The aim of the study was to characterize antioxidant and textural property differences of edible films prepared with the addition of lapacho extract (LE). The experimentally produced edible films also contained different carrageenans (ι- and κ-carrageenan). The κ- and ι-carrageenan, glycerol and the different addition of LE (5%, 10%, 20%) were used as ingredients for forming films. The pH and viscosity were measured for film forming solutions (before drying). The following analyses were performed on films: the total polyphenol content (TPC), Ferric Reducing Antioxidant Power (FRAP) and 2-Diphenyl–1-Picrylhydrazyl (DPPH). Optical parameters were analyzed by the determination of UV-Vis spectra. The structure of films was characterized by scanning electron microscopy. The gained results indicated that the use of different gelling agents (ι- and κ-carrageenan) resulted in statistically significant (p < 0.05) differences in textural properties (strength and breaking strain) of produced edible films. The highest antioxidant properties and TPC had a κ film with 20% LE (DPPH: 87.63 ± 0.03%; TPC: 233.75 ± 0.104 mg gallic acid/g). According to these results, it can be concluded that edible films with the highest concentrations of added lapacho extract can serve as a good source of antioxidant compounds. Certainly, these properties can be usefully incorporated into the wrapped food commodity.

The aim of the research was to verify the necessity of secondary fixation with osmium tetroxide in various types of meat products and evaluation of structural changes of products using different fixation procedures. The material for the study consisted of 11 types of meat products that were analyzed using a scanning electron microscope (SEM) with two different methods of chemical fixation. The first method included the usual processing of biological samples: glutaraldehyde primary fixation, the use of a buffer, secondary fixation by osmium tetroxide (OsO₄), buffer, and dehydration using ethanol of increasing concentrations. The second method comprised the glutaraldehyde primary fixation and dehydration using the ethanol of increasing concentrations only. The results unambiguously suggest that the main difference between these methods is in fixation and visibility of fat. Our analysis principally suggests that fixation of the product with OsO₄ allows the tracking of all components (fat droplets, muscle fibers, connective tissue) in meat products. At the same time, our results also support the possibility that the secondary fixation can be skipped during the analysis, where the main objection is an observation of lipid-free structures of the meat products (e.g., connection between muscle and starches or spices) or meat products with an insignificant amount of fat.

One of the options to determine botanical origin of trees or honey is the analysis of pollen grains. The characteristics of pollen grains in Czech flora has not been sufficiently described yet. Within this work, fruit trees pollen of Czech origin was characterized on the basis of morphological and spectral description of pollen grains produced by fruit species of M. domestica, P. armenica, P. persica, P. domestica, P. avium and P. cerasus. The morphological characterization results of the studied fruit species are consistent with results by other authors, but certain differences between the pollen grains of some fruit trees were confirmed. Most morphological differences were confirmed among the Malus and Prunus genera. Results of morphological and spectral analyzes further confirmed the differences between some types of fruit trees, but homogeneity remained for individual species even in mixed samples. Morphological and spectral analysis can therefore be used for botanical identification of pollen. If this knowledge is applied to pollen analysis in honey, these methods can also be used to verify the botanical origin of honey.

The aim of the study was to analytically evaluate quantum dots in immunohistofluorescence (IHF-QD) microscopic imaging as detectors of food allergens—peanut and wheat. The experiment was designed as two in silico experiments or simulations: (a) models of pastry samples were prepared with the addition of allergenic components (peanut and wheat protein components) and without the addition of allergenic components, and (b) positive and negative commercial samples underwent food allergen detection. The samples from both simulations were tested by the ELISA and IHF-QD microscopic methods. The primary antibodies (secondary antibodies to a rabbit Fc fragment with labeled CdSe/ZnS QD) were labelled at 525, 585, and 655 nm emissions. The use of quantum dots (QDs) has expanded to many science areas and they are also finding use in food allergen detection, as shown in the study. The study indicated that differences between the ELISA and IHF-QD microscopic methods were not observable among experimentally produced pastry samples with and without allergenic components, although differences were observed among commercial samples. The important value of the study is certainly the differences found in the application of different QD conjugates (525, 585, and 655). The highest contrast was found in the application of 585 QD conjugates that can serve for the possible quantification of present food allergens—peanuts and wheat. The study clearly emphasized that QD can be used for the qualitative detection of food allergens and can represent a reliable analytical method for food allergen detection in different food matrixes.