B. Žlender

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.

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.

Oxidative stability of n-3-enriched chicken patties under different package-atmosphere conditions

The oxidation processes were studied in chicken patties, enriched with n-3 fatty acids, after 8days of storage at 4°C, under different aerobic conditions, and following heat treatment. Significant effects were seen on lipid and cholesterol oxidation and the sensory qualities for whole flaxseed addition in the chicken feed (i.e., n-3 fatty acid enrichment), and for the different package-atmosphere conditions. For the raw chicken patties, n-3 enrichment increased the colour L(∗) values while, after the heat treatment, there were higher thiobarbituric acid-reactive substances (TBARs) and cholesterol oxidation products (COPs), and the rancidity was more pronounced. In comparison with the low O2 (<0.5%) package-atmosphere condition, O2 enrichment (80%) increased the instrumentally measured colour values, TBARs, total and individual COPs, and the rancidity became pronounced. The most suitable package-atmosphere condition of these raw n-3-enriched chicken patties is a very low O2 atmosphere, with or without an O2 scavenger.

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.

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.

External, Internal and Sensory Qualities of Table Eggs as Influenced by Two Different Production Systems

This study was conducted to determine the effects of two production systems (organic vs conventional cages) on egg quality parameters during the late laying period. The effects of a production system were investigated on external and internal quality and on the sensory attributes. The eggs produced in organic system had paler yolks (P<0.001) and thinner egg shells (P<0.05) than the eggs produced in the cages. Overall sensory quality was improved in eggs deriving from hens allocated in cages. Differences between organic and cage eggs indicated lower redness and higher yellowness (P<0.001) in organic eggs than in cage eggs. The organic eggs were characterised by a higher content of a-linolenic and docosapentaenoic acid (P<0.05) and lower content of linoleic acid (P<0.05) than the eggs from cages. The ratio of omega fatty acids, n-6/n-3, was most favourable in the organic eggs (5.93:1). In the cage eggs, the ratio n-6/n-3 was significantly (P<005) higher (955:1).