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Career-related possible selves of rural adolescents
2013
Pavulens, J., Latvia Univ. of Agriculture, Jelgava (Latvia)
The first independent career related decisions are made during the ninth grade of the elementary school when the further educational institution is selected. The concept of possible selves can be used in career education to help students increase self-awareness, explore and generate options, and formulate plans to achieve future goals. The aim of the article is to examine rural adolescents’ ability to generate career-related possible selves and plausible strategies to attain these possible selves. On the basis of the Possible Selves Theory, the open-ended measure was developed by the author. The pilot research was carried out in Latvia in January 2013. Forty six nine-graders from two rural elementary schools and two rural secondary schools participated in the research. Next year and adult possible selves generated by rural adolescents include such domains as education, employment, leisure activities, physical and personal development, as well as interpersonal relationships and lifestyle. The most important ones are domains of education and employment. Statistically significant differences of the results among the gender subgroups are not found in the research, statistically significant differences exist between the possible selves and their attaining strategies generated by rural secondary school students and rural elementary school students.
Afficher plus [+] Moins [-]Impact of harvest timing and cultivar on biogas outcome from winter wheat silage
2012
Jansone, I., Latvia Univ. of Agriculture, Jelgava (Latvia);State Stende Inst. of Cereal Breeding, Dizstende, Talsu reg. (Latvia) | Gaile, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
Biogas can be produced from industrial by-products, household waste and raw materials of agricultural origin. Agricultural resources can be agricultural by-products, for example, manure as well as biomass of energy crops. The objective of the trial was to evaluate the methane outcome from the winter wheat (Triticum aestivum L.) silage depending on the variety and the growth stage during the harvest. The trial was carried out in State Stende Cereals Breeding Institute in the autumn of 2009. The biomass of three varieties of winter wheat, harvested at three stages of maturity - at the beginning of flowering (GS 60-62), early milk ripeness (GS 70-72), and early yellow ripeness (GS 80-82) - was ensiled in laboratory conditions. The silage was analysed 180 days after it had been ensiled. The biogas and methane outcome in laboratory conditions (in Germany) was determined for samples of silage made from winter wheat variety ‘Skalmeje’ at all harvesting times according to VDI 4630 method. The theoretically obtainable methane outcome was calculated for silage samples of all varieties by using the results of chemical composition analysis (crude protein, crude fibre, crude fat, N-free-extracts). The highest methane outcome from one ton of winter wheat silage was acquired by harvesting and ensiling the biomass during the flowering stage. However, evaluating the methane yield from one hectare, the best results were obtained by harvesting and ensiling the biomass at the early milk stage of ripeness and at the stage of early yellow ripeness.
Afficher plus [+] Moins [-]Combustion ability of energy crop pellets
2012
Platace, R., Latvia Univ. of Agriculture, Jelgava (Latvia) | Adamovics, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Future perspective of the research is the production of fuel pellets from energy plant (Phalaris arundinacea L., Festuca arundinacea, etc.) biomass, because it can be better burnt in granule burners and is more environmentally friendly, if compared to the fossil mineral resources (coal, oil, gas), moreover it has low moisture content (70 – 90 g kgE-1) and correspondingly it produces higher combustion energy. The research covered preparation of various content tablets from reed canary grass (Phalaris arundinacea L.) variety ’Marathon’ (N fertilizer rate on the N-90 kg haE-1), energy wood - osier (Salix viminalis L) and poplar (Populus tremula L.) with N fertilizer norms N-0 and N-120 kg haE-1, and afterwards research of the combustion ability of and ash content in these tablets. Combustion ability of reed canary grass (Phalaris arundinacea L.) variety ‘Marathon’ reached 17.48 MJ kgE-1. The highest average combustion ability with different pellet content was found for the fast-growing poplar both with doses of N fertilizer - 18.55 MJ kgE-1 and without N fertilizer - 18.49 MJ kgE-1. Optimum content of various component pellets for biomass was a mixture of components 1/3 (reed canary grass/osier or poplar). The lowest indicators in respect to the ash content were observed for osier (Salix viminalis L.) - 27.9 g kgE-1. The best ash content indicators for a mixture of granular composition was in a mixture of components one-fourth of the reed canary grass with three parts of osier - 34.3 g kgE-1 or with poplar - 41.8 g kgE-1.
Afficher plus [+] Moins [-]Rehydration of dried Latvian cranberries affected by drying conditions
2012
Ruse, K., Latvia Univ. of Agriculture, Jelgava (Latvia) | Rakcejeva, T., Latvia Univ. of Agriculture, Jelgava (Latvia) | Berzina, L., Latvia Univ. of Agriculture, Jelgava (Latvia)
The aim of the current research was to study the effect of drying conditions on the rehydration kinetics of Latvia wild grown and on cultivated cranberries. The research was accomplished on fresh wild cranberries and cultivated cranberry cultivars ‘Ben Lear’ and ‘Pilgrim’ harvested in Kurzeme region of Latvia in the first part of October 2010 and immediately used in the drying experiment. Three methods were used for pre-treatment of berries: perforation, halving and steam-blanching. Before drying in a convective drier the berries were pre-treated using all three methods and berries were dried in a microwave vacuum drier using two pre-treatment methods – steam-blanching and halving. Parts of berries were dried in the microwave vacuum drier without pre-treatment (whole berries). For drying experiments, convective and microwave vacuum drier were used. Cranberry samples were rehydrated in water at +20±1 °C and +40±1 °C. The moisture content of the cranberry samples after rehydration was estimated as oven-dry method. The rehydration properties of cranberries increased with the increase in temperature, up to +40±1 °C, the increase being more significant at the initial stages of the process. Microwave drying possibly produces a sample with increased porosity, which in turn leads to improved rehydration characteristics and a softer product and may reduce processing time. Pre-treatment of berries did not significantly influence the increasing intensity of moisture content during rehydration, but the drying methods within rehydration at the temperature of +40±1 °C significantly influenced the increasing intensity of moisture content.
Afficher plus [+] Moins [-]Preliminary results of 1-methylcyclopropene influence on apple quality during storage
2012
Juhnevica, K., Latvian State Inst. of Fruit-Growing, Dobele (Latvia);Latvia Univ. of Agriculture, Jelgava (Latvia) | Skudra, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Skrivele, M., Latvian State Inst. of Fruit-Growing, Dobele (Latvia) | Seglina, D., Latvian State Inst. of Fruit-Growing, Dobele (Latvia) | Skudra, G., Latvia Univ. of Agriculture, Jelgava (Latvia)
Apples are the most popular and common fruits in Latvia. Storage technology is crucial to preserve fruit quality as long as possible. Choosing the appropriate gas content of the storage environment can prolong storage life two to three times for apples. The aim of the research was to compare six different type of apple grown in Latvia, which was stored in diverse conditions. All experiments were performed at Latvia State Institute of Fruit-Growing through 2011 – 2012. For fruits before storage, 1-methylcyclopropene (1-MCP), which blocks the emission of ethylene, was used. Apples were stored in a cooler and in ULO type plastic bags in a modified environment with two different gas contents. The temperature of the environment was +2 ±1 °C with 90% relative humidity. Changes in physicochemical (soluble solids, total acids and flesh density) indexes were examined before and during the storage. The results showed 1-MCP has a positive effect on quality preservation of fruit. Fruits stored in ULO type plastic bags (gas content: 1.5% O2 and 2.5% CO2) had the best results in preservation of physico-chemical indexes. Examination of results revealed that physico-chemical indexes changed the most in samples stored in the cooler.
Afficher plus [+] Moins [-]Influence of genotype and harvest time on the phenolic content of horseradish (Armoracia rusticana L.) roots
2012
Tomsone, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kruma, Z., Latvia Univ. of Agriculture, Jelgava (Latvia) | Lepse, L., Pure Horticultural Research Centre, Tukuma reg. (Latvia)
Horseradish (Armoracia rusticana L.) is a perennial plant, with a particularly pungent flavour and significant antioxidant properties. The aim of current research was to determine the total phenol content and antioxidant properties of horseradish depending on genotype and harvest time. For experiments nine genotypes of horseradish roots collected at different times were investigated. Fresh plant material was extracted with ethanol/water solution (80:20 v/v). Total phenols content (TPC) of plant extracts was determined according to the Folin-Ciocalteu spectrophotometric method and results were expressed as gallic acid equivalents (GAE). Antioxidant activity of the extracts was measured on the basis of DPPH˙ free radical scavenging activity and the final results were expressed as inhibition of 2,2-diphenyl-1- picrylhydraziyl (DPPH˙) in percent (I, %). Total phenols content varied among analysed types of horseradish. The highest TPC was detected in horseradish root genotype 280 harvested in September and it also demonstrated the highest DPPH˙ radical scavenging activity, whereas the lowest TPC was detected in horseradish root genotype 26B also harvested in September. TPC and DPPH˙ scavenging antioxidant activity were also significantly influenced by harvest time. Positive correlation was found between antiradical activity and the total phenols content in horseradish roots harvested in September. In further experiments, use of horseradish as natural antioxidants in different food matrixes should be studied.
Afficher plus [+] Moins [-]Consumers’ attitude towards availability and quality of gluten-free products in the Latvian market
2012
Ozola, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Straumite, E., Latvia Univ. of Agriculture, Jelgava (Latvia)
Celiac disease is an autoimmune enteropathy disease, triggered in genetically susceptible individuals by ingested gluten from wheat (Triticum), rye (Secale cereale), barley (Hordeum vulgare) and other closely related cereal grains. The only way of the effective daily treatment is a strict gluten-free diet. From the investigation of products available in the local market, it was found that Latvian producers do not offer gluten-free products. The aim of this research was to study a celiac patient’s attitude to gluten-free product quality and availability in the Latvian market and purchasing habits. The survey was designed using website www.visidati.lv, and a questionnaire was sent to people suffering from celiac disease. The respondents were asked to fill in the questionnaire from the beginning of December 2010 till the end of July 2011. The questionnaire was performed with 131 celiac patients, respondents were from all Latvian regions and they answered 15 questions. One of the most important questions was aimed to find out consumers’ opinion about quality of gluten-free products, consumption patterns of gluten-free products, and, moreover, their interest in products made in Latvia. Respondents were asked to name gluten-free products they mainly buy and give specific purchase locations, evaluate the quality of products and necessity for products produced in Latvia. The results of questionnaire show that the consumers are satisfied with the quality of gluten-free flour, flour blends and pasta, but are not satisfied with the quality of bread and confectionery available in the Latvian markets.
Afficher plus [+] Moins [-]Physical-chemical characterization of industrial wheat bran from Latvia
2012
Radenkovs, V., Latvia Univ. of Agriculture, Jelgava (Latvia) | Klava, D., Latvia Univ. of Agriculture, Jelgava (Latvia)
Cereal and whole grain products are an important source of dietary fiber in the human diet. Since the milling process highly influences the proportions of the different cell types in the bran, it is expected that brans originating from different genetic/agricultural backgrounds and produced by different processes have different chemical composition. Wheat (Triticum aestivum) bran has not been studied in Latvia, therefore the aim of the present study was to analyze physical – chemical characteristics of wheat bran from Latvia’s industrial mills. Four bran samples were collected from two industrial mills: Stock Company ‘Dobeles dzirnavnieks’ and SC ‘Rigas dzirnavnieks’. All experiments were performed at the Food Technology of Latvia University of Agriculture in May 2011-February 2012. The particle size distribution of the bran samples was determined by sieving. The content of titratable acidity (TA) was detected by titration with 0.1 M NaOH till pH 8.5 was stable for 1 minute. Wheat bran colour was analysed by Hunter Lab colour measurement instrument using ColorTec colorimeter PCM/PSM in CIE L * a * b* system. Moisture content was analyzed using standard ICC 110/1 method by sample drying for 2 h at 150 °C. Results showed that there were significant differences between varieties (p0.05) for titratable acidity and for particle size, but no significant differences (p0.05) were found between the varieties in moisture, pH and colour. TA varied from 6.40±0.71 to 12.05±0.21°, moisture content- from 10.01±0.51% to 11.61±0.47%, pH–from 6.31±0.61 to 6.80±0.05, but colour of bran between the samples did not significantly differ.
Afficher plus [+] Moins [-]The influence of different selenium concentrations on the barley grain 'class' sprouting activity and content of total phenols
2012
Antonenko, K., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kreicbergs, V., Latvia Univ. of Agriculture, Jelgava (Latvia)
Barley (Hordeum vulgare L.) grain is the main raw material in brewing industry, because beer taste and production process depend on barley grain qualitative indices. One of the barley grain’s qualitative indices is grain sprouting activity. There have been numerous researches that showed the effects of selenium (Se) on hull-less barley sprouting activity and positive influence on biologically active substances and high vitamins concentration in grain (Dūma et al., 2002), but hull-less barley is not widely used. The aim of this study was to explore the influence of different selenium concentrations on the barley grains sprouting activity and content of total phenols. Barley with grain viability of 92% have been soaked in diverse solutions (Se concentration 0.5 mg LE-1 – 10 mg LE-1) for 12 hours, then the grain sprouted at the temperature of +18±2 °C for 5 days and dried in the oven for 48 hours at a temperature of +50 °C. After sprouting, the sprouting activity of the grain was determined, but total phenols amount was determined after grain desiccation. The obtained results showed that the increase in selenium concentration in a solution increased barley grain sprouting activity from 16.3% (0.5 mg LE-1) to 27.9% (10 mg LE-1), but the amount of total phenols decreased.
Afficher plus [+] Moins [-]Investigations into the enhancement of cow's milk oxidative stability
2012
Antone, U., Latvia Univ. of Agriculture, Jelgava (Latvia) | Sterna, V., Latvia Univ. of Agriculture, Jelgava (Latvia) | Zagorska, J., Latvia Univ. of Agriculture, Jelgava (Latvia)
The quality and nutritional value of milk and dairy products are considerably influenced by the stability of its constituents. The aim of the present study was to evaluate the possibility of enhancing oxidative stability of cow’s milk fat and vitamin B2 using carrots and palm oil feed supplement CAF 100 as sources of natural antioxidants in cow feed. Milk samples were collected after 25-day period of feed supplementation. The intensity of riboflavin losses during its photo oxidative degradation in sunlight was measured by the fluorometric method. A slight and significant (p is less than 0.05) difference in higher vitamin B2 stability was seen in carrot-supplemented group (TG1) milk, where the losses of vitamin B2 were by 3.01% less compared to CG (CG). The oxidative stability of butter oil samples stored in 60 °C temperature was analyzed by peroxide value (PV) method. The oxidative stability of samples initially affected by light from both trial groups was significantly (p is less than 0.05) higher compared to CG showing the good potential of the cow diet enrichment with carotenoid additives. The longest induction period (larger than 14 days) was observed in CAF-100- supplemented (TG2) cow milk fats, which can be explained by carotenoids and tocopherol presence and its possible synergism in fat protection. The induction periods of the TG1 and CG were 12.03 and 10.97 days, respectively.
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