Degradation of PCBs in dry fermented sausages during drying/ripening.

The effects of several commercial meat starter cultures on degradation of polychlorinated biphenyls (PCBs) in dry fermented sausages over 28days of drying/ripening were investigated. The sausage batter was prepared according to a classic recipe and spiked with a standard solution of a PCB congener mixture. With addition of different commercial meat starter cultures, five experimental groups were prepared: no further addition; and separate addition of each of four starter cultures: Texel DCM-1, Texel LM-30, Biostar Sprint, and SM-181. Samples were taken at the beginning of fermentation (zero time), and after 4, 7, 14, 21 and 28days. PCB residues were extracted with hexane. The PCB contents were determined using gas chromatography-mass spectrometry. The PCB levels were reduced in all of the experimental groups tested, where addition of starter culture Biostar Sprint (Lactobacillus sakei, Staphylococcus carnosus, Staphylococcus xylosus) showed the highest PCB degradation rates.

Classification of dry-cured hams according to the maturation time using near infrared spectra and artificial neural networks.

An attempt to classify dry-cured hams according to the maturation time on the basis of near infrared (NIR) spectra was studied. The study comprised 128 samples of biceps femoris (BF) muscle from dry-cured hams matured for 10 (n=32), 12 (n=32), 14 (n=32) or 16 months (n=32). Samples were minced and scanned in the wavelength range from 400 to 2500 nm using spectrometer NIR System model 6500 (Silver Spring, MD, USA). Spectral data were used for i) splitting of samples into the training and test set using 2D Kohonen artificial neural networks (ANN) and for ii) construction of classification models using counter-propagation ANN (CP-ANN). Different models were tested, and the one selected was based on the lowest percentage of misclassified test samples (external validation). Overall correctness of the classification was 79.7%, which demonstrates practical relevance of using NIR spectroscopy and ANN for dry-cured ham processing control.

PRKAG3 and CAST genetic polymorphisms and quality traits of dry-cured hams--III. Associations in Slovenian dry-cured ham Kraski prsut and their dependence on processing.

The aim of the present study, the third in a series of three papers, is to show the effects of PRKAG3 and CAST gene polymorphisms on the quality traits of the Slovenian dry-cured ham "Kraski prsut" and their interaction with ham producers. Significant interaction of polymorphisms with producer in the case of salt content, lipid oxidation (PRKAG3 Ile199Val), proteolysis index (CAST Arg249Lys) and pastiness (CAST Ser638Arg) indicated that genotype manifestation was reliant on the manufacturing practice. PRKAG3 Ile199Val polymorphism affected several physico-chemical, rheological and sensory traits. The Ile/Ile genotype yielded less salty and softer hams, indicating beneficial effects on dry-cured ham quality. The effect of CAST polymorphisms was less pronounced, although the observed associations with pastiness, proteolysis index and several free amino acid concentrations indicate its possible influence on proteolysis, with haplotype CAST 249Arg/638Ser being associated with a higher degree of proteolysis.

Degradation of PCBs in a frankfurter-type meat emulsion: effects of a meat starter, its proteins extract and thermal treatments.

The degradation of a series of polychlorinated biphenyl (PCB) congeners (PCBs 10, 28, 52, 138, 153, 180) in meat emulsions of a frankfurter type was investigated. With a pool of these PCBs added to the meat emulsion, three initial experimental groups were used: no further addition, or plus a commercial meat starter (containing Staphylococcus xylosus and Staphylococcus carnosus), or plus the protein extract from this commercial meat starter. Prior to further treatments, these samples were incubated for 72 h at 4°C. These meat emulsions were then either left at 4 °C (raw) or thermally treated to two different internal temperatures: 78 and 100 °C. Following cooling and a further 24 h at 4 °C, all of the samples were extracted with hexane to recover the PCB residues, following method EPA 608, with some modifications. The addition into the meat emulsion of the commercial meat starter and the proteins extract both affected PCB degradation. Also, the effects of thermal treatment at both temperatures saw the PCB contents successfully reduced, as compared to the raw meat emulsions.

Cholesterol concentration and fatty acid profile of red deer (Cervus elaphus) meat.

The effects of gender and age on intramuscular fat (IMF) levels, cholesterol concentration, and fatty acid composition were investigated in the semitendinosus (ST) and triceps brachii (TB) muscles of feral red deer (Cervus elaphus). Six stags of >2years of age, four hinds of 1year, and six calves of 6months were shot in Slovenia. Generally, all parameters measured were influenced by interaction of muscle and treatment group (hinds, stags and calves) at the 5% level or less. In ST muscle, the IMF levels were highest for hinds. In the TB muscle, cholesterol was lower for stags than for hinds and calves. The saturated fatty acids were the highest for stags and the mono-unsaturated fatty acids for hinds. The polyunsaturated fatty acids (PUFAs) were the highest for calves and lowest for hinds. The n-3 PUFAs were the lowest for hinds. In both muscles, the calves had higher n-6 PUFAs than stags and hinds. Only the ST muscle of the hinds contained >1% (1.44%) of the conjugated linoleic acid isomer 18:2cis-9,trans-11, while in the TB of hinds and calves this fatty acid was higher than with stags. We conclude that gender and age of feral red deer influence the IMF content, the cholesterol concentration, and the fatty acid composition of the meat.

Pork quality, processing, and sensory characteristics of dry-cured hams as influenced by Duroc crossing and sex.

This study was designed to evaluate Duroc (DU) crossing for Carso dry-cured ham production. One hundred fifty-four pigs (81 females and 73 castrates) of four different genotypes, pure Landrace pigs (LAN), offspring of LAN females crossed with Large White (LW) males (LWxLAN), offspring of LAN females crossed with DU males (DUxLAN), and offspring of LWxLAN females crossed with DU males (DUx[LWxLAN]), were chosen in the weight range of 105 to 120 kg (112.7 +/- 0.4 kg). Raw material quality was evaluated for ham fatness (intra- and intermuscular and subcutaneous) and meat quality (pH, color, water-holding capacity) of longissimus dorsi, biceps femoris, and semimembranosus muscles. Ham weight losses were recorded at different stages of processing. The biceps femoris and semimembranosus muscles were analyzed for chemical composition before (lipid, moisture, total nitrogen, nonprotein nitrogen) and after (moisture, salt, total nitrogen, nonprotein nitrogen) processing. Chemical and sensory analyses were performed on 96 dry hams (12 castrates and 12 females per genotype). Biceps femoris and semimembranosus muscles were evaluated for color, saltiness, aroma, and texture. Pigs of the four genotypes had similar ham fatness as estimated by subcutaneous fat thickness. Duroc crosses exhibited higher intramuscular fat content, marbling, and intermuscular fat. Crossing with DU resulted in lower weight losses during ham processing. Castrates were fatter and had more intra- and intermuscular fat and lower ham processing weight losses than females. A strong negative relationship between ham fatness and ham processing losses was observed. Chemical and sensory traits of dry ham muscles were little affected by DU crossing. Lower salt content of biceps femoris was found in DU crosses. Dry hams from female pigs had higher total and nonprotein nitrogen, but drier, firmer texture and higher resistance to cutting force compared to dry hams from castrated pigs. Crossing with DU demonstrated some disadvantages (more intermuscular fat, more slice visible fat) and advantages (lower weight loss and salt intake) for the quality of dry-cured ham.

Colour of beef heated to different temperatures as related to meat ageing.

The effects of ageing (10-12 days at +5°C), thermal treatment (internal temperature, T(i): 45, 60, 75°C) and oxygenation on the colour and some colour related physical and biochemical parameters of beef longissimus dorsi (LD) muscle were studied. The colour components (L(∗), a(∗) and b(∗) values) for the raw and heated LD, both before and after ageing and oxygenation, were instrumentally and sensorily evaluated. Ageing influenced colour components (except b(∗) value), specific activity of cytochrome c oxidase (SACCO) and amount of oxygen consumed (AOC). An increase in internal temperature was usually accompanied by a lower SACCO, AOC and total native muscle pigment concentration, as well as a change in all colour parameters. Oxygenation of the raw and heated slices (except T(i)=75°C) led to a less of black colour and a higher of red colour, a(∗) and b(∗) values.

Genotoxicity testing of cooked cured meat pigment (CCMP) and meat emulsion coagulates prepared with CCMP.

The preformed cooked cured meat pigment (CCMP) synthesized directly from bovine red blood cells or through a hemin intermediate was found to be a viable colorant for application to comminuted pork as a nitrite substitute. However the genotoxicity of CCMP and meat emulsion coagulates prepared with CCMP has not been evaluated. Therefore the objectives of this work were to investigate genotoxicity of CCMP and the influence of CCMP addition on genotoxicity and the content of residual nitrite in model meat emulsion coagulates. Meat emulsions were prepared from white (musculus longissimus dorsi) and red (musculus quadriceps femoris) pork muscles with two different amounts of synthesized pigment CCMP. Comparatively, emulsions with fixed addition of nitrite salt and emulsions without any addition for color development were made. Genotoxicity of CCMP and meat emulsion coagulates was tested with the SOS/umu test and the Ames test. Neither CCMP nor meat emulsion coagulates prepared with CCMP or nitrite salt were genotoxic in the SOS/umu test. In the Ames test using Salmonella Typhimurium strains TA98 and TA100 samples of coagulates prepared with CCMP and with nitrite showed weak mutagenic activity in Salmonella Typhimurium strain TA100 but only in the absence of the metabolic activation, while CCMP was not mutagenic. Coagulates prepared with CCMP contained significantly less residual nitrite than coagulates prepared with nitrite salt. These results indicate that from the human health standpoint the substitution of nitrite salt with CCMP would be highly recommendable.

Colour of normal and high pH beef heated to different temperatures as related to oxygenation.

The effects of oxygenation and thermal treatment (internal temperature, T(i): 45, 60, 75°C) on the colour and some colour related physical and biochemical properties of beef longissimus dorsi (LD) muscle, both normal (pH(u)∼5.6) and DFD (pH(u)>6.6), were studied. The colour components (L (∗), a (∗), b (∗) values) for the raw and heated LD, both before and after oxygenation, were instrumentally and sensorily evaluated. The colour of raw and heated (60°C) DFD beef before and after oxygenation differed significantly from the normal meat and contained more native muscle pigment (TMP). pH also influenced the depth of the oxygenated layer, specific activity of cytochrome c oxidase (SACCO) and the amount of oxygen consumed. An increase in internal temperature was usually accompanied by a lower SACCO and a significant decrease of TMP, as well as a change of all colour parameters. Oxygenation of the raw and heated slices (except at 75°C) of both types of meat led to higher L (∗), a (∗) and b (∗) values.

Effects of age and/or weight at slaughter on longissimus dorsi muscle: Biochemical traits and sensory quality in pigs.

The effect of increasing either age alone through feed restriction, or both age and weight at slaughter, on the quality of the longissimus dorsi muscle (LM) was investigated. Starting at 83 days of age and 32 kg, 80 pigs were allotted within litter to four experimental groups. All pigs were free of RYR1 mutated gene. Pigs were fed either ad libitum (A100, A130) or restricted 30% (R100, R130) and slaughtered at either 100 kg (A 100, R100) or 130 kg (A130, R130) body weight. Restricting feed intake in order to increase age at the same weight resulted in slower growth, better feed efficiency and increased leanness, whereas increasing age and weight simultaneously elicited slower growth, reduced feed efficiency and fatter carcasses. Intramuscular fat (IMF) and muscle collagen concentration were reduced by restricted feeding. Increase in both age and weight of pigs resulted in lower water, and higher protein and IMF concentrations. Although pigs were free of RYR1 gene, the PSE condition (defined as pH1 ≤ 5.9) developed in 25 carcasses, with a higher incidence in restricted pigs. PSE animals were excluded from the subsequent analysis of meat quality data. Feed restriction resulted in higher drip loss and lower a(∗) and c(∗) (saturation index) values. Longer myofibril fragments in muscle of restricted pigs on day 1 post mortem are indicative of slower maturation, while longer fragments on day 4 in heavier pigs, suggest that the extent of post mortem tenderisation could be negatively affected by the elevation of slaughter weight. Feed restriction had no significant effect on meat sensory quality, whereas increase in both age and weight resulted in lower tenderness, chewiness and mouth coating scores. Our results indicate that increasing age at a given body weight, via feed restriction, reduced IMF and collagen concentrations, and the rate of post mortem proteolysis, however, this had no significant impact on pork quality assessed after 4 days of ageing. On the other hand, increasing both age and weight at slaughter could alter pork texture, in spite of elevated IMF concentration.