef quality attributes as affected by increasing the intramuscular levels of vitamin E and omega-3 fatty acids

In order to investigate the effects of increasing beef n-3 fatty acid content and the protective effects of vitamin E antioxidant activity on meat quality characteristics, 80 feedlot steers were fed 4 different diets (control, high vitamin E, 10% ground flaxseed or high vitamin E-10% ground flaxseed). While dietary treatments had no effect (P > 0.05) on meat composition or tenderness values, the increase in oxidation products was lower (P = 0.046) in meat from vitamin E supplemented steers and higher (P = 0.006) in meat from flaxseed fed animals. The increase in α-tocopherol tissue levels (P < 0.001) in meat from animals fed flaxseed and increased dietary vitamin E resulted in the lowest drip loss values (P = 0.013). As expected, display time had a large effect on retail traits in both steaks and patties (P < 0.001). While retail traits of steaks were not affected by the dietary treatments (P > 0.05), feeding flaxseed decreased (P < 0.05) ground beef retail scores, which were not corrected by higher levels of dietary vitamin E. Finally, although no effect (P > 0.05) was observed among treatments for sensory attributes in steaks, the correlations of a combined n-3:α-tocopherol ratio against retail and sensory attributes (P < 0.05) suggest that increased n-3 fatty acids levels require increased dietary antioxidants, such as vitamin E to avoid negative effects on meat quality from a loss in oxidative stability.     

Meat quality attributes of the Longissimus lumborum muscle of the Kh'ara genotype of llama (Lama glama) reared extensively in northern Chile

Twenty male llama of the Kh'ara genotype, reared extensively in the north of Chile, were slaughtered at ages between 2 and 4 permanent teeth (2 to 3.5 years) and analyses were carried out on the Longissimus lumborum muscle, including composition (moisture, fat, protein, ash, cholesterol, amino acids, fatty acid profile and collagen content) and meat quality parameters (pH, color, water holding capacity and Warner–Bratzler shear-force). Llama meat was characterized by a low cholesterol (39.04 mg/100 g) and intramuscular fat (1.56%) content, a total collagen content of 6.28 mg/g, of which 20.28% was soluble collagen. Amino acid composition and fatty acid profile were similar to those found for beef finished on forage. Llama meat showed a low n − 6/n − 3 (4.69) and hypocholesterolemic/hypercholesterolemic (1.55) ratio and acceptable values of DFA (65.78%). Quality parameters in llama Longissimus muscle were within the ranges reported for more traditional meats such as beef and lamb.     

Chemical composition, cytotoxicity effect and antimicrobial activity of Ceratonia siliqua essential oil with preservative effects against Listeria inoculated in minced beef meat

The present study describes the phytochemical profile and the protective effects of Ceratonia siliqua pods essential oil (CsEO), a food and medicinal plant widely distributed in Tunisia. Twenty five different components were identified in the CsEO. Among them, the major detected components were: Nonadecane, Heneicosane , Naphthalene, 1,2-Benzenedicarboxylic acid dibutylester, Heptadecane, Hexadecanoic acid, Octadecanoic acid, 1,2-Benzenedicarboxylic acid, Phenyl ethyl tiglate, Eicosene, Farnesol 3, Camphor, Nerolidol and n-Eicosane. The antimicrobial activity of CsEO was evaluated against a panel of 13 bacteria and 8 fungal strains using agar diffusion and broth microdilution methods. Results have shown that CsEO exhibited moderate to strong antimicrobial activity against the tested species. In addition, the inhibitory effect of this CsEO was evaluated in vivo against a foodborne pathogens Listeria monocytogenes, experimentally inoculated in minced beef meat (2 × 10² CFU/g of meat) amended with different concentrations of the CsEO and stored at 7 °C for 10 days. The antibacterial activity of CsEO in minced beef meat was clearly evident and its presence led to a strong inhibitory effect against the pathogens at 7 °C. On the other hand, the cytotoxic effects of the essential oil against two tumoral human cell lines HeLa and MCF-7 were examined by MTT assay. The CsEO showed an inhibition of both cell lines with significantly stronger activity against HeLa cells. The IC₅₀ values were 210 and 800 μg/ml for HeLa and MCF-7 cells, respectively. Overall, results presented here suggest that the EO of C. siliqua possesses antimicrobial and cytotoxic properties, and is therefore a potential source of active ingredients for food and pharmaceutical industry.     

Comparison of wheat- versus corn-based dried distillers’ grains with solubles on meat quality of feedlot cattle

A considerable amount of information has been generated on the feeding value and impact of corn dried distillers’ grains with solubles (DDGS) on meat quality, whereas little is known about the effects of wheat DDGS on meat quality, and no direct comparison of these two sources of DDGS has been completed. The current study was conducted to examine the objective and subjective carcass and meat quality traits of cattle fed diets containing corn or wheat (20% or 40%) DDGS (DM basis) as compared to a standard barley-based finishing diet (control). In general, meat obtained from animals fed the barley-based control diet was slightly darker in colour (lower chroma and hue at 24 h, P < 0.01) and less tender (highest proportion of tough shears at 2 d and lowest proportion of tender shears at 20 d). Meat from corn DDGS was rated as more tender and palatable than control samples (P < 0.05), and 20% corn samples were rated better for beef flavour intensity (P < 0.01) and desirability (P < 0.05) than 40% corn DDGS samples. In contrast, meat from steers fed wheat DDGS showed intermediate characteristics between steers fed control and corn DDGS diets. Hence, feeding wheat DDGS had no negative effects, and feeding corn DDGS had some positive effects on meat quality characteristics of beef.