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Nutritional and sensory analysis of plant-based alternatives to dairy products
Gregorová, Ema ; Doležal, Marek (advisor) ; Ilko, Vojtěch (referee)
While interest in plant-based alternatives to animal foods has been growing significantly in recent years, the question is to what extent these plant-based foods are able to replace animal products - both in terms of nutrition and organoleptic properties. The aim of this study was to nutritionally and sensorially evaluate 18 samples of plant-based alternatives compared to 14 samples of dairy products of the same type. The samples of the plant-based alternatives were subjected to chemical analysis, where their composition in terms of water, protein, calcium, fat and individual fatty acid content was examined by analytical methods. The water content of the plant-based alternatives to dairy products was determined to be in the range 39-89 %, which corresponds directly to the physical nature of the samples. The protein content determined for the plant-based dessert and plant-based yoghurt ranges from 0,7-4,3 g/100 g. For plant-based cheese alternatives, calcium values were determined between 9 and 330 mg/100 g. The fat determined in all vegetable samples ranges from 1-27 g/100 g. The fatty acid profile of the samples was highly variable, with saturated fatty acids predominating in the presence of coconut fat, and unsaturated fatty acids predominating in products based on sunflower or rapeseed oil. None...
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Study of the possibilities of using fruits of sorbus domestica in the food industry
Šmídová, Vendula ; Gajdušek, Martin (referee) ; Mikulíková, Renata (advisor)
The aim of this bachelor thesis is exploring of food industry usage of fruits of genus Sorbus. Recipes of homemade service tree fruit pastes (Sorbus domestica), homemade rowanberry liqueurs (Sorbus aucuparia) and homemade rowanberry confectionery (Sorbus aucuparia) were made for this purpose. All prepared products were evaluated by sensory analysis and the overall most acceptable service tree paste was the one with 50% of vegetable mixture added; the most acceptable rowanberry liqueur was made by macerating of precooked rowanberry fruit in mixture of ethanol and water in which the rowanberry fruit was cooked with sugar content of 830 g/l; the most acceptable rowanberry confectionery was the one with 6% of rowanberry macerate in ethanol. Results of vitamin C evaluation in the most acceptable service tree paste and unfrozen service tree fruit by HPLC were 0,0000915 mg/ml and 0,0000534 mg/ml respectively while the antioxidant capacity obtained by spectrophotometric TEAC method was 44 g/ml TEAC in paste and 33 g/ml TEAC in fruit. The antioxidant capacity was also measured in all samples of rowanberry liqueurs and in the most acceptable one it was the highest: 108 g/ml TEAC.
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Possibilities of processing selected exotic fruits into jams and jellies
Pavlíková, Michaela ; Obračaj, Jan (referee) ; Mikulíková, Renata (advisor)
This bachelor thesis deals with the preparation and statistical evaluation of jams and jellies prepared from selected types of exotic fruits, which are passion fruit and pomegranate. The theoretical part characterizes both types of exotic fruits used for the preparation of named products. Bioactive compounds and the production of jams and jellies were also described. One of the chapters also focuses on methods and requirements of sensory analysis. The experimental part focuses on the production of jams and jellies from passion fruit and pomegranate and on the preparation of these products with the addition of varieties of spices (vanilla, cinnamon, ginger, lime). These samples were subjected to sensory analysis, where the respondents had to evaluate the appearance and colour, smell, taste, and texture of the products using a scale in the received questionnaire. Based on the results of the sensory analysis, samples containing lime or vanilla were rated very positively, both in the case of passion fruit and pomegranate. For jams, the preferences differed. It turned out, that jams made of passion fruit were rated better than jams made of pomegranate. On the other hand, jellies made from pomegranate were preferred to passion fruit jellies.
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Processing of grapes into non-traditional products
Černý, Marek ; Pacasová, Viktorie-Alexandra (referee) ; Mikulíková, Renata (advisor)
This bachelor’s thesis focuses on the processing of grapes into non-traditional products, mainly on grape jelly with the addition of spices, herbs and juices. The aim of this work is to investigate, which combination of herbs, spices or juices leads to the best sample. In the theoretical part of the thesis is described morfology of grapevine, it’s technological processing and variation of uses in food industry. Sensory analysis is also described, which represents a big part of thesis. The experimental part focuses on the desription of preparation of flavoured jelly and on it’s sensory analysis. Vitamin C was also studied with the usage of HPLC. Based on the sensory analysis data, the best sample was with lemon balm. Vitamin C was evaluated using HPLC and was determined to be around 0,017 – 0,028 mg per jelly.
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Production of pates with the addition of dried fruits
Stoianova, Diana ; Nábělek, Jakub (referee) ; Mikulíková, Renata (advisor)
This bachelor thesis deals with the preparation and sensory evaluation of pates enriched with dried fruits. For the sensory evaluation, 6 samples of pates containing different proportions and types of dried fruits were produced. The theoretical part of the work describes the pates and their division, then the composition and technological steps of production. Furthermore, the theory presents the methods of fruit drying and the description of the fruits that were used. The literature search includes the characteristics of sensory analysis, conditions and methods of its performance. The experimental part focuses on the preparation of the pate samples first for the evaluation of the heat treatment, then on the production of the pate samples for sensory analysis and actually performing the sensory analysis. During the assessment of the heat treatment process, it was found that the pates had undergone sufficient heat treatment and were therefore ready for consumption. After evaluation of the results of the sensory analysis, it was found that the pates enriched with ground figs and fig pieces were among the best.
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Production of agar candy with the addition of plant extract
Kameníková, Magda ; Gross, Michal (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the optimization of the production of jelly confectionery with agar as gelling agent, application of herbal extract to the prepared confectionery and subsequent identification of the content of aromatic active substances, characterization of phenolic content, antioxidant and antimicrobial activity and sensory quality. Calendula officinalis was selected as the source of the herbal extract, which is known for its high content of bioactive compounds. Determination of aromatic compounds was carried out by gas chromatography with mass detection, antioxidant activity by DPPH method, antimicrobial activity by diffusion method, determination of total phenolics by Folin-Ciocalteu method and sensory analysis was also carried out. Based on the sensory analysis, the optimum added amount of agar, extract and citric acid was determined. The additions of 1,25 % agar and 1 % acid were found to be optimal. The most sensory acceptable sample was the one without extract, while the sample with extract was the one with 4 % extract. The sample with Calendula extract of the above-mentioned optimal composition contained 14 identified aromatic compounds, of which guaiol, -cadinol and -muurolol were the most abundant; the total phenolic content was 464.30 ± 14.99 µgGAEg-1, and the antioxidant activity was determined to be 1.73 ± 0.01 mgTEACg-1 (or a radical quenching of 74.36 %). The antimicrobial effects of the above extract were tested against Gram-negative Escherichia coli and Gram-positive Bacillus cereus. The highest antimicrobial activity was exhibited by the extract alone and among the samples, it was the sample containing 4 % of the extract. The extract appeared to be more effective against B. cereus than E. coli. The results show that the content of extract in the samples increases their nutritional value and antimicrobial efficacy (increases the content of antioxidant and phenolic compounds).
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The effect of reducing the salt content on the sensory quality of liver pâtés
Adamusová, Sandra ; Slavíková, Zuzana (referee) ; Mikulíková, Renata (advisor)
The bachelor thesis examines the impact of salt reduction on the sensory quality of liver pâté. The aim of the thesis is to create a sensorially acceptable pâté, in which a portion of the added salt will be replaced with potassium chloride. The theoretical part describes the composition and properties of meat, ingredients used in pâté production, and the technological process of its manufacture. Furthermore, the theoretical part elaborates on the conditions and methods of sensory analysis and sensory evaluation of pâté. The literature review also includes a description of the ICP-OES technique. The experimental part deals with the preparation of samples for sensory analysis, optimization of salt in the basic recipe, and evaluation of heat treatment. Finally, the total concentration of sodium and potassium in the individual samples was measured using ICP-OES. The results of the sensory analysis showed that the optimal salt content in the pâté is 1.09 wt. %.This content was partially replaced by KCl. It was found that a 20–40% substitution has no significant impact on the sensory properties of the product. For higher substitution, the addition of L-arginine was necessary, which positively influenced the overall perception of the pâté.
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Comparison of the microbial composition of English Blue Stilton cheese with related cheeses
Druláková, Tereza ; Vodička, Juraj (referee) ; Brázda, Václav (advisor)
This bachelor’s thesis focuses on the comparison of English blue-veined cheese Blue Stilton with commonly available cheeses of the same type, Roquefort and Niva, in terms of microbial composition, aromatic volatile content and also by sensory analysis. These methods distinguish the expensive Blue Stilton cheese from common and cheaper cheeses of the same type in the Czech Republic. The presence of 15 selected species of microorganisms was determined by RT-PCR. Three of them proved to be specific for Blue Stilton, specifically bacteria Brevibacterium linens and the yeasts Geotrichum candidum and Kluyveromyces lactis. Aromatic volatile compounds were determined by HS-SPME-GC-MS. Heptan-2-one, nonan-2-one, non-8-en-2-one and hexanoic and octanoic acids were the most important substances contributing to the aromatic profile of all cheeses. The cheeses can be distinguished according to the content of these substances in their aromatic profile or according to the amount of these substances in the individual samples. The sensory evaluation revealed that in most parameters like appearance, consistency and taste, Niva cheese was the most acceptable for Czech consumers while Blue Stilton was the most popular in the aroma category. On the basis of the obtained data, we are able to distinguish English Blue Stilton from other blue-veined cheeses according to specific microorganisms and the unique aromatic profile.
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Aromatisation of wine by different types of wood
Hrošíková, Monika ; Slavíková, Zuzana (referee) ; Pořízka, Jaromír (advisor)
This thesis deals with aromatised red wines using different woods as an alternative method of colouring. It focuses on the phenolic profile of the wine, more specifically on the substances extracted from the wood into the wine, the organic acids and the overall sensory character of the wines aged in contact with the wood. The theoretical part describes the technology of red wine production, its chemical composition, the method of colouring and its alternatives and the associated treatment and modification of the chemical composition of the wood. It also focuses on the phenolic substances extracted and the changes in the sensory profile during the ageing of wine in contact with wood and the possibilities of determining the chemical and sensory profile of these aromatised wines. The experimental part focuses on the chemical and sensory analysis of the changes of a reference Merlot wine during ageing with different types of wood in a two-week and two-month maceration. Changes in the concentrations of total phenolic compounds by Folin-Ciocalteu method, organic acids by ion chromatography, selected phenolic compounds by LCxMS, furfural compounds by GC-FID and colour parameters were monitored.
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Possibilities of processing the fruit of lesser-known fruit tree species
Vachta, Jonáš ; Hudečková, Helena (referee) ; Mikulíková, Renata (advisor)
This diploma thesis deals with the possibilities of using the fruits of common quince (Cydonia oblonga), common medlar (Mespillus germanica) and flowering quince (Chaenomeles speciosa) for food purposes, specifically for the production of jellies and jams. The goal was to create a product that would capture the character of the fruit used, preserve its beneficial properties, such as aromas and the content of bioactive substances, and at the same time be pleasant for consumers. A total of three types of products were prepared, namely gelatin jelly, agar jelly and jam for each type of fruit used. The product samples were subjected to sensory analyses, the aim of which was to determine the optimal addition of sugar to the product, to determine the overall consumer acceptability of the individual samples, and in the case of jelly, also to compare the sensory properties of the gelatin and agar variants. For chemical analyses, model samples were prepared, the composition corresponding to the best sensorially evaluated samples from each type of product. The total content of polyphenols, the total content of flavonoids, the content of vitamin C, the content of lipophilic pigments, ubiquinone and phytosterols and the profile of volatile compounds in individual samples were studied. The analysis results showed that the jams, as heat-processed products, generally retained a greater amount of bioactive substances compared to the jelly samples, and in certain cases even a greater amount than the fruit samples. The jelly samples, on the other hand, retained a greater amount of the original fruit aroma.
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