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Freeze-dried fermented dairy products
Omelková, Viktorie ; Slavíková, Zuzana (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the production of yogurt, his lyophilization and reconstitution. By comparing all three forms of yoghurt in terms of sensory quality and volatile profile. The theoretical part deals with a characterization of fermented milk products, their production technology, lyophilization process, sensory quality and possibilities of determination of volatile compounds in yoghurt samples. In the experimental part of the thesis, a model sample of white yoghurt was produced and subsequently lyophilized. Freeze-dried yoghurt was first subjected to a consumer evaluation, where the general opinion of potential consumers on this type of product was investigated. The results show that it potentially could be applied on the market as a durable product. In the next phase, the lyophilized yoghurt was reconstituted again with the addition of water, from the point of view of a texture, the addition of approximately 30 % of the originally taken amount of water turned out to be optimal. The reconstituted yoghurt was then compared with the freshly made yoghurt, which was, as expected, rated as better, which could have contributed mainly to the positively rated aroma and the flavour. In reconstituted yoghurts, some evaluators detected an overly sour, bitter taste or an aftertaste of dried milk. Finally, all three types of yoghurt (fresh vs. freeze-dried vs. reconstituted) were compared in terms of volatile profile determined using solid phase microextraction combined with gas chromatography with mass detection. In total, 51 volatile substances were identified in all samples. The composition of the samples differed mainly in terms of the content of identified compounds, the most represented compounds were alcohols, followed by acids and ketones.
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Low temperature heat exchanger
Křivánek, František ; Toman, Filip (referee) ; Hejčík, Jiří (advisor)
The aim of this work is to design a low-temperature heat exchanger for a lyophilization device. The theoretical part of the work includes a basic description of lyophilization technology, a literature review of heat transfer at low temperatures with a focus on suitable construction materials and heat transfer fluids, and an overview of utilized heat exchanger designs. The practical part of the work deals with the actual design of the heat exchanger for indirect cooling in two variants, one of which utilizes a direct vaporization system of the heat transfer fluid, while the other focuses on purely liquid cooling.
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Addition of probiotics to baby food products
Dudrová, Markéta ; Skoumalová, Petra (referee) ; Márová, Ivana (advisor)
This Diploma thesis deals with preparation of probiotic cultures Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium breve enriched with prebiotics meant for application in baby food products. Natural extracts from matcha, moringa, young beat, young barley, chlorella and spirulina were selected as prebiotics. The theoretical part is focused on probiotic bacteria, their biological effects and their effects on the child´s body. The experimental part deals with the cultivation of probiotic bacteria with plant extracts, monitoring their viability and stabilization in an encapsulated form. Mixtures of probiotic cells with prebiotics were encapsulated into alginate particles to increase stability. Some of the alginate particles were processed by freeze drying. Mixtures of probiotic cultures with plant extracts were subjected to model human digestion by the action of model digestive juices in unencapsulated, encapsulated and lyophilized form. Selected extracts of plant materials were characterized in terms of amount of total and reducing sugars, total phenolic substances, individual phenolic substances and antioxidant activity. Further, two baby commercial dietary supplements containing probiotics were selected, which were characterized in terms of cell number and viability. Probiotic products were also subjected to model digestion.
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Preparation and characterization of foods and food supplements containing selected vitamins
Krupičková, Lucie ; Hoová, Julie (referee) ; Skoumalová, Petra (advisor)
The thesis is focused on preparation of protected form of vitamins for aplication to food and diatery supplemets. The theoretical part characterizes vitamins and describes their role in human organism. Furthermore, this chapter summarizes different methods of determination vitamins soluble in water and encapsulation of substances into liposomes. The last sections are focused on functional foods and dietary supplements. In experimental part, an optimalization of determination method was made. Selected vitamins were encapsulated into liposomes. Size, stability, encapsulation efficiency, long-term stability and long-term encapsulation efficiency after two weeks was determined there. All prepared liposomes were found to be stable enough. Furthermore, the vitamin solutions, liposomes and lyophilized particles were analyzed during the process of model digestion. The active forms of vitamins were degraded during the model digestion of vitamin solutions. Vitamins were gradually released from the liposomes and lyophilized particles into the digestive juice. The analysis of content declared by producer was executed for functional foods and dietary supplements. Finally, applications of protected form of vitamins into the food and dietary supplemets were created.
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Extraction of antioxidants from the elderberry blossom and preservation of the extract for further possible use
Krůzová, Sabina ; Němcová, Andrea (referee) ; Vespalcová, Milena (advisor)
The thesis deals with the extraction of antioxidants from elder flowers and the way of storage obtained extract. The elder flowers which are obtained by cutting trees as a waste product and after their processing it could be used as an ingredient to cosmetics products for body and face skin or in a spa like additive to baths. In theoretical part are information about black elder, its botanical characteristics, utilization and about substances contained in it. There is also a chapter about lyophilization as a method which was used for concentration of extract. The last chapter describes theoretical information about liquid chromatography because this method was used for analysis of contents of extract. Experimental part describes optimalization steps in preparation of extract. It was found that the biggest content of polyphenolic compounds was when the proportion between flower and water was 1:10, optimal temperature of water for extraction is 100 °C and it was also found that the time of extraction don´t have any influence on content of polyphenols. Thanks to the lyophilization it was obtained dry light brown powder which is stable for long time. The lyophilizate was tested for some physical properties like pH, refractive index, solubility etc. There was also determined antioxidant activity by DPPH method and there was found quenching activity is 64,9 %. In determining of heavy metals in sample was found trace amounts of lead and chrome. By liquid chromatography was determined content of polyphenols, caffeic acid was in an amount 59,6 mgl1, chlorogenic acid 398 mgl1 and ferulic acid wasn´t detected. All of analysis was for 1% solution of extract because to cosmetic it could be just this amount to addition. In the last step was prepared a skin lotion with elder flower extract and it was tested for stability also was prepared an ointment from pork lard.
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Use of encapsulation techniques for production of food for infants
Hoová, Julie ; Čarnecká, Martina (referee) ; Skoumalová, Petra (advisor)
The Diploma thesis deals with use of selected probiotic strains Lactobacillus acidophilus and Bifidobacterium breve in different forms in food for infants. The theoretical part is focused on describing probiotics, encapsulation methods and intestinal gut microbiota of infants. Further, characterization of individual periods of infant feeding and food for infants were introduced. In experimental part the possibilities of encapsulation and lyophilisation of probiotic cells were observed. Probiotic cells were encapsulated into alginate particles. The encapsulator was used for preparation of particles and the most appropriate particles were prepared by encapsulation nozzle with size of 300 µm. Moreover, probiotics viability was monitored by Flow Cytometry, Fluorescence Microscopy and by cultivation (CFU method). Viability of probiotics was monitored during long-term storage in selected food for infants. The appropriate shelf life of non-lyophilized alginate particles in real food have been set at 1 to 2 months. Lyophilized alginate particles could be stored for more than 3 months. Finally, the stability of the particles and viability of encapsulated and non-encapsulated cells in the gastrointestinal tract conditions were also examined. The viabilities of lyophilized cells and cells encapsulated in lyophilized particles were also compared. From the results obtained, non-encapsulated probiotic bacteria cells are more susceptible to negative effects of digestive juices, the percentage of dead probiotic cells after digestion was approximately 80 %. On the other hand, alginate particles showed cell protection from digestive juices, after incomplete cell releasing from particles the percentage of dead probiotic cells did not exceed 20 %. After adequate rehydration, similar results were gained with lyophilized alginate particles. Lyophilized alginate particles have been determined to be the most suitable application form for infants’ food.
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Possibility of further use of elderberry marc
Sedláčková, Lucie ; Pořízka, Jaromír (referee) ; Vespalcová, Milena (advisor)
This Diploma thesis talks about the production of concentrates and lyophilisate from the extract of elderberry moldlings (elderberry, Sambuvus nigra L.) and by determination by chosen chemical characteristics of these products. The theoretical part includes the botanical characteristics of the plant species Sambucus nigra L. Next is the part that is dedicated to biologicaly active substances found in elderberry and it‘s possible usage in the food industry. Next is the part where the extraction, purification and indentification of anthocyanic dyes are described. In the next part is the analyrical method HPLC described, including the description of instrumentation. The last part talks about the description of the used methods: methods for the concentration of the extract, UV-VIS spectrophotometry, determination of phenolic compounds, determination of dry matter, determination of active acidity and the overall titrating acidity. The experimental part contained the optimalization of the process of producing the extract from elderberry moldings. The extract obtained was then concentrated for preservation and characterization purposes based on selected chemical properties. The total content of anthocyanin dyes was chosen as a quality parameter. The most suitable process for the preparation of the extract was chosen to be the ratio of moldings and solvent 1:2, 4 (m/V). The most suitable solvent was chosen to be a mixture of water and ethanol in a ratio of 1:1 (V/V). According to the needs of the submitter, an extract with the use of water as the extraction agent is also provided. The prepared extract was then concentrated on a vacuum evaporator or lyophilized for storage purposes. The dye degradation while using the evaporator was the lowest in a 40 ° C water bath. The final products were characterized by the determination of soluble solids, pH, titration acidity, total phenolic compounds and total anthocyanin dyes. The anthocyanin pigments contained identified by liquid chromatography are: cyanidine-3-sambubioside, cyanidine-3-glucoside, cyanidine-3-sambubioside-5-glucoside, and cyanidine-3,5-diglucoside The total content of anthocyanins in the concentrate was determined to be equivalent to cyanidine-3-glucoside at 2.8 gl-1 and in the lyophilisate 2.5 gl-1.
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Encapsulation of probiotics for use in nutritional products for children
Šmídová, Veronika ; Hudečková, Helena (referee) ; Skoumalová, Petra (advisor)
This bachelor thesis is focused on optimization and development of probiotic food supplement with attractive look and active ingredient, like prebiotic or “superfood”, which are there for afford useful substances for organism. In the theoretical part is focused on probiotics and its encapsulation, also on prebiotics, which are used for work and screening probiotics food supplements in our market. The practical part is focused on optimization of composition of new probiotic food supplement, polysaccharide particles in the shape of a teddy bear were prepared. At first, the basic composition was optimized, as the best alginate-agar particles were determined. Addition of nutritionally valuable ingredients was also optimized. Particles with inulin, acerola, chia fiber, yacon syrup, chlorella and spirulina were prepared. Another part of this work was focused on the determination of the viability of probiotic bacteria Lactobacillus acidophilus and Bifidobacterium breve in various forms and after exposed to model digestion. The highest viability of the cells was measured after encapsulation of lyophilized cells into a polysaccharide particle. Prepared particles were finally subjected to a sensory analysis.
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Ovlivnění životaschopnosti enkapsulovaných bakterií přídavkem vybraných druhů nutrientů
Resová, Daniela
Probiotics are sensitive to external conditions, which can result in reduced viability during handling, processing and storage. One option to increase viability and stability is to immobilize them. In the experimental part of this thesis, probiotic bacteria, specifically a collection strain of Lb. rhamnosus, are lyophilized with the addition of cryoprotectants. The culture enriched with 10% sucrose solution or 2.5% glycerol solution was lyophilized and then the suitability of the substances for the protection of the lyophilized bacteria was evaluated. Sucrose was chosen as the more suitable cryoprotectant since the decrease in viability after lyophilization was only 3.28% of the original amount of CTCs before lyophilization. The decrease in the control and glycerol sample was statistically significant (p < 0.01). Encapsulation of Lb. rhamnosus by extrusion method was also introduced in this study. Nutrients were added to the alginate matrix and then the effect of encapsulation, added nutrients and capsule dissolution on the viability of the encapsulated probiotics was tested. The nutrient with the most favourable effect on the viability and stability of Lb. rhamnosus was evaluated to be alginate with the addition of whey. Compared to the alginate variant with the addition of inulin and the control, a statistically significant difference was observed (p < 0.01). The same viability test was performed after 2 weeks of storage at 4 °C. Storage had a negative effect on all the variants. However, the smallest decrease was observed in the control sample and the sample with cryoprotective sucrose and whey addition.
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Možnosti lyofilizace a enkapsulace probiotických kultur
Faitová, Barbora
This bachelor thesis entitled "Options for lyophilization and encapsulation of probiotic cultures" is prepared as a literature search. As such, microorganisms play an important role in human health, hence the effort to spread probiotic bacteria among con-sumers and through food. Because of the limited viability of these cells, treatment by lyophilization or encapsulation is possible. These methods appear to be very suitable as they ensure their stability during storage, incorporation into food and passage through the digestive tract where they are exposed to adverse conditions.
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