Sirvi Autor "Sterna, V." järgi
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Kirje Application of microwave and infrared treatment to reduce antinutrients in lupine seeds(Estonian University of Life Sciences, 2025) Sterna, V.; Jansons, I.; Jansone, Z.; Zhylina, M.Lupins are group of legumes that produce seeds containing up to 40% protein, making them an excellent source of food or feed. However, the nutritional value of legumes can be adversely affected by the presence of various anti-nutrients, including phytic acid, alkaloids etc. The aim of this study was to evaluate the potential of microwave and infrared radiation to reduce the levels of anti-nutrients - alkaloids and urease activity - in lupine seeds. The seed treatment was carried out using two different applications - microwave with time regimes 2 minutes or 6 minutes and infrared toplight with time regimes: 10 minutes at 25 °C and 30 minutes at 35 °C. Content of protein, fat, amino acids, alkaloids and urease activity were determined. The results show that in the samples of lupins the alkaloid content decreased from 0.07% to 0.05% after 6 min of microwave treatment and from 0.07% to 0.03% after 10 min of infrared treatment. Concluded that both treatments reduced the content of alkaloids and urease activity in lupine seeds, without significantly changing either the protein content or the amino acid composition and can be used for antinutrient reduction without loss of nutrients.Kirje The effect of growth stimulants based on humic acids from Ukrainian lignite and biochar from agricultural residues on the growth and development of lettuce (Lactuca sativa)(Estonian University of Life Sciences, 2025) Zhylina, M.; Karnozhytskyi, P.P.; Miroshnichenko, D.; Konohrai, V.; Sterna, V.; Ozolins, J.Significant amounts of plant-based waste are generated annually in the agricultural and food industries, including straw, corn residues, nutshells, and fruit pits. Disposing of this waste often relies on basic methods that avoid further processing, presenting an urgent environmental challenge. One efficient solution is converting biomass into biochar, which serves as a soil amendment. Developing cost-effective recycling methods has become critical with the increasing scarcity and rising cost of raw materials. The Dnipro Lignite Coal Basin in Ukraine offers extensive lignite reserves, enabling the production of affordable, high-quality humates for soil enhancement. In this study, wheat and barley straw were pelletized with barley bran at a 90:10 ratio. Pyrolysis was conducted at 500 °C with a heating rate of 5 °C·min⁻¹ and a one-hour holding time. The resulting biochar was added to a lettuce cultivation substrate at a 1:10 biochar-to-peat ratio. Humic substances derived from lignite were applied in 3% and 9% aqueous solutions, and environmental conditions, such as humidity and temperature, were monitored throughout the 35-day trial. Results showed that granulated biochar increased lettuce rosette diameter by 7.5% compared to perlite substrates and by 11.6% compared to peat. Additionally, 3% humate solutions enhanced rosette diameter by 11.6% and biomass weight by 25.77%. These findings confirm that biochar from agricultural residues and lignite-derived humates effectively boost lettuce yield and quality.Kirje Evaluation of various legume species and varieties grown in Latvia as a raw material of plant-based protein products(2020) Sterna, V.; Zute, S.; Jansone, I.; Ence, E.; Strausa, E.Nutrition value of legumes has been traditionally attributed to its high protein content. Protein content of legumes is variable dependent on different species and varieties, and highly affected by environmental factors. Usually protein quality is characterized by its owns amino acid profile in nutritional point of view. Therefore, the present study was conducted to determine the protein contents and amino acid profiles of pea (Pisum sativum L), faba beans (Vicia faba L) and soya (Glycine max L) grown in Latvia and evaluate their potential for food production. Overall results of a five-year analysis (2013–2017) showed that the protein content of peas, faba beans and soybean ranged from 20.0 to 26.1%, 26.6 to 30.5% and 35.9 to 40.9%, respectively. The corresponding values of total crude fat ranged from 0.8 to 1.2%, 0.7–1.3% and 16.6 to 19.3%, respectively. Results of study showed that the protein content of peas, faba beans and soybean was not differed by growing system (p < 0.05). The percentage of essential amino acids for pea, faba bean and soya were 34 to 38%, 57 to 59% and 62 to 64% respectively. The composition of pea flakes was preserved protein content of raw material. The pea flakes has high content of lysine of 10.1 g kg-1 , phenylalanine+thyrosine of 11.6 g kg-1 and the sum of essential amino acids of 66.4 g kg-1 . In nutritional point of view, pea flakes could be product with high-quality proten composition.Kirje Influence of local extruded soybean cake and imported soybean meal on fattening pig productivity and pork quality(2020) Jansons, I.; Degola, L.; Sterna, V.; Zute, S.The aim of this study was to determine the influence of feeding local and imported soybean protein feeds to fattening pigs and examining it impact on the quality of pork. The trial was created with 40 pigs divided in two groups (20 in each). Pigs in the control group received imported soybean meal, in the trial group local farm grown in Latvia extruded soybean cake mixed in the compound feed. The diets were designed to be nutritionally equivalent. For fattening pigs each diet were available on an ad libitum basis to pens. During the study pigs were weighed three times at 84, 140 and 190 days at age. Feed consumption, pig carcass traits and meat chemical composition were determined. The final live weight in control group was 108.33 ± 2.904 kg and in trial group was 111.88 ± 2.793 kg there were no significant difference (P > 0.05). Average daily live weight gain in the all experimental period in control group was 0.779 ± 0.096 kg and in trial group was 0.822 ± 0.103 kg, there were no significant difference (P > 0.05). Feed consumption per kg of live weight in control group was 2.39 kg in trial group was 2.24 kg. Pig carcass traits and meat chemical composition were similar for both groups without significant differences (P > 0.05). Soybeans grown and processed in Latvia were equivalent to imported soybeans and gives good rates of pig growth and quality of pork.Kirje The nutrition value of soybeans grown in Latvia for pig feeding(2019) Degola, L.; Sterna, V.; Jansons, I.; Zute, S.Soybean products are excellent sources of protein for pigs because their amino acid profiles complement those of cereal grains. Soy protein is rich in the limiting amino acids lysine, threonine, and tryptophan that are present in relatively low concentrations in the most commonly fed cereal grains. Amino acids in soy protein are more digestible than amino acids in most other plants proteins, which results in less nitrogen being excreted in the manure from pigs fed diets containing soybean meal than if other protein sources are used. The phosphorus in soy products is bound to phytic acid, which has a low digestibility to pigs, but the digestibility of phosphorus in soy products may be increased to more than 60% if diets are supplemented with microbial phytase. There are no much results about nutrition value of soybean growing in Latvia. Therefore the aim of study was determined chemical composition of soybeans growing in Latvia and evaluates their potential in pig feeding. Research object were soybeans growing in Latvia. In the studied samples content of protein, fat, ash, fibre, composition of amino acids were determined and metabolizable energy were calculated. Evaluated that protein content varied from 32.7 till 40.7%, fat content was from 18.4–21.4% and significantly differed (p < 0.05) among growing places, but the sum of essential amino acids in the soy beans determined 115–125 g kg-1 , and were not differed significantly by varieties. The content of lysine in protein were determined 5.1–5.5 g 100 g -1 . Concluded that soy bean growing in Latvia provides equilibrium high metabolizable energy for pigs – from 13.2 to 17.6 MJ kg-1 and could be used in feed.