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Honey is composed mainly of carbohydrates which are represented by mono-, di-, tri-, tetra-, pentasaccharides, and oligosaccharides. The content and proportions of individual carbohydrates reveal information about the origin and technological properties of honey. A total of 5 987 samples of natural honeys originating from the Czech Republic and harvested during a period of nine consecutive years were analysed to research their carbohydrate content, sum of fructose and glucose (Fru + Glc), fructose and glucose ratio (Fru/Glc), and electrical conductivity (Ec). Monosaccharides, melezitose (Mel), and Ec varied according to the source of nectar or honeydew. Sucrose (Suc) content was low 0.87 ± 1.26 g (100 g)-1 and did not exceed 15 g (100 g)-1.

This work compares the commonly used immunochemical methods for soya protein detection and alternative microscopic methods. Immunochemical methods were represented by the competitive ELISA method. Histochemical and immunohistochemical methods were used for microscopical examination. From a group of 252 meat products, each sample was examined for soya proteins by ELISA, histochemical, and immunohistochemical methods. The products came from the following categories: cooked sausages, ham, dry cooked sausages, and fermented sausages. The results showed that the highest accuracy was achieved by immunohistochemical examination. However, in the category of cooked sausages, this result was not statistically significant. Since the results in the individual categories differed, our results demonstrate that one single method does not always provide reliable and completely objective results. Immunohistochemical methods seem to be the most suitable for the verification of the reference immunochemical method results and prevention of false results.

The addition of plant proteins into meat products is nowadays a commonly used practice especially for the technological and economical reasons. Their properties have been known and used in meat products production for a long time. In the past, wheat protein or flour had been used most frequently, however, in these days they are being replaced by soya protein which has much more favourable properties in its use. Considering the possible misuse of raw materials of plant origin for the adulteration of meat products, the existence of highly sensitive and accurate procedures for their detection is needed including the determination of their content. Soya protein can be detected using various methods. In our work, an immunohistochemical method was used with image analysis for the quantification of soya protein. Model meat products with the addition of known amounts of soya protein in various forms were made for this experiment.

The study focused on the optimisation of immunohistochemical examination for gluten content detection in model samples (pork meat with wheat semi-smooth flour, pork meat with wheat protein edible vital). The best results were achieved with immunohistochemical method based on ABC (avidin-biotin complex) method utilising polyclonal antibodies diluted 1:1000. The results demonstrate that for pure wheat protein detection, the utilisation of immunohistochemical detection, which can detect as little as 0.1% of the added wheat protein, is more advantageous, while the commonly used ELISA method reliably proves this additive approximately from 0.4% upwards.

A functional immunohistochemical method for soya proteins detection was developed. The procedure is based on the avidin-biotin complex (ABC) method that attains sufficient sensitivity. The method was verified by the analysis of the model samples of different forms of soya additives containing various concentrations of soya isolate. The detection limit of soya present in the model samples was 0.5%. Different possibilities of the background staining were tested. The best results were obtained with the background staining according to Calleja. The results were confirmed by the accredited indirect ELISA method. The method allows the identification of various forms of soya proteins such as isolates, texturates, concentrates, and flour.