Electrophoretic methods can be used to identify meat of various animal species. The protein electrophoresis, especially the IEF of the sarcoplasmic proteins, is a well-established technique for species identification of raw fish and is used in the control of seafood authenticity. However, in the case of the analysis of heat-processed fish, the method is applicable only to those species which possess characteristic patterns of the heat-stable parvalbumins. Heat-denatured fish muscle proteins may be solubilised by urea or sodium dodecylsulfate (SDS) and separated by urea-IEF or SDS-PAGE, respectively. The comparison of these two methods allowed to conclude that, basically, each of them can be used for species identification of heated fishery products. However, extensively washed products may be preferentially analysed by the SDS-PAGE, because most of the parvalbumins are washed out leaving mainly myosins. On the other hand, the IEF method may be preferred for the differentiation of closely related species rich in parvalbumins isoforms. It is evident from the literature data that species-specific protein separations yield proteins of low molecular weight made up of three light chains of myosin (14-23 kDa), troponin (19-30 kDa) and parvalbumin (about 12 kDa). Investigations showed that the SDS-PAGE method can be used to identify meats of: cattle, sheep, lambs, goats, red deer and rabbits. The technique allowed researchers to identify the following myofibrillar and sarcoplasmic muscle proteins: myosin and actin, α-actinin, tropomyosin, troponin. SDS-PAGE allowed the identification of myofibrillar proteins taking into account their molecular weights which was not possible with the assistance of the PAGIF because too many protein bands were obtained. It was possible to obtain differences in the separation of proteins characteristic for certain species, e.g. beef, resulting from the presence of single myofibrillar proteins.

Addition of natural antioxidants is one of the ways to extend the durability of meat and meat products. The effects of added pepper extracts on the colour and potential redox changes of beef patties during storage were studied. There were four types of ethanol based extracts of two types of pepper (sweet and hot), compacted at different temperatures: 35 and 50°C. Experimental material consisted of meat samples produced from lean beef 24-hours postmortem. The colour in a CIE L*a*b* systems was examined using an X-Rite reflection spectro-colorimeter. Oxidation-reduction potential was determined using a pH meter (CPC-501) set to the milivolt scale and equipped with a redox electrode ERPt- -13. The results indicate the influence of extracts of different types of pepper added on oxidation-reduction potential values. Meat samples with pepper extract compacted at 35°C addition had a lower oxidation-reduction potential compared with the samples with pepper extract compacted at 50°C addition. Oxidation-reduction potential values of meat samples increased during storage. No significant effects of type of a particular pepper extract on redox potential values were observed. Pepper extracts increased redness (a* value) of meat samples compared to the control, but had no effects on L* values (lightness). During storage of meat samples slight changes of CIE a* parameters were noted.

The aim of the study was to investigate the influence of the type of solvent and time on efficiency of the extraction of polyphenols and antioxidant properties extracts obtained from green tea. Extraction was conducted at room temperature using four solvents: water and 80% ethanol, 80% methanol and 80% acetone (water solutions, v/v) at 15, 30 and 60 minutes. Extracts were analysed for contents of polyphenols and catechins. The antioxidant properties have been determined by two methods: scavenging activity against DPPH^· and the method with ABTS^·+. The abilities of extracts to chelate iron ions (II) have been investigated too. On the basis of findings it turned out that both type of solvent and time have a significant influence on extraction of polyphenols from green tea. The best solvent for the extraction of total polyphenols was 80% acetone, whereas for catechins was water. The increase of extraction of polyphenols with prolonged extraction time was observed. All extracts had antioxidant properties against DPPH^· and ABTS^·+ and abilities to chelate iron ions (II).

The purpose of the research was to determine the effect of diversified nitrogen fertilization (0, 25 and 50 kg·ha^-1) on selected properties of grains, malts and brewing worts. Brewing value of barley grain was determined by Molina-Cano method. It was stated that the higher doses of nitrogen caused an increase of yield, as a result of stronger productive tillering of plants. Significant growth of grain yield was obtained by the increasing of nitrogen fertilization from 25 to 50 kg·ha^-1. Malts from naked barley grain were produced in the same way as malts of the Pilzen type. According to Molina-Cano method, the naked barley grain of Rastik cultivar was qualified as brewing, because of high malt extractivity. Laboratory worts were characterized by a high extract content, but not suitable viscosity, total attenuation and low soluble nitrogen content.

The aim of the research was to study the influence of the pullulan and pullulan- -protein edible coatings on the reduction of the apples mass loss during the storage. The research was carried out on pullulan received from A. pullulans white mutant B-1 in a batch cultivation process and the ‘Malinova’ and ‘Champion’ apples. In the first stage of the research the apples were covered with 15% and 20% pullulan water solution and storage at 4°C and 22°C during 39 days. In the second stage of the research the apples were covered with pullulan-protein coating obtained from the mixture of pullulan and soy protein. Apples covered with the pullulan-protein coatings were stored at the temperature of 2°C during 10 weeks. Mass losses of apples, durability of the pullulan and pullulan-protein coatings as well as changes in the appearance of the surface coating covered fruit in comparison with the one uncovered were evaluated. Pullulan edible coating significantly limited apples mass losses. Apples covered with coatings showed lower mass losses than the ones uncovered. The smallest mass losses were observed in apples covered with the coatings where the pullulan to protein ratios were: 6:4 and 5:5. It was observed that by adding protein to pullulan the coating stuck better to apples surface. During the storage process the protein-containing layer was less susceptible to crumbling and to peeling off.

Investigations were carried out into the capacity of waste brewery yeast Saccharomyces uvarum for biosorption of magnesium originated from a solution of dehydrated salt of magnesium chloride, depending on the number of cells and diferent pH of the suspension during 6 hours. The concentration of MgCl₂·6H₂O in the solution was adjusted so as to maintain a stable content of magnesium as expressed per pure element, i.e. 1.25 g/dm³ of solution. In the first stage, the number of cells was differentiated in yeast slurry through either condensation or dilution. In the second stage, pH of yeast suspension was differentiated (pH 5.5, 6.0 and 7.0) at a constant number of cells. The solutions examined were kept under anaerobic and aerobic conditions. Determination of magnesium content of yeast biomass was carried out with the method of atomic adsorption spectroscopy after 15 min, 1 h, 2 h, 4 h and 6 h of experiments. The highest content of magnesium (13.76 mg/g d.m.) was obtained at the lowest number of cells in the solution, i.e. 3.5 × 10⁸ cells/cm³ under aerobic conditions. An increase in solution pH facilitated biosorption of magnesium by the yeast. At pH 7.0, after 6 hours of the experiment, the yeasts contained 15.19 mg Mg/g d.m. when kept under anaerobic conditions and 17.22 mg Mg/g d.m. when kept under aerobic conditions.

It is possible to obtain malt beverage, which includes high number of viable lactic acid bacteria and has a good sensor quality for eight weeks of storage at the temperature of 22°C. L. plantarum ATCC 4080 strain after four weeks of storage did not reveal antagonistic activity against spoilage and pathogenic bacteria. This strain after two, six and eight weeks of storage had antagonistic properties. The tested strain after two and four weeks of storage did not survive during incubation at pH 2.5 and next in malt beverage with 3 mmol/dm³ deoxycholate sodium, while survived in these conditions after six and eight weeks. In case of incubation at pH 2.5 and next in aqueous solution of deoxycholate sodium tested strain after four and six weeks of storage had survival ability. The survival ability in these conditions of the tested strain after two and eight weeks of storage were not investigated.

The ability to in vitro cholesterol level reduction in laboratory media has been shown for numerous strains of lactic acid bacteria, but not for all strains of lactic bacteria used in the dairy industry. The aim of this work was the determination of the ability of selected thermophilic lactic acid bacteria to cholesterol assimilation during 24 h culture in MRS broth. Commercial starter cultures showed various ability to cholesterol assimilation from laboratory medium. In case of starter cultures used for production of traditional yoghurt, consisting of Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, the quantity of assimilated cholesterol did not exceed 27% of its initial contents (0.7 g in 1 dm³). Starter cultures used for bioyoghurt production, containing also probiotic strains (came from Lactobacillus acidophilus species or Bifidobacterium genus) assimilated from almost 18% to over 38% of cholesterol. For one monoculture of Lb. acidophilus, cholesterol assimilation ability of 49-55% was observed, despite that the number of bacterial cells in this culture was not different from number of bacteria in other cultures.

In the article the results of a research carried out in 2005 on the sample of 134 respondents are presented. The results of the research indicate that young consumers are very active on the food market. Teenagers derive their knowledge about nutrition mainly from their family home but also from school as well as from books and literature publications. Together with age the range of participation of grammar school teenagers in family shopping has declined, while their role and activeness of individual purchaser has risen. Families were commonly shopping mainly in small near-home shops and also, but less frequently, in hyper- and supermarkets. Teenagers were shopping individually mainly in small near home shops and school shops spending on average 9 PLN per week. While choosing the shopping place grammar school teenagers took under consideration mainly the price level and the quality of goods offered. The most important factors taken into consideration by the tested teenagers while buying food individually were: the freshness, the taste and the brand. Teenagers were engaged in decisive process of purchasing food for the family household mainly as far as products which were meant for them as consumers. Products such as beverages, chips, sweets and ice-creams were the main items of their individual purchase. Basing on the results of the survey a rather positive attitude of the tested teenagers was noticed towards promotion of sales. They were also more prone to impulsive purchase and more than averagely prone to novelties.