Effect of vacuum ageing on quality changes of lamb steaks from early fattening lambs during aerobic display

The effects of vacuum ageing on the quality changes of lamb steaks during retail display were assessed. Biceps femoris and Quadriceps femoris muscles from thirty early fattening lambs fed barley straw and concentrate or alfalfa and concentrate were used. Half of the muscles were vacuum aged for three weeks (VA), and the other half were not aged (control). Control and VA muscles were sliced and aerobically displayed. Weight loss, pH, aldehyde contents, instrumental color characteristics and color acceptance were measured at display days 1, 3, 7 and 14. At day 1 redness was higher in VA lamb. However, redness of VA lamb decreases more rapidly during further storage. Redness and color acceptance decreased in VA lamb from day 3, whereas in not-aged lamb the decrease was observed from day 7 onwards. From days 7 to 14 a drop of color acceptance accompanied by an increase in pH and a decrease in lightness was observed in control and VA lamb.     

Effects of dietary inclusion of sunflower soap stocks on colour,oxidation and microbiological growth of meat from light fattening lambs

Thirty-two lambs were finished on a total mixed ration (TMR) pelleted alone (00SS) or including sunflower soap stock (SS): 15SS (15 g SS per kg TMR), 30SS (30 g SS per kg TMR) and 60SS (60 g SS per kg TMR). Lambs (8 per group) were slaughtered at 27 kg live weight. Colour evolution, lipid oxidation, microbial growth and detection of diarrhoeagenic Escherichia coli were studied in meat samples. SS in the diet reduced meat lipid oxidation (P < 0.05), but had no significant effect (P > 0.05) on the cholesterol oxidation products. Meat from 60SS and control animals (00SS) revealed greater discoloration (P < 0.05) than 15SS. SS supplementation did not affect the microbiological populations, whereas high doses of SS seemed to increase the proliferation of diarrhoeagenic E. coli on day 14 (P < 0.10). These results suggest that the rate of SS inclusion in the diet of fattening lambs should not be above 15 g SS per kg TMR.     

Non-equilibrium thermodynamic approach to analyze the pork meat (Longissimus dorsi) salting process

Salting treatment is a common operation in high quality meat production, which main objectives are to conserve the product by water activity depression and to transform the sensorial properties of fresh meat to the final meat products (like salted, cured, dried or cooked meat products). One of its main problems is the difficulty to control the simultaneous water and salt fluxes into the product and the protein fibers transformation throughout process. Water and salt transport during osmotic treatment of pork meat (Longissimus dorsi) immersed in saturated salt solution, were investigated by using a thermodynamic approach. In this work the effect of rigor mortis state in the salting treatment has been demonstrated. A thermodynamic model in non-equilibrium has been developed for describing the different behaviors involved in salting process.     

Development of a dielectric spectroscopy technique for the determination of key biochemical markers of meat quality

Dielectric measurements of different standard solutions (nucleotides, nucleosides, lactic acid and myoglobin) were assayed simulating the concentrations of these substances in early postmortem meat. These assays were performed for considering the potential use of dielectric spectra for the quality control of meat. Good correlations among solutions of Adenosine Triphosphate (ATP), Inosine Monophosphate (IMP) and lactic acid with loss factor at punctual frequencies (0.5, 0.915 and 1 GHz) were found. The other assayed substances did not present a marked effect over the electromagnetic spectra. Good correlations of dielectric properties with IMP and lactic acid content of real pork meat samples were also found at 0.5 GHz. This work is presenting prospective data of dielectric spectra for certain key biochemical markers in order to consider its potential application as a non-destructive control sensor for the prediction of pork meat quality.     

Assessment of nutritive value of cereal and legume straws based on chemical composition and in vitro digestibility

The nutritive value of 17 straws was determined on the basis of their chemical composition, in vitro dry matter (DM) digestibility and rumen fermentation kinetics (from gas production curves measured in vitro). Five roughages were from the cereal species Avena sativa (oat), Hordeum vulgare (barley), Secale cereale (rye), Triticum aestivum (wheat) and Zea mays (maize stover). The other 12 samples were legume straws, two samples from each of the species Cicer arietinum (chickpea), Lens culinaris (lentil) and Phaseolus vulgaris (bean) and one sample from each of the species Lathyrus sativus (chickling vetch), Lupinus albus (white lupin), Pisum sativum (field pea), Vicia articulata (one‐flowered vetch), Vicia ervilia (bitter vetch) and Vicia sativa (common vetch). All samples were collected after harvesting from different farms located in León (northwestern Spain). Based on their chemical composition, digestibility and gas production characteristics, species could be clustered into two groups with a significant linkage distance, one for cereal straws that merged at a level of similarity of 80% and the other for legume straws with a degree of similarity of 50%. Species varied widely and significant differences (P < 0.05) were observed between the two groups of straws. Legume straws showed higher crude protein (74 ± 6.1 vs 29 ± 2.2 g kg^?1 DM) and lower fibre (584 ± 18.1 vs 793 ± 27.5 g neutral detergent fibre kg^?1 DM) contents than cereal straws and, consequently, DM digestibility coefficients (0.670 vs 0.609; standard error of difference 0.0054) and metabolisable energy values (7.4 ± 0.15 vs 5.7 ± 0.24 MJ kg^?1 DM) were significantly greater in legume than in cereal straws. Although there were noticeable differences among species within each botanical family, legume straws showed better nutritional quality than cereal straws, indicating that they could be considered promising and interesting sources of roughage for incorporation into ruminant diets. Copyright © 2005 Society of Chemical Industry     

Low frequency dielectric measurements to assess post-mortem ageing of pork meat

The use of dielectric properties at low frequencies to estimate the progress of pork meat (Longissimus dorsi) ageing was evaluated. Dielectric measurements were perfomed at 140 Hz, 1 kHz and 300 kHz in perpendicular to the long axis of the meat muscle fibers at 12, 24, 48 and 168 h post-mortem. Principal Component Analysis (PCA) was used to describe the relationships between meat physical/biochemical parameters and dielectric parameters of pork meat. Good correlations were found between the ageing indexes (AI^σ and AI^?′) calculated from dielectric properties and some parameters of texture such as hardness and chewiness. Moreover, both indexes correlated well with free amino acids content, and with K value. The high degree of correlation confirms the viability of using the ageing indexes obtained from dielectric measurements to evaluate the degree of ageing of pork meat, giving information about some important eating quality parameters.     

Milk replacer restriction during early life impairs the live body weight and progesterone patterns of ewe lambs during the replacement period

Nutritional programming caused by feed restriction during the early life may counteract the profitability of the dairy sheep farm. However, most studies have been focused exclusively on the prenatal period, and scarce information regarding the effect of milk replacer (MR) restriction on feed efficiency [residual feed intake (RFI)] and progesterone patterns of replacement ewe lambs is available. Therefore, in the present study 40 Assaf female newborn lambs were penned individually and assigned randomly to 1 of 2 treatment groups (n = 20 per treatment). The first group of lambs was fed MR ad libitum (ADLB), whereas the second one (restricted, RES) only received approximately 62.5% of the MR intake measured in the ADLB group. All the lambs were weighed twice a week until they were 35 d old. Then 8 lambs from each group were killed and a morphological study of the gut was performed. Moreover, a piece of liver was cut to measure fat content and oxidative status. The rest of the ewe lambs (24) were weaned and offered a total mixed ration ad libitum to calculate the RFI during the replacement phase. Plasma samples were collected when ewe lambs were 8 mo old to perform a nontargeted metabolomic analysis on a hybrid quadrupole-time-of-flight mass spectrometer coupled to an ultra-high-performance liquid chromatographic system. Progesterone was also measured weekly on serum samples by sequential competitive immunoassay until the end of the experiment (9.5 mo old). The results observed indicate that moderated MR restriction promoted differences in the morphology of the gut of the 35-d-old lambs, but not in the apparent digestibility or feed efficiency traits (RFI) during the replacement phase. However, there was a trend toward reduced live body weight of the RES ewe lambs when they were 9.5 mo old. Moreover, progesterone patterns revealed that only 1 RES versus 4 ADLB ewe lambs had ovulated for the first time at the end of the experiment. This evidence suggests the existence of long-term effects caused by early feed restriction with negative consequences on live body weight and reproductive traits of replacement ewe lambs.     

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.     

Assessing Reference Evapotranspiration by the Hargreaves Method in Southern Spain

The Hargreaves method enables reference crop evapotranspiration (ET0) estimation in areas where meteorological information is scarce, as, for example, southern Spain. However, this method is known to produce considerable bias in this region, especially during the dry, hot summer months. An evaluation of the method is made by comparing daily estimates with those made by the more commonly recommended Penman–Monteith method at 16 meteorological stations. Computed ET0 values at the coastal stations are, on average, 0.69 mm?d?1 smaller than the Penman–Monteith estimates whereas at inland stations a small average overestimation of 0.13 mm?d?1 is shown. The adjusted Hargreaves coefficient (AHC), obtained through regression analysis, increases at the coastal stations, on average, to 0.0029, and decreases at the inland stations to 0.0022. Adjustment with the Samani method does generally not produce more accurate estimates in this region. Finally a linear relationship between the AHC and the rate of the average temperature to the average daily temperature range is proposed for the regional adjustment of the Hargreaves coefficient.