Martin Král

Application of principal component analysis method for characterization chemical, technological, and textural parameters of farmed and pastured red deer

ABSTRACT Sixteen male red deer (age <1.5 year), both farm reared and pastured in Slovakia, were assessed with an emphasis on the variability of pH, chemical, structural, and textural parameters of their Musculus longissimus thoracis et. lumborum. Pastured deer had a higher pH than farmed deer. Regarding chemical compounds, meat from pastured deer contained less protein, fat, and ash, and regarding technological parameters, drip loss and cooking loss was higher when fried at 80°C. Meat cohesiveness was quite similar for both groups, while shear force was lower in pastured deer after being roasted in an oven and being fried, and it had less coefficients of variation than hardness. The total variation higher than 85% was explained by the first five principal components for pH, chemical, and technological parameters, and 86% for textural parameters. The principal component analysis illustratively divided the pastured and farmed deer according to the assessed parameters.

Effect of probiotics and thyme essential oil on the essential amino acid content of the broiler chicken meat.

BACKGROUND Differences in the types and percentages of essential amino acids (EAAs) in food could influence the value of protein consumed and proteins with a high content of EAAs are the most important components of poultry meat. The use of probiotics for meat and carcass quality improvement has been questioned, while feed supplementation with thyme essential oil (TEO) could be considered as useful natural supplement to be applied in the poultry industry to improve meat quality. METHODS Day-old broilers Ross 308 (n = 400) were randomly divided into four groups based on the feed supplement as follows: control, probiotics 0.05%, TEO 0.05% and combination of probiotics and TEO, while the fattening period was 42 days. Six birds of both sexes from each group were selected as a sample, slaughtered and then stored (-18°C) for 6 months till the analysis. The muscular homogeneous sample (50 g) from the breast and thigh of each sample bird was analysed by the Fourier Transform Infrared Spectroscopy method using the device Nicolet 6700. The essential amino acids content was determined and the quality indicators include chemical score, amino acid score, EAA index and biological value were calculated. RESULTS The obtained results show that for all the tested EAAs of the breast and thigh muscles, the content numerically increased gradually and progressively within the groups as the control scored the minimum followed by the probiotics group, then the combination group and finally the TEO group which scored the highest results. CONCLUSIONS It can be concluded that the TEO promoted the increase of all the EAAs and consequently the quality indicators with significant different compared with the control group and significantly different for some EAAs and quality indicators compared with the probiotics group and the combination group.

Pork protein addition effect on structural and qualitative parameters of frankfurter-type sausage: Pork protein effect on frankfurter-type sausage

BACKGROUND Several raw materials and additives are used in meat production. In terms of origin, proteins which are the closest related to meat are derived from slaughtered carcasses. The aim of the work was to assess the effect of their addition on the microstructure, texture and colour of frankfurter-type meat products. RESULTS Calleja staining, instrumental textural analysis and colour analysis were applied. The microscopic results were evaluated qualitatively. Canonical component and Tukeys HSD were used for textural and RGB evaluation. Microscopically, protein matrix formation in products containing pork haemoglobin (155_16) and pork plasma P (158_16) was found to be different from that in other samples. Texture analysis revealed differences (P < 0.05) in shear force between pork haemoglobin 155_16 and all tested samples, in the hardness between the control (154_16) and pork collagen protein (157_16) and between 157_16 and 160_16. Chewiness showed differences between control 154_16 and collagen proteins 157_16. Colour analysis showed a difference between pork haemoglobin (155_16) and other products (P < 0.05) by component analysis. CONCLUSION All tested additives were incorporated into the protein matrix. Therefore, they may be used as additives even for unrecommended meat products. Addition of pork haemoglobin has a significant impact on the colour of the final product.

Substitution of sodium chloride by salt microspheres in dough: Effect on dough rheological properties

This research aimed to evaluate the impact of different salts on dough rheology parameters and gas cell development during dough preparation. Three types of salts in four concentrations each were used in dough preparation and following analyses were conducted: sodium content, salt structure analysis, dough hardness, dough stickiness and dough image analysis. The research showed how significantly (p < .05) the measured properties of dough can be influenced by the used type of salt, salt concentrations and fermentation time. The emphasis is put on salt substitutes of hollow microsphere salt (Hs) substitutes due to its special physical characteristics. The uniqueness of Hs physical characteristics was confirmed by electron microscope photomicrographs. The gained results are indicating that even low changes in salt concentration (0.40; 0.30; 0.25; and 0.15) make noticeable changes in dough characteristics. The usage of salt substitutes in food industry has been constantly growing and it makes the research a valuable source of information for further application of this salts. PRACTICAL APPLICATIONS The different salt types (table-Ts, sea-Ss and hollow microsphere-Hs) which were studied in our work differ just slightly. However, an important issue in choosing salt should also be the nutritive perspective, in particular low sodium content as a preventive measure against cardio-vascular diseases. Hs and Ss are therefore suitable alternatives to typical Ts.

Concentration of Micro- and Macro-Elements in Green and Roasted Coffee: Influence of Roasting Degree and Risk Assessment for the Consumers

The aim of the present study was to determine concentrations of 15 macro- and micro-elements in 10 commercially available plantation Arabica coffee brands. The elemental concentration was studied in 50 samples of green and roasted coffee beans of various roasting degrees and their infusions. There were four different roasting degrees: City + (C+), Full city (FC), Full city ++ (FC++), and Dark (D). The attention was given to the impact of the roasting process on the elemental composition. Statistically significant differences were found between the green coffee beans and the different roasting degrees in both macro- and micro-elements. The results showed that roasting degrees affected the concentration of elements in resulting infusions. Dietary intakes for macro- and micro-elements based on RDA and PTWI (in the case of Al) were calculated. Based on the RDA values for macro- and micro-elements, it can be concluded that coffee infusions are not an important source of elements in nutrition. In the case of Al, consumption of coffee was considered non-hazardous based on the PTWI value.

Comparison of selected sensory properties of wholemeal breads

The aim of this study was to compare textural (firmness) and sensory properties (surface colour, crumb colour, crumb texture, appearance, appearance and colour preferences) between whole breads made from conventional wheat (Triticum aestivum, L.) and whole breads made from unconventional wheat (Triticum aestivum, L., winter variety Skorpion, grains with blue aleuron). Wholemeal breads (control samples with marks C1, C2 and C3) were prepared of 100, 90 and 80 % amount of conventional wholemeal wheat flour to 0, 10 and 20% amount of smooth white flour made from conventional wheat using bakers experiment. Wholemeal breads (experimental samples with marks S1, S2 and S3) were prepared of unconventional wholemeal wheat flour to smooth white wheat flour in same ratio as control samples of breads. Our results showed, that negative evaluation of some sensory attributes of breads made from unconventional wheat correlated with increasing addition of wholemeal flour of this wheat. It was found that breads made from conventional wheat (100, 90 and 80% amount of conventional wholemeal flour) were more acceptable in surface colour, colour and appearance preferences than these sensory attributes of breads made from unconventional wheat (same amount of wholemeal flour). Appearance and crumb colour of breads made from conventional wheat (100 and 90% amount of wholemeal flour) were evaluated better than these attributes of breads made from blue coloured wheat (same amount of wholemeal flour). Appearance and crumb colour of both groups of whole wheat breads (80:20) was similarly evaluated. Crumb texture of breads made from conventional wheat (90% and 80% amount of wholemeal flour) was worse than crumb texture of breads produced of same ratio of flour, but made from unconventional wheat. Breads with addition of 80% of wholemeal flour milled of blue coloured wheat were most acceptable in all of sensory attributes for evaluators. Significant difference (p <0.05) of crumb fimness of breads were demonstrated between samples of breads (80:20) made from conventional or unconventional wheat. Crumbs of breads (100:0 and 80:20) made from blue coloured wheat had higher firmness than crumbs of breads (100:0 and 80:20) made from conventional wheat. But crumbs of breads (90:10) made from conventional wheat were firmer than crumbs of breads (90:10) made from unconventional wheat. Breads produced of blue coloured wheat were also more friable than breads made from conventional wheat. Although evaluation of wholemeal breads made from unconventional wheat had not better scores than evaluation of wholemeal breads made from conventioval wheat, but evalution of breads produced of unconventional wheat wholemeal flour were not below average and its market position could be very high in the future, due to the content of health benefit substances, which will be the subject of further research.