The effect of processing techniques and brine formulations on the development of surface sheen in enhanced beef strip loin steaks

The surface sheen phenomenon in enhanced beef steaks, packaged under modified atmosphere, was studied using various combinations of processing techniques and brine formulations. There was no effect (P > 0.05) of time between enhancement and when steaks were cut on surface sheen. Beef temperature less than 0 °C prior to enhancement, resulted in less (P ≤ 0.05) sheen and less retained pump (P ≤ 0.05) than beef greater than 2 °C. Removal of phosphate from the brine resulted in lower (P ≤ 0.05) sheen, and the addition of lactate decreased (P ≤ 0.05) sheen but resulted in less (P ≤ 0.05) retained pump. Sheen was correlated (P ≤ 0.05) with pump uptake (r = 0.58) and pH (r = -0.29). Results indicate that surface sheen can be significantly affected by ingredients used, but caution must be taken as retained brine and pH can also be affected, causing secondary influences on instrumental and visual traits.     

Nitrite-embedded packaging film effects on fresh and frozen beef color development and stability as influenced by meat age and muscle type

Muscles (Longissimus lumborum, LL; Psoas major, PM, semitendinosus, ST) were aged (2, 9 d postmortem), cut into steaks, anaerobically packaged (nitrite-embedded film, NEF), and displayed (fresh, 19 d; frozen, 39 d). Fresh NEF increased (P < 0.05) in redness (first 48 h). Upon opening fresh NEF (d 6) and overwrapping in PVC film, redness declined (P < 0.05). NEF cooked LL had more red surface compared to non-NEF. Meat age influenced NEF color. Intact NEF maintained acceptable red color throughout display. Residual nitrite and nitrate associated with fresh NEF and nitrate in NEF cooked LL were found (P < 0.05) in the outer layer. Consideration should be given to providing sufficient time for nitric oxide myoglobin development when using NEF which may be influenced by meat age and muscle differences. NEF packaging has potential to extend fresh beef color display life. NEF appears to offer the opportunity to display bright red beef in frozen display by limiting typical effects of photooxidation.     

Moisture sorption isotherm of fresh lean beef and external beef fat

The moisture sorption isotherm (MSI) of lean beef and fat beef was experimentally determined. The experimental procedure used was that of the COST 90 project with some modifications to accelerate equilibration. The procedure was validated with the standard reference material microcrystalline cellulose. The MSI of the beef at the highest humidity range was obtained by accelerating equilibration with changes of salts, using a low water activity salt for some time. This procedure was reliable for beef samples but not for the fat samples. No significant changes were found for lean beef in the temperature range 5–40 °C. Three models, GAB, Peleg and Lewicki, were used to fit the experimental data. The best fit was obtained with the GAB equation. The fat MSI was determined at 5, 15 and 25 °C and it was best fitted with the Lewicki model.     

Effects of lactate-enhancement on surface reflectance and absorbance properties of beef longissimus steaks

A completely randomized block design was used to assess the effects of lactate-enhancement on surface reflectance and absorbance properties of beef longissimus steaks. Loins were divided into sections, assigned to one of four treatments (non-enhanced day 0, non-enhanced day 5, water-enhanced, and 3% lactate), vacuum packaged, stored for 5 days at 4 °C, and then cut into steaks that were used to prepare 100% of deoxy-, oxy-, met-, and carboxymyoglobin according to AMSA (1991). Surface color was analyzed using a HunterLab Miniscan Plus Spectrocolorimeter. Lactate-enhanced steaks had the least overall surface reflectance and the darkest surface color (lower L*; P < 0.05). For 100% of each myoglobin form, K/S values and ratios (isobestic wavelengths ÷ 525 nm) at 474, 525, 572, and 610 also were influenced by lactate-enhancement. Hence, when estimating surface myoglobin forms using K/S ratios, separate 100% myoglobin reference standards should be prepared from both non-enhanced and enhanced steaks.     

肉及肉制品中彩虹色斑点现象的调查分析

彩虹色斑点是近年来发现存在于肉及肉制品中的一种非正常颜色。对我国几家大型屠宰场的猪、牛分割肉及南京各大超市销售的部分肉制品进行了调查,结果表明:猪肉的各部位均无彩虹色斑点现象;牛肉半腱肌中彩虹色斑点的发生率为83%,其他部位从高到低分别为背最长肌(21%),腰大肌(7%),股二头肌(5%)。牛肉制品中帕斯雀牛肉、烤牛肉和酱牛肉彩虹色斑点最明显,猪肉制品中西式火腿片和咸肉最明显。     

Effects of postmortem storage time on color and mitochondria in beef

To assess the effects of aging time (0, 15, 30, and 45 d) and temperature (0 or 5 °C) on beef mitochondria and steak color, vacuum packaged longissimus (n = 15) and cardiac muscles were assigned to 1 of 6 temperature × time combinations. As time increased, initial red color intensity increased whereas both mitochondrial oxygen consumption and color stability decreased. The decrease in mitochondrial oxygen consumption associated with longer aging times will increase initial color intensity. However, this improvement in color development will be negated by the decreased color stability that results from the effects of storage on mitochondria.     

Demographics and beef preferences affect consumer motivation for purchasing fresh beef steaks and roasts

Surveys completed by 1370 consumers determined the motivational factors affecting consumer purchasing decisions for fresh beef steaks and roasts in three regions in the United States. Females placed greater importance on tenderness, ease of preparation, and nutritional value of steaks and roasts when compared to males. Age influenced tenderness, product consistency, and nutritional value of steaks, but influenced flavor, product consistency, and nutritional value of roasts. Consumers felt juiciness, nutritional value, and natural products were less important in determining their purchasing choices of steaks and roasts as their level of education increased. The preferred degree of doneness of steaks influenced the value placed on six of the nine purchasing motivators. Beef preferences and demographics influenced consumer purchasing decisions for fresh beef steaks and roasts. Results from this study can be used to help identify factors to positively influence purchasing decisions within targeted market segments.     

Meat color and iridescence: Origin,analysis, and approaches to modulation

Meat color is an important aspect for the meat industry since it strongly determines the consumers’ perception of product quality and thereby significantly influences the purchase decision. Emergence of new vegan meat analogs has renewed interest in the fundamental aspects of meat color in order to replicate it. The appearance of meat is based on a complex interplay between the pigment-based meat color from myoglobin and its chemical forms and light scattering from the muscle's microstructure. While myoglobin biochemistry and pigment-based meat color have been extensively studied, research on the physicochemical contribution of light scattering to meat color and the special case of structural colors causing meat iridescence has received only little attention. Former review articles focused mostly on the biochemical or physical mechanisms rather than the interplay between them, in particular the role that structural colors play. While from an economic point of view, meat iridescence might be considered negligible, an enhanced understanding of the underlying mechanisms and the interactions of light with meat microstructures can improve our overall understanding of meat color. Therefore, this review discusses both biochemical and physicochemical aspects of meat color including the origin of structural colors, highlights new color measurement methodologies suitable to investigate color phenomena such as meat iridescence, and finally presents approaches to modulate meat color in terms of base composition, additives, and processing.     

A modified hot processing strategy for beef: effects on fresh meat quality

A modified hot processing (MHP) strategy for beef carcasses using known chilling technology to maintain quality in the higher priced cuts while retaining lower value cuts for further, immediate hot processing was evaluated. Following high voltage electrical stimulation, paired sides from 36 carcasses were either conventionally processed (CP) or reduced in a manner similar to the French pan traité cut. The sides were help in a pre-chiller for 1 h prior to blast chilling at −20°C for 3 h at an air speed of 2·3 m s⁻¹, followed by chilling at 2°C for the remainder of the 24 h period. Overall, MHP of beef carcass sides had minimal effects on fresh meat quality in the longissimus thoracis et lumborum (LTL) and the semimembranosus (SM) muscles despite removing over 50% of the carcass side weight in the form of lower value cuts. Sarcomere length was significantly shorter (P ≤ 0·05) in the anterior (AL) and posterior (PL) LTL which was attributed to the removal of skeletal restraint and carcass weight. The increase in shear value in the AL, location of MHP sides although statistically significant (P ≤ 0·05) would not likely be percieved by consumers. Hence a non-traditional method of processing carcasses by treating low value and high value primal cuts separately, may be viable.     

Effects of succinate on ground beef color and premature browning

The objective of this experiment was to determine the effects of succinate on raw and cooked ground beef color. Chubs (n=10) were divided in half and assigned to either succinate (final w/w concentration of 2.5%) or distilled water. Patties (n=14 per chub half) were assigned to initial day 0 color and each of 6 treatment combinations, created by crossing 3 packaging types (vacuum, high-oxygen/80% O(2), and PVC) with 2 storage times (days 1 and 3). After storage, patties were cooked to either 66 °C or 71 °C. Succinate increased (P<0.05) ground beef pH and metmyoglobin reducing activity but had no effect (P>0.05) on raw a* and chroma values. Moreover, succinate decreased (P<0.05) raw L* values, lipid oxidation, and premature browning for patties packaged in PVC and high-oxygen. Succinate may increase cooked patty redness via its influence on meat pH.     

Spoilage-related microbiota associated with chilled beef stored in air or vacuum pack

In order to study the spoilage-related microbiota of beef at species level, a combination of culture-independent and culture-dependent methods was used to analyse nine different beef samples stored at 4 °C in air or in vacuum pack. Plate counts on selective agars after 0, 7 and 20 days of storage showed that vacuum packaging reduced the viable counts of Brochothrix thermosphacta, Pseudomonas spp. and Enterobacteriaceae, whereas the growth of lactic acid bacteria (LAB) was unaffected. Storage in vacuum pack mainly affected viable counts and not necessarily the species diversity of microbial populations on meat. Such populations were studied by PCR-DGGE of DNA directly extracted from meat and from bulk cells from culture media, followed by sequencing of DGGE fragments. Pseudomonas spp., Carnobacterium divergens, B. thermosphacta, Rahnella spp. and Serratia grimesii, or close relatives were detected in the meat at time zero. The use of the culture-independent method highlighted the occurrence of species that were not detected by plating. Photobacterium spp. occurred in most meat samples stored in air or in vacuum pack, which indicates this organism probably has a role in spoilage. In contrast, culture-dependent analysis allowed detection of bacterial species that were not found in DNA extracted directly from meat. This was the case for several species of Serratia or Rhanella among the enterobacteria, and Leuconostoc spp. among the LAB. Besides advancing our knowledge of the species involved in the spoilage of vacuum-packaged meat, this study shows the benefits of combining culture-based and direct approaches to enhance understanding of populations of spoilage bacteria.     

Factors associated with tenderness in young beef

One hundred and twenty-two crossbred steers of varying percentages of Bos Indicus and Bos Taurus breeding were slaughtered to determine the relationship of carcass and meat characteristics to tenderness. Carcasses were graded and longissimus dorsi muscle samples were evaluated for fibre type characteristics, sensory and shear force determination, sarcomere length, intramuscular fat content, collagen content and solubility and fragmentation index. Sarcomere length and collagen content and solubility were not significantly related to shear force values or sensory tenderness ratings. The fragmentation index was highly correlated to sensory tenderness ratings (r = −0·60) and shear force values (r = 0·53) indicating that variation in tenderness is associated with myofibrillar protein degradation. A four variable regression equation that included fragmentation index, lean colour, marbling and per cent red fibres accounted for 56% of the variation in sensory tenderness. Fragmentation index directly accounted for 30% of the variation in sensory tenderness in the four variable equation.     

Meat color stability affected by barley variety fed in finishing diet to beef steers

Angus crossbred steers were assigned randomly to one of four finishing diets based on corn, Chinook, Logan, or H3 barley. Steers were harvested and after a 72-h chill, carcass quality and yield grade data were collected. Beef ribs were removed from 72 carcasses for further analysis. Ribs were aged in vacuum bag at 2 °C for 14 days. After aging three adjacent steaks (3.18 cm) were removed to determine color stability, tenderness, proximate analysis and pH. Diets fed to steers had no effect on quality and yield grade or tenderness of beef steaks. Steaks from steers fed Logan barley variety were significantly less red at 10 days of storage (Hunter a* = 24.06) than steaks from steers fed the other barley varieties (Chinook a* = 26.4; H3 a* = 28.05) or corn (a* = 26.14). Identification of barley varieties that affect color stability could result in designing diets specifically for improved color and increase the use of barley as a finishing grain.     

Predicting beef tenderness using color and multispectral image texture features

The objective of this study was to investigate the usefulness of raw meat surface characteristics (texture) in predicting cooked beef tenderness. Color and multispectral texture features, including 4 different wavelengths and 217 image texture features, were extracted from 2 laboratory-based multispectral camera imaging systems. Steaks were segregated into tough and tender classification groups based on Warner-Bratzler shear force. The texture features were submitted to STEPWISE multiple regression and support vector machine (SVM) analyses to establish prediction models for beef tenderness. A subsample (80%) of tender or tough classified steaks were used to train models which were then validated on the remaining (20%) test steaks. For color images, the SVM model correctly identified tender steaks with 100% accurately while the STEPWISE equation identified 94.9% of the tender steaks correctly. For multispectral images, the SVM model predicted 91% and STEPWISE predicted 87% average accuracy of beef tender.     

Storage and packaging effects on sensory and color characteristics of ground beef

Effects of irradiation (2 kGy) of ground beef patties from trimmings stored aerobically for 0 or 6 days on lean color, odor, and sensory attributes were investigated. Beef trimings were coarse ground and split into 2 groups. Group one was fine ground, pattied, and packaged immediately; group-two was stored 6 days then fine ground, pattied, and packaged. Irradiated beef patties had greater (P<0.05) off-odors, and off-flavors, lower (P<0.05) CIE L^*, a^* and b^* and saturation indexes values (P<0.05) after four days of storage at 0±1 °C. Irradiation of patties produced from trimmings aged an extra 6 days resulted in increased (P<0.05) saturation indexes and b^* values, but not off-odors when compared to non-aged and irradiated patties. Thus, the production of irradiated beef patties should utilize beef trimmings with the shortest postmortem aging time and a dose of less than 2 kGy to minimize discoloration and off-odors.     

Desorption isotherms for fresh beef: An experimental and modeling approach

Desorption isotherms for fresh beef were determined at 30, 40 and 50 °C by the static gravimetric method. The resulting isotherms exhibited a type II sigmoid shape. The BET, GAB and Halsey models were used to fit these experimental data. The GAB model was most accurate for all temperatures and all levels of water activity, followed by the BET and Halsey models. The temperature dependence of GAB constants was estimated. The isosteric heat of desorption and its evolution in relation to moisture content were calculated using Clausius–Clapeyron equations. The monolayer moisture content was determined using the GAB model: it decreased as the temperature increased. The density of bound water, the number of adsorption sites, the sorption surface area and the percentage of bound water were calculated using the Caurie equation: all these quantities decreased as the temperature increased. The Kelvin and Halsey equations were used for calculation of pore size, which increases with an increase in moisture levels and sorption temperature.     

Influence of vacuum skin packaging on color stability of beef longissimus lumborum compared with vacuum and high-oxygen modified atmosphere packaging

The objective of this study was to investigate how color stability of beef is affected by vacuum skin packaging (VSP) compared with vacuum packaging (VP) and high-oxygen modified atmosphere packaging (MAP; 80% O(2) and 20% CO(2)). Longissimus lumborum muscles were aged in vacuum for 7days and then cut into 2-cm-thick slices and repacked using VSP, VP and MAP for another 7days. Color stability was measured during the next 5days in air and samples for α-tocopherol and NADH analyses were obtained at the beginning and end of aerobic storage. Color stability, α-tocopherol and NADH of steaks were affected by packaging methods and storage time in air (P<0.05). Higher a* value was obtained in VSP on day 5 compared with VP. Steaks packed in VSP had better color stability than in VP and their color was similar to MAP at the end (day 5) of storage.     

Colour change with longitudinal compression supports hypothesis of multilayer interference as cause for meat iridescence

The mechanism of iridescence in meat and meat products is still not fully understood but a widely accepted hypothesis is that it originates from a multilayer interference from sarcomere discs. In multilayer interference, the reflected wavelength is affected by the refraction angles, the thicknesses and refractive indices of the intermittent layers. A variation of these factors should therefore cause a disappearance or shift of iridescent colours. To test this hypothesis, we progressively compressed iridescent rolled fillets of ham longitudinal to the long axes of the muscle fibres and measured the interference colours by reflection spectrophotometry. We observed an interference colour shift from longer to shorter wavelengths and reflection intensity decreased with increasing compression pressure. Our data indicate that the compression decreased the layer thickness, so that constructive interference occurred at shorter wavelengths. The results thus provide support for multilayer interference being a primary cause and mechanism for meat iridescence.     

Comparison of fresh beef and camel meat proteolysis during cold storage

The objective of this research was to determine the difference in myofibrillar fragmentation of camel meat and beef during postmortem aging. Semitendinosus muscle was excised at slaughter and muscle pH was measured at 6, 12, 24, 48, and 72h postmortem. Myofibril fragmentation index was measured on 1, 3, 5, and 7 days postmortem. Also, myofibrils isolated from semitendinosus muscles of camel and cattle at 1, 3, 5 and 7 days postmortem storage were analyzed using sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. Results showed that the camel semitendinosus muscle had significantly higher myofibril degradation values compared to that in beef which was supported by a difference in troponin-T degradation and appearance of a 30kDa band. Postmortem pH decline of camel meat was significantly slower than that of beef. This study demonstrated that the semitendinosus protease activity of camel meat was superior to that of beef, which may have been due to the difference in pH decline.     

The effect of family beef taboos on beef consumption on young Taiwanese adults

A family tradition of beef taboos exists in Chinese societies. The marketplace for beef in Taiwan is imported mainly from the U.S., Australia, and New Zealand. For mechanised-farming families or even for those no longer engaged in agriculture, beef consumption is often not encouraged nor allowed by family members. Using quantitative data in the analyses, this study was undertaken to examine whether family beef taboos influenced beef consumption for young adults in Taiwan. Respondents from beef-consuming families consumed more beef (4.34 times/week: average, 150.07 g/week: cooked) than respondents from non-beef-consuming families (1.87 times/week: average, 56.67 g/week: cooked). For the respondents from non-beef-consuming families, spiritual burden was a main factor affecting their own beef consumption. The implications based on this study’s findings are provided.