Growing interest of consumers in healthy eating has provided the development of new range of food. Therefore the task of research was to determine the nutritional value, calculate energy value and investigate the sensory properties of yoghurt samples enriched with flakes from biologically activated hull-less barley grains and malt extract. Results showed that by adding flakes from biologically activated hull-less barley grain and malt extract it was possible to improve the nutritional value of yoghurt, i.e., increased protein, carbohydrate and decreased fat content. The energy value of yoghurt samples enriched with flakes from biologically activated hull-less barley grain and malt extract ranged between 65.96 and 75.72 kcal 100 gE-1, which is significantly lower comparing with mean energy value of commercial yoghurts. The changes of sensory properties were affected by the amount of added malt extract in yoghurt samples. The optimal amount of added malt extract for sensory evaluation in yoghurt samples was determined as 2%. The content of carbohydrate in yoghurt sample enriched with 5% of biologically activated hull-less barley grain and 2% of malt extract was two times lower than commercial yoghurts therefore its energy value was significantly lower. Yoghurt enriched with flakes from biologically activated hull-less barley grain and malt extract could be competitive.

Products of organic origin used in agriculture to reduce the application of artificial pesticides and fertilizers are investigated world-wide now. Composting organic fertilizers, plant residue and household waste, results in new products of organic origin. In several countries (USA, Russia, Belorussia, and some others), the role of earthworms in organic waste processing and the possible further use of this processed product have been investigated. In Latvia, similar investigations are few but they are needed. A goal of our investigation was to investigate the impact of extracts made from the products of organic origin on potato (Solanum tuberosum) tuber yield in biological crop production system. A field experiment was established at the State Stende Cereals Breeding Institute in 2011, using an early-maturing potato variety ‘Borodjanskij Rozovij’ suitable for growing both in conventional and organic production systems. Tubers or plants were treated with peat elixir and earthworm bio-humus extract obtained at different temperatures: +45 °C and +95 °C, and their mixtures. In total, 18 treatments and untreated control variant were included in the experiment. Tubers were treated just prior to planting, but potato plants were treated three times in season. In the first production year, the obtained potato tuber yield ranged 26.16-45.38 t haE-1 in treated plots, and 35.27 t haE-1 in untreated control plot. Data were subjected to analysis of variance. In 2011, tuber yield was significantly dependent on organic extracts applied, which increased the yield significantly (p is lee than 0.05) in four treatments, but in the rest of them significantly decreased if compared to control.

Agricultural farms in modern production system are specialized; therefore, animal-origin organic fertilizers are not available for many of them. Researches on the use of organic products in agriculture to restrict the use of pesticides and mineral fertilizers have been performed for a long time. Nowadays different organic preparations that are acquired as a result of complex processes are produced, ensuring ready-to-use biologically active substances in them and also activating their properties. One of the purposes of the research was to evaluate the impact of extracts from organic products on the potato (Solanum tuberosum) yield and tuber quality in the conventional cultivation system. A field experiment using cultivars ‘Borodyansky Rozovij’ (early maturity) and ‘Lenora’ (mid-early maturity) was arranged in the State Stende Cereals Breeding Institute in 2011 and 2012. Peat elixir and vermicompost extract obtained at different temperatures: + 45 °C and + 95 °C, as well as a mixture of these extracts were used for treatment of tubers and plants. The research included 24 treatments in total, including control (without treatment) and a standard potato cultivation technology. Tubers were treated immediately before planting, but plants were treated three times during the vegetation period. Average two-year research results showed that the use of organic product extracts significantly (p is less than 0.05) affected the tuber yield in different treatments for both cultivars ‘Borodyansky Rozovij’ and ‘Lenora’. The content of nitrates in tubers, using extracts, did not exceed the allowable level (160 mg kgE-1) in any of treatments.

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.

There is growing interest in products without added sugar; thus, sugar consumption is directly related to diabetes and other illnesses such as obesity. A change in the type of sugar and content may therefore both change the perception of sweetness and texture of products. The aim of the research work was to evaluate properties of agar-agar jellies prepared with inulin syrup, galactose syrup and malt extract to replace sugar. Agar gels were prepared to substitute sugar with inulin syrup, galactose syrup and malt extract. Texture of experimental samples was determined by using a Texture Analyser (Model TA.XT Plus; Stable Micro Systems). Colour of jellies was evaluated by using Colour Tec-PCM and Jenway 3510 was used for pH measurements. Obtained results showed that different kinds of sugar containing syrups could be used as sugar substitute for production of a new type jellies. Hardness of the experimental samples is influenced by the sugar type containing syrup. The hardness is determined in the experimental samples by replacement of sugar by increasing concentration of inulin syrup. Decreasing hardness values are observed by increase of added malt extract (maltose) and galactose syrup concentration in samples. The pH values of experimental samples ranged between 3.11 and 4.45. Higher L* value of experimental samples are with galactose syrup. Lightness “L” changed between 20.92 and 18.11 increasing inulin syrup concentration. The same situation can be observed using malt extract as sugar substitute.

The composition of extracts isolated from black alder bark by ‘green’ microwave assisted water extraction in the temperature range of 70–150 °C was studied using the wet chemistry Folin-Ciocalteu method and Py-GC-MS/FID. The composition data were compared with those of the extracts obtained at the same temperature by accelerated solvent extraction (ASE) of bark. It was shown that microwave assisted extraction, compared with ASE, resulted in more significant transition of major cell wall components, including hemicelluloses and phenolics of lignin origination, into the solution. Depending on the microwave assisted extraction regimes, products with different portion of major cell wall components and secondary phenolic metabolites can be isolated that enlarge the possibilities of products valorisation. Thus, a significant promotion of secondary phenolic metabolites’ transition into extracts as a result of microwave extraction was observed at 70 °C. At that time the relative portion of carbohydrates in extracts was increased at high temperature extraction, combining dynamic and isothermal microwave heating. Water extraction of black alder bark in a microwave extractor revealed 25–50% lower specific energy consumption and 1.8–2.6 times higher productivity in comparison with the conventional extraction, that is beneficial in view of the upscale and practical application of this innovative biomass processing.

The present work aimed to evaluate the effect of sea buckthorn (Hippophae rhamnoides) extract on Cryptosporidium spp. invasion in calves. Sea buckthorn is a good source of vitamins, carotenoids, organic acids and tannins. It has been reported that it possesses anti-inflammatory effect, as well as anthelmintic and antibacterial activity. Research was conducted in a dairy cattle farm ‘Mežacīruļi’ during April and July 2015. Experimental (n = 10) and control (n = 10) groups of calves were used. The experimental group received a mix of aqueous alcohol sea buckthorn leaf and berry pomace extract, administered with milk, at dose of 5 – 8 mL twice a day for 20 days. The control group received only milk. Samples were analysed with the concentration McMaster technique. The results showed that there is no significant (p is greater than 0.05) difference in the number of oocysts per gram of faeces between the experimental and control groups. It was concluded that the administration of sea buckthorn leaf and berry pomace extract had no effect on Cryptosporidium spp. invasion in calves. Studies will be continued with a higher dose of extract.

Kvass is a non-alcoholic beverage produced by fermenting kvass mash with yeast; alcohol content in kvass must be less than 1.2% by volume. Kvass extracts have longer shelf-life and they are essentially free of ethanol. The aim of this research was to evaluate and compare aroma compounds in naturally fermented kvass and kvass extracts. Experiments were carried out at the Latvia University of Agriculture, Department of Food Technology from November 2014 to February 2015. Three commercially available kvass samples (Bruveris, Bauskas and Liepkalni) were used to produce kvass extracts applying vacuum evaporation. The investigation of volatile compounds in kvass and kvass extracts was performed using solid phase microextraction and gas chromatography mass spectrometry. Dry matter content in kvass extracts was 32.4 ± 0.3% (ISO 2173:2003). In all kvass and extract samples in total 25 volatile compounds were detected. Ten of them were esters, five alcohols, five acids, four aldehydes and three ketones. Such aroma compounds as ethyl acetate (fruity flavour), hexyl acetate (fruit, herb) and ethyl decanoate (grape) were found only in Bruveris kvass, 2,3-butanedione (buttery) and phenethyl butyrate (floral) were found only in Bauskas alus kvass and three volatile compounds were identified only in Liepkalni kvass – acetic acid (sour), furfuryl alcohol (burnt) and carvone (caraway). Less than a half of the main aroma volatiles in kvass were also identified in kvass extracts and total values of peak areas were significantly lower in kvass extracts compared to kvass (p = 0.01).

One of the main objectives for the Baltic Sea regions is the harmonisation of the economic development and environmental sustainability. The identification of knowledge-intensive bioeconomy as one of the primary fields of the strategy for smart specialization (RIS3) in Latvia indicates the transition to sustainable and climate neutral approach for the development of Latvia. The strategy aims to promote a more sustainable and efficient use of natural resources, to create high added value, to promote coordination of export and economic interests with environmental protection. This is a multi-faceted and complex process. A scientifically sound approach is needed to develop the most appropriate solutions. The article examines algae biomass as a potential for renewable resources in the agriculture of Latvia in the context of sustainability. The research is aimed at exploring the potential of the Baltic Sea algae as a sustainable agricultural resource in Latvia, focusing on its impact on cultivated plants during the study. The potential is being assessed by conducting a practical study in two stages. The results of the study confirm the potential use of Baltic Sea algae as an agricultural resource in Latvia, which requires further evaluation of the effect of the liquid digestate fraction on crop green mass to determine its potential applicability in agriculture using algal biomass.

Two approaches to incorporating black alder (BA) bark extractives-derived polyol into a polyurethane (PU) network were studied. In the first case, fractionation of bark extractives with tetrahydrofuran (THF), focusing on isolating the biomass fraction available for obtaining PU elastomers by casting methods using cyclic ethers as a solvent, was employed. Another approach aimed to obtain liquid bio-polyols that could be suitable for producing rigid PU foams. For this purpose, oven-dried crude BA bark water extracts were liquefied with polyethylene glycol (PEG 400) at temperatures of 130–170 °C. The effect of adding sulfuric acid as a catalyst on biomass processing was studied. Wet chemistry, GC, FTIR spectroscopy, analytical pyrolysis (PyGC/MS/FID) and rheological methods were employed to characterize the obtained polyols and insoluble fractions, enabling an assessment of biomass transformation during processing. The resulting THF-soluble fraction comprised 62% of the BA bark extract, mainly consisting of the xyloside form of the diarylheptanoid compound oregonin, along with oligomeric flavonoids and carbohydrates. The THF-insoluble fraction was most enriched with carbohydrate compounds. Moreover, it was observed that the PEG 400-insoluble fractions were predominantly composed of carbohydrate components. The results indicated that the use of sulfuric acid as a catalyst (1–1.5% of solvent) promotes the complete liquefaction of extractives, enabling biomass content in polyols of up to 15–25%. Surpassing the extract content in the starting suspension up to 30% resulted in incomplete liquefaction of biomass. These findings offer valuable insights into tailoring BA bark extractives as building blocks suitable for obtaining PU materials.