A modified hot processing strategy for beef: reduced electrical energy consumption in carcass chilling

A beef processing strategy for improving energy and labour efficiencies, modified hot processing (MHP), was developed in a research abattoir. The work reported herein investigated carcass chilling rates and electrical energy usage in the chilling of carcasses that were processed using this approach. The MHP procedure removes the lower value cuts from the dressed carcass along with associated bone and fat. The remaining high value meat (posterior carcass quarter) is chilled in the usual manner, while the low value cuts are immediately processed (e.g. reduced into pre-blended, salted, chilled meat for emulsion-type products; rendered; directly processed as fresh, hot-boned meat, etc.). Carcasses prepared by the MHP method were dissected to quantify the amounts of lean meat, separable fat and bone removed in the procedure. These data were used with a simple model to predict the amount of chilling energy that could be saved by applying MHP prior to chilling. Electrical power to operate a blast chilling facility containing carcasses that had been processed either by conventional processing or by MHP methods was monitored and recorded, and the resulting data was used to confirm the model result. The MHP procedure reduced the refrigeration load for beef chilling by as much as 51% (P < 0·05). The amount of chilling energy to be saved would depend upon the methods employed to further process the low value tissues, and was calculated to be no less than 7%. The time for the reduced MHP carcass quarters to chill to 10°C at the fat-muscle interface of the longissimus dorsi muscle (12/13 rib) was shorter for MHP carcasses than for conventional carcasses (5·77 h vs 7·08 h, respectively) (P < 0·05). However, the times to chill the deep hip location of MHP hind quarters and conventional beef sides were not significantly different (P < 0·05).     

A modified hot processing strategy for beef: functionality of electrically-stimulated and hot-boned meat preblended with different NaCl concentrations

Chucks from 20 electrically-stimulated hot-boned (HB) and cold-boned (CB) beef carcasses were preblended with different concentrations of NaCl (0, 0·5, 1·0, 1·5 and 2·0% w/w). Preblends were analysed for pH, 2-thiobarbituric acid (TBA) values, protein extraction and emulsifying capacities. Bologna (with and without added sodium tripolyphosphate) and ground meat patties prepared from these preblends were also evaluated for cooking yield, color and texture parameters. Ultimate pH values of HB preblends increased with increasing NaCl concentration. At 1% NaCl, HB had higher ultimate pH than CB preblends (P ≤ 0·05) but preblending HB meat with 2% NaCl reduced TBA values (P ≤ 0·05) because the pH was maintained above 6·0. Higher amounts of protein were extracted from HB than from CB preblends (P ≤ 0·01), but boning and salting treatments did not affect their emulsifying capacities (P > 0·05). Two percent NaCl was required to fully achieve the prerigor salting effect. At this concentration, cooking yields of bologna prepared from HB preblends and phosphate containing bologna prepared from CB preblends were not different (P > 0·05) and were higher than those of bologna without added phosphate made from CB preblends (P ≤ 0·05). No meaningful effects were observed on color and texture parameters. Cooking losses were lower in patties made from HB than CB preblends (P ≤ 0·05) independent of NaCl concentration, but boning and salting treatments had no further effects on color or textural parameters (P > 0·05). Therefore, the superior functional properties of electrically stimulated prerigor meat can be maintained by the addition of 2% NaCl up to 2 h post-mortem.     

Preserving pre-rigor meat functionality for beef patty production

Three methods were examined for preserving pre-rigor meat functionality in beef patties. Hot-boned semimembranosus muscles were processed as follows: (1) pre-rigor ground, salted, patties immediately cooked; (2) pre-rigor ground, salted and stored overnight; (3) pre-rigor injected with brine; and (4) post-rigor ground and salted. Raw patties contained 60% lean beef, 19.7% beef fat trim, 1.7% NaCl, 3.6% starch, and 15% water. Pre-rigor processing occurred at 3-3.5h postmortem. Patties made from pre-rigor ground meat had higher pH values; greater protein solubility; firmer, more cohesive, and chewier texture; and substantially lower cooking losses than the other treatments. Addition of salt was sufficient to reduce the rate and extent of glycolysis. Brine injection of intact pre-rigor muscles resulted in some preservation of the functional properties but not as pronounced as with salt addition to pre-rigor ground meat.     

Effect of muscle stretching on meat quality of biceps femoris from beef

The objective of this study was to examine the effect of muscle stretching on meat quality and ultrastructure of biceps femoris (BF) from beef. After slaughter, the right side of the carcasses were suspended from the Achilles tendon (AS; n=10), while the left sides were re-hanged from the pelvic bone (PS; n=10). Meat quality was evaluated by water holding capacity (WHC), cooking loss (CL), color, shear force (SF) and sarcomere length (SL). As a result, PS had no impact on WHC, CL and color parameters. PS significantly decreased SF values by 7.5% only at 2 days postmortem. At pelvic suspended sides, SL was increased by 0.13 μm, 0.14 μm and 0.12 μm at 2, 7 and 10 days postmortem, respectively (P<0.001). Electron microscopy showed that the ultrastructure of BF have longer sarcomeres and smaller fiber diameter after PS. In conclusion, PS is a useful method for improving tenderness by stretching muscles.     

Eating quality of young bulls from three Spanish beef breed-production systems and its relationships with chemical and instrumental meat quality

Sensory characteristics of longissimus thoracis muscle from three local Spanish beef breed-production systems and their relationships with chemical and instrumental meat quality traits were studied. Young bulls of Bruna dels Pirineus (BP; n = 69), Avileña-Negra Ibérica (A-NI; n = 70) and Morucha (MO; n = 70) breeds were reared in their own production systems. MO breed showed the highest water holding capacity and also the highest thawing loss and haem pigment content (P < 0.001). No differences in moisture and protein contents were found among breeds. A-NI showed the highest intramuscular fat (IMF, P < 0.05) and total collagen (P < 0.001) contents, whereas BP showed the lowest IMF content (P < 0.05) and the highest collagen solubility (P < 0.001). Beef flavour, tenderness and juiciness accounted for the eating quality differences among the three breed-production systems. Meat from A-NI was rated significantly higher (P < 0.01) for beef flavour and tenderness than that from BP and MO animals. Furthermore, MO showed the lowest juiciness (P < 0.001) which could be due to its higher thawing loss. Within the three breeds, thawing loss was negatively correlated with juiciness and, likewise cooking loss with juiciness and tenderness (P < 0.05). The canonical discriminant analysis showed that the three breeds were significantly different (P < 0.05) from each other according to sensory attributes, which justifies their involvement in different protected geographical indications (PGI).     

Effects of corn grain particle size and treated soybean meal on carcass and meat quality characteristics of beef steers finished on a corn silage diet

Thirty-nine steers were distributed into a 2 × 2 factorial arrangement of treatments to determine the effect of corn grain particle size (cracked [CC] vs ground [GC] corn) and soybean meal treatment (solvent extracted soybean meal [SS] vs lignosulfonate treated soybean meal Soypass™ [SP]) on carcass and meat quality traits. When CC diet was supplemented with SS carcass quality grade score tended to decrease (P = 0.09). GC had no effect on meat quality, while SP only increased the intramuscular fat content when added to CC (P = 0.01). The CC diet supplemented with SP increased the proportion of saturated fatty acids (P = 0.01). Despite the positive effects on carcass quality, the lack of improvement in meat quality and the more saturated fatty acid profile would not justify the use of processed corn or treated soybean meal in the finishing diet of steers.     

Innovations in beef production systems that enhance the nutritional and health value of beef lipids and their relationship with meat quality

Consumers are becoming more aware of the relationships between diet and health and this has increased consumer interest in the nutritional value of foods. This is impacting on the demand for foods which contain functional components that play important roles in health maintenance and disease prevention. For beef, much attention has been given to lipids. This paper reviews strategies for increasing the content of beneficial omega-3 polyunsaturated fatty acids (PUFA) and conjugated linoleic acid (CLA) and reducing saturated fatty acids (SFA) in beef. Particular attention is given to intramuscular fat (IMF) and the relationships between fatty acid composition and key meat quality parameters including colour shelf life and sensory attributes. Despite the high levels of ruminal biohydrogenation of dietary PUFA, nutrition is the major route for increasing the content of beneficial fatty acids in beef. Feeding grass or concentrates containing linseed (rich in α-linolenic acid, 18:3n-3) in the diet increases the content of 18:3n-3 and its longer chain derivative eicosapentaenoic acid (EPA, 20:5n-3) in beef muscle and adipose tissue, resulting in a lower n-6:n-3 ratio. Grass feeding also increases docasahexaenoic acid (DHA, 22:6n-3). Feeding PUFA rich lipids which are protected from ruminal biohydrogenation result in further enhancement of the PUFA in meat with concomitant beneficial improvements in the ratio of polyunsaturated:saturated fatty acids (P:S ratio) and n-6:n-3 ratio. The main CLA isomer in beef is CLA cis-9, trans-11 and it is mainly associated with the triacylglycerol lipid fraction and therefore is positively correlated with level of fatness. The level of CLA cis-9, trans-11 in beef is related to (1) the amount of this isomer produced in the rumen and (2) synthesis in the tissue, by delta-9 desaturase, from ruminally produced trans vaccenic acid (18:1 trans-11; TVA). Feeding PUFA-rich diets increases the content of CLA cis-9, trans-11 in beef. Trans-fatty acids in foods are of rising importance and knowledge of the differential effects of the individual trans isomers is increasing. TVA is the major trans 18:1 isomer in beef and as the precursor for tissue CLA in both animals and man should be considered as a neutral or beneficial trans-isomer. Increasing the content of n-3 PUFA in beef can influence colour shelf life and sensory attributes of the meat. As the content of n-3 PUFA increases then sensory attributes such as "greasy" and "fishy" score higher and colour shelf life may be reduced. Under these situations, high levels of vitamin E are necessary to help stabilise the effects of incorporating high levels of long chain PUFA into meat. However, grass feeding not only increases n-3 PUFA and CLA but, due to its high content of vitamin E, colour shelf life is improved. It is evident that opportunities exist to enhance the content of health promoting fatty acids in beef and beef products offering opportunities to add value and contribute to market differentiation. However, it is imperative that these approaches to deliver "functional" attributes do not compromise on the health value (lipoperoxidation) or the taste of beef products.     

Assessment of meat quality properties and development of a palatability prediction model for Korean Hanwoo steer beef

Effects of the Korean carcass-grading system on carcass traits and meat quality parameters for the longissimus dorsi (LD) and semimembranosus (SM) muscles were investigated for Hanwoo steer beef. High quality grade beef cuts had significantly higher intramuscular fat content than those of low quality grade beef cuts. To establish a guaranteed system of eating quality for Hanwoo steer beef, a palatability prediction model was developed. The model development approach used canonical discriminant analysis and multivariate regression to assess effects of muscle type, cooking method, and aging treatment on Hanwoo beef quality grade. The palatability prediction model can provide Korean consumers with detailed information about expected eating quality for an individual cut, as well as provide critical information to the industry for maintaining high-quality beef production. The model is a significant advance in grading compared with the traditional carcass grading system, which applies a single quality grade to an entire carcass.     

Monitoring the effects of high pressure processing and temperature on selected beef quality attributes

The combined effects of high pressure processing (HPP) and temperature on meat quality attributes were assessed in bovine M. pectoralis profundus, with particular focus on lipid oxidation and fatty acid composition. Beef samples were pressurised at 200, 300 and 400 MPa at two different temperatures 20 °C and 40 °C. Both pressure and temperature regimes had significant effects on colour, cook loss and lipid oxidation. Pressurisation at 200 MPa had a lower impact on colour parameters than higher pressurisation levels. Cook loss also increased when higher levels of pressure were applied. Across all pressure conditions, lower cook loss was observed at 40 °C compared to 20 °C. An increase in TBARS values was observed at the higher pressure levels (300, 400 MPa). While some alterations of individual fatty acids were observed, high pressure had no effect on polyunsaturated/saturated fatty acid (PUFA/SFA) or omega 6/omega 3 (n6/n3) ratio. The temperature at which HPP was applied had a significant effect on the sum of saturated (SFA), monounsaturated (MONO) and polyunsaturated (PUFA) fatty acids. HPP at 40 °C showed higher SFA and PUFA and lower MONO compared to HPP at 20 °C. These results show that high pressure at low or moderate temperatures improves the microbiological quality of the meat with minimal affects on meat quality.     

高压处理对调理肉制品食用品质影响的研究进展

调理肉制品具有方便快捷、附加值高、营养美味等特点,深受城乡居民青睐,消费量持续快速增长。但目前该类产品存在汁液损失高、食盐和多聚磷酸盐等添加剂使用超标、货架期短等问题。高压处理是一种新型非热加工技术,不仅抑菌和灭酶,还会修饰肌肉蛋白等生物大分子,改善其凝胶质构和保水保油等加工特性,可有效解决调理肉制品存在的上述质量问题。该文对调理肉制品的分类、加工中存在的主要问题以及高压技术的最新研究进展进行概述,探讨了高压技术改善调理肉制品保油保水和质构的可行性,并展望了高压技术在调理肉制品精深加工中的应用前景,为调理肉制品品质改善和新产品研发提供科技支撑。      

Conventional freezing plus high pressure-low temperature treatment: Physical properties, microbial quality and storage stability of beef meat

Meat high-hydrostatic pressure treatment causes severe decolouration, preventing its commercialisation due to consumer rejection. Novel procedures involving product freezing plus low-temperature pressure processing are here investigated. Room temperature (20 °C) pressurisation (650 MPa/10 min) and air blast freezing (−30 °C) are compared to air blast freezing plus high pressure at subzero temperature (−35 °C) in terms of drip loss, expressible moisture, shear force, colour, microbial quality and storage stability of fresh and salt-added beef samples (Longissimus dorsi muscle). The latter treatment induced solid water transitions among ice phases. Fresh beef high pressure treatment (650 MPa/20 °C/10 min) increased significantly expressible moisture while it decreased in pressurised (650 MPa/−35 °C/10 min) frozen beef. Salt addition reduced high pressure-induced water loss. Treatments studied did not change fresh or salt-added samples shear force. Frozen beef pressurised at low temperature showed L, a and b values after thawing close to fresh samples. However, these samples in frozen state, presented chromatic parameters similar to unfrozen beef pressurised at room temperature. Apparently, freezing protects meat against pressure colour deterioration, fresh colour being recovered after thawing. High pressure processing (20 °C or −35 °C) was very effective reducing aerobic total (2-log₁₀ cycles) and lactic acid bacteria counts (2.4-log₁₀ cycles), in fresh and salt-added samples. Frozen + pressurised beef stored at −18 °C during 45 days recovered its original colour after thawing, similarly to just-treated samples while their counts remain below detection limits during storage.     

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.     

A fresh look at meat flavor

Hundreds of compounds contribute to the flavor and aroma of meat. Complex interactions between various compounds influence the perception of meat flavor. Inherent flavor of a meat product can be influenced by oxidation, lipid content, feeding/diet, myoglobin, and pH. Diet plays an important role in both ruminants and nonruminants. New research reveals important relationships in flavor among multiple muscles within a single animal carcass. This animal effect includes the presence of off-flavors. Diets high in polyunsaturated fatty acids may be contributing to the appearance of off-flavors in beef. Compounds associated with liver-like off-flavor notes in beef have been identified in raw tissue.     

Listeria monocytogenes: Occurrence in beef and identification of the main contamination points in processing plants

This study aimed to establish the occurrence of Listeria spp., especially L. monocytogenes and its main serotypes, in beef and processing plants. A total of 443 samples were obtained from equipment, installations and products from 11 meat processing establishments from Paraná state, Brazil. All samples were analyzed using USDA methodology for Listeria spp. detection, followed by species identification. The occurrence of Listeria spp. in the samples was 38.1% of which 51.4% were from equipment, 35.4% from installations and 30.2% from products. The identified species were: L. monocytogenes (12.6%), L. innocua (78.4%), L. seeligeri (1.2%), L. welshimeri (7.2%) and L. grayi (0.6%). The identified serotypes of L. monocytogenes were 1/2a and 4b. The results demonstrate the significance of equipment and installations as sources of contamination by Listeria spp. and L. monocytogenes in the processing of beef and meat products.     

Effect of South African beef production systems on post-mortem muscle energy status and meat quality

Post-slaughter muscle energy metabolism meat colour of South African production systems were compared; steers (n = 182) of Nguni, Simmental Brahman crossbreds were reared on pasture until A-, AB-, or B-age, in feedlot until A–AB-age. After exsanguination carcasses were electrically stimulated (400 V for 15 s). M. longissimus dorsi muscle energy samples were taken at 1, 2, 4 and 20 h. Post-mortem samples for meat quality studies were taken at 1, 7 and 14 days post-mortem. Production systems affected muscle glycogen, glucose, glucose-6-P, lactic acid, ATP, creatine-P glycolytic potential (P < 0.05), with the muscles of feedlot carcasses having a faster glycolysis rate than pasture carcasses. Energy metabolites correlated (0.4 < r < 0.9) with meat colour (CIE, L*a*b*), (0.3 < r > 0.5) water holding capacity, drip loss, and Warner Bratzler shear force. Muscle energy only affected muscle contraction of the A-age-pasture system (shortest sarcomere length of 1.66 μm vs 1.75 μm highest WBS of 6 kg vs 5 kg 7 days post-mortem).     

Opportunities for predicting and manipulating beef quality

Meat quality is a complex concept and can be defined as the characteristics of meat which satisfy consumers and citizens. The quality concept can be divided into intrinsic quality traits (which are the characteristics of the product itself) and extrinsic quality traits (which are more or less associated to the product for instance the price, a major determinant of purchase, or any brand or quality label). Quality can also be generic for the mass market or specific for niche markets. The relative importance of the different quality traits varies with human culture and time with a general trend of an increasing contribution of healthiness, safety and extrinsic quality traits. This review underlines the need for the development of methods to interpret and aggregate measures under specific rules to be defined in order to produce an overall assessment of beef quality. Such methods can be inferred for example from genomic results or data related to muscle biochemistry to better predict tenderness or flavor. A more global assurance quality scheme (the Meat Standards Australia System) based on the aggregation of sensory quality traits has been developed in Australia to ensure palatability to consumers. We speculated that the combination of indices related to sensory and nutritional quality, social and environmental considerations (carbon footprint, animal welfare, biodiversity of pasture, rural development, etc.) and economic efficiency (incomes of farmers and of others players along the supply chain, etc.) will provide objective assessment of the overall quality of beef (i.e. incorporating an all encompassing approach) not only for the mass market but also to support official quality labels of niche markets which are so far mainly associated with the geographical origins of the products.     

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.     

High pressure induced changes in beef muscle proteome: Correlation with quality parameters

The relationship between pressure induced changes on individual proteins and selected quality parameters in bovine longissimus thoracis et lumborum (LTL) muscle was studied. Pressures ranging from 200 to 600 MPa at 20 °C were used. High pressure processing (HPP) at pressures above 200 MPa induced strong modifications of protein solubility, meat colour and water holding capacity (WHC). The protein profiles of non-treated and pressure treated meat were observed using two dimensional electrophoresis. Proteins showing significant differences in abundance among treatments were identified by mass spectrometry. Pressure levels above 200 MPa strongly modified bovine LTL proteome with main effects being insolubilisation of sarcoplasmic proteins and solubilisation of myofibrillar proteins. Sarcoplasmic proteins were more susceptible to HPP effects than myofibrillar. Individual protein changes were significantly correlated with protein solubility, L*, b* and WHC, providing further insights into the mechanistic processes underlying HPP influence on quality and providing the basis for the future development of protein markers to assess the quality of processed meats.     

Effects of feeding strategy during a short finishing period on performance, carcass and meat quality in previously-grazed young bulls

Twenty-one Brown Swiss × Limousin young bulls reared on pasture were housed for a short finishing period (60 days). CA group (concentrate-ad libitum group) received concentrate and straw ad libitum for the whole finishing period. CR group (concentrate-restricted group) received 4 kg of concentrate/animal per day and ad libitum alfalfa hay throughout the 60 days. CRA group (concentrate-restricted/ad libitum group) received the same diet as CR group for the first 30 days and the same diet as CA group for the last 30 days. CA and CRA groups presented higher fatness values. Myoglobin concentration in muscle was highest in CA group (P < 0.05) and carotene content in subcutaneous fat was highest in CR group (P < 0.01), while Warner–Bratzler shear force and sensory traits were unaffected (P > 0.05). It is concluded that, in this type of young animal, 4 kg concentrate plus ad libitum alfalfa hay for a 60-day finishing period, despite lower fatness, provides carcasses and meat with acceptable quality characteristics, similar to those obtained from ad libitum fed animals for the same period.     

The effects of slaughter weight, breed type and ageing time on beef meat quality using two different texture devices

Physical characteristics of meat texture were measured on the M. longissimus dorsi of 103 entire yearling bulls in terms of the effect of slaughter weight (300 or 550 kg), breed type (double muscle, fast growth, dual purpose and unimproved) and ageing time (1, 7 and 21 days). Live weight, breed and ageing effects were statistically significant for all the Warner–Bratzler variables measured on cooked meat. For compression values (raw meat), live weight had a significant effect at higher compression rates, which were higher in the heaviest animals, and ageing had a significant effect at lower compression rates, which were progressively lower as ageing time increased. Breed effect was significantly different for all compression values. At the highest rates of compression, unimproved and dual purpose breed types had the highest values. At 20% compression, double muscled animals had the lowest values, but only at one day of ageing. The differences between breed types tended to decrease or disappear with longer periods of ageing.