Intensive oxidative processes occuring in human organism lead to formation of oxygen reactive forms, which can damage systemic cells and tissues. It is shown, that body endogenous protective system can be supported in that case by natural antioxidant compounds provided from food. The assessment of food products as the potential sources of antioxidants was performed, taking into consideration the kinds of compounds supplied, and their significance in the diet of different nations.

The chemical conservation was chosen in the study as the method for preserving fresh corn grain for distilleries. Five types of preserved corn samples were prepared. The control (with no additives) and four preserved with the preparation, based on formic and propionic acids (KemiSile 2000 Plus), at different levels. All the samples were stored for two months. Ethanol fermentations of low-temperature-cooked and pressure-cooked corn starch were carried out using commercial distillery yeast. The yeast strain, after starch hydrolysis with two enzymes, was able to produce 86-93% of theoretical ethanol yield from low-temperature-cooked corn. The ethanol production was almost equal to that produced from pressure-cooked corn starch (121°C), which was 87-94% of theoretical ethanol yield. The quality of distillates was also investigated. The most common by-products found were: acetaldehyde, ethyl acetate, propanol, isobutanol and 3-metylo-1-butanol. There were no important differences of spirits chemical composition between low-temperature-cooking and pressure-cooking method as well as between the kind of corn sample.

In the study the effect of nitrogen fertilization of durum wheat on grain and flour properties was examined. Grain of four durum wheat varieties: ‘Durabon’, ‘Durabonus’, ‘Duraprimus’ and ‘Rusticano’ cultivated in the Swadzim at Experimental Station of Agricultural University of Poznań were investigated. Three different doses of nitrogen fertilization (50, 100 and 150 kg per hectare) were applied during plant growth. In addition, grain cultivated in the same conditions without any nitrogen fertilization was examined. The results indicate that nitrogen fertilization had a distinct effect on grain physical characteristics such as hardness and vitreousness. It also influenced protein and wet gluten content in flour. No significant effect on carotenoids content and colour of pasta dough was observed.

The influence of pepsin (EC 3.4.1.1) and trypsin (EC 3.4.4.4) action on the chemical composition of legume flours was the aim of this study. The level of proteins and lipids in hydrolysed flours was changed significantly. In comparison to the raw flours also fatty acid composition in treated flours was altered. In the lentil flours both trypsin and pepsin digestion conditions have decreased the level of unsaturated fatty acid. It is noteworthy that in all investigated, hydrolysed flours ratio linoleic: oleic fatty acid was significantly decreased in comparison to unhydrolysed flours (about 40%-pea; 60%-lentil). Our investigations were also focused on the potential implementations of IMAC method in the separation and purification of peptides. Generally, peptides separation profiles, performed on immobilized Zn (II), were dependent on the kind of flour and enzyme used in the hydrolysis process. In the lights of our results is clearly visible that investigated peptides had a weak affinity to the chelated metal ions. It is noteworthy, that in some cases the influences of chelating factor on separation profiles were noticeable.

The aim of the present studies was to determine the changes in daily dietary supply of energy, total protein, animal protein, total fat and carbohydrates in pensioners’ households during beginning and stabilization of market economy in Poland, i.e. in the period of 1989-2004. The calculations were based on data from the Statistical Yearbooks of the Republic of Poland, sections “Household Budgets” from 1990-2005, published by the Central Statistical Office (CSO). Daily dietary supply of energy and fat in pensioners’ households was excessive over the study period (150% and 200% of reference intake, respectively). Superfluous dietary fat supply could have resulted from the fact that the method used for these studies did not account for fat losses during frying and 10% inevitable wastage, which might also have contributed to overestimation of percentage of the reference intake for protein and total carbohydrates. There was a declining tendency in supply of all nutrients and energy over the study period, with the largest decrease in carbohydrate supply and the smallest for protein.

Tea infusions are consumed frequently and in large amounts, so they may play a role in modelling intestinal microflora or in preventing bacterial diseases. The present study examined the effect of different kinds of tea (black, green and pu-erh) on Lactobacillus rhamnosus, Lactobacillus plantarum, Leuconostoc mesenteroides subsp. mesenteroides, Escherichia coli, Staphylococcus aureus and Salmonella enteritidis. In order to ascertain the connection between antioxidant and antimicrobial properties, the content of polyphenolic compounds and the reducing power of the teas were assessed. The rate of bacterial proliferation was measured by calculating the generation time between the 2nd and 6th hour of incubation. Staphylococcus aureus was the most sensitive to the addition of tea extracts to the media. Among lactobacilli (LAB), Lactobacillus casei proved to be sensitive mainly to the extracts of black and pu-erh tea. The value for reducing power does not fully correspond to the content of polyphenols and antimicrobial properties.