The theoretical part of the diploma thesis deals with cultivation of the plant Stevia rebaudiana. This plant is 300x sweeter than sucrose. It is often used as a compensation for sugar sweetener, suitable for diabetics and people who suffer from overweight. There is processed the characteristics of the plant, botanical description, conditions of cultivation and chemical composition. There are described the methods of determination of steviol glycosides. The practical part elaborates on a sensorical analysis. This analysis has two parts. The first part is the evaluation of stevia concentrates with the flavour of aronia, sour cherry and beetroot and stevia powder in 10 milk products bought in supermarkets. The second part deals with the evaluation of black tea sweetened with few different easily available sorts of sweetening products. The currently valid legislative in the area of the Czech Republic allows the food industry to use steviol glycosides of high purity under the name E960. The use of the plant stevia or its parts as food isn't enabled.

Memoria para optar al título de Ingeniero en Alimentos / El objetivo de esta memoria fue determinar las características del secado convectivo de las hojas de Stevia rebaudiana y estudiar la factibilidad técnico-económica de una planta productora de edulcorante en polvo en base a las hojas de Stevia, las cuales poseen steviolglicósidos que son compuestos dulces (300 veces más que el azúcar), no calóricos ni dañinos para el ser humano. Se determinaron isotermas de sorción y se ajustaron a modelos matemáticos. El modelo que mejor se ajustó a la isoterma a 25°C de la hoja fresca fue BET con un r2 de 0,9591, mientras que GAB fue el modelo que mejor se ajustó a las isotermas a 30°C y 40°C de la hoja fresca con un r2 de 0,9816 y de 0,9659, respectivamente, y para la isoterma a 25°C de la hoja seca con un r2 de 0,9899. Se realizó el secado convectivo de las hojas de Stevia hasta una humedad de 10%, mediante aire por convección forzada. El secado a 70°C tuvo una duración de 85 minutos, a 60°C fueron 95 minutos y a 50°C fueron 150 minutos. El modelo exponencial fue el que mejor se ajustó a los datos de secado a 50°C y a 70°C con r2 de 0,997 y 0,990 respectivamente, mientras que para el secado a 60°C el modelo que mejor se ajustó fue el cúbico con un r2 de 0,991. Para la realización del proyecto de instalación de la planta productora de edulcorante a base de Stevia, se evaluó la oferta y la demanda tanto nacional como internacional, en donde la Stevia ya ocupa el 4% del mercado. Además se determinó que el área de la planta es de 640 m2 y la capacidad productiva de 310 toneladas de edulcorante en polvo a base de Stevia y eritritol, lo que se traduce en 6.174.110 de cajas de 100 sobres de 0,5 g, anualmente. Para evaluar la rentabilidad se determinó: TIR (131%), VAN ($10.075.505.856) y PRI (0,78 años), aplicando una tasa de descuento de 17% y utilizando el precio de la hoja de Stevia secada en túnel ($3.500). Los índices obtenidos permiten indicar que el proyecto es rentable. A la vez que se determinó que la rentabilidad del proyecto se ve afectada por el precio de la hoja seca de Stevia / The objective of this work was to determine the characteristics of convective drying of Stevia rebaudiana leaves and study the technical and economic feasibility of a production plant of powder sweetener based in Stevia Rebaudiana leaves. The leaves has steviolglicosides, sweet compounds (300 times sucrose), non caloric and not harmful to humans. Sorption isotherms were determined and fitted to mathematical models. BET was the best model which fitted to 25°C isotherm of fresh leaves (r2 = 0.9591) and for dry leaves, at the same temperature, GAB was the best fit (r2 = 0.9816). GAB also fitted to 30°C (r2 = 0.9659) and 40°C (r2 = 0.9899) in fresh leaves isotherms. Convective drying was performed in Stevia leaves until 10% moisture, through forced convection air. Drying at 70°C lasted 85 min, while at 60°C and 50°C, were 95 and 150 minutes, respectively. Exponential model was the best model which fitted to 50°C and 70°C drying curves (r2 = 0.997 and 0.990, respectively). Cubic model was the best model which fitted to 60°C drying curve (r2 = 0.991). To evaluate the feasibility of a production plant of powder sweetener based in Stevia leaves, the supply and demand, local and international, was assessed. Stevia already occupies 4% of the market The production plant area is 640 m2 and the capacity is 310 tons of powder sweetener based in Stevia leaves mixed with erythritol, this means 6,174,110 boxes with 100 sachets each one (0.5 g/sachet) annually. For profitability´s measurement were determined IRR (131%), NPV ($ 10,075,505,856) and PRI (0.78), as indicators, applying a discount rate of 17% and using the dried, in tunnel, Stevia leaves value ($3,500). The indicators obtained suggest that the project is profitable. While it was determined that the project´s profitability is affected by the price of Stevia dried leaves

Dental caries affects people worldwide. The oral microflora has been found to be less responsible than the carbohydrate diet, which is considered the main cause of dental caries. Carbohydrates from sucrose are processed by oral bacteria and acids are produced as a byproduct. High sugar intake is a risk factor for systemic health and for overall health of the oral cavity. Artificial sweeteners are considered a healthy alternative for people who prefer the sweet taste but renounce sucrose. In the United States there are several artificial sweeteners approved by the Food and Drug Administration. Among these, stevia is the only natural sweetener. Stevia is extracted from the Stevia rebaudiana plant. Steviol glycosides are extracted from the stevia leaf and refined to get the best taste quality. There are many types of steviol glycosides that are extracted from the stevia plant and the most important steviol glycosides will be discussed in the thesis. Scientific research (PubMed, EMBASE), appropriate websites (Colgate, Pure Circle Stevia Institute), the World Health Organization, HealthInfo Clinical Advisers and vectorstock as well as books in English and in Russian (The Stevia Deception: The Hidden Dangers of Low Calorie Sweeteners By Bruce Fife, and Puti Izbavlenie of Bolezne by Neumyvakin) were consulted. Electronic searches were limited to publications in the past five years. The scope of the thesis is to review the basic statistics on dental caries, the types of caries and the number of people affected, discuss the advantages and benefits of stevia relative to other artificial sweeteners, review the safety of stevia including side effects and potential as an addictive sugar substitute and lastly, to assess and recommend which form of stevia is most effective against dental caries.

The theme of this thesis is Technology of production of ice cream with alternative sweeteners. This work was divided into two parts. The theoretical and practical part. In the theoretical part, there are described general information about the ice cream related to basic materials, technological process of production and rheological characteristics. The chapter about sugar and sweeteners is described in more detail. The main point of it are sweeteners which can replace sucrose. Information related to history of sweeteners, division of alternative sweeteners, allowed sweeteners in the EU and their use. In detail is described plant Stevia rebaudiana, it is origin, content substances, sweetening substances and the use of stevia as a sweetener for a production of the ice cream. In the practical part, there was the main aim to product an ice cream with alternative sweeteners. As a standard was used fructose, which was replaced with many others. In this experiment I made the sample in two flavours: vanilla and cacao. Ice cream was produced with sweetener stevia, next ice cream with sweetener stevia, wchich was enriched by fiber. In next experiments was produced ice cream with the sweetener DiaChrome with sucralose, date syrup, coconut sugar, xilovit and agave syrup. I had 14 samples which where divided into two halves. The first half was with vanilla flavour and the second half was with cacao flavour. They were rated right after the production. The results were received by sensorican analysis and drain tests and it was graphically evaluated. The main aim was to formulate a suitable recipe for the production of ice cream with sweeteners. To focus on new materials used in production of ice cream, including using the alternative sweeteners in production of ice cream, including their influence on the sensoric quality of the finished products. To evaluate their influence on rheological properties and sensory quality.

El presente trabajo de investigación tiene como objetivo realizar un estudio de mercado para determinar la viabilidad de comercialización de la stevia en la ciudad de Chiclayo, así mismo determinar la oferta y demanda actual de este producto. Para alcanzar estos objetivos, se utilizaron fuentes secundarias: libros, revistas, páginas webs, entre otros. Con respecto a determinar la oferta actual de la stevia en la ciudad de Chiclayo, se hizo uso de entrevistas no estructuradas, la observación y visitas a diferentes centros de venta, con lo se pudo conocer todos los edulcorantes que se ofrecen en el mercado, sus presentaciones, cantidades comercializadas, precios a los que son adquiridos y canales de comercialización. Finalmente, para determinar la demanda actual de la stevia en la ciudad de Chiclayo, se realizó un focus group y se aplicaron encuestas a 164 personas de ambos sexos para determinar el perfil del consumidor de la stevia. Como principales conclusiones encontramos que sí es viable la comercialización de stevia en la ciudad de Chiclayo porque encontramos que en el ciudad mencionada existe una demanda de este producto y el factor por los cuales sí la consumirían es el cuidado de la salud, además la búsqueda de un producto natural y de calidad. Así mismo tenemos que las características de las personas que demandarían un edulcorante a base de stevia son de sexo masculino y femenino, con edades de 25 a más años y zona de residencia urbanización. Cuyo motivo principal de consumo es por receta médica (problema de salud) con frecuencia de consumo diario (de 2 a 3 veces al día) para ser usado en bebidas y alimentos. Los lugares de compra de este producto son las farmacias o boticas y supermercados, con respecto a la disposición de pago hacia este edulcorante depende de la presentación que se adquiera.

Stevia or Stevia rebaudiana Bertoni are two of the numerous names of this subtropical plant with a sweetening power as much as 300 times higher than in case of sucrose. Stevia is a plant with a very interesting, but up to this date not very utilised potential. The fields of its application, processing, cultivation and wintering options have not been explored very extensively, and therefore I have decided to elaborate this topic related to the impact of the environmental conditions for growing of Stevia rebaudiana. The resources for the text of the diploma thesis were formed by available specialised publications and the Internet. The first part of the thesis represents a brief overview of the whole issue concerning the topic of Stevia rebaudiana. The objectives, hypotheses and methodology of the conducted research, including the findings based on the plant growing as well, and the evaluation of the experiment results have been included in the second part. The purpose of the thesis was to expand the knowledge regarding cultivation, reproduction methods and wintering options of the stevia plants. A field and a greenhouse experiments were staged with a focus on temperature indicators during the growing season and their impact on the total number of wintered plants. Simultaneously, an evaluation of the dry matter yield of the plants per an area unit and statistical processing and evaluation of the experiment results have been performed. Further, a determination of seed germination for Stevia rebaudiana in laboratory conditions has been conducted. The research results have shown that the plants obtained vegetatively are more suitable for cultivation due to a higher yield of the dry matter in both greenhouse as well as field conditions. The only pests invading stevia were the whiteflies appearing only in the greenhouse environment. Variable conditions were arranged for the wintering of the Stevia rebaudiana plants within the experiment; and in spite of the various materials and thermal insulation layers, the plants have not successfully wintered in an unheated environment. On the contrary, in the heated greenhouse space, most of the plants have successfully wintered. The stevia seed germination was low and proves the opinion of the majority of authors. The dry matter yields also matched the yields mentioned in the specialised literature.

This master thesis is oriented on study antimicrobial effects extracts and macerates from cure Stevia rebaudiana Bertoni. Teoretical part describes basic information about plant Stevia, summary of health significant matters contained in Stevia and posobilities preparing extracts from Stevia. Antimicrobial effects extracts and macerates from cure Stevia were testing on food-borne bacteria (Bacillus cereus and Micrococcus luteus) and yeasts (Geotrichum candidum and Hansenula anomala). Microorganism, extracts and macerates were chosen on basis previous study (Study of antimicrobial effects Stevia Rebaudiana extracts, Eva Rakovská). For screening antimicrobial activity were determined the growth curves by using turbidimetrie for bacteria and direct treetment metod of cells number for yeasts. Antimicrobial effects were confirmed aplication with diffusion pit method on the agar ranges. From the results flow the testing extracts and macerates from stevia analysed antimicrobial effects. The best effect was demostrated on macerates and the most sensitive was bacteria Micrococcus luteus with the best inhibitoring effects.

The steviolglycosides are the natural, sweet substances from Stevia rebaudiana Bertoni. It affect human health positively and its sweetness is 300x stronger than the sweetness of sucrose. That's why it's used to sweetening the commercial products. Because of its potential properties it's good to have an appropriate method to isolate it. High performance liquid chromatography ( HPLC) is based on the separation of analyte between two immiscible phases with high pressure pump and appropriately chosen stationary phase in the column. Than the analytes come out from the column in different retention times. This master´s thesis follows up selection of the best HPLC system for isolation of the main steviolglycosides and its analysis in commercial products. In the theoretical part of the thesis is described the origin, basic characteristics, botanical description, cultivation and affect to the human health of Stevia rebaudiana Bertoni and its use in food industry. There are also concisely characterized the sweet substances contained in the plant, so called steviolglycosides. Than there are given the theoretical basics of high performance liquid chromatography, HPLC instrumentation and its specific applications at sleviolglycosides with the basic chromatographic parameters. The object of the first experimental part was to research the optimum conditions for time and separation effective chromatographic analysis and select the best chromatographic system for isolation of steviolglycosides. In the second experimental part, I have compared and defined the main steviolglycosides (stevioside, rebaudioside A) in nine selected products, commercially available in Czech republic, with the best chromatographic method. In these products was the contain of the stevioside or rebaudioside A confirmed or refused.

The diploma thesis deals with content substances with antioxidant effects in green spice. In the literary part, green spices, antioxidants are defined, and lesser known species are introduced, as well as the determination methods used in the practical part. In the practical part are given the individual determinations. The DPPH method was used to determine the antioxidant capacity, to determine the nitrate content ISE method was used, the flavonoids were determined using the Folin-Ciocalteaue reagent, and the standard in the phenols was gallic acid. Vitamin C was determined by liquid chromatography.

Pese a que las golosinas no son un producto imprescindible en la dieta, no hay que duda de que su consumo está muy generalizado tanto en la población infantil como en la adulta. Sin embargo, su ingesta elevada está relacionada con problemas de sobrepeso, caries y elevado índice glicémico. Para contrarrestar estos problemas se ha invertido mucho esfuerzo en el desarrollo de productos dietéticos. Para ello, se sustituyen los azúcares convencionales por edulcorantes artificiales que dan lugar a productos hipocalóricos, pero que presentan otros problemas relacionados con su efecto laxante y con una posible mayor incidencia de determinados cánceres. Actualmente existen en el mercado azúcares y edulcorantes naturales alternativos a la sacarosa con propiedades funcionales muy interesantes, como es el caso de la Isomaltulosa y la estevia. En el primer caso se trata de un azúcar no cariogénico, que aporta energía de forma gradual (bajo índice glicémico) y en el caso de la estevia se trata de un intenso edulcorante natural acalórico. Estudiar la sustitución total o parcial de los azúcares convencionales de las golosinas por este tipo de azúcares y edulcorantes más saludables y su influencia sobre la calidad de los productos es el objetivo general de este proyecto. Cabe resaltar que no se pretende formular un producto dietético sino un producto energéticamente similar a las golosinas tradicionales pero que aporten energía saludable. La sustitución de ingredientes implica cambios en las características de los productos que deben ser evaluados para optimizar el nivel de sustitución, por lo que es necesario abordar estudios sobre la influencia de estos ingredientes en las propiedades ópticas, mecánicas, sensoriales así como sobre la aceptación del producto y su estabilidad a lo largo del almacenamiento. / Periche Santamaría, A. (2014). STEVIA Y OTROS EDULCORANTES SALUDABLES EN LA FORMULACION DE GOLOSINAS FUNCIONALES: IMPLICACIONES TECNOLÓGICAS Y DE CALIDAD [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/45995 / Alfresco