|
|
The basic chemical parameters of berries from some black currant cultivars
Sailová, Genar ; Vítová, Eva (referee) ; Hrstka, Miroslav (advisor)
This thesis deals with the chemical analysis of the juice from fruits of cultivated varieties of blackcurrant (Ribes nigrum L.) The theoretical part is dedicated to botanical characteristic of black currant including the origin and the extension. There are also mentioned the history of cultivation currant and breeding of the varieties of black currant. Chemical composition of currant is also described in this part. In the experimental part some basic chemical parameters (yield of juice, soluble dry matter content, dry matter general content, pH, titratable acidity, formol number and reducing saccharides content) of four black currant cultivars were determined.
|
|
|
Analysis of juices of selected blackcurrant varieties
Kaniová, Lenka ; Hrstka, Miroslav (referee) ; Vespalcová, Milena (advisor)
The work deals with the chemical analysis of juices selected varieties of black currant (Ribes nigrum L.). The theoretical part is divided into three main chapters. In the first chapter there are short botanical characteristics of black currants, content of biologically active substances in fruit and utilization of black currant fruit in food industry. In the second chapter there are characteristics, importance and methods of determination of phenolic compounds. Vitamin C is describe in the last chapter, its characteristics, importance and methods of determination. Experimental part describes determination of three chemical characteristic of black currant fruits: content of total phenolic compounds, content of total anthocyanins and content of vitamin C. Twelve modern varieties of black currant were selected for determination. Based on these results, it is possible to deduce the more important varieties. The content of total phenolic compounds was in the range of 326,7–641,4 mg•100 g-1 in all samples. The content of total anthocyanins was analysed in the range from 102,5 to 284,5 mg•100 g-1 in all samples. And content of vitamin C was in the range from 82,0 to 379,1 mg•100 g-1 in all samples. The overall comparison of the varieties of black currant was found, the varieties Ceres, Ben Hope, Ben Lomond, Démon and Ometa are the most promising varieties in terms of the content of the above mentioned compounds.
|
|
| |
|
|
Analysis of juices of selected blackcurrant varieties
Kaniová, Lenka ; Hrstka, Miroslav (referee) ; Vespalcová, Milena (advisor)
The work deals with the chemical analysis of juices selected varieties of black currant (Ribes nigrum L.). The theoretical part is divided into three main chapters. In the first chapter there are short botanical characteristics of black currants, content of biologically active substances in fruit and utilization of black currant fruit in food industry. In the second chapter there are characteristics, importance and methods of determination of phenolic compounds. Vitamin C is describe in the last chapter, its characteristics, importance and methods of determination. Experimental part describes determination of three chemical characteristic of black currant fruits: content of total phenolic compounds, content of total anthocyanins and content of vitamin C. Twelve modern varieties of black currant were selected for determination. Based on these results, it is possible to deduce the more important varieties. The content of total phenolic compounds was in the range of 326,7–641,4 mg•100 g-1 in all samples. The content of total anthocyanins was analysed in the range from 102,5 to 284,5 mg•100 g-1 in all samples. And content of vitamin C was in the range from 82,0 to 379,1 mg•100 g-1 in all samples. The overall comparison of the varieties of black currant was found, the varieties Ceres, Ben Hope, Ben Lomond, Démon and Ometa are the most promising varieties in terms of the content of the above mentioned compounds.
|
|
|
The basic chemical parameters of berries from some black currant cultivars
Sailová, Genar ; Vítová, Eva (referee) ; Hrstka, Miroslav (advisor)
This thesis deals with the chemical analysis of the juice from fruits of cultivated varieties of blackcurrant (Ribes nigrum L.) The theoretical part is dedicated to botanical characteristic of black currant including the origin and the extension. There are also mentioned the history of cultivation currant and breeding of the varieties of black currant. Chemical composition of currant is also described in this part. In the experimental part some basic chemical parameters (yield of juice, soluble dry matter content, dry matter general content, pH, titratable acidity, formol number and reducing saccharides content) of four black currant cultivars were determined.
|
|
|
Enzymatic Reactions in Supercritical CO2
Rochová, Kristina ; Sovová, Helena ; Zarevúcka, Marie
Enzymatic hydrolysis of black current seed oil was carried out in supercritical CO2 (sc-CO2), in continuous flow reactor packed with immobilized enzyme Lipozyme. Black currant seed (Ribes nigrum L.) is rich in alfa- and gama-linolenic acids, bound in triacylglycerols, which have different dietetic effect. Selective hydrolysis allows preparation of fractions with different ratio of the two acids. Effect of reaction conditions (T=30–40°C, P=10-28 MPa) on reaction kinetics, composition of reaction mixture, selectivity and stability of enzyme. Results showed good stability of Lipozyme in sc-CO2. Alfa-Linolenic acid was unbound preferably due to enzyme stereospecificity. Combination of supercritical extraction with enzymatic reaction of extracted oil and subsequent fractionation of reaction mixture in two separators was tested in order to separate desired compounds. Further, stability of several enzymes prepared in our laboratory was tested in sc-CO2.
|
|
|
Enzyme Catalysed Hydrolysis in a Continuous-Flow Reactor
Bernášek, Prokop ; Sovová, Helena
Hydrolysis of black currant (Ribes nigrum) seed oil was carried out in supercritical carbon dioxide medium; the substrates dissolved in CO2 passed a reactor containing immobilised enzyme Lipozyme. Conversion of the fatty acid esters to free fatty acids was examined in dependence on the amount of enzyme in the reactor and on the solution flow rate. A rapid colorimetric method was developed for determination of the sum of free fatty acids in the reaction mixture. Other analytical procedures were applied to perform a more complex investigation of fatty acid composition: partial esters of fatty acids were determined using HPLC and the free alfa- and gamma-linolenic acids were distinguished using LC-NMR.
|
guest ::
