Influence of key factors on the time of initial coagulation of cow’s milk using milk-clotting enzyme of camel origin

P. Panayotov, K. Yoanidu, P. Boyanova, B. Milenk
Abstract. The process of rennet coagulation of cow’s milk, obtained using the milk-clotting enzyme of camel origin was studied. The rate of the coagulation process conducted by enzymes of various origins is also different. Coagulation process was evaluated using chymosin of camel origin. The influence of the amount of milk-clotting enzyme, the amount of calcium chloride and the active acidity (pH) of the milk on the initial coagulation time were defined by conducting a multifactorial experiment with three factors at two levels. The time of the initial coagulation of milk is determined by the use of heuristic methods. Determination of levels of variation was made on the basis of preliminary conducted experiments and in major industrial values. With the help of mathematical modeling the possibility of studying the process of rennet coagulation of milk and the mutual impact of selected technologically significant factors was established. As a result of analyzing the data obtained, very strong influence of active acidity (pH), strong effect of the amount of milk-clotting enzyme and moderate influence of the amount of CaCl on the time of initial coagulation of cow’s milk were established. The values obtained allow for analysis, as well as to 2 predict the course of rennet coagulation of cow’s milk carried by chymosin of camel origin.

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Comparative GC/MS analysis of lavender (Lavandula angustifolia Mill.) inflorescence and essential oil volatiles

T. Zagorcheva, S. Stanev, K. Rusanov, I. Atanassov
Abstract. The composition of lavender inflorescence volatiles and distilled essential oils is significantly influenced by a number of factors, which makes it difficult to perform comparative analysis for larger lavender genetic resource collections and segregating populations. In the present study we test a simple procedure for GC/MS analysis of inflorescence volatiles, including frozen inflorescence sample storage, milling and hexane extraction of volatiles. A comparative GC/MS analysis of volatiles extracted from inflorescence samples and present in the distilled lavender oils derived from single bushes of seven Bulgarian lavender cultivars was carried out. The GC/MS analysis identified a total of 32 individual volatiles including all 11 volatiles included in the lavender ISO Standard 3515. The analysis of three parallel hexane extracts from the same inflorescence samples showed good reproducibility of the determined relative abundances of the analyzed volatiles. The relation of the GC/MS data on inflorescence volatiles with the composition of the distilled lavender essential oils was evaluated through analysis of the volatile recovery rates for the analyzed cultivars. The performed ANOVA test of the variances of the calculated recovery rates of individual volatiles showed that they are significantly influenced by the studied cultivars. The possibilities for application of the applied extraction procedure and comparative analysis of flower and inflorescence volatile compositions for large sets of lavender accessions and segregating populations are discussed.

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Study of bee honey by spectral analysis in the near infrared spectrum

I. Zhelyazkova, S. Atanasova , K. Elencheva – Karaneycheva
Abstract. The objective of the present study is to examine samples of bee honey of different origin and create models for their classification through spectral analysis in the near infrared spectrum. Representative samples unifloral (sunflower, acacia, lime and coriander), multifloral and honeydew honey are used. The origin of the above honey samples has been determined in advance by pollen analysis. The spectral measurement (NIR spectroscopy) of each sample was done non-destructively, by measuring the diffuse reflection of the honey samples using the spectral device NIRQuest 512 within the range 900–1700 nm. The spectral differences between the different types of bee honey have been studied. For classification of the samples based on their spectra the SIMCA method (Soft Independent Modeling of Class Analogy) was used. Models for distinguishing different types of bee honey – unifloral, multifloral and honeydew – have been obtained. The results show 100% accuracy of classification of the samples from the three groups based on the received spectral information. The most compact is the group of honeydew honey.

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Sanitary hygienic assessment of drinking water from underground source at a pig farm

G. Kostadinova
Abstract. The aim of the study was to investigate and assess the quality of drinking water, obtained from own well source at a pig farm (with an average daily number of reared pigs 532 units), situated in South Bulgaria, Plovdiv Municipality, on the base of main organoleptic, physical, chemical and microbiological indices. For this purpose once a month (from July 2009 to March 2010.) water samples were collected and analyzed by reference methods of Bulgarian State Standard. It was found that the quality of water correspond to the norms concerning organoleptic indices (smell – State 0, norm up to State 2; color – 5°color degrees, norm up to 15°color degrees; visibility – over 65 cm thickness of the water plast through that should clearly seen special text, norm at least 30 cm; taste – no flavor, norm no flavor), chemical indices (pH 7.45÷7.75, norm 6.5–9.5; oxidizability 0.72÷2.16 mg O /L, norm up to 5.0 mg O /L; total hardness 2.82÷4.45 2 2 mg Σqv/L, norm up to 12.0 mg Σqv/L; content of chlorides 20.3÷36.0 mg/l, norm up to 250.0 mg/L, ammonia – not proved, norm up to 0.50 mg/L, nitrites 0.007- 0.094 mg/L, norm up to 0.50 mg/L, and nitrates 3.0÷25.0 mg/L, norm up to 50.0 mg/L) and total number of cultivable microorganisms (5 -18 CFU/mL), norm – without significant variability of the index value of the investigated water. The only exception was found for the water temperature, whose maximum values exceeded the requirements of the standard (16 oC) and number of Escherichia coli (Coliform’s test), which values were higher than norm (0 CFU/100 mL), for both indices during five months from the studied period. The deviation in the quality of water in respect content of E. coli suggests anthropogenic pollution on groundwater of the own well with coliform bacteria, containing in manure and urine from the pigs in the farm. Organoleptic, chemical and microbiological characteristics of the sampled water meet the requirements of the Dutch standard for drinking water for pigs. This standard allows higher level of oxygenation of the water and higher levels of ammonium and nitrate content in water compared to Bulgarian standard for humans and animals drinking water. Perhaps time has come, as in the Netherlands to develop a national standard for drinking water, which be applied only to farm animals.

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The influence of organic carbon on bioremediation process of wastewater originate from aquaculture with use of microalgae from genera Botryococcus and Scenedesmus

I. Sirakov, K. Velichkova, G. Beev, Y. Staykov
Abstract. Advantages of using algae for wastewater treatment include: low operational cost, possibility of recycling assimilated nitrogen and phosphorus within the algae biomass as a fertilizer, accumulated biomass for biofuel. Our purpose was to study the influence of organic carbon on bioremediation process of wastewater originate from aquaculture with use of microalgae from genera Botryoccocus and Scenedesmus. Algae cultivation was initiated in a bioreactor of 500ml Erlenmeyer flask containing 250ml wastewater. The experiment was conducted in variants without any organic carbon sources and the other with organic carbon source – glucose (1,125g.l-1). Light regime was adjusted at 15:9 h light:dark cycle in an illumination incubator until the end of experiment. The temperature was kept between 25 and 27oC. The pH varied between 6.5 and 7.5 and by this reason it was not adjusted. Species grown in wastewater with added glucose showed a better cleansing effect compared with the same grown in wastewater without any carbon sources. Better growth indicators and faster absorption of wastewater compounds was observed in S. dimorphus.

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Comparative assessment of plant resources as substrates for bioshlam production

Z. Shindarska, V. Kirov, G. Kostadinova, B. Baykov
It was made a comparative assessment of the main technological parameters of the silages of different types as a source for the production of biogas as well as it was given an assessment to the bioshlam derived from them. For this purpose the following silages were studied: corn silage, sweet corn silage, forest silage and silages of straw and three types of beet (sugar beet, red beet and fodder) in a ratio of 10 : 90%. It was found that the investigated energy resources in terms of the technologically permissible parameters (dry matter, organic matter, macro and micro-elements) can be used as raw materials in the mix for biogas production. The forest silage as a general term which is specific for each forest ecosystem, due to substantial differences in the structure of the biocoenoses as well as in the soil composition, can be an alternative raw material to the energy crops for the production of biogas with dry matter content of 26.68%, organic carbon content – 39.50% and nitrogen content – 1.30%, as the ratio between them is 30,38:1 (C:N). After methane fermentation, a high rate of mineralization of organic matter is observed in all tested materials, expressed by high values in the bioshlam of the main macro-elements (N, K, P, Ca and Mg). Established concentrations of the 8 toxic elements (Cu, Zn, As, Cd, Cr, Hg, Ni and Pb) in the bioshlam, derived from the studied plant materials, are below the critical limit for the soil and plants.

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Productivity of green beans, irrigated at different pre-irrigation soil moisture

R. Petrova, A. Matev, K. Koumanov, B. Harizanova-Petrova
Abstract. The aim of the study was to establish productivity of green bean, variety “Strike” irrigated at different pre-irrigation soil moisture. The field experiment was conducted during the period 2010 – 2012 on the experimental field of Agricultural University, Plovdiv. The tested variants are as follows: 1) no irrigation; variants 2) 3) 4) and 5) irrigated at soil moisture of 60, 70, 80 and 90% of FC. The irrigation rate for each of the variants is calculated to moisten the soil layer 0-60 cm. The type of irrigation is by gravity on short closed furrow. Summary data showed that without irrigation the average yield is 4248 kg/ha, with a range of 1144 kg/ha in dry years to 8393 kg/ha in medium wet years. Best results are obtained by maintaining soil moisture above/up to 80% of FC, and the yield was more than three times higher than that without irrigation and the mean value is 14805 kg/ha, varying from 12046 kg/ha to 16683 kg/ha.

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Feasibility of the use of heat energy from alternative sources for air conditioning in sows facility

K. Peichev, R. Georgiev
Abstract. A heat engineering analysis of the heat flows in a typical housing facility for raising lactating sows was made. The results obtained were used to design a conceptual model for air conditioning (cooling) by a thermally powered cyclic process of an absorption refrigeration machine. Alternatives for thermal powering by a wood pellet boiler and solar thermal array installed on the roof of the sow raising housing facility were proposed and analyzed. An estimate of the energy consumption of the proposed alternatives and the corresponding electrical energy equivalent was made.

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Productivity and economic traits of winter oilseed rape (Brassica napus var. biennis) under the conditions of Dobrudzha

G. Georgiev, G. Georgiev, P. Chamurliyski
Abstract. During the last decade oilseed rape has become a main field crop in Bulgaria. In 2001, about 240 thousand ha were sown with this crop, mainly with foreign varieties and hybrids. The increasing demand and the large market for this oil seed crop has lead to introduction of new varieties of different production potential and economic indices. The aim of this investigation was to study the main economic indices related to yield formation and the production potential of winter oil seed rape cultivars under the conditions of Dobrudzha region. The investigation was carried out during 2009 – 2010 in the trial field of Dobrudzha Agricultural Institute (DAI). A total of 23 cultivars of winter oil seed rape were tested. The materials were obtained from international genetic stock centers and foreign companies: Gatersleben (Germany), Institute of Plant and Genetic Resources (Sadovo, Bulgaria), Limagrain (France), NPZ (Germany) and Novi Sad (Serbia). The trials were performed in three replications according to the Latin square design, the harvest plot area being 10 m2. Variety Rasmus was used as a standard. Yield and productivity elements were investigated. Two-factor dispersion analysis, and variation and correlation analyses were applied for statistical processing of the results, using software XLSTAT Pro. ver 7.0.1. Varieties Ilia and Anna demonstrated high and stable yield during the two years of investigation, reaching 5.12 t/ha and 4.93 t/ha, respectively. The highest values of the trait 1000 seed weight were measured in Kata (4.66 g) and Catalina (4.51 g). Varieties Kata and Branka significantly exceeded the standard Rasmus by number of pods per plant. Kata, Ilia and Branka can be considered suitable initial material for breeding programs aimed at developing new synthetic winter varieties of oilseed rape possessing excellent economic traits and high productivity.

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Evapotranspiration of corngrop for silage

R. Bazitov, A. Stoyanova
Abstract. During the period of 2009–2012 in the experimental field of the Agricultural Institute, Stara Zagora on soil type meadow cinnamon soil was conducted experiment with silage corn first crop. Corn was grown after predecessor wheat – pea mixture. Five options of irrigation regime of maize were examined. It has been found that during the years of prolonged drought when sowing of corn is in non-irrigated evapotranspiration embodiments in the range of 301.5 to 308.4 mm, and in average wet years with uniform distribution of precipitation greater than 350 mm. Under conditions of irrigation evapotranspiration of culture was increased to an optimal embodiment irrigated reaches values 471.4 mm, and an irregular irrigation regime – 397.2 mm and 372.3 mm, respectively, in 60% M, and 40% M. Average for the three years of study, evapotranspiration reaches maximum average values during the second ten days of August – 6.13 mm at the optimal option and 3.76 mm for versions without irrigation in phase tasseling-dark silks, and then at the end of the vegetation gradually decreases and reaches values of 3.70 mm to 2.20 mm.
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