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The influence of enzymes applied on processed sugar beet bulbs on the quality of saturated juice
Langrová, Petra ; Pulkrábek, Josef (advisor) ; Ilona, Ilona (referee)
The thesis focuses on the determination of dextran presence and its potential amount in sugar made semi-products. Dextran is a polysaccharide which is created on a sugar beet tuber due to inappropriate storing, because of low temperatures or wound of beet tissue, which is subsequently prone to infections caused by Leuconostoc mesenteroides microorganism. The infection results in creation of polysaccharides and other secondary products which have a negative influence on technological processing of beet. Levan and dextran create the highest amount of these polysaccharides in sugar beet. They significantly increase the viscosity of sugar juice. It is subsequently seen on crystallization of calcium carbonate during the second saturation and this causes the deterioration of filterability. In case of dextran or other polysaccharides presence other problems arise in the technological process of sugar production. For its elimination enzymatic hydrolysis is used with the aid of dextranase or alfa amylase. This element splits dextran polysaccharide into smaller oligosaccharids which are not caught in filtration device and therefore do not cause reduction in production capacity. Commercially accessible dextranase; however, is financially demanding so that there are researches trying to find more economical ways. This diploma thesis evaluates the presence of dextran in extracted juice by means of ICUMSA GS8-19 (year 2009). The method evaluates the presence of dextran in diffused, heavy and II. saturated juice. The research was focused on determination of alkalinity, pH, sedimentation and filtration coefficient, polarization, sugar content and purity. The aim of this thesis is to evaluate the correlation between recorded numbers and the application of the two enzymes which are used for removal of these problems. After completion of the experiment and evaluation of measured results in operating laboratory of sugar factory Tereos TTD Dobrovice, connection among laboratory measured data was not proved. Our recorded data did not prove reciprocal relation. The only proved connection was about number of rinsed filters (per day) after II. saturation and amount of used enzymes. The amount of enzymes influences how many times per day filters must be rinsed in order to get rid of deposit. In case of high amount of dextran, filters started to be clogged by impervious layer of molecules and in case that enzymatic way was not used for elimination of this saccharide, the only solution was frequent filters rinsing or reduction in working capacity connected to subsequent prolongation of processing campaign.
Further, we proved the efficiency of alfa amylase which was used during beet processing (after New Year). This enzyme had the same impact on elimination of polysaccharides and clearance of filters. It is to say that in following campaigns it is possible to substitute financially demanding enzyme for cheaper alfa amylase.
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Influence of soil compaction on production parameters of sugar beet
Balák, František ; Pulkrábek, Josef (advisor) ; Milan, Milan (referee)
The methods of autumn tillage in sugar beet are still oriented mainly on classic cultivation, which is based on ploughing. Minimalization methods have recently appeared in sugar beet as well, mainly due to their anti-erosion effect. This thesis deals with question, whether is the minimalization tillage able to match classic cultivation in its positive effect on soil fertility. To compare the effect, penetration resistance has been measured, as it serves as an indicator of field compaction, which should be alleviated by autumn tillage. Aim of this thesis is to measure the effect of soil compaction on soil cultivated by ploughing or deep chiseling in a particular area of sugar beet and to assess the impact of soil compaction on its production.
Research has taken place in semi-practice experiments in fields in the vicinity of Jičín in years from 2012 to 2015. Measured field parameters were soil penetration resistance and soil wetness. Rated parts of vegetation have been manually harvested in technological maturity and from sampled tubers has been determined yield, sugar content and other quality parameters. Tested fields were medium compacted, penetration resistance to 40 cm was in average between 3 to 4 MPa, depending on tillage quality and on sampling date. Ploughing and deep chiseling managed to provably alleviate soil compaction and thus considerably helped to setup sugar beet vegetation well. Yield and qualityparameters were very good, yield of tubers reached in average 95 t.ha-1 and the sugar content 18,7 %. Yield of polarization sugar reached in average 17,8 t.ha-1.
As the research has shown, autumn tillage by deep chiseling is in its soil loosening effect comparable with ploughing and even exceeds it a little in its influence on vegetation quality. Good autumn tillage raises values of all yield factors and quality parameters. Between basic parameters of yields were found no statistically significant differences for the two autumn tillage methods. In the yield of polarization sugar per hectare was found a statistically significant difference of 1,5 % for the benefit of deep chiseling.
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Utilization of predatory mite Typhlodromus pyri Scheuten within IPM and organic hop growing
Nesvadba, David ; Pulkrábek, Josef (advisor) ; Kamil, Kamil (referee)
The objective of my work was to evaluate the efficiency of a native species of predatory mite Typhlodromus pyri Scheuten against two-spotted spider mite (Tetranychus urticae Koch) within IPM and organic hop growing and to find out if hop protection against T. urticae with the help of T. pyri can replace conventional hop protection based on miticides and if it can be profitable.
The trials were carried out since 2011 till 2015 in three hop gardens at a research farm Stekník, which belongs to Hop Research Institute in Žatec (Saaz). The first experimental hop garden, where IPM is practiced, is called Černice I. The other one BIO is, as the name says, under organic regime. The third one called Kaplička (Little Chapel) I., served as a reference one because hop is grown there under a common conventional system with the use of miticides to control T. urticae.
In regular intervals since the time when the first spider mites were observed at hop leaves till the harvest fifty leaves were sampled (17 from lower, 17 from middle and 16 from upper parts of hop plants) in the hop garden with IPM regime and in the organic hop garden. Population densities of eggs, mobile stages of T. urticae and T. pyri were assessed together with nymphs of predatory Thrips of the genus Aeolothrips, which occurred there naturally as the dominant native acarophagous predators. The results were statistically evaluated with the help of correlation analyses and t-test for independent groups. Efficiency of T. pyri and economical comparison with chemical protection were made as well.
It is possible to conclude that after release of predatory mites and under using of selective pesticides the biodiversity is higher. Hop protection against two-spotted spider mite with the help of T. pyri can be profitable and it can replace chemical protection against this dangerous pest for many years. T. pyri is commonly more efficient if population density of T. urticae is lower. The tightest dependence at the level of 90% was statistically confirmed between occurrence of T. urticae eggs and its mobile stages. Statistically important difference was found out between the two different types of hop growing in the most of the cases.
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Evaluation of creation of yield parameters of Kazbek and Saaz Late cultivars
Štefanová, Lucie ; Pulkrábek, Josef (advisor) ; Jaroslav, Jaroslav (referee)
Hops has been grown in Saaz region for 700 years. The first written mention about local hop garden comes from 1348, but it is certain that the hop gardens were owned by brewers and church dignitaries even earlier. First, hops was grown on the monastery grounds on a large scale. Czech, and thus Saaz hops, reached its peak in the 19th century, mainly for its fragrance, color and kontent of lupulin, and became a benchmark for determining the quality and price of hops.
Kazbek is the first variety of "flavour hops" bred in the Czech Republic. Its unique sensory properties were examined with numerous brewing tests in several breweries of different sizes. Breeding of "flavour hops" is a real challenge for hop breeders. The first hop in that category, for example Citra, Amarillo, Simcoe, Bravo, were bred in the United States. Variety Kazbek was obtained by selecting progeny of the hybrid material, which has origins in Russian wild hops. It was registered in 2008 due to high stability and efficiency. Robustness and stability is expressed in the name of the variety, because Kazbek is the highest mountain of the middle Caucasus. From the brewing point of view, it belongs among the bitter types.
Saaz Late variety was obtained by selecting F1 offspring of parental combination of unfinished breeding material that is the origin of Saaz. It has a charakter of late variety. Saaz Late is an aromatic variety for the second and third hopping. Aroma is genuine, fine, hoppy.
The most important quality aspect of hops is alpha acids content. Content of alpha acids has been reagularly assessed since 1981. The evaluation results show, that the alpha acids kontent in varieties Saaz Late and Kazbek is proven statistically different.
Selection of suitable location is the key element for cultivation of hybrid varieties. It is very important to focus on the evaluation of natural conditions of each location. This paper shows that there is no statistically significant difference between locations Stekník and Blšany.
Optimal temperature for growth and subsequent yield formation should not drop below +7 °C in April, +11 °C in May and from June to August should range between +15 and +18 °C. The stability and balance of temperature is also important. Precipitation has a bigger
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impact on yield formation than temperature. This statement was confirmed in 2015, when tropical temperatures and drought during the flowering and cone formation caused significant decrease of yield. Low yield level
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Integrated system of hop cultivation
Krofta, Karel ; Ježek, Josef ; Klapal, Ivo ; Křivánek, Jindřich ; Pokorný, Jaroslav ; Pulkrábek, Josef ; Vostřel, Josef
Certifikovaná metodika shrnuje zásady integrovaného způsobu pěstování chmele. Pěstitelský proces je veden snahou o prevenci a potlačení výskytu škodlivých organismů podporou užitečné entomofauny. Navrhovaná opatření směřuji ke zvýšení půdní úrodnosti, schopnosti půdy vytvořit optimální prostředí pro kořenovou soustavu rostlin chmele a během celé jejich vegetační doby jim zajistit dostatečné množství živin, vzduchu a vody pro jejich růst a vývoj, směřující k maximální produkci chmelových hlávek. Ošetřeni pesticidy se provádí jen v nezbytně nutném rozsahu až po dosažení prahu hospodářské škodlivosti. Zásady integrované produkce chmele jsou aplikovatelné v klasických vysokých konstrukcích i systému pěstovaní chmele v nízkých konstrukcích.
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