Nuria Prieto

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.

Ability of near infrared reflectance spectroscopy (NIRS) to estimate physical parameters of adult steers (oxen) and young cattle meat samples

The potential of NIRS-based models to predict several physical parameters of oxen and young cattle beef protected by a quality mark was evaluated. Fifty-three and 67 samples of Longissimus thoracis muscle corresponding to oxen and young cattle reared in extensive conditions were analyzed for pH, colour (L(∗), a(∗), b(∗)), water holding capacity (WHC) and Warner-Braztler shear force (WBSF), according to the conventional methods. Several factors which might have jeopardized the prediction of pH, a(∗), WHC and WBSF by NIRS are considered in the discussion section. However, the best NIR calibrations, tested by full cross-validation, were for L(∗) (R(2)=0.869; SE(CV)=1.56) and b(∗) (R(2)=0.901; SE(CV)=1.08) colour parameters in meat samples from young cattle. It can be concluded that NIRS could be a useful tool for estimating the colour of young cattle meat samples, primary consideration for consumers when making purchasing decisions.

Potential use of near infrared reflectance spectroscopy (NIRS) for the estimation of chemical composition of oxen meat samples

Near infrared reflectance spectroscopy (NIRS) was evaluated as a tool to estimate several chemical parameters of oxen meat protected by a quality mark. Fifty-three samples of longissimus thoracis muscle corresponding to oxen reared in extensive conditions were homogenized and scanned over the NIR spectral range (1100-2500nm). Immediately after scanning, the samples were analyzed for crude protein (CP), myoglobin, collagen, ether extract (EE), gross energy (GE), dry matter (DM) and ash content, according to the official methods. Best NIR calibrations for chemical composition tested by cross-validation showed R(2) and SE(CV) of 0.874 and 20.33gkg(-1) DM (CP), 0.924 and 16.22gkg(-1) DM (EE), 0.941 and 0.293MJkg(-1) DM (GE) and 0.874 and 6.75gkg(-1) FM (DM). Calibrations for myoglobin, collagen and ash content showed a poor predictability, probably as a consequence of the lack of correlation between these parameters and EE content. However, NIRS technology could be an useful tool for estimating the main chemical parameters of oxen meat samples, thus guaranteeing the standards of quality marks.

On-line application of visible and near infrared reflectance spectroscopy to predict chemical―physical and sensory characteristics of beef quality

The aim of this study was to assess the on-line implementation of visible and near infrared reflectance (Vis-NIR) spectroscopy as an early predictor of beef quality traits, by direct application of a fibre-optic probe to the muscle immediately after exposing the meat surface in the abattoir. Samples from M.longissimus thoracis from 194 heifers and steers were scanned at quartering 48h postmortem over the Vis-NIR spectral range from 350 to 1800nm. Thereafter, samples from M.longissimus thoraciset lumborum were analysed for colour (L(∗), a(∗), b(∗); 48h postmortem), cooking loss (14 days postmortem), instrumental texture (Volodkevitch, 10 days aged meat; slice shear force, 3 and 14 days aged meat) and sensory characteristics. Vis-NIR calibrations, tested by cross-validation, showed high predictability for L(∗), a(∗) and b(∗) (R(2)=0.86, 0.86 and 0.91; SE(CV)=0.96, 0.95 and 0.69, respectively). The accuracy of Vis-NIR to estimate cooking loss and instrumental texture ranged from R(2)=0.31 to 0.54, suggesting relatively low prediction ability. Sensory characteristics assessed on 14 days aged meat samples showed R(2) in the range from 0.21 (juiciness) to 0.59 (flavour). Considering the subjective assessment of sensory characteristics the correlations of Vis-NIR measurements and several meat quality traits in the range from 0.46 to 0.95 support the use of on-line Vis-NIR in the abattoir. Improvement of predictability was achieved if only extreme classes of meat characteristics have to be predicted by Vis-NIR spectroscopy.

Accumulating behaviour of Lupinus albus L. growing in a normal and a decalcified calcic luvisol polluted with Zn

Lupinus albus L. is a leguminous plant that is starting to generate interest for the phytoremediation soils showing intermediate metal pollution. Among these metals, Zn causes major phytotoxicity problems and is common in polluted soils of central Spain. The purpose of this study was to explore the nutritional behaviour of this plant species towards increasing Zn concentrations in two calcic luvisol soils: a normal basic soil and a decalcified acid soil. For this purpose the effects of different Zn concentrations on mineral nutrition, growth, nodulation and nitrogenase activity of nodulated Lupinus albus cv. Multolupa plants has been investigated. A 12-week trial was performed in pots under greenhouse conditions. In each soil, four replicate pots were set up per treatment (100, 150, 300, 500 and 700 ppm Zn). Seeds were inoculated with a Bradyrhizobium sp. (Lupinus) strain ISLU-16. Statistical analysis of data revealed significant effects of soil Zn on grown, plant mineral composition and nodulation. Lupin growth was better in acid soil than in basic soil with the low dose of Zn applied, although plant growth in acid soil was severely affected from 300 ppm Zn, where the pH of the soil was 4.7. Zn application produce nutritional imbalances, especially with the higher dose added. Most of Zn accumulation occurred in the roots in both types of soils. In acid soil, lupin absorbs high amounts of Zn in both root (4650 ppm) and aerial part (3605 ppm), when the doses of Zn applied was 300 ppm. This feature permits Lupinus albus cv. Multolupa to be considered as potential phytoremediator and also for the revegetation of degraded landfill areas with slightly acid or neutral soils polluted with Zn.

Associations between response to handling and growth and meat quality in frequently handled Bos taurus beef cattle

Fearful behavioral responses to handling (temperament) are undesirably associated with ADG and meat quality in infrequently handled Bos indicus cattle. It has never been assessed whether these relationships exist in calmer Bos taurus breeds in systems where handling is more frequent. Such systems predominate in some countries where beef production is a major agricultural activity. During fattening, 144 crossbred cattle from Limousin and Aberdeen Angus sires were assessed for temperament using 4 approaches: response to movement along a race (race score; 4 occasions), restraint in a crush (crush score; 4 occasions), flight speed from the crush (flight speed; 4 occasions), and isolation in a pen with a human (isolation score; 1 occasion in yr 1, 2 occasions in yr 2). Measurements of ADG were made between birth and slaughter and between 16 and 18 mo of age during fattening. Fattening occurred indoors on a complete mixed diet fed for ad libitum intake. Meat quality was measured by pH, color, and Volodkevitch shear force and by a sensory panel. The repeatability of temperament traits was 0.17 (race score), 0.35 (crush score), 0.51 (flight speed), and 0.36 (isolation score). The proportion of the total variance of temperament traits attributable to the sire and the social group was low (0.003 to 0.402). However, the sire did affect behavior in all tests apart from the crush score (ranging from P = 0.02 to P < 0.001). Correlations between behavior in the different tests (ranging from r = 0.21 to 0.54, and P = 0.02 to P < 0.001) apart from between-flight speed and isolation score indicate that fearful behavior was consistently shown across assessment methods. A calm response in the crush score test was associated with a greater ADG during fattening (P = 0.05), whereas a calm response during the isolation test was associated with a greater ADG in cold carcass weight (P = 0.02). Animals with a calm isolation score had less tender meat as judged by the sensory panel (P = 0.03), but no other effects were apparent between temperament and meat quality measures, although several tendencies (0.06 ≤ P ≤ 0.10) were found. Temperament did not appear to relate to meat quality in this study of frequently handled Bos taurus genotypes, which is in contrast to other studies using different beef production systems. Genetic correlations between temperament and meat quality under these conditions could, although not measured in this study, still exist in the absence of phenotypic correlations.

Meat texture and antioxidant status are improved when carnosic acid is included in the diet of fattening lambs.

Thirty-two Merino lambs fed barley straw and a concentrate alone (CONTROL group) or enriched with carnosic acid [0.6 g kg(-1) dry matter (DM), CARN006 group; 1.2 g kg(-1) DM, CARN012 group] or vitamin E (0.6 g kg(-1) DM, VITE006 group) were used to assess the effect of these antioxidant compounds on meat quality. After being fed the experimental diets for at least 5 weeks, the animals were slaughtered with the 25 kg intended body weight and the different muscles (longissimus lumborum; LL, gluteus medius; GM) were sliced and kept refrigerated under modified atmosphere packaging during 0, 7 and 14 days. The results indicate that carnosic acid seemed to be useful to delay lipid peroxidation in a medium colour-stable muscle such as GM, but this effect was lower than that observed when vitamin E was supplemented to fattening lambs. On the contrary, meat texture and protection against cholesterol oxidation were equally improved with both compounds.

Discrimination of adult steers (oxen) and young cattle ground meat samples by near infrared reflectance spectroscopy (NIRS)

Near infrared reflectance spectroscopy (NIRS) was used to discriminate different types of ground beef samples. Fifty-three and sixty-seven samples of longissimus thoracis muscle corresponding to adult castrated steers (over 4 years old) and young cattle (under 14 months old), respectively, were homogenized and scanned over the NIR range (1100-2500nm). The results showed that NIRS could successfully discriminate 100% of ground beef samples depending on the sort of animal, probably as a consequence of differences in the intramuscular fat and water contents. Thus, NIRS is a fast, inexpensive, and non-destructive method that can be used to discriminate these beef products.

Predicting beef cuts composition, fatty acids and meat quality characteristics by spiral computed tomography

The potential of X-ray computed tomography (CT) as a predictor of cuts composition and meat quality traits using a multivariate calibration method (partial least square regression, PLSR) was investigated in beef cattle. Sirloins from 88 crossbred Aberdeen Angus (AAx) and 106 Limousin (LIMx) cattle were scanned using spiral CT. Subsequently, they were dissected and analyzed for technological and sensory parameters, as well as for intramuscular fat (IMF) content and fatty acid composition. CT-PLSR calibrations, tested by cross-validation, were able to predict with high accuracy the subcutaneous fat (R2, RMSECV=0.94, 34.60 g and 0.92, 34.46 g), intermuscular fat (R2, RMSECV=0.81, 161.54 g and 0.86, 42.16 g), total fat (R2, RMSECV=0.89, 65.96 g and 0.93, 48.35 g) and muscle content (R2, RMSECV=0.99, 58.55 g and 0.97, 57.45 g) in AAx and LIMx samples, respectively. Accurate CT predictions were found for fatty acid profile (R2=0.61-0.75) and intramuscular fat content (R2=0.71-0.76) in both sire breeds. However, low to very low accuracies were obtained for technological and sensory traits with R2 ranged from 0.01 to 0.26. The image analysis evaluated provides the basis for an alternative approach to deliver very accurate predictions of cuts composition, IMF content and fatty acid profile with lower costs than the reference methods (dissection, chemical analysis), without damaging or depreciating the beef cuts.

Carnosic acid dietary supplementation at 0.12% rates slows down meat discoloration in gluteus medius of fattening lambs

Thirty-two Merino lambs fed barley straw and a concentrate alone (CONTROL) or enriched with vitamin E (VITE006) or carnosic acid (CARN006; CARN012) were used to assess the effect of these antioxidant compounds on meat quality attributes. The animals were slaughtered after being fed for at least 5weeks with the experimental diets. The longissimus lumborum samples of VITE006, CARN006 and CARN012 groups showed higher values (P<0.001) of L* (lightness) through the complete storage period under modified atmosphere when compared to the CONTROL group. Moreover, the VITE006 and CARN012 samples revealed lower discoloration when compared to the CONTROL group, these differences being more apparent in a less color stable muscle such as gluteus medius (P<0.05 for hue after 14days of refrigerated storage). Meat sensory traits were not significantly affected by carnosic acid and microbiological analyses were not conclusive at the doses administered.