خيارات البحث
النتائج 1121 - 1130 من 2,106
Effect of selenium on thiamine, riboflavin and pantothenic acid content in different grains
2007
Duma, M., Latvia Univ. of Agriculture, Jelgava (Latvia) | Karklina, D., Latvia Univ. of Agriculture, Jelgava (Latvia)
The effect of selenium on the content of thiamine (vitamin B1), riboflavin (vitamin B2), as well as pantothenic acid (vitamin B5) in wheat (Triticum aestivum L), hull-less barley (Hordeum vulgare L.) and hull-less oats (Avena sativa L.) grains during germination were investigated. The winter wheat grain variety 'Zentos', hull-less barley and hull-less oats were used for study. Grains were soaked for 120 hours totally in solutions containing selenium from 10 to 200 mg lE-1 in the form of sodium selenate (Se+6). Grains with moisture content of 43%-44% were let to sprout at ambient temperature of 18+-2 deg C. The content of B1, B2 and B5 vitamins in germinated grains were determined using standard methods. Laboratory studies showed that changes in vitamin B1, B2 and B5 content depend on selenium concentration and kind of grains. Selenium additives promote biochemical activity of vitamin B1 and content of this vitamin decreases after 5 days' germination in all investigated grains at all applied selenium concentrations. Selenium concentrations of 10 and 25 mg lE-1 promote forming of vitamin B2 in wheat, barley and oat grains. The changes in vitamin B5 content depend on selenium concentration and kind of grains.
اظهر المزيد [+] اقل [-]Assessment of food safety risks in catering establishments
2007
Melngaile, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Karklina, D., Latvia Univ. of Agriculture, Jelgava (Latvia)
The aim of the research was to assess food safety risks in catering establishments. To analyse food safety risks during production and distribution of ready-to-eat food in catering establishments, internal database of the Food and Veterinary service of the Republic of Latvia was used. Catering establishments, food items, technological processing methods, as well as environmental objects were encoded to perform mathematical analyses of state's monitoring and surveillance data. The probability of the microbiological risk factors coliforms and S.aureus in food and environmental samples as well as the total plate count in ready-to-eat food was assessed to forecast common risks in catering establishments and to set hygiene management priorities in frame of HACCP procedures. For estimation of individual risk factors, results were statistically analysed using SPSS statistical package and a p is less than 0.05 was considered to be statistically significant. The significant differences were established between certain bacteria presence in food and such factors as food group, method of technological processing, and type of catering establishment. The results on bacterial contamination of food correlate with the results on contamination of environmental objects. The research suggests that control of food safety risks that is built on testing of pathogenic bacteria is not effective enough to evaluate actual level of implementation of hygiene measures in catering establishments. Risk assessment during routine monitoring both in state's official control level and catering establishments' self-control level should be concentrated on testing of hygiene indicator microorganisms rather than pathogenic microorganisms to establish and prevent food safety risks.
اظهر المزيد [+] اقل [-]Microbiological quality aspects of ready-to-eat foods from catering establishments
2007
Marcenkova, T., Latvia Univ. of Agriculture, Jelgava (Latvia) | Rucins, M., Latvia Univ. of Agriculture, Jelgava (Latvia)
A total of 120 food samples from 6 traditional and 3 non-traditional (Oriental) public catering establishments in Latvia were taken. Preliminary all food samples were divided in three food groups (categories) depending on the components of the products and processing methods. Ready-to-eat foods (RTE) with high level of total amount of microorganisms (aerobic colony count-ACC) and total coliforms (TC), as well as appropriate infringements of hygienic requirements in public catering establishments which had an impact on microbial contamination were clarified. The reasons for microbiological contamination of RTE and the growth of the microorganisms were analyzed in dependence on food category group, the activity of hydrogen ions (pH) in food, food temperature at the sampling point, their processing mode and composition. Different indicator microorganisms including Staphylococcus, Enterobacter, Escherichia, Bacillus, yeasts, moulds and etc. were identified. The comparison between the temperature and pH and the level of microbiological contamination of the samples of food and hygienic practice in the catering establishments were clarified.
اظهر المزيد [+] اقل [-]Elaboration of solid phase extraction method for analysis of sterigmatocystin
2007
Versilovskis, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Mikelsone, V., Latvia Univ. of Agriculture, Jelgava (Latvia)
Sterigmatocystin is a mycotoxin produced by fungi of many Aspergillus species and it is a biogenic precursor of aflatoxin B1. For analysis of various mycotoxins to clean up sample extracts, mainly solid phase extraction (SPE) is used. An elution of sterigmatocystin from Strata X and Strata C18 SPE columns by different acetonitrile-water and methanole-water solutions were checked in this paper. Acquired results showed a possible suitability of both columns for the analysis of sterigmatocystin.
اظهر المزيد [+] اقل [-]Investigation of the quality of vegetable oils
2007
Vucane, S., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kuka, M., Latvia Univ. of Agriculture, Jelgava (Latvia)
Vegetable oils are essential providers of energy to a human body; they play important role as a foodstuff. During processing and storage of vegetable oils, they may undergo molecular changes adverse to the human organism affecting the quality of the oils. The content of fatty acids of fresh rapeseed, linseed and hemp oils and of the mixture of rapeseed (800 g kgE-1) and linseed (200 g kgE-1) oils was determined by the method of gas chromatography (GH). Alpha - , delta - and gamma - tocopherols were analyzed in the vegetable oils by the methods of the highly effective liquid chromatography (HPLC). The hemp oils contain the indispensable polyunsaturated fat acids: linoleic acid - 53.0%, and linolenic acid - 23.2%. Such proportion of the fatty acids (3:1) is considered optimal in the nutrition. When using both hot and cold pressure technology for the obtaining of oil, it is possible that the polycyclical aromatic hydrocarbon - Benzo[a]pyrene - may be created and influenced the quality of the oil. The environment also affects the content of the lead in the oils. The density of the various vegetable oils at the temperature of 20 +- deg C proved to be within the limits of 0.917 and 0.942 kg dmE-3.
اظهر المزيد [+] اقل [-]The study of rheological property of functional fermented milk
2007
Beitane, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ciprovica, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
The role of Bifidobacterium lactis and the effect of the addition of inulin and lactulose on the viscosity of a functional fermented milk product have been investigated. The effect of chosen starter and prebiotics on the properties of the functional fermented milk was significant for the apparent viscosity. Generally the viscosity of analyzed products was lower than the viscosity of classical fermented milk products, such as yoghurt, kefir or others. The viscosity was strongly affected by the content of total solids of the analyzed products: with an increase in the total solids there was increase in the viscosity. Among analyzed fermented milk samples, sample with 5% of lactulose had the highest viscosity. In general, inulin did not seem to have an effect on the viscosity of the analyzed product samples compared with the control sample. Bifidobacterium lactis has a weak proteolytic activity; therefore the structure and consistency of functional fermented milk product were characterized as weak, too. It is known that inulin is not only dietary fibre or prebiotic, it has the functions of food additives, too. Inulin is added to food formulations to modify products' texture or viscosity and sweetness of products. Comparison of the obtained results shows that the viscosity of the functional fermented milk product with various concentrations of lactulose or inulin is different. This suggests that the role of inulin in a food matrix is bi-functional. Inulin does not increase the viscosity of a milk product but gives a richer texture to liquid products and spreads.
اظهر المزيد [+] اقل [-]Vitamins in ostrich meat
2007
Kivite, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Karklina, D., Latvia Univ. of Agriculture, Jelgava (Latvia)
Meat is muscle tissue from animals. It is a good source of protein. The meat of various species also is good source for micronutrients and vitamins. Ostrich meat differs from the meat of other animals. It is no fat; it is lean and easily separated from bones and connective tissue. It is more digestible compared to other types of meat, soft and does not require long culinary treatment. Although it can be compared with beef due to its red colour and taste, ostrich meat is as tender as chicken meat, and is characterized by short muscle fibre. The objective of study was to determine the A, E, B1, B2 and B5 vitamins content in ostrich meat and compare it with beef and chicken produced in Latvia and available at retail. All vitamins are determined by standard methods according to AOAC Official Standard Methods: vitamin A - 974.29, vitamin E - 971.30, vitamin B1- 986.27, vitamin B2 - 970.25, and vitamin B5 - 961.14. The obtained results showed that ostrich meat contains significant quantities of vitamins B1, B2 and B5. The highest content in ostrich meat was calculated for B5 (11.45 mg 100gE-1) and the lowest - for B2 (0.098 mg 100gE-1). Ostrich meat contains more than 18 % of vitamins B1 and B2 and more than 7.5 % of B5 compared with beef, and more than 30 % of vitamins B1 and B2 and more than 27 % of B5 compared with chicken. The content of vitamin E is highest in ostrich meat then follows chicken and beef. Regarding vitamin A, ostrich meat has only traces of it.
اظهر المزيد [+] اقل [-]Untraditional beer drinks
2007
Cinkmanis, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Cakste, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
A research has been done on the possibility to increase the range of beer drinks by substituting hops with additives of other plants in the wort boiling process. The obtained data present evidence of the possibility of substituting hops by oak bark, yarrow, wormwood and oak acorn.
اظهر المزيد [+] اقل [-]Problematic character of forest land transformation
2007
Bara, G., Latvia Univ. of Agriculture, Jelgava (Latvia)
In order not to decrease the significance of a forest in the environmental maintenance and its role in the national economy, Latvian Forest policy needs to ensure that the existing forest areas are not decreasing, establish forest land transformation restrictions, thus, maintaining a long lasting development of forests. The preconditions for the change of the forest land use is one of the instruments for the state policy realisation, with the help of which a long-term development of forests can be ensured. At the moment working out the land policy in Latvia on a country level is being started. The publication is in the context of setting strategic targets for forestry and human resource development planning strategy, within the framework of Latvian forest and related department national programme. Due to the reasons mentioned, the topic discussed in the article is a problem of the day, and the research in this direction has got both theoretical and practical significance. The author investigate the forest land transformation process, by analysing normative acts and political documents in the article, as well as by summarising statistical data about the relevant processes in Latvia and in the world, during last six years. The issues, related to the forest land transformation process have been covered in the article; it has been analysed whether there are cases when a necessity arises to review the existing normative regulations. The answers have been given how to eliminate identified shortcomings, contradictions or problems.
اظهر المزيد [+] اقل [-]Use of simulation method for the analysis of wood resource flow
2007
Oss, J., Latvia Univ. of Agriculture, Jelgava (Latvia)
The task of this paper is to create a simulation model of wood resource flow, enabling analysis of the flow of resources to the customer. The model consists of four modelling steps - the study of the system, the creation of conceptual and logical model, as well as data analysis. The model has been developed in UML (Unified Modelling Language) diagrams and the simulation model has been created using software EXTEND Industry. For the simulation of the model the scenario has been created. Based on this scenario, extended scenarios have been developed. Model of basic simulation represents the loading of resources into the transport, transportation, discharging from the transport and the return to the loading point. Using this basic scenario, the extended scenario has been created. This scenario analyzes the flow of wood resources to the customer, taking into account two criterions restricting the flows - assortment to be processed and the distance from the loading place to the customer's location. Extended scenario allows to analyze the load of each sector, as well as to follow each unit existent in the process of simulation. There are attributes of information (type, assortment etc.) added to the unit equivalent to 1m**3 of wood resources. These attributes can provide information about the unit flow within any part of the process.
اظهر المزيد [+] اقل [-]