Milk is a food of high nutritional value processed by heat treatment. Heat treatment of milk is a technological process designed to inhibit the growth of microorganisms and extend the shelf life of products. The heating process directly affects the molecular structure of whey proteins by the process of denaturation. It leads to the formation of a whey protein–casein polymer complex. Based on these facts, milk heat-treatment conditions should be controlled during milk processing. This work focuses on describing the whey protein denaturation process and formation of the complex of whey protein with casein. The effect of heat treatment on individual milk protein fractions alpha-casein (α-cas), beta-casein (β-cas), kappa-casein (κ-cas), beta-lactoglobulin (β-lg) and alpha-lactalbumin (α-la) was studied by SDS-PAGE. Formation of the whey protein–casein polymer complex increased significantly (p < 0.05) on increasing the temperature and duration of the heat treatment.

The review summarizes the latest scientific findings and recommendations for the prevention of three very common wine faults of non-microbial origin. The first group, presented by the reductive aromas, is caused mainly by excessive H₂S and other volatile sulfur compounds with a negative impact on wine quality. The most efficient prevention of undesirable reductive aromas in wine lies in creating optimal conditions for yeast and controlling the chemistry of sulfur compounds, and the pros and cons of correction methods are discussed. The second is browning which is associated especially with the enzymatic and non-enzymatic reaction of polyphenols and the prevention of this fault is connected with decreasing the polyphenol content in must, lowering oxygen access during handling, the use of antioxidants, and correction stands for the use of fining agents. The third fault, atypical aging, mostly occurs in the agrotechnics of the entire green land cover in the vineyard and the associated stress from lack of nutrients and moisture. Typical fox tones, naphthalene, or wet towel off-odors, especially in white wines are possible to prevent by proper moisture and grassland cover and alternating greenery combined with harmonious nutrition, while the correction is possible only partially with an application of fresh yeast. With the current knowledge, the mistakes in wines of non-microbial origin can be reliably prevented. Prevention is essential because corrective solutions for the faults are difficult and never perfect.

In this work, chemical parameters such as sugar (glucose and fructose) content, organic acid (total acids, malic and tartaric acids), total phenolic content and the antioxidant activity of 12 white wines (chardonnay, pinot blanc and pinot gris) from various wine regions in Slovakia were studied in order to identify differences among the varieties and wine-growing regions. The wine samples were examined by Fourier-transform infrared spectroscopy (FTIR) and UV-VIS spectrophotometry (for determination of total polyphenolic content (TPC) and total antioxidant activity (TAA)) methods. Content of alcohol ranged between 11.50% and 13.80% with the mean value 12.52%. Mean content of total acids varied between 4.63 ± 0.09 and 6.63 ± 0.05 g.L⁻¹, tartaric acid varied between 1.62 ± 0.09 and 2.93 ± 0.03 g L⁻¹, malic acid was found in the concentrations ranged from 0.07 ± 0.05 and 2.50 ± 0.08 g L⁻¹ and lactic acid was present between 1.53 and 0.01 g L⁻¹. The content of fructose was, in general, higher in the samples from the Južnoslovenská and Nitrianska wine regions and glucose was higher in the Malokarpatská wine region. Chardonnay wines showed the highest content of total polyphenols and the antioxidant activity in the samples ranged from 51.06 ± 027 to 72.53 ± 0.35% inhibition of DPPH. The PCA analysis based on chemical descriptors distinguished the Nitrianska and Stredoslovenská wine regions. According to similarities among the wine samples, four main classes were formed by cluster analysis.

The high-performance liquid chromatography coupled with a diode array detector (HPLC-DAD) was optimized for the simultaneous determination of 11 compounds, belonging to polyphenols (gallic acid and seven catechins) and methylxanthines (caffeine, theobromine, and theophylline). The results obtained for all the validation parameters of the HPLC-DAD method showed that the method is sensitive enough for routine analysis with basic chromatographic equipment, thus it has a significant potential to be highly applicable in common laboratory practice. The method was used in the analysis of 60 green tea infusions originating from four tea-producing countries. The dataset contributes to enhancing current data on green tea. The analysis of green tea extracts revealed significant differences depending on the origin of the samples. Linear Discriminant Analysis (LDA) was applied to test the accuracy of identification of the origin of the tea samples, based on the chemical composition of tea with a focus on polyphenolic compounds and methylxanthines analysed in this study. Based on cross-validation results, the model showed 93.75 % accuracy in the classification of green tea originating from Japan, China (Mainland), China (Taiwan) and South Korea.

In the present work, we focused on two aspects of mercury (Hg) bioconcentration in the above-ground parts of Neoboletus luridiformis. In the first part, we monitored the bioconcentration potential of individual anatomical parts of a particular fruiting body and evaluated the obtained data by the spline interpolation method. In the second part, we focused on assessing the mercury content in 378 samples of N. luridiformis and associated samples of substrates from 38 localities with different levels of Hg content in Slovakia. From the obtained data of Hg content in samples of substrate and fungi, we evaluated ecological indicators (geoaccumulation index - Igeo, contamination factor - Cf a potential ecological risk - PER), bioconcentration indicators (bioconcentration factor - BCF; cap/stipe quotient - Qc/s) and health indicators (percentage of provisional tolerable weekly intake - %PTWI a target hazard quotient - THQ). Based on the Hg distribution results, the highest Hg content was found in the tubes & pores (3.86 mg/kg DW), followed by the flesh of cap (1.82 mg/kg DW). The lowest Hg content was in the stipe (1.23 mg/kg DW). The results of the BCF values indicate that the studied species can be included in the category of mercury accumulators. The results of the ecological indices representing the state of soil pollution pointed out that two localities (Malachov and Nižná Slaná) stood apart from all monitored localities and showed a state of an extremely disturbed environment. This fact was also reflected in the values of Hg content in the fruiting bodies of the studied mushroom species. In the case of the consumption of mushrooms from these localities, it can be stated that long-term and regular consumption could have a negative non-carcinogenic effect on the health of consumers. It was confirmed by the %PTWI (Malachov: 57.8%; Nižná Slaná: 53.2%) and THQ (Malachov: 1.11 Nižná Slaná: 1.02). The locality Čačín-Jelšovec is interesting from the bioconcentration characteristics point of view, where the level of environmental pollution was the lowest (Hg content in the soil was below the background value) compared to other localities, however, the THQ value was the highest (1.29).