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Characterization and optimization of sensory quality of jelly sweets
Knotek, Vojtěch ; Vespalcová, Milena (referee) ; Vítová, Eva (advisor)
This bachelor thesis focuses on monitoring and optimization of moisture of starch during jelly sweets processing. The theoretical part focuses on technology of manufacturing jelly sweets and description of raw materials needed for production. The methods for measurement of starch moisture are briefly described. The experimental part focuses on stabilization of moisture of starch during jelly sweet processing, specifically when pouring gelatinous mass into starch forms. The drying scale method was used to measure starch moisture. Recommended starch moisture is up to 8 %. During the two-month measurement, this value was always 0.5 % higher. On the basis of the results of this work, slight modification in the starch drying was made. This led to a reduction in starch moisture but not yet optimal.
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Sensory quality of chosen types of meat products
Javorská, Kateřina ; Sůkalová, Kateřina (referee) ; Vítová, Eva (advisor)
This Bachelor’s thesis deals with the evaluation of sensory quality of meat products. The 5 samples of pork ham of different quality and from different producers were selected for evaluation. The theoretical part focuses on the composition and properties of meat and meat products, and their production technology. The selected methods for sensory evaluation of quality are also mentioned. Ordinal and graphical scales were used for sensory evaluation of samples. The assessors evaluated these basic characteristics of the ham samples - color, appearance in the cut, preparation, consistency, smell, taste, saltiness and tenderness. The results were written down in the prepared questionnaires which were subsequently statistically and graphically evaluated. Sensory analysis was performed by group of students from the Faculty of Chemistry BUT.
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Sensory quality of fruit juices
Hamalová, Veronika ; Hrstka, Miroslav (referee) ; Vítová, Eva (advisor)
This Bachelor‘s thesis deals with the evaluation of sensory quality of orange juice from different producers. All selected samples were made from concentrate. In total five samples bought in Tesco Stores CZ in Brno were evaluated The theoretical part focuses on the composition and properties of orange and orange juice, and their production technology. The selected methods for sensory evaluation of foods are mentioned. The definition of orange juice according to Czech Standard 56 8541 is also presented in this part. The appearance, color, taste, smell and consistency were evaluated using ordinal scales, taste development using graphic scale. The ranking test was also included. Written results were graphically evaluated and statistically treated.
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Evaluation of the sensory quality of bread
Mahdalová, Martina ; Vránová, Dana (referee) ; Vítová, Eva (advisor)
This work deals with the evaluation of sensory quality of selected samples of bread. The samples of bread were bought in TESCO Stores a. s. ČR in Brno. Totally five samples were evaluated, two of them were rye-wheat and three of them were wheat-rye. All products were packaged and sliced. Purchased samples were subjected to sensory evaluation by the ranking test and scale tests. The assessors judged three main organoleptic properties of bread – taste, odour (aroma) and texture. The results were written down in the questionnaires and consequently graphically and statistically evaluated. The assessors which took part in sensory analysis were chosen from students of Faculty of chemistry BUT.
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Sensory quality of chosen types of beer
Lišková, Michaela ; Divišová, Radka (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the sensory guality of chosen types of beer. The teoretical part was focused on the production of malt and beer and raw materials needed and also an introduction to sensory analysis was described. The experimental part was focused on evaluation itself. Nineteen untrained assesors were invited for sensory evaluation, who evaluated five selected beer kinds using the preprepared form. Unstructured graphic scale with a verbal description of anchor points was used to evaluate the appearance and color, taste and odour, fullness, bite, foaming, bitterness and any off-taste or off-odour of each sample. Five-point category ordinal scale was used for assessment of the overal acceptability of the samples. Results of the analysis were then evaluated graphically and statistically.
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Sensory quality of French cheese Brie de Meaux in connection with chemical and microbial composition
Májková, Monika ; Němcová, Andrea (referee) ; Vítová, Eva (advisor)
This thesis deals with the assessment of the effect of storage of French Brie de Meaux (AOC) on its volatile (aromatic) compounds, free and bound fatty acids and microbial composition, in relation to its sensory quality. The theoretical part is devoted to cheeses with white mould on the surface. In the experimental part, the influence of temperature and storage time on the sensory quality and safety of cheese is assessed. In the storage experiment, the cheeses were stored for 21 days at 5 °C (one bulk, one vacuumed) and at 20 °C. The samples were evaluated by SPME-GC-MS for volatile (aromatic) compounds. Fatty acids were identified and quantified by GC-FID after conversion to methyl esters using BF3. RT-PCR method was used for microbial profile. Fifty-nine volatile compounds were identified in the samples and contribute to the flavour characteristics of the cheese. Among the fatty acids, palmitic, oleic, myristic and stearic acids were predominant. The microbial profile confirmed Micrococcus luteus as a contaminant in cheese stored at 20°C, while the other contaminants were not detected positively. From a sensory point of view, the standard cheese (analysed immediately after purchase) together with cheese stored at 5 °C in vacuum form for 21 days was the best performing cheese.
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Optimization of fresh cheese production and their characterization
Bittnerová, Eva ; Pořízka, Jaromír (referee) ; Vítová, Eva (advisor)
This thesis deals with the optimization of fresh cheese production and their characterization in terms of free and bound fatty acids, volatile (aromatic) substances and sensory quality. The theoretical part deals with the characterization of fresh cheeses, their production technology and sensory quality. It also includes options for determining volatile substances and fatty acids in fresh cheeses. In the experimental part, produced fresh cheese samples were analyzed during 14-day storage. The fat was extracted from fresh cheeses with a mixture of diethyl ether and petroleum ether, fatty acids were converted to the appropriate methyl esters by acid esterification with boron trifluoride as a catalyst and determined by gas chromatography with a flame ionization detector. Volatile substances were identified based on the comparison of mass spectra with a library of spectra and retention indices (according to Van den Dool and Kratz). The content of the identified substances was expressed semi-quantitatively using the areas of the respective peaks. A total of 20 fatty acids were identified, palmitic, myristic, stearic, capric, caproic and lauric acids predominated as representatives of saturated fatty acids, oleic acid as a representative of monounsaturated fatty acids, and linoleic acid was abundantly represented among polyunsaturated fatty acids. In terms of volatile substances, a total of 37 compounds were identified in the frozen samples and 42 compounds in the fresh samples. Alcohols, acids, aldehydes and ketones were the most represented. The results of the sensory evaluation show that the evaluators liked the stored cheeses better, so the cheeses maintain a good quality of min. for 14 days when stored in the refrigerator.
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Sensory quality of French cheese Brie de Meaux in connection with chemical and microbial composition
Májková, Monika ; Němcová, Andrea (referee) ; Vítová, Eva (advisor)
This thesis deals with the assessment of the effect of storage of French Brie de Meaux (AOC) on its volatile (aromatic) compounds, free and bound fatty acids and microbial composition, in relation to its sensory quality. The theoretical part is devoted to cheeses with white mould on the surface. In the experimental part, the influence of temperature and storage time on the sensory quality and safety of cheese is assessed. In the storage experiment, the cheeses were stored for 21 days at 5 °C (one bulk, one vacuumed) and at 20 °C. The samples were evaluated by SPME-GC-MS for volatile (aromatic) compounds. Fatty acids were identified and quantified by GC-FID after conversion to methyl esters using BF3. RT-PCR method was used for microbial profile. Fifty-nine volatile compounds were identified in the samples and contribute to the flavour characteristics of the cheese. Among the fatty acids, palmitic, oleic, myristic and stearic acids were predominant. The microbial profile confirmed Micrococcus luteus as a contaminant in cheese stored at 20°C, while the other contaminants were not detected positively. From a sensory point of view, the standard cheese (analysed immediately after purchase) together with cheese stored at 5 °C in vacuum form for 21 days was the best performing cheese.
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Characterization and optimization of sensory quality of jelly sweets
Knotek, Vojtěch ; Vespalcová, Milena (referee) ; Vítová, Eva (advisor)
This bachelor thesis focuses on monitoring and optimization of moisture of starch during jelly sweets processing. The theoretical part focuses on technology of manufacturing jelly sweets and description of raw materials needed for production. The methods for measurement of starch moisture are briefly described. The experimental part focuses on stabilization of moisture of starch during jelly sweet processing, specifically when pouring gelatinous mass into starch forms. The drying scale method was used to measure starch moisture. Recommended starch moisture is up to 8 %. During the two-month measurement, this value was always 0.5 % higher. On the basis of the results of this work, slight modification in the starch drying was made. This led to a reduction in starch moisture but not yet optimal.
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Acid whey utilization for beverage production
Šíša, Daniel ; Legarová, Veronika (advisor) ; Musilová, Šárka (referee)
Whey is a byproduct of cheese, curd and casein manufacture and as an excellent source of proteins, vitamins, minerals and lactose can be used in wide range of industrial production. If treated as waste material without further processing, it can have negative impact on the environment.
Main components of whey are water (93% of total volume), lactose (70 to 72% of dry matter), whey protein (8 to 10% solids), and minerals (12 to 15% solids). Of the minerals, most abundant are magnesium, phosphorus, calcium, potassium, sodium, zinc, and their salts which are passed to whey from milk. Predominantly represented vitamins are water-soluble vitamins (B1, B2, B12, B6, and C) from which the vitamins B2, B12 and C are bound to the whey proteins. The most abundant whey proteins are betalactoglobulin, alfa lactalbumin, GMP (glycomacropeptide), bovine serum albumin, immunoglobulins, lactoferrin and lactoperoxidase. For each of these proteins have been demonstrated or at least implied, unique functional, nutritional or nutraceutical properties.
The aim of the thesis was to compile a literature review focused on the possibility of using whey from the production of cheese and curd as raw materials for the manufacture of various types of beverages and monitoring the effect of the addition of various flavor components and whey proteins on the sensory quality of the drink prepared from fresh sour whey.
The hypothesis of this work was that flavored whey drinks made from acid whey supplemented with whey protein have a higher sensory quality score than flavored drinks without the addition of whey protein and that whey drinks flavored with mango flavour are more acceptable by consumers they are able to mask undesirable off-tastes of sour whey better than flavor peaches, cherries and black currants.
In all specimens, the effect of 8 different recipes and flavors of peaches, cherries, mango and blackcurrant on the final sensory quality and acceptability to consumers was observed. It was found that the best rated drinks were of cherry and mango flavors. Beverages with the addition of mango juice were able to reliably mask natural off-taste of whey, which supports the hypothesis about the appropriateness of using this flavor. Drinks with peach flavor were evaluated to be of the worst senzory quality. As of the best sensory quality were evaluated drinks flavored with cherry flavor, which reached the best overall evaluation. In all variants of formulas was observed that drinks with added WPC achieved better overall evaluation than similar variations without addition of WPC. Statistically significant results of this finding, however, were observed only in the context of mango flavors.
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