Genotypic effects of the Texel Muscling QTL (TM-QTL) on meat quality in purebred Texel lambs

Texel Muscling QTL (TM-QTL) increases loin muscling in lambs inheriting it from their sire only. This study investigated TM-QTL effects on meat quality in 209 Texel lambs that were CT-scanned then slaughtered at 20weeks (carcasses aged for ~1week). Loin meat quality traits included: CT-measured muscle density (predicting intramuscular fat); mechanical tenderness using Volodkevich-type jaws or MIRINZ tenderometer; intramuscular fat; sensory eating quality (sub-sample of 40 lambs). Volodkevich tenderness was also measured in the leg (Vastis lateralis). TM-QTL genotypes were determined, giving 40 non-carriers (+/+), 70 heterozygotes-53 inheriting TM-QTL from the sire (TM/+) and 17 from the dam (+/TM), 34 homozygote TM-QTL lambs (TM/TM) and 65 uncertain. Multiple regression identified no genotype effects on meat quality. For MIRINZ-measured loin tenderness only, contrasts revealed a significant additive effect of TM-QTL (1.27kgF difference between homozygotes). However, the taste panel identified no significant differences between +/+ and TM/TM lambs. Results show little evidence of TM-QTL affecting meat quality.     

The effect of the Texel muscling QTL (TM-QTL) on meat quality traits in crossbred lambs

A quantitative trait locus (QTL) has been identified on chromosome 18 in Texel sheep (TM-QTL) that increases depth and area of the longissimus dorsi muscle. The study aimed to assess the pleiotropic QTL effects on key meat quality traits (toughness and intramuscular fat content after ?7 days aging) of crossbred lambs carrying one copy of the TM-QTL. The results showed that male Texel × Mule lambs carrying the TM-QTL had significantly less intramuscular fat (1.86% versus 2.25%) and higher toughness, with increased variation, in the loin muscle, compared to non-carrier males. Similar conclusions were obtained using two different types of tenderometer equipment: one using the Volodkevitch test (average shear force of 4.17 kgF or 40.9 N for carrier males, 2.61 kgF or 25.6 N for non-carrier males) and one using the MIRINZ test (average shear force of 6.18 kgF or 60.6 N for carrier males, 5.22 kgF or 51.2 N for non-carrier males). Although most toughness measurements were within published consumer acceptability limits, a few individual TM-QTL carrier lambs had unacceptably tough meat, despite enhanced post-slaughter processing. The TM-QTL did not significantly affect loin toughness in female lambs, leg toughness in either sex, or intramuscular fat content. These results should be considered, alongside direct effects of the TM-QTL on muscling and carcass composition, in recommendations for the use of this QTL by sheep breeders.     

Application of near infrared reflectance spectroscopy to predict meat and meat products quality: A review

Over the past three decades, near infrared reflectance (NIR) spectroscopy has been proved to be one of the most efficient and advanced tools for the estimation of quality attributes in meat and meat products. This review focuses on the use of NIR spectroscopy to predict different meat properties, considering the literature published mainly in the last decade. Firstly, the potential of NIR to predict chemical composition (crude protein, intramuscular fat, moisture/dry matter, ash, gross energy, myoglobin and collagen), technological parameters (pH value; L*, a*, b* colour values; water holding capacity; Warner–Bratzler and slice shear force) and sensory attributes (colour, shape, marbling, odour, flavour, juiciness, tenderness or firmness) are reviewed. Secondly, the usefulness of NIR for classification into meat quality grades is presented and thirdly its potential application in the industry is shown. The review indicates that NIR showed high potential to predict chemical meat properties and to categorize meat into quality classes. In contrast, NIR showed limited ability for estimating technological and sensory attributes, which may be mainly due to the heterogeneity of the meat samples and their preparation, the low precision of the reference methods and the subjectivity of assessors in taste panels. Hence, future work to standardize sample preparation and increase the accuracy of reference methods is recommended to improve NIR ability to predict those technological and sensory characteristics. In conclusion, the review shows that NIR has a considerable potential to predict simultaneously numerous meat quality criteria.     

The effects of electrical stunning and percussive captive bolt stunning on meat quality of cattle processed by Turkish slaughter procedures

The effects of electrical and percussive captive bolt stunning both on initial and up to 14 days post mortem meat quality of Friesian young bulls were studied. The first group (NS; n=10) were slaughtered without stunning under Turkish slaughter procedure (these animals were slaughtered under conditions acceptable to the appropriate ethics committee) in a modern abattoir. In the second group (ES; n=10) animals were electrically stunned. In the third group (PS; n=10) animals were stunned with percussive captive bolt. Meat quality was assessed by examining muscle glycogen concentration, pH and WHC. Also cooking loss, texture parameters and consumer sensory properties were assessed at 24 h, 4, 7 and 14 days post mortem. Meat colour as L^*, a^*, b^*, C^*, h^* values were evaluated at 0, 48 h, 3, 5, 7, 9 and 14 days post mortem. Pre-slaughter handling affected muscle glycogen concentration (P<0.05). Animals in electrical and percussive captive bolt stunned groups had higher muscle glycogen concentrations compared to animals in the non-stunned group (P<0.05). Although pre-slaughter handling did not affect significantly pH_{24 h} and WHC, differences were significant for cooking loss, colour coordinates and texture parameters at some storage times. For all sensory attributes (odour, flavour, tenderness and overall acceptability) at all ageing periods (24 h, 4, 7 and 14 days) the percussive stunned (PS) group was significantly superior to the non-stunned (NS) group. The electrically-stunned (ES) group also tended to be superior to the NS group although not all differences were statistically significant. These results indicate that percussive captive bolt stunning of cattle improved meat quality compared with cattle electrically stunned using head only tongs and those non stunned under approved Turkish slaughter procedure.     

Meat cooking shrinkage: Measurement of a new meat quality parameter

Chemical, physical and sensory aspects of quality were compared on encased rolls (1kg) prepared from single muscle beef (biceps femoris) cooked in a steam oven (80°C) or by radio frequency (RF) heating (500W, 27.12MHz) under recirculating water at 80°C. The RF protocol reduced cooking times to 23 and 31% of steam cooking times, respectively, in non-injected meat (PG1) and in rolls prepared with curing brines possessing similar dielectric properties (PG2-4). Compared to steam heating, cooking yields were significantly higher (P<0.05) and instrumental texture measurements related to toughness significantly lower (P<0.05) for RF cooked PG1 rolls and for meat injected with brines containing water binding dielectrically inactive additives (PG4) but not for brined rolls lacking the latter ingredients (PG2 and PG3). Participants in a 50 member untrained sensory panel were unable to detect texture differences which had been indicated by instrumental analysis for PG1 and PG4.     

SmartStretch™ technology. III. The impact of medium voltage stimulation and SmartStretch™ technology on sheep topside (m. semimembranosus) meat quality traits under commercial processing conditions

This study evaluated the interaction between medium voltage electrical stimulation, SmartStretch™ stretching and ageing treatments on key meat quality traits of hot boned sheep m. semimembranosus. Medium voltage stimulation reduced initial pH (P < 0.001), but did not impact on other meat quality traits. There was a significant interaction between stretch treatment and ageing (P < 0.001) for shear force such that samples which were both stretched and aged were the most tender. Sarcomere length was significantly (P < 0.001) increased by SmartStretch™ treatment. Control (no stretching) resulted in greater (P < 0.05) cooking loss, but there was significantly less purge loss (P < 0.05). The ratio 630/580 nm and a* colour values at 0 and 5 days decreased at a significantly (P < 0.05) slower rate when SmartStretch™ was applied. Overall medium voltage stimulation did not inhibit the effectiveness of the SmartStretch™ treatment. The SmartStretch™ treatment provided significant improvement in tenderness and the potential to increase meat display time.     

Integrated technologies to enhance meat quality - An Australasian perspective

Ensuring meat quality attributes meet the requirements of the diverse range of markets is a critical component for the continued success of the New Zealand and Australian meat industries. Developing cost-effective and flexible technologies to help meet this requirement is a central objective of a current Meat and Wool New Zealand and Meat and Livestock Australia funded programme. This initiative was developed three years ago; it is a collaborative programme that involves meat scientists, electrical engineers and commercial meat processors. To ensure this programme successfully delivers technologies and knowledge to the Australasian meat industry, the following strategies have been developed: measurement of meat quality attributes 'on-line' during processing; development of 'expert systems' that can integrate and interpret on-line measurements and development of quality-related feedback systems from the market that can be fed back to producers; and, development of methods to manipulate structural and biochemical events in meat to create new commercial opportunities for both producers and processors. This paper gives an overview of some of the new technologies that have developed from this programme that are being used commercially or, are undergoing the final stages of commercial validation.     

A review of the growth, and of the carcass and meat quality characteristics of the one-humped camel (Camelus dromedaries)

The dromedary camel is a good source of meat especially in areas where the climate adversely affects the performance of other meat animals. This is because of its unique physiological characteristics, including a great tolerance to high temperatures, solar radiation, water scarcity, rough topography and poor vegetation. The average birth weight of camels is about 35kg, but it varies widely between regions, breeds and within the same breed. The meat producing ability of camels is limited by modest growth rates (500g/day). However, camels are mostly produced under traditional extensive systems on poor levels of nutrition and are mostly slaughtered at older ages after a career in work, racing or milk production. Camels reach live weights of about 650kg at 7-8 years of age, and produce carcass weights ranging from 125 to 400kg with dressing-out percentage values from 55% to 70%. Camel carcasses contain about 57% muscle, 26% bone and 17% fat with fore halves (cranial to rib 13) significantly heavier than the hind halves. Camel lean meat contains about 78% water, 19% protein, 3% fat, and 1.2% ash with a small amount of intramuscular fat, which renders it a healthy food for humans. Camel meat has been described as raspberry red to dark brown in colour and the fat of the camel meat is white. Camel meat is similar in taste and texture to beef. The amino acid and mineral contents of camel meat are often higher than beef, probably due to lower intramuscular fat levels. Recently, camel meat has been processed into burgers, patties, sausages and shawarma to add value. Future research efforts need to focus on exploiting the potential of the camel as a source of meat through multidisplinary research into efficient production systems, and improved meat technology and marketing.     

Effect of different stunning systems on meat quality of light lamb

The present study was proposed to compare the effect that different types of stunning (TS) had on the quality of refrigerated meat from light lambs of the Spanish Manchega breed at 24 h and 7 days post-mortem. Lambs were electrically stunned (ESL; n = 10), using CO₂ (GSL; n = 10) or slaughtered without previous stunning (USL; n = 10). Measurements on meat quality were carried out by evaluating pH, colour coordinates (L^*, a^*, b^*), water holding capacity (WHC), cooking loss (CL), shear force (SF) and drip loss (DL). At 24 h post-mortem, no significant differences were found in any of the variables studied. However, at 7 days post-mortem, meat quality was affected by the different TS: pH, CL and DL were lower (P < 0.001) in the USL group and GSL obtained the lowest a^* (redness) and b^* (yellowness) values (P < 0.01) than in the other groups. Ageing of meat affected SF in the ESL group (P < 0.01), although there were no significant differences due to treatments at any of the ageing times.     

The relevance of different near infrared technologies and sample treatments for predicting meat quality traits in commercial beef cuts

Visible and near infrared reflectance (Vis-NIR, 350 to 1800 nm), and near infrared transmittance (NIT, 850 to 1050 nm) spectroscopy were used to predict beef quality traits of intact and ground meat samples. Calibration equations were developed from reference data (n = 312) of pH, color traits (L*, a*, and b*), ageing loss (%), cooking loss (%), and Warner–Bratzler shear force (WBSF, N) using partial least squares regressions. Predictive ability of the models was assessed by coefficient of determination of cross-validation (R²_CV) and root mean square error of cross-validation. Quality traits were better predicted on intact than on ground samples, and the best results were obtained using Vis-NIR spectroscopy. Predictions were good (R²_CV = 0.62 to 0.73) for pH, L*, and a*, hardly sufficient (R²_CV = 0.34 to 0.60) for b*, cooking loss, and WBSF, and unsatisfactory for ageing loss (R²_CV = 0.15). Vis-NIR spectroscopy might be used to predict some physical beef quality traits on intact meat samples.     

Effect of electrical stunning on meat quality of lamb

The effects of stunning on both initial and up to 2 weeks post mortem storage meat quality of Spanish Manchega breed lamb were studied. Twenty-four lambs were distributed into two groups. The first group (US; n =12) were slaughtered without previous stunning. In the second group (ES; n =12) animals were electrically stunned. Meat quality was assessed by examining pH, colour as L*, a*, b* values, water holding capacity (WHC) and shear force (SF). Stunning did not affect any parameter studied in the first 24 h post mortem. There were increasing differences between groups in pH (P<0.001) from 5 days onwards. In general stunning did not have an effect on WHC, SF and colour parameters. Ageing of meat affected SF in the ES group but not in the US one; however, there were no significant differences between treatments at any of the ageing times.     

Sensory quality of meat from lambs fed garlic

The objective of this study was to determine whether the inclusion of garlic in a ration would have a negative impact on the flavour of lamb. The study used meat from 31 Merino wether lambs fed diets with varying levels of garlic (0%, 1.8% and 3.6%) for 10 weeks. Cooked samples of meat from the lambs were assessed for flavour and acceptability as lamb by an untrained consumer panel. There was no difference (P>0.05) between the treatments in flavour score, but the 3.6% garlic treatment group scored significantly higher in terms of acceptability as lamb (P<0.05) and was commented on positively by the panellists more frequently than the meat from any other treatment (P<0.05). These results suggest that the inclusion of garlic into the animals' feed did not have a negative impact on the flavour of the lamb and, at the high rate (3.6%), made the meat more acceptable to the panellists.     

Carcass and meat quality of Thai native cattle fattened on Guinea grass (Panicum maxima) or Guinea grass-legume (Stylosanthes guianensis) pastures

Carcass and meat quality of Thai native cattle, fattened for 2 years on Guinea grass (Panicum maxima) and Guinea grass-legume (Stylosanthes guianensis) pastures, were investigated in twelve 3-years old males. Groups had similar carcass quality except for kidney fat percentage (higher in cattle of the grass-legume group). This group also had a lighter meat (Longissimus dorsi, Infraspinatus) than the grass-only fed cattle. Shear force was generally at the borderline to tender meat, and was unaffected by treatment as were other texture-related properties except muscle fibre diameter. Meat of the grass-legume group was perceived less juicy (P<0.05) but more tender (P<0.1). The meat of the grass-legume-fed cattle also had more intramuscular fat (4.3% vs. 3.4%) and a slightly less favourable n-6:n-3 fatty acid ratio (2.2 vs. 2.0). In conclusion, the mostly weak differences in carcass and meat quality did not clearly favour one of the grazing systems.     

Application to proteomics to understand and modify meat quality

The use of proteomics in the field of meat science has gained in robustness and accuracy. This is consistent with the genomic and bioinformatic tools. Its application to sensorial and technological meat quality traits is discussed as well as the emergence of sanitary and nutritional issue which will grow in a next future.     

Influence of meat exudates on the quality characteristics of fresh and freeze-thawed pork

The influence of the accumulated exudates released from pork loin of itself on the quality characteristics of fresh and freeze-thawed pork during cold storage was investigated. Pork loins were divided into four groups (fresh pork with exudates, fresh pork without exudates, freeze-thawed pork with exudates and freeze-thawed pork without exudates) and stored at 1.0 °C for 7 days. Exudate amount increased due to freeze-thawing and with storage, and most quality traits such as drip loss, cooking loss, tenderness, lightness, redness, and moisture content were affected by freeze-thawing (p < 0.05). Freeze–thaw increased drip loss but decreased moisture content, cooking loss, tenderness, lightness and redness of meat (p < 0.05). Microbial growth was solely affected by exudate removal and the removal of initial exudates decreased microbial growth (p < 0.05). Exudates were positively correlated with total protein content and total plate count but negatively correlated with pH and cooking loss. Therefore, removing meat exudates and avoiding freeze can slow down the quality deterioration of pork during cold storage.     

Non-invasive mobile monitoring of meat quality

Detailed investigations into the time-dependent changes of pork meat quality and composition have been carried out using standard analytical techniques and Raman and fluorescence spectroscopy. Characteristic changes in soluble protein content, microbial load and biogenic amine content have been measured in the time period from slaughter up to 20 to 30 days post mortem on samples of porcine musculus longissimus dorsi. Characteristic behaviour indicative of a deterioration of meat quality and an increase in microorganism population on the meat surface has been observed. Fluorescence and Raman optical signals have been identified which change over this time period, correlating with the standard measurements and these can be used as indicators of meat properties. These signals can be measured rapidly and without the destruction of the meat sample allowing non-invasive testing. The combination of these two powerful measurement techniques provides a pathway to comprehensive meat quality monitoring. Furthermore we have developed a hardware concept for carrying out these spectroscopic measurements using a compact and light handheld device and we present concepts for the use of such a device in the logistic chain in combination with a transponder chip and integrated sensors which provide product identification and information about storage conditions along the entire logistic chain to the supermarket shelf. Received: September 16, 2008; accepted: October 5, 2008     

Carcass and meat quality traits of four different pig crosses

The study compared properties of Finnish Landrace × Yorkshire crossbred sows mated with Finnish Landrace (FL), Norwegian Landrace (NL), Norwegian Duroc × Norwegian Landrace (NDL), or Swedish Hampshire (SH) boars. The focus was to study the cross-sectional area of loin, cross-sectional area and number of muscle fibres, loin colour and pH value as well as the ratio of water to protein in the loin.The four studied crosses were quite similar having only small differences in carcass and meat quality. The carcass lean content was the lowest in NDL. The loins of FL and NL were longer than the loins of NDL and of SH. The cross-sectional area of loin was the largest in SH. The loin of FL was lighter in colour and the loin of SH was redder than the loins of the other crosses studied. The protein content was lower and the ratio of water to protein higher in loin of SH than in the other crosses.     

Comparison of the meat quality and fatty acid composition of traditional fat-tailed (Chall) and tailed (Zel) Iranian sheep breeds

The aim of this study was to compare the meat quality of a traditional fat-tailed breed, Chall, to a tailed Iranian sheep breed, Zel. Lambs were grazed on pasture until weaning, and then were finished until slaughter at 10-12months. Meat quality traits were measured on the longissimus dorsi (LD) muscle. Zel lambs accumulated more intramuscular fat (IMF) (p<0.01) and had lower shear force and drip loss than Chall lambs (p<0.05). The meat color of Zel lambs was higher for both a* (p<0.001) and b* (p<0.01) compared to Chall lambs. Meat from Zel lambs was more tender (p<0.01) and more juicy (p<0.05) than Chall lambs. The PUFA:SFA fatty acid ratio (P:S) was higher (p<0.05) and the n-6:n-3 PUFA ratio was lower in Chall compared to Zel lambs (p<0.05). Overall, these results show that the eating quality of Zel lambs was better, but that this was at the cost of less favorable fatty acid profiles and poorer meat color.     

The calibration temperature of pH-glass electrodes: significance for meat quality classification

In this short communication we show important factors concerning pH measurements in pork. The purpose of the study was to investigate the effect of the calibration temperature of pH-buffer and of the pH-electrode on pH measured 1–120 min post mortem in pork, and to evaluate its significance for prediction of meat quality. The calibration temperature of pH-electrodes as well as the sample temperature is essential for pH measurements, as pH measurements are highly temperature-dependent. This is especially important when using pH measurement for prediction of meat quality or when different experiments are compared. We have used two calibration temperatures of 15 °C (normal) and 35 °C (modified) in the present investigation. Based on our findings, we therefore recommend a buffer and electrode temperature of 35 °C as a standard procedure for measuring pH early post mortem. As a minimum the pH should be presented along with the measuring and calibrating temperatures.