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.

Colour, texture and aroma are the main quality attributes of food influencing consumer acceptability of food products. Colour of the product is one of the factors affecting hedonic evaluation. Strawberry mass for a consumer is characteristic by its distinct red colour. The stability of anthocyanins becomes most significant in the case of colour quality. To investigate colour quality, it is necessary to measure colour, as well as pigment concentration. Fresh and thermally treated strawberry mass was analyzed. Formation and stability of anthocyanins, which is the main colour formation substance of berries, are determined by different factors. Anthocyanin colors can be enhanced and stabilized by the addition of different natural or artificial acidifiers. Data of the research indicate that anthocyanin amount during storage period decreases. After 2 days storage their amount increased, but afterwards decreased, both, in fresh and thermally treated mass. The taste evaluation of strawberry mass was essentially affected by the enhancers added. The aim of research was to analyze the quality parameter – colour of strawberry mass with added acidifier which further could be used in production of different products for the needs of public catering, e.g. in production of desserts. The anthocyanin content in strawberry mass with acidifiers was determined to see the organic acid impact to colour stability. Research shows, that natural enhancers – quince and sea buckthorn juices used in the research, did not substantially affect each other’s pH in the product.

Determination of organic acids in honey samples from Latvian market by high-performance liquid chromatography Honey is a naturally sweet product, which is produced by honeybees (Apis mellifera). Honey is a natural source of antioxidants and has been known to mankind since ancient times. Honey contains approximately 200 different compounds. Organic acids can be used as an indicator to detect the freshness, authenticity and acidity of honey. The aim of this research was to determine and quantify organic acids such as oxalic, L-tartaric, D-quinic, L-malic, L-ascorbic, citric, fumaric and succinic in honey samples from Latvian market u sing high-performance liquid chromatography. The chromatographic separation of organic acids was carried out with PerkinElmer C18 (4.6 mm Í 250 mm I.D, particle size 5 mm) analytical column at the temperature of 35 °C in wavelength at 210 nm. The obtained results showed that the analysed honey samples contain L-tartaric, D-quinic, L-malic, L-ascorbic, citric, fumaric and succinic acids. The concentration of these acids was found to be variable. Oxalic acid was not detected in the analysed honey samples. L-tartaric acid was the main acid in all analysed honey samples.

Progressive type of controlled environment horticulture, such as plant factories, enables the precise control of cultivation environment parameters. The experiments were performed at the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry in the year of 2017. The aim of this study was to evaluate the effects of different irradiance levels produced by solid state light-emitting diodes (LEDs) on nitrates, nitrites and organic acids contents in tatsoi (Brassica rapa var. rosularis), cultivated in the controlled environment chambers. Plants were cultivated under combinations of red (640, 660 nm), blue (445 nm) and far red (731nm) LEDs at photosynthetic photon flux density (PPFD) level of 200 µmol mE-2 sE-1. At the pre-harvest stage, PPFD was increased to 300 µmol mE-2 sE-1 by elevating the fluxes of different spectral components for 3 days. The contents of nitrates, nitrites and organic acids were evaluated. The results propose the metabolic interface between nitrates, nitrites and organic acids in green vegetables, sensitive for lighting conditions. The higher intensity of LED light at pre-harvest stage led to decreased contents of nitrates in tatsoi. The increased intensity of blue 455 nm light led to lower contents of nitrates and higher of organic acids in comparison to red 640 nm. In addition, the increased intensity of red 640 nm led to significantly higher (p≤0.05) contents of nitrites. The target management of LED light spectra and intensity at pre-harvest stage could be used to reduced nitrates and increased organic acids in tatsoi.

A study was conducted to determine efficiency of an organic acids and phytogenic additives on pigs' growth processes and digestive tract microflora. The feed of the control group (C) did not contain the additives. The feed of the organic acid group (A) contained 6 kg of organic acids additive per tonne feed for pigs after weaning, 4 kg per tonne feed for grower pigs, and 3 kg per tonne feed for finished pigs. The feed of the phytogenic additive group (F) contained 0.5% of phytogenic additive per tonne feed for pigs after weaning, and 0.2% per tonne feed for grower and finished pigs. The feed of organic acids plus phytogenic additives group (A+F) contained 6 kg of organic acids additive per tonne feed for pigs after weaning, 4 kg per tonne feed for grower pigs, and 3 kg per tonne feed for finished pigs 0.5% of phytogenic additive per tonne feed for pigs after weaning, and 0.2% per tonne feed for grower and finished pigs. Compared to groups pigs from the group (F) had by 9.7%, group (A+F) - by 8.3 % and from group (A) had by 3.2% higher mass. The bests results of feed conversion were found in the group (A+F) - 2.84 kg, which was by 8.5% less than in the group (C), whereas the group (F) had by 5.1% and group (A) - by 6.7% better results than the control group. The results of Duodenum and Rectum microflora analyses showed that use of organic acid and phytogenic additives reduced mould yeast Staphylococcus sp. colony formed units (CFU gE-1).

A study was conducted to determine efficiency of an organic acids additive on pigs metabolic processes and diggestive tract microflora. The pigs of control group were fed without an organic acids additive. The feed of the trial group piglets contained 6 kg of organic acids additive per tonne feed, for starter pigs - 4 kg per tonne feed, for finished pigs - 3 kg per tonne feed. The study indicated that at the age of 130 days, pig mass in the trial group was 54.08 kg an average, but in the control group - 51.06 kg, which showed that pigs from the trial group had by 6% higher average mass than in the control group (p is less than 0.005). At the age of 160 days, pig mass in the trial group was an average 94.3 kg, in the control group - 90.63 kg; pigs from the trial group had by 4% higher mass than in the control group (p is less than 0.005). Feed consumption for the trial group was by 1% less than in the control group. Average daily gain for the trial group was 0.663 kg, which was by 6% more than for the control group pigs (p is less than 0.005). Feed conversion in the trial group was 3.06 kg, but in the control group - 3.275 kg, i.e. 6.4% higher than in the trial group. Analyses of Jejunum microflora showed that use of acidifier additive reduced Mould colony formed units - CFU amount in 1 g of the trial group sample by 6%. Staphylococcus species amount in the trial group was 500 CFU in 1 g of sample, but in the control group - 40000 CFU, i.e. 80 times more. In the trial group, Lactic acid bacteria CFU amount in 1 g of sample was by 6% higher than in the control group. The results of Rectum microflora analyses showed that Staphylococcus species amount in the trial group was 12000 CFU in 1 g of sample, but in the control group it was by 34% higher.