Monitoring of the influence of yeasts on the chemical and sensory qualities of manufactured wine

Tato diplomová práce se zabývá sledováním vlivu kvasinek na chemické a senzorické vlastnosti vyráběného vína. Cílem experimentální části bylo pomocí metody SPME-GC-MS identifikovat aromaticky aktivní látky v kvasícím moštu a víně odrůdy Hibernal a ve víně Rulandské bílé. U obou odrůd byla při výrobě využita autochtonní kvasinka izolovaná v naší laboratoři z povrchu bobulí odrůdy Hibernal. Bylo zjištěno, že obě vyráběná vína mají při použití naší kvasinky podobný aromatický profil. K dalším cílům patřilo sledování změn chemických parametrů u těchto vzorků s využitím spektrofotometrických metod a metod HPLC. Posledním cílem byla izolace a identifikace kvasinek z vína Rulandské bílé metodou PCR-RFLP a porovnání těchto kvasinek s kvasinkami izolovanými z moštu odrůdy Hibernal. Identifikace byla provedena amplifikací 5,8S-ITS úseků DNA pomocí primerů ITS1 a ITS4 a pro restrikční analýzu byly využity restrikční endonukleázy HaeIII, HinfI, HhaI a TaqI.The thesis deals with monitoring of the yeast's impact to the chemical and sensorial characteristics of produced wine. The aim of experimental part was obtaining of the aroma-active substances in the fermenting must and wine Hibernal and wine Pinot Blanc. SPME-GC-MS methods were used for identify wines and must aroma. The same autochthonous yeasts were used for wine production. This yeast was isolated from surface of grapes in our laboratory. It was found that both wines have a similar aromatic profile. The next aim was the monitoring of chemical parameters of samples and their changes. For this measurement were used spectrophotometric methods and HPLC methods. The last goal of the thesis was the isolation and identification of yeasts from wine Pinot Blanc by PCR-RFLP. These yeasts were then compared with yeasts isolated from Hibernal must. Identification of yeasts were done by amplification 5,8S-ITS DNA stretches using primers ITS1 and ITS4. Restriction endonuclease HaeIII, HinfI, HhaI and TaqI. were used for restriction analysis then.

The influence of microflora on the sensoric characteristic of the wine

Tato bakalářská práce se zabývá vlivem mikroflóry na senzorické vlastnosti vína. Teoretická část informuje o botanickém popisu hroznů vína Veltlínské zelené, dále o jeho složení, o technologii zpracování bílého vína a o vlivu kvasinek na aromatický profil vína. V další části popisuje metodu stanovení aromaticky aktivních látek pomocí plynové chromatografie v kombinaci s mikroextrakcí tuhou fází (SPME-GC). Cílem experimentální části bylo proměřit vzorky 4 různých moštů odrůdy Veltlínské zelené během kvasného procesu a porovnat aromatické látky u moštů, ve kterých byla využita autochtonní kvasinka s látkami, které byly identifikovány v moštu s aplikací spontánního kvašení.The bachelor thesis is focused on the influence of the microflora on the sensory characteristics of the wine. The theoretical part provides information of the botanical description of Grüner Veltliner grape wine varietal, as well as its chemical composition, the white wine processing technology, and the influence of yeast on the aroma profile of this varietal. The experimental part describes the method of determining the aroma-active compounds by gas chromatography in combination with solid phase micro-extraction (SPME-GC). The object of the study was to measure samples of four different cider varieties of Grüner Veltliner during the fermentation process, and to compare the aromatic compounds in the cider with the indigenous yeast and in the cider where spontaneous fermentation was used.

Stereological analysis of pea protein in model samples

With the growing popularity of various plant proteins used as raw materials for meat production, interest of manufacturers to extend the range of such raw materials is increasing as well. Manufacturers are trying to minimize the cost of manufacturing their products with simultaneous preserving the nutritional value of their products to the maximum extent possible. Such cheaper raw materials, which are also nutritionally rich, include pea protein. Another advantage for manufacturers is the fact that legislation does not order them to indicate pea protein presence in case of its addition, as it does for other allergenic ingredients, although this legume contains storage proteins which can cause a variety of allergic reactions, just like other legumes. Currently no method used for its qualitative determination has been described in literature, let alone its quantitative determination. Our work describes a possible method that can be applied for its quantification. It is a stereological method applied to microscopic sections stained by immunohistochemical staining based on the avidin-biotin complex using monoclonal legumin (1H9) as the primary antibody. The stereological method is based on geometry, it applies knowledge of geometry to analyze a sample of diverse origin, size and internal structure. Despite potential shortcomings in staining microscopic preparations, stereology allows us to perform quantification based on knowledge of morphology of the observed structures. This work describes a procedure of a known pea protein addition quantification in model meat products by means of Ellipse software. Pea protein quantification was performed in two ways. In the first case ten microimages of all sections prepared were examined, while in the second case one scan of the entire section was analyzed. Based on the results, Spearman's correlation coefficient was calculated, which confirmed our assumption of correlation between the protein added into the product and the measured area in microimages. In both ways Spearman's correlation coefficient was rSp = 1000. We obtained regression equations in MS Excel, which can be used for calculation of pea protein addition based on measured area of this protein in microscopic section. <!--[endif] --