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The content of carbohydrates and organic acids in organically grown vegetables and dried vegetable products Full text
2010
Ozolina, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kuka, P., Latvia Univ. of Agriculture, Jelgava (Latvia)
The content of carbohydrates (fructose, glucose, and sucrose) and organic acids (citric acid, succinic acid, malic acid, sorbic acid, and ascorbic acid (vitamin C)) in organically grown vegetables (carrots, parsnips, celeriacs, and red beets) and dried vegetable products were analyzed by the HPLC reverse phase and ion exchange methods. The main carbohydrate detected in fresh vegetables invariably was sucrose (1.29 – 11.17 g 100 gE-1). Fructose and glucose were found in similar ranges (0.09 – 2.47 g 100 gE-1, 0.14 – 3.02 g 100 gE-1 respectively). A similar distribution of carbohydrates was determined in dried products. The highest fructose and glucose contents were found in fresh carrots - 2.47 g 100 gE-1 and 3.02 g 100 gE-1 respectively; but in dried carrot products – 14.53 g 100 gE-1 and 15.43 g 100 gE-1. High amounts of sucrose were found in red beets: 11.17 g 100 gE-1 in fresh samples, and 48.50 g 100 gE-1 in dried products. Malic and citric acids were detected as the main acids of fresh vegetables. Highest citric acid amount was in red beets (266.19 mg 100 gE-1), whereas celeriacs and parsnips had a high malic acid content. The results from this study demonstrated variability and concentration range of carbohydrates and organic acids, wherewith the organoleptic profile of the products. Dried products are considered as a good source of energy.
Show more [+] Less [-]Distribution of nitrogen and phosphorus compounds in filter media of constructed wetland Full text
2010
Gasiunas, V., Lithuanian Univ. of Agriculture, Vilainiai, Kedainiai (Lithuania). Faculty of Water and Land Management. Water Research Inst.
The objective of the present studies is to estimate a distribution of nitrogen and phosphorus compounds in filter media of horizontal filters. The studies were carried out in 2009 within two wastewater treatment facilities of horizontal flow in Lithuania. From both treatment facilities sand samples of different depth and separate profiles in the direction of water flow were taken. These samples were used to determine sandmoisture and concentration of N-NO3, N-NH4 and total P. The measurements of sand moisture showed that the filtration of wastewater through the sand is in process only in the lower layer of sand filter and near the distribution pipe. Moisture regime in the sand influences the composition of nitrogenous compounds in it. In the part of the filter, where sand's moisture is lowest, nitrate concentration is highest. Ammonia concentrations are completely opposite. In the lower part of the filter anaerobic conditions are dominant and nitrification processes stop. Analysis of phosphorus concentrations in filter's sand showed similar tendencies as nitrogen analysis. In the upper part of the sand phosphorus concentration turns out to be 2-3 times lower than in the lower part of the sand. In the filters of horizontal flow, part of the sand contributes little or does not contribute to the wastewater treatment process at all; therefore, it is advisable to use wastewater recirculation for the improvement of nitrogen and phosphorus removal. For that purpose in the part of the filter not included in the treatment process the filter of vertical flow could be arranged.
Show more [+] Less [-]The influence of selenium and copper on microbiological indicators of rye malt Full text
2013
Antonenko, K., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kozlinskis, E., Latvia Univ. of Agriculture, Jelgava (Latvia)
Malt is a natural food product produced by germinating cereal grains. Safety of cereal grains and cereal products is a very important area. Experiments were carried out at the Faculty of Food Technology of the Latvia University of Agriculture. The research object was rye malt. The purpose of the research was to investigate and compare the influence of copper and selenium on microbiological indicators of rye malt. Rye grains of 96% viability were soaked and germinated at temperature +6 ± 2 °C for 4 days, using copper(II) sulphate pentahydrate CuS04*5H2 O solutions (Cu concentration 10 mg LE-1, 50 mg LE-1, 100 mg LE-1) and for 3 days using sodium selenate Na2 SeO4 solutions (Se concentration 3 mg LE-1, 5 mg LE-1, 10 mg LE-1) then the soaked grains dried in the oven for 24 hours. The total plate count and yeast colony forming units were determined in rye malt samples. The obtained results showed that the increasing of copper and selenium concentration in solution significantly changes microflora of rye malt comparing with the control sample.
Show more [+] Less [-]Characteristics of wood chips from logging residues and quality influencing factors Full text
2013
Gruduls, K., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Bardule, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Zalitis, T., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
The aim of this paper is to characterize and ascertain quality influencing factors of wood chips produced from forest residues in clear-cuts. The quality of food fuels varies according to the harvesting season, site characteristics and silvicultural treatment. For this study 89 piles of logging residues from clear-cuts located in Western part of Latvia were used. Piles were stored in different parts of clear-cut according to its direction against nearby stand. Piles of logging residues were pre dried and then chipped. A period of chipping and sample acquisition was from February to May of the year 2012. Results show that chips from forest residues can be successfully used for medium scale boilers. Chips with lower carbon content, calorific value, relative moisture and bulk density of wet chips can be produced in May. Location of the pile in centre and SE part of the clear cuts can decrease resulting ash content in wood chips.
Show more [+] Less [-]Rheological properties of triticale (Triticosecale wittmack) flour blends dough Full text
2012
Sabovics, M., Latvia Univ. of Agriculture, Jelgava (Latvia) | Straumite, E., Latvia Univ. of Agriculture, Jelgava (Latvia)
Triticale is an amphidiploid hybrid between wheat and rye having protein-rich grain. For expanding the range of bakery and pastry production in the world there are being developed various recipes for product enriching with fibre, especially b-glucan, proteins, vitamins and other nutrients for a healthier diet. It can be done making a flour blend from whole grain triticale, rye, hull-less barley, rice and maize flour. The aim of research was to evaluate the rheological properties of dough made from different cereals flour and flour blends. Whole grain flour of triticale, rye, hull-less barley, rice, maize and flour blends were used in this research. Flour blends were made from triticale in a combination with other flour (whole grain rye, hull-less barley flour, rice and maize flour) in various proportions. Wheat flour (Type 405) was used as a control. Rheological properties of mixed flour dough were studied using Farinograph (Brabender Farinograph-AT, GmbH and Co. KG, Germany). Moisture content of flour and flour blends was determined using AACC method 44-15A. Water absorption and dough development time decrease, but dough stability, time of breakdown and farinograph quality number increases, increasing proportion of other flour in triticale flour. The flour blends need less time for dough development comparing with triticale flour. Enriching triticale flour with whole grain rye, whole grain barley, rice and maize flour in various proportions made triticale flour dough more rheologically stable during mixing.
Show more [+] Less [-]Influence of packaging conditions on the quality of pickled venison Full text
2012
Silina, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Gramatina, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
Venison is well known as a traditional meat type in Europe, and it is lower in calories, cholesterol and fat content than common cuts of beef, pork or lamb. The aim of the current research was to determine physico-chemical parameters such protein, fat, pH, moisture content as well microbiological quality of pickled venison during storage. Beef as a control was analyzed for comparison of obtained results. The meat (2×3×2 cm) pieces were pickled in vinegar marinade (composition: tomato sauce, mayonnaise, vinegar, lemon, onion, parsley, paprika, basil, black pepper, rosemary, salt) at 4±2 °C temperature for 48±1 h. The marinated meat was placed in polypropylene trays and hermetically sealed with high barrier polymer film under modified atmosphere (C02 40%+N2 60%) without and with iron-based oxygen scavenger sachets (Mitsubishi Gas Chemical Europe Ageless®). As a control, packaging in air ambiance packed pickled products was used. During storage time, the moisture and protein values significantly (p is less than 0.05) decreased and pH, fat content and colony forming units significantly (p is less than 0.05) increased in the pickled venison samples of all packages. Slower changes in pH of pickled venison and in the protein and moisture content of marinated beef were observed in modified atmosphere with oxygen scavenger during storage.
Show more [+] Less [-]Solid fuel boiler automation for briquette use Full text
2012
Komass, T., Latvia Univ. of Agriculture, Jelgava (Latvia)
Nowadays all engineering technologies are based on the automation, but still there are some processes that are not easy to automate. One of them is the heating process using solid fuel boilers. The paper deals with automated double-link air flow control of the combustion process. The research target was to find more effective solutions of furnace air flow regulation to improve the combustion process efficiency. The research object was a 56 kW wood briquettes water heating boiler. The results of the experiment research show a higher efficiency of the combustion process with double-link air flow PI control using motor valves.
Show more [+] Less [-]Research of 'duration of load' effects in timber elements in bending Full text
2012
Brokans, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
The Duration of Load (DOL) effect is the combined influence of the mechanical loading history and climatic history on the strength of materials. DOL effect is one of the most important characteristics of wood and wood-based materials. The material degradation or damage induces strength reductions. Creep is one of the most important effects of DOL. Creep is a phenomenon that negatively affects functional compliance, behaviour and strength of timber structures in extended years of exploitation. The creep phenomenon is affected by surrounding temperature, relative humidity, timber moisture content and other factors. The study aimed to establish a correct factor system for accurate prediction of long-term deformations of timber structures that is corresponding to environmental conditions and timber properties in the region of Latvia. The experimental research was made in Jelgava, Latvia, and represents timber beam four-point long-term loading in bending with variable cross section height-span length ratio under uncontrolled climatic conditions. There were 12 timber beams with two different span lengths – 1.32 m and 1.50 m used. The timber beam cross section dimensions: height – 60 mm, width – 30 mm. The timber beams were not dried and the moisture content at the start of the experiment varied from 19% to 33%. The applied load values – 0.40 kN and 0.31 kN. Moisture content fluctuations and negative air temperature accelerated creep development and intensity. Prediction of final long-term deformations should rate not only the type of timber material and service class but the strength class, too.
Show more [+] Less [-]Comparison of different solvents for isolation of phenolic compounds from horseradish (Armoracia rusticana L.) leaves Full text
2013
Tomsone, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kruma, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
Horseradish (Armoracia rusticana L.) is a perennial herb belonging to the Brassicaceae family and contains biologically active substances. The aim of the current research was to determine the most suitable extraction method and solvent for obtaining horseradish leaf extracts with high antiradical activity. For experiments fresh leaves of horseradish were extracted with seven different solvents: n-hexane, diethyl ether, 2-propanol, acetone, ethanol (95%), ethanolwater/acetic acid (80/20/1 v/v/v) and ethanol / water (80/20 by volume) using two extraction methods (conventional and Soxhlet). For all extracts, total phenolic, flavonoid content and DPPH˙, ABTS radical scavenging activity, and reducing power were determined using a spectrophotometric method. As the best solvent can be used ethanol. Total phenolic content and total flavonoid content was higher in Soxhlet extracts. Comparing to other plants, the proportion of flavonoids in the amount of total phenolics is average, and it increases by increasing the polarity of used solvent. It can be concluded that by using Soxhlet extraction method it is possible to obtain extracts that are effective antioxidants. A very strong and a strong correlation has been identified between levels of phenolic compounds and antioxidant capacities of the extracts.
Show more [+] Less [-]Investigation of physically-chemical parameters of conventional and organic hull-less barley harvested in Latvia Full text
2013
Kalnina, S., Latvia Univ. of Agriculture, Jelgava (Latvia) | Rakcejeva, T., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kunkulberga, D., Latvia Univ. of Agriculture, Jelgava (Latvia)
The main purpose of the research was to investigate the physically-chemical parameters of organic and conventional hull-less barley (Hordeum vulgare) harvested in Latvia. In the experiment the following hull-less barley harvested in 2012 from the State Priekuli Plant Breeding Institute (Latvia) was used: ‘Irbe’, PR4651, PR3808.21 and PR5099. The following quality parameters of grain – protein, starch, the bulk density and β-glucan content – were measured by standard methods – Infratec™ 1241 Grain Analyser (Denmark) corresponding to ISO 12099; thousand-grain weight (TGW) (ISO 520:2010); the falling number (ISO 3093:2009); moisture content (LVS 272:2000) were also determined. In the present experiments no significant differences in protein, moisture, starch, β-glucan content and TGW were detected, however, significant differences in the bulk density of all analyzed hull-less barley samples were established. The lower analyzed parameter value of 780 ± 1 g LE-1 was obtained for the conventional and organic hull-less barley PR 5099. However, the higher bulk density value of 821 ± 1 g LE-1 was obtained in the conventional hull-less barley variety ‘Irbe’. No significant differences in the bulk density of conventional and organic hull-less barley ‘Irbe’, PR4651 and PR3808.21 were found. Significant differences in the falling number were detected in the analyzed hull-less barley samples harvested in the conventional and organic farming. The lower falling number value was obtained in the organic hull-less barley line PR 5009 – 81 ± 4 s, the higher in the conventional and organic hull-less barley line PR 3808.21 as 362 ± 5 s and 373 ± 2 s, respectively.
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