Calcium and potassium content in beef: Influences on tenderness and associations with molecular markers in Nellore cattle

Calcium (Ca) and potassium (K) are essential nutrients in animal nutrition. Furthermore, the Ca content can influence meat tenderness because it is needed by the proteolytic system of calpains and calpastatins, major factors in postmortem tenderization of skeletal muscles. K content, which is needed for muscle contraction, can also affect meat tenderness. This study showed that K positively affects the Warner–Bratzler shear force (WBSF), measured at 14 days of meat aging, which means that higher levels of K are related to lower meat tenderness. Additionally, a significant effect (P ≤ 0.015) of a SNP in the calcium-activated neutral protease 1 (CAPN1) gene on Ca content was observed. Metal content in beef can affect not only nutritional values but also meat quality traits. Part of this effect may be related to variation in specific genes.     

Tenderization and fragmentation of myofibrillar proteins in bovine longissimus dorsi muscle using proteolytic extract from Sarcodon aspratus

The objective of this study was to examine the Sarcodon aspratus extract including protease how to affect tenderness of the bovine longissimus dorsi muscle. In addition, we investigated myofibrillar protein fragmentation, particularly in myosin, and its influence on meat tenderness. Beef loin chunks were marinated with 0.5 g/100 g, 1 g/100 g, and 2 g/100 g powdered S. aspratus extract, 0.2 g/100 mL papain, and distilled water (control), respectively. Although tenderness of meat is increased by adding S. aspratus extract, differences in meat quality traits, such as muscle pH and meat color, were small and not considered to have practical importance between the control and enzyme-treated samples. Furthermore, the S. aspratus extract influenced the myofibril fragmentation index (MFI) as well as protein solubility. The changes in MFI and protein solubility were due to the myofibrillar protein degradation. Through Western blotting, we found that the S. aspratus extract, as well as papain, caused fragmentation of the myosin heavy chain, but the mushroom extract induced more fragmentations of myofibrillar proteins, and caused more tender meat.     

Nutritional composition of blubber and meat of hooded seal (Cystophora cristata) and harp seal (Phagophilus groenlandicus) from Greenland

Seal blubber and skin are widely used, but the utilisation of blubber and meat for human consumption is limited. The aim of this study was to evaluate the nutritional composition of seal blubber and meat. The fatty acid composition, selected minerals and trace-elements, vitamins, amino acids and proximal composition of blubber and meat from hooded seal (Cystophora cristata) and harp seal (Phagophilus groenlandicus) from the “West Ice” near Greenland were analysed. The results showed that seal blubber is an excellent source of long- and very long-chain (VLC) n − 3 polyunsaturated fatty acids (PUFAs), in addition to long- and VLC monounsaturated fatty acids (MUFAs). Eicosapentaenoic acid (EPA) content contributed to a clear separation between blubber and meat from the two species. The blubber of harp seal showed the highest EPA (9.2%), whereas the muscle of harp seal showed the lowest EPA (3%) content. Seal meat is lean with less than 2% total fat, mainly composed of MUFAs, long- and VLC n − 3 PUFAs. In addition, the meat contains a high amount of proteins with a well-balanced amino acid composition. The trace-element content of seal meat is very high, particularly iron (379 μg/g muscle in hooded seal) and zinc (30 μg/g muscle in harp seal), as also is the vitamin content, especially vitamins A, D₃ and B₁₂. The seals included in this study varied greatly in age and size, which in turn may be the principal reason for the great individual variation observed in nutritional composition. On average, however, consumption of only 40 g seal meat covers the recommended daily intakes of iron and vitamin B₁₂ for young women. In conclusion, as long as the products fulfil the amending legislations regarding contaminants, both seal blubber and meat, from the present species, represent high quality food regarding nutrients and bioactive components beneficial for human health.     

Beef quality assessed at European research centres

Loin steaks and cubes of M. semimembranosus from eight (12 month old) Galloway steers and eight (16–18 month old) Charolais cross steers raised in England and from which the meat was conditioned for 2 or 10 days, were assessed in research centres in Belgium, Denmark, England, France, the Federal Republic of Germany, Ireland, Italy and the Netherlands. Laboratory panels assessed meat by grilling the steaks and cooking the cubes in casseroles according to local custom using scales developed locally and by scales used frequently at other research centres.The meat was mostly of good quality but with sufficient variation to obtain meaningful comparisons. Tenderness and juiciness were assessed most, and flavour least, consistently. Over the 32 meats, acceptability of steaks and casseroles was in general compounded from tenderness, juiciness and flavour. However, when the meat was tough, it dominated the overall judgement; but when tender, flavour played an important rôle. Irish and English panels tended to weight more on flavour and Italian panels on tenderness and juiciness. Juciness and tenderness were well correlated among all panels except in Italy and Germany. With flavour, however, Belgian, Irish, German and Dutch panels ranked the meats similarly and formed a group distinct from the others which did not. The panels showed a similar grouping for judgements of acceptability.French and Belgian panels judged the steaks from the older Charolais cross steers to have more flavour and be more juicy than average and tended to prefer them. Casseroles from younger steers were invariably preferred although the French and Belgian panels judged aged meat from older animals equally acceptable. These regional biases were thought to be derived mainly from differences in cooking, but variations in experience and perception of assessors also contributed.     

u-Calpain生物学性质及其活性调控

u-calpain降解肌纤维骨架蛋白在肉品嫩化中起关键作用,肉中u-calpain与calpastatin含量比、pH、离子强度等影响u-calpain的活性发挥,影响肉品嫩度。u-calpain的基因变异与肉品嫩度关系的研究揭示肉品嫩度的分子基础,同时肌纤维类型的差异对肉品嫩度也存在一定影响,其中ATP酶活性和钙离子浓度影响u-calpain活性决定肉品最终嫩度。     

Imaging optical diffuse reflectance in beef muscles for tenderness prediction

The objective of this study was to investigate the potential of a novel optical reflectance imaging method to predict beef tenderness. Two-dimensional (2D) optical reflectance in beef muscles induced by a point incident light was acquired. A set of five parameters were extracted from each reflectance image to describe quantitatively the reflectance profiles. Two parameters, q and B, were derived by numerically fitting the equi-intensity contours of the reflectance pattern. Two spatial gradients were calculated along the directions parallel and perpendicular to muscle fibers and total scattering intensity was obtained by excluding the specular reflectance. This method was applied to analyze 2D images of optical diffuse reflectance in 336 beef samples obtained from 14 steers in which large variations in tenderness were generated by altering animal genetics, suspension method and aging time as well as utilizing muscles varying in their inherent tenderness. Tenderness was evaluated using Warner–Bratzler shear force (WBSF). The effects of animal breed, muscle, types of suspension, and aging were investigated and results indicate that the scattering intensity measured at 1-d was correlated (R² = 0.50 at λ = 720 nm) with 10-d WBSF in M. longissimus dorsi muscles; and the q parameters measured at 1-d was correlated (R² = 0.46 at λ = 720 nm) with 10-d WBSF in M. psoas major muscles. These results show analyzing 2D reflectance images of meat surfaces provides valuable information regarding the physical characteristics of meat that are responsible for beef tenderness.     

The influence of carcass backfat and intramuscular fat level on pork eating quality

To evaluate the contribution of fatness level towards pork eating quality, carcass and meat eating quality data were analysed from 721 pigs of three genotypes (with 0, 0.25 and 0.50 Duroc inclusion level). Animals (entire male and female) were reared from 30 to 90 kg liveweight on one of seven feeding regimens which involved combinations of diet formulation and feeding level, so as to produce carcasses of widely differing fatness levels. This experimental design produced coefficients of variation for classification P₂ backfat thickness of 21.11 (mean 11.59 mm, SE 0.093) and intramuscular fat (IMF) of 63.60 (mean 13.4 g kg⁻¹, SE 0.33). The treatments also produced considerable variation for eating quality as assessed by trained sensory panel (1–8 scale) and objectively (shear force) as shown by the following coefficients of variation: shear force 22.01% (mean 334 N, SE 2.77), juiciness 16.12% (mean 4.95, SE 0.297), tenderness 19.65% (mean 5.06, SE 0.370), pork flavour 13.22% (mean 4.56, SE 0.225), abnormal flavour 34.46% (mean 2.02, SE 0.259) and overall acceptability 18.42% (mean 4.78, SE 0.328). Correlation coefficients between carcass fatness measurements and eating quality characteristics were calculated. Although shear force was significantly correlated with both classification P₂(r = −0.213) and IMF (r = − 0.189), taste panel tenderness was not significantly correlated to fatness level. Of the taste panel parameters evaluated, only juiciness showed a significant correlation (P < 0.05) with classification P₂(r = − 0.086). None of the eating quality characteristics as evaluated by taste panel correlated significantly with IMF. These results do not support the belief that fatness level per se has a major influence on pork eating quality. © 2000 Society of Chemical Industry     

The influence of breed,gender, and PSS (Halothane) genotype on meat quality,cooking loss,and palatability of pork

A total 851 swine of four breeds (Duroc, Hampshire, Landrace, and Yorkshire), three genders (barrows, gilts, and boars) and two PSS (halothane) genotypes (carriers and non-carriers of the halothane gene) were evaluated for meat quality, cooking, and palatability traits. Breed exerted a major influence on meat quality, cooking, and palatability traits. The most palatable meat was produced by Hampshires and the least desirable meat was produced by Yorkshires. Although juiciness was negatively correlated with cooking loss (r=−0.60), meat from Hampshires received the highest ratings for juiciness, despite sustaining the greatest cooking losses. Gender exerted minor influences on meat quality and palatability attributes, and no indication was obtained genders differed sufficiently in palatability to warrant discrimination based upon gender. Therefore, entire males can be utilized to capitalize on reported production advantages without influencing palatability, particularly if adequate means for screening boar taint are available for carcasses from heavier or more mature animals. Halothane genotype exerted substantial influence on meat quality traits and statistically significant but relatively minor influence on palatability traits. Carriers of the halothane gene produced meat which was of clearly inferior quality to the meat produced by non-carriers. Carriers of the halothane gene consistently produced a higher proportion of unacceptable chops than non-carriers, although differences were not statistically significant.     

Expression of genes related to quality of Longissimus dorsi muscle meat in Nellore (Bos indicus) and Canchim (5/8 Bos taurus × 3/8 Bos indicus) cattle

This study was performed to compare CAPN1, CAPN2, CAST, TG, DGAT1 and LEP gene expressions and correlate them with meat quality traits in two genetic groups (Nellore and Canchim) in order to assess their expression profile and use their expression profile as genetic markers. We analyzed 30 young bulls (1 year old), 15 of each genetic group. Samples of the Longissimus dorsi muscle were collected for analysis of: total lipids (TL) and meat tenderness measured as Warner-Bratzler shear force (SF) and myofibrillar fragmentation (MFI) at day of slaughter and 7 days of aging. Gene expression profiles were obtained via RT-qPCR. TL and MFI showed differences between breeds, higher MFI in Canchim and higher TL in Nellore. Calpains showed no differential expression between groups, as did DGAT1, TG, and LEP. CAST was expressed more in the Nellore cattle. The only significant within-breed correlation (0.79) between gene expression and meat traits was found for DGAT1 and MFI in Canchim breed. Although the number of animals used in this study was small, the results indicate that the increased expression of CAST in Nellore may reflect tougher meat, but the lack of correlations with the meat traits indicates it is not a promising genetic marker.     

Associations of sire estimated breeding values and objective meat quality measurements with sensory scores in Australian lamb

The impact of selecting for lean meat yield using breeding values for increased eye muscle depth (PEMD) and decreased fat depth (PFAT) on the consumer acceptance of lamb meat was evaluated. Consumer sensory scores (tenderness, juiciness, flavour, odour, overall liking) were obtained for the longissimus lumborum (loin) and semimembranosus (topside) muscles of 1471 lambs. On average loin samples were more acceptable for consumers. Sensory scores increased with higher IMF levels, with lower shear force levels, and when animals were younger and less muscular. Increasing PEMD decreased tenderness, overall liking and flavour scores in both muscles, and decreasing PFAT reduced tenderness within the loin samples only. This negative impact of PEMD and PFAT is not solely driven through the phenotypic impact of IMF and shear force on sensory scores. Our results confirm the growing concerns that selecting for lean meat yield would reduce consumer eating quality, and highlight that careful monitoring of selection programmes is needed to maintain lamb eating quality.     

Proteins in longissimus muscle of Korean native cattle and their relationship to meat quality

Proteomic profiling by two-dimensional gel electrophoresis and mass spectrometry of longissimus dorsi muscle tissue from Korean native cattle identified seven proteins that are differentially expressed in animals producing low and high quality grade beef. The expression level of alpha actin is increased in high quality grade beef and the expression levels of T-complex protein 1 (TCP-1), heat shock protein beta-1 (HSP27), and inositol 1,4,5-triphosphate receptor type1 (IP3R1), a new protein to be associated with meat quality, are increased in low quality grade beef. In particular, the quantitation of HSP27 and IP3R1 by both silver staining and immunoblotting correlated well with intramuscular fat content, meat tenderness, and free calcium levels. The data suggest that HSP27 and IP3R1 are potential meat quality biomarkers and their identification provides new insight into the molecular mechanisms and pathways associated with overall beef quality.     

Quality and proteome changes of beef M.longissimus dorsi cooked using a water bath and ohmic heating process

This study investigated the effects of different cooking methods, namely water bath cooking (WB), short time ohmic cooking (STOH) and long time ohmic cooking (LTOH) on color, cooking loss, shear force value and proteome changes in beef M.longissimus dorsi at the same endpoint temperature of 72 °C. The cooking loss and shear force value of the ohmically cooked meat were significantly lower (P < 0.05) and redness a* value was significantly higher than that of the WB cooked samples. Proteomics analysis showed that ohmically cooked meat had less protein damage than those of WB cooked ones. Seventeen protein spots of differential abundance in two-dimensional gel electrophoresis (2-DE) image between STOH and WB cooked samples were successfully identified, and thirteen protein spots between LTOH and WB cooked samples were identified. Most of them belong to myofibrillar and sarcoplasmic proteins and may be related to changes of meat quality parameters.Industrial relevanceDuring thermal processing, proteins, the primary constituents of meat, undergo structural modifications such as oxidation, degradation, denaturation and aggregation. These changes of proteins have important effects on the quality of the final meat products, such as color, tenderness and flavor, and ultimately affect meat palatability and acceptability. Nowadays, innovation is necessary in developing new cooking methods to meet the industrial demand for more efficient production and consumer's demand for higher quality and safer meat products. Ohmic cooking, also known as electric resistance cooking, relies on the heat that is generated when electrical current passes directly through conductive foodstuff to cook the food. Compared to conventional cooking, ohmic cooking has the advantages of much shorter cooking time, higher yield and more uniform heating distribution, and ohmically cooked meat has superior color, higher tenderness, etc. Therefore, as a potential food processing technology, ohmic heating not only increases energy efficiency, but also improves meat quality. In this study, two-dimensional gel electrophoresis and tandem mass spectrometry were used to investigate the quality and proteome changes of beef M.longissimus dorsi following ohmic cooking and water bath cooking, and the results indicated that protein damages in ohmically cooked meat were much less than that of water bath cooked ones, and this might contribute to the lower cooking loss, higher tenderness and better color in ohmically cooked meat. The results of the study suggested that ohmic cooking has a great potential in industrial production of meat products.     

Genetic and management factors affecting beef quality in grazing Hereford steers

Attributes contributing to differences in beef quality of 206 Hereford steers finished on pasture were assessed. Beef quality traits evaluated were: Warner-Bratzler meat tenderness and muscle and fat color at one and seven days after slaughter and trained sensory panel traits (tenderness, juiciness, flavor, and marbling) at seven days. Molecular markers were CAPN1 316 and an SNP in exon 2 on the leptin gene (E2FB). Average daily live weight gain, ultrasound monthly backfat thickness gain and rib-eye area gain were estimated. Molecular markers effects on meat quality traits were analyzed by mixed models. Association of meat quality with post weaning growth traits was analyzed by canonical correlations. Muscle color and marbling were affected by CAPN1 316 and E2FB and Warner-Bratzler meat tenderness by the former. The results confirm that marker assisted selection for tenderness is advisable only when beef aging is a common practice. The most important sources of variation in tenderness and color of meat remained unaccounted for.     

Genetic and management factors affecting beef quality in grazing Hereford steers

Attributes contributing to differences in beef quality of 206 Hereford steers finished on pasture were assessed. Beef quality traits evaluated were: Warner–Bratzler meat tenderness and muscle and fat color at one and seven days after slaughter and trained sensory panel traits (tenderness, juiciness, flavor, and marbling) at seven days. Molecular markers were CAPN1 316 and an SNP in exon 2 on the leptin gene (E2FB). Average daily live weight gain, ultrasound monthly backfat thickness gain and rib-eye area gain were estimated. Molecular markers effects on meat quality traits were analyzed by mixed models. Association of meat quality with post weaning growth traits was analyzed by canonical correlations. Muscle color and marbling were affected by CAPN1 316 and E2FB and Warner–Bratzler meat tenderness by the former. The results confirm that marker assisted selection for tenderness is advisable only when beef aging is a common practice. The most important sources of variation in tenderness and color of meat remained unaccounted for.     

Structural and biochemical characteristics of bovine intramuscular connective tissue and beef quality

The aim of the study was to evaluate the impact of structural and biochemical characteristics of muscle intramuscular connective tissue on beef quality. The experimental design was based on three muscles of three breeds sampled as fresh material and cooked at 55 °C (Longissimus thoracis and Semimembranosus) or at 70 °C (Semimembranosus and Biceps femoris) for quality assessment. The results showed that muscle characteristics influence beef quality differently from one muscle to another. In grilled LT, proteoglycan content contributed negatively to juiciness, and intramuscular lipids were linked positively to tenderness, flavour, residues and overall liking scores. In grilled SM, cross-link and lipid contents were involved in beef quality. In BF cooked to 70 °C, perimysial branch points were negatively linked to tenderness. In SM cooked to 70 °C, perimysial area was involved in beef quality. These results should allow a better understanding of the factors involved in background toughness, in juiciness and flavour of meat.     

Colour properties,stability, and free radical scavenging activity of jambolan (Syzygium cumini) fruit anthocyanins in a beverage model system: Natural and copigmented anthocyanins

The colour and stability properties of jambolan anthocyanins, both natural and copigmented forms, were investigated in beverage model as well as their radical scavenging ability. Natural anthocyanins of jambolan revealed low colour intensity due to glycosylation structure of the anthocyanins as diglucoside. The intermolecular copigmentation of anthocyanins with sinapic acid, caffeic acid, ferulic acid, and rosemary polyphenolic extract could enhance the colour intensity, which was observed through spectrometric parameters, such as hyperchromic effect (ΔA_vis-max) and bathochromic shift (Δλ_vis-max). In addition of sinapic acid, caffeic acid, and rosemary polyphenolics also increased the stability of the anthocyanin colour during exposure to white fluorescent light and storage at refrigeration and room temperatures, whereas on high thermal treatments, this phenomenon was not observed. Furthermore, beverage model coloured with natural or copigmented anthocyanins revealed DPPH radical-scavenging activity. The AEAC values indicated that the beverage models with copigmented anthocyanins had higher scavenging activity than the beverage with natural anthocyanins.     

细胞凋亡对肌肉宰后嫩化的贡献

嫩度是肉品最重要的品质指标,而成熟是改善肉的嫩度的重要途径。肉成熟嫩化的原因普遍认为是肌细胞的细胞骨架降解造成的。目前,细胞骨架降解的机理研究方面报道较多的是钙激活酶系统、组织蛋白酶系统和蛋白酶体,而有关细胞凋亡酶在肉成熟中的作用国内外还鲜见报道。本文综述了宰后肌细胞内生理条件的变化,以及细胞可能选择的死亡方式,即凋亡;概述了能作为caspase酶家族底物的几类主要的肌细胞骨架蛋白;对常用的几类诱导细胞凋亡的细胞毒素进行了介绍;最后,对细胞毒素注射应用于宰后牛肉品质形成机理研究的潜在意义进行了探讨。     

Intramuscular connective tissue and its role in meat quality

The amount, spatial distribution and composition of the connective tissue within muscle vary with muscle position in the carcase and with animal age. This has long been recognised to influence the tenderness of cooked meat. This paper builds upon some historical perspectives with a review of some recent clarifications of the biological function of intramuscular connective tissue (IMCT) and of its contribution to meat texture, which is clearly multifactorial. The perimysial component of IMCT varies most in amount between muscles and is also the IMCT structure most involved in defining the mechanical integrity of cooked meat. The distribution of perimysium defines muscle fascicle size (muscle "grain" size), which is also still regarded as an indicator of tenderness. Postmortem conditioning of meat has consistently been shown to reduce the strength of intramuscular connective tissue in the raw state, but with equal consistency, this has been shown not to affect the toughness of cooked meat. Cooking increases IMCT strength in the range 20-50 °C and decreases its contribution at higher temperatures and longer cooking times. Crosslinking of collagen in older animals is generally considered to result in tougher meat, although definitive links between mature crosslink content and cooked meat toughness have been difficult to prove. In the last quarter-century, IMCT has been increasingly viewed as a "background" contributor to meat texture, which is difficult to change. However, the large variation in perimysial content of muscles in one animal represents an incredible range of expression. This appears to be firmly fixed to the functional properties of different muscles. In particular, it is hypothesised that definition of muscle fascicle size and shape by the bounding perimysium is related to the need for sub-sections of the whole muscle to slip past each other in the normal contractile function of the tissue. Despite this, the amounts and composition of IMCT can be manipulated by animal nutrition and exercise, and factors affecting the turnover of IMCT may especially be a future target for manipulation of meat texture.     

Outdoor rearing of cull sows: Effects on carcass, tissue composition and meat quality

The objective of this study was to provide some information on the influence of outdoor rearing on pasture (O) compared with indoor (I) on carcass and meat quality of cull sows. Twelve sows (6 per group) originating from the same breeding unit were slaughtered 11 days after their last weaning. O sows had heavier and fatter carcasses, however lipid content in Longissimus (L) and Triceps brachii (TB) muscles was not affected. Grazing of O sows led to a high increase in the n − 3 fatty acid content, particularly the C18:3 linolenic acid in the backfat and L muscle, thus improving the meat nutritional quality. Vitamin E content appeared (P = 0.13) to be increased in the backfat of O sows, but not in the muscles. Lipid oxidation in meat during storage was similar between groups. Histological and metabolic observations showed that outdoor rearing increased the glycolytic capacity of the L muscle, and the oxidative capacity of the TB. Outdoor rearing did not influence meat pH1 and pHu, but decreased colour (a¹ and b¹ values) of the TB, and increased the processing yield of loin into cured bacon. Outdoor rearing decreased the red colour intensity and homogeneity, but improved tenderness of cured loins.