Since sweet potatoes, which also furnish vitamin A, are a common food in the popular diets of Texas and are so generally grown over the state, the purpose of this study is (1) to ascertain the amount of vitamin C in eight of the varieties most commonly grown and (2) to determine the effect of the three most popular methods of cooking (boiling, baking, and candying) on the vitamin C content of these varieties of sweet potatoes.

The purposes of this study are (1) to determine the ascorbic acid content of a variety of fruit juices available in Denton, Texas, during March to July, 1943; (2) to ascertain the loss of ascorbic acid when canned grapefruit, orange, pineapple, and apple juices are opened and stored in the home refrigerator for several days' use; and (3) by means of data obtained, to make recommendations as to the most advantageous ways of using one's "points" in purchasing canned fruit juices for their ascorbic acid value.

The purpose of the present study is to determine the ascorbic acid values of orange marmalades made with and without commercial pectin; and to compare these values with those obtained by testing random samples of home and commercial prepared orange marmalades.

A study of the ascorbic acid metabolism of a group of fifty college women in the North Texas State Teachers College between the months of April and July, 1943.

Reações de oxidação lipídica são responsáveis pelo desenvolvimento de sabores e odores desagradáveis tornando os alimentos impróprios para consumo, sendo necessário o uso de antioxidantes. O ácido ascórbico (AA) é um antioxidante muito eficaz, que exibe função vitamínica, no entanto é relativamente instável. Com o objetivo de aumentar a estabilidade do AA e, consequentemente, facilitar sua aplicação em produtos alimentícios, os métodos de encapsulação por coacervação complexa e por dispositivos microfluídicos foram testados. Primeiramente foi apresentada a Revisão Bibliográfica no Capítulo 1, e em seguida, a encapsulação por coacervação complexa, como será visto no Capítulo 2. Neste caso, nove tratamentos foram obtidos utilizando-se gelatina e goma arábica como materiais de parede e analisados com relação à morfologia, por microscopia ótica e eletrônica de varredura, umidade, atividade de água, higroscopicidade, solubilidade, potencial zeta, espectroscopia no infravermelho por transformada de Fourier (Ftir), tamanho e distribuição de tamanho de partículas, cor instrumental, eficiência de encapsulação e estabilidade do material encapsulado. No capítulo 3 serão apresentados resultados obtidos na encapsulação do AA pelo método de dispositivos microfluídicos. Cinco tratamentos foram obtidos, sendo analisados com relação à morfologia, por microscopia ótica, eletrônica de varredura e confocal, eficiência de encapsulação, tamanho e distribuição de tamanho de partícula e estabilidade do material encapsulado. A obtenção das microcápsulas de AA pelos dois métodos citados foi viável uma vez que apresentaram altos valores de eficiência de encapsulação e ótima atuação em relação à proteção do AA durante estocagem. Comparando-se os dois métodos, as cápsulas obtidas por dispositivos microfluídicos conferiram melhor estabilidade ao ácido ascórbico, no entanto amostras obtidas por coacervação complexa foram aplicadas em salsicha devido a maior quantidade de AA presente em sua constituição. O efeito da aplicação das microcápsulas nas salsichas foi avaliado durante 40 dias de armazenamento refrigerado como será visto no Capítulo 4. Cinco tratamentos foram elaborados e analisados de acordo com a estabilidade da emulsão cárnea durante o processamento, umidade, atividade de água, alteração do pH, determinação da cor instrumental, perfil de textura instrumental, estabilidade oxidativa pelo método de substâncias reativas ao ácido tiobarbitúrico (TBARS) e aceitação sensorial. A aplicação das microcápsulas de AA em salsicha foi possível sem comprometer a qualidade do produto final. Todos os dados obtidos foram analisados estatisticamente por análise de variância ANOVA e teste de Tukey, ao nível de 5% de significância com auxílio do programa SAS. Os experimentos relacionados à encapsulação por coacervação complexa e aplicação das microcápsulas em salsicha foram realizados no Laboratório de Produtos Funcionais, nas dependências do Departamento de Engenharia de Alimentos da FZEA/USP. Os experimentos relacionados à utilização de dispositivos microfluídicos foram realizados nos laboratórios do professor David A. Weitz, da Escola de Engenharia e Ciências Aplicadas de Harvard, da Universidade de Harvard, Cambridge, Estados Unidos. / Lipid oxidation reactions are responsible for the development of unpleasant tastes and odors making food unfit for consumption. For this reason, the use of antioxidant is necessary. Ascorbic acid (AA) is a very effective antioxidant with vitamin function, however it is relatively unstable. With the aim of increasing the stability of AA and thus improve its application in food products, the methods of encapsulation by complex coacervation and microfluidic devices were tested. First of all the Literature Review is presented in Chapter 1. The encapsulation by complex coacervation can be seen in Chapter 2. For this methodology, nine treatments were obtained using gelatin and gum Arabic as encapsulant agent and analyzed regarding to morphology by optical and scanning electron microscopy, moisture, water activity, hygroscopicity, solubility, Zeta Potential, Fourier transform infrared Spectroscopy (FTIR), particle size and particle size distribution, instrumental color, encapsulation efficiency and stability of the encapsulated material. The results obtained for AA encapsulation by microfluidic device will be presented in Chapter 3. Five treatments were obtained and analyzed regarding to morphology by optical, scanning electron and confocal microscopy, encapsulation efficiency, particle size and particle size distribution and stability of the encapsulated material. The production of AA microcapsules by the two methods mentioned was feasible once that showed high levels of encapsulation efficiency and optimal performance regarding to the protection of AA during storage. Comparing the two methods, the microcapsules obtained by microfluidic device conferred better stability to AA, however samples obtained by complex coacervation were applied in sausage due to the greater amount of AA in its constitution. The effect of the application of microcapsules in sausages was evaluated during 40 days at refrigerated storage as it will be seen in Chapter 4. Five treatments were prepared and analyzed according to the stability of the meat emulsion during processing, moisture, water activity, pH changes, determination of instrumental color, instrumental texture profile, oxidative stability by the method of thiobarbituric acid reactive substances (TBARS) and sensory acceptance. The application of AA microcapsules in sausage was possible without compromising the quality of the final product. All data were statistically analyzed by ANOVA and Tukey test, at 5% of significance with the use of SAS software. The experiments related to encapsulation by complex coacervation and application of microcapsules in sausage were carried out at Laboratory of Functional Products, at Department of Food Engineering, FZEA / USP. The experiments related to the use of microfluidic devices were performed in the laboratories of Professor David A. Weitz, at School of Engineering and Applied Sciences of Harvard, at Harvard University, Cambridge, USA.

This master's thesis deals with the characterization of elderberry fruit (Sambucus nigra L.) with emphasis on the aroma active compounds (AAC) and vitamin C (ascorbic acid (AA), dehydroascorbic acid (DHA)). The theoretical part gives a brief outlook on the chemical composition and attributes of Sambucus berries, its healing properties and the means of processing. The rest of the theoretical part thoroughly examines the AAC and vitamin C. The suitable assessment methods are also discussed. The experimental part of the work consists of two main tasks. The first one was to assess the aroma profile of Sambucus berries using the HS-SPME-GC-FID. 18 samples were examined (the wild elderberry and 17 cultivated varieties). In total, 24 different volatile aroma active compounds were identified and quantified, 12 of which belonged to alcohols, 5 to aldehydes, 4 to esters, 1 to acids and 2 “other” compounds (linalool and -damascenone). The chemical composition of the individual samples was not uniform; no single sample contained all of the identified compounds. The second task was to assess the total vitamin C content (the sum of DHA and AA) using the HPLC. For the purpose of reducing DHA to AA three reducing agents were examined (DTT, TCEP and L-cysteine) at two different pH levels (7 and 4). TCEP at pH 4 turned out to be most efficient and was subsequently applied on the samples of 5 selected elderberry varieties. The measured vitamin C content was within the range of 5,1 – 13,0 mg per 100 g of fruit.

Objetivos: La presente tesis tuvo como objetivo general caracterizar nutricionalmente un néctar elaborado a partir de lactosuero dulce, y Myrciaria dubai (camu - camu) edulcorado con Sstevia rebaudiana (stevia). Materiales y métodos: Fue un estudio experimental de laboratorio, donde se evaluó el efecto de las dosis de lactosuero (30%, 50% y 70%) y pulpa de camu camu (70%, 50% y 30%) sobre sus propiedades nutricionales y sensoriales. Resultados: Los análisis físicoquímicos de las tres formulaciones cumplieron con los estándares de calidad para bebidas de frutas. La evaluación sensorial se realizó a 79 panelistas no entrenados, los cuales determinaron que la formulación que contenía 70% pulpa de camu - camu y 30% lactosuero fue la que presentó el mayor puntaje en la evaluación sensorial siendo solo de 2,5/7 en una escala hedónica, por lo que se recomienda mejorar las formulaciones. Discusión: El análisis físico químico de las bebidas formuladas mostró que el néctar a base de lactosuero con camu camu presentó en 100 gramos de producto un bajo nivel de calorías un promedio de 23 Kcal/ 100g, 5,3% de carbohidratos, 0,4% de proteína, 0,1% de grasa, 93,8% de agua, 0,4% de cenizas. El análisis microbiológico indicó que cumplen con la Norma sanitaria que establece los criterios microbiológicos de calidad para néctares, lo que garantiza la inocuidad del producto. Se realizó el análisis de vitamina C en la pulpa de camu-camu, la mezcla de la bebida antes de la pasteurización y luego de la pasteurización siendo estos: 195,8mg/100g, 180,7 mg/100g, 168,3mg/100g respectivamente observándose que en el producto final existe una disminución de alrededor del 14,04% con respecto al contenido inicial en el camu-camu. Conclusión: Las características nutricionales del néctar elaborado a partir de lactosuero, camu camu edulcorado con Stevia presentó un leve incremento en el valor de proteínas (0,3g/100ml) que los néctares comerciales (0g/100ml) que se expenden en el país, pero destaca por su contenido alto de vitamina C (168,3mg/100ml), sin embargo, la incorporación del lactosuero no resultó en una clara aceptabilidad sensorial en jóvenes por ende se rechaza la hipótesis que el lactosuero aumenta la aceptabilidad sensorial. Asimismo, se acepta la hipótesis que aumenta la calidad nutricional del néctar en comparación con bebidas similares que se expenden en el mercado nacional. / Objective: The aim of this thesis was to characterizing nutritionally a nectar elaborated from whey and Myrciaria dubai (camu - camu) sweetened with Stevia rebaudiana (stevia).Materials and Methods: It was an experimental laboratory study, where was evaluated the effect of the dose of whey (30%, 50% and 70%) and camu camu pulp (70%, 50% and 30%) on its sensory and nutritional properties. Results: The physical-chemical results of the three formulations got the quality standards for fruit beverage. The sensory evaluation was performed with 79 untrained panelists, who determined that the formulation contained 70% of camu-camu pulp and 30% of of whey it was the one that presented the highest score in the sensory evaluation being only 2.5 / 7 on a hedonic scale, so it is recommended to improve the formulations. Discussion: The physical chemical analysis of the formulated beverages showed that the whey-based nectar with camu camu showed a low calorie level in 100 grams of product, an average of 23 Kcal / 100g, 5.3% carbohydrates, 0.4% of protein, 0.1% fat, 93.8% water, 0.4% ash. The microbiological analysis indicated that they satisfy the sanitary norm that establishes the microbiological criteria of quality for nectars, which guarantees the safety of the product. We realized the analysis of vitamin C in the camu-camu pulp, in the mixture of the beverage, before the pasteurization and after the pasteurization, being these: 195,8mg / 100g, 180,7 mg / 100g, 168,3mg / 100g respectively, evidencing that in the final product there is a decrease of about 14,04% with respect to the initial content of camu -camu. Conclusion: The nutritional characteristics of the nectar made from whey, camu camu sweetened with Stevia presented a slight increase in the value of proteins (0.3g / 100ml) than commercial nectars (0g / 100ml) that are sold in the country, but it stands out Due to its high content of vitamin C (168.3mg / 100ml), however, the incorporation of whey did not result in a clear sensory acceptability in young people, therefore the hypothesis that whey increases sensory acceptability is rejected. Likewise, the hypothesis that increases the nutritional quality of nectar in comparison with similar beverages that are sold in the national market is accepted. / Tesis

This thesis deals with the evaluation of the available books and possibilities of the growing of sea buckthorn (Hippophaë rhamnoides L.) in the Czech Republic. Physical and chemical values which are necessary for planting sea buckthorn in the area of Lednice were measured and specified. The female plants of the species of ´Buchlovsky 1´, ´Hergo´, ´Leikora´, ´Vitamínová´, and the male plant of ´Buchlovsky 2´, ´Pollmix´ and ´Ruský´ were studied and evaluated. As for the products made of sea buckthorn, speads and juices with various amount of sugar, baked tea and sweetened sea buckthorn powder were evaluated from the sensory point of view. The issues of the growing and processing of s ea buckthorn were discussed with the producers of planting stock, commercial croppers and manufacturers within the whole Czech Republic. Sea buckthorn is not widespead and commercial area for growing does not meet the needs of the manufacturers. If all biotic and abiotic factors are taken into account, the growing of sea buckthorn is recommended in the Czech Republic.

The Diploma Thesis is focused on the analysis of the antioxidant qualities and attributes of different kinds of tea under their specific methods of preparation. Literature overview provides history, processing technology, distribution and the most common means of tea preparation as well as its content substances. The Thesis discusses the overall containment of polyphenols and antioxidant capacity based on the FRAP and DPPH methods but also the amount of vitamin C in the tea samples. The Thesis elaborates on the undertaken sensor analysis of chosen samples and examines the tea content substances during its traditional preparation as well as during its preparation in a non-typical way.

In the literary part this work focuses on the history, botanical classification and description of plants. The method of cultivation and harvesting is summarized. Described are varieties that can be use the practical part. It is the use of seabuckthorn and its contents. The experimental parts summarize and evaluate the possibilities of growing seabuckthorn on the experimental plot in Žabčice. Here were observed female varieties ´Aromat´, ´Augustinka´, ´Buchlovický 1´, ´Habeg´, ´Hergo´, ´Krasavice´, ´Leicora´, ´Perčik´, ´Sibirskij rumjaněc´, ´Sluníčko´, ´Trofimofský´ and ´Vitamínová´, male varieties ´Buchlovický 2´, ´Gnom´ and ´Polmix´. Habitat conditions of varieties and phenological phase were observed. The color, shape, weight and size of the fruit were assessed. Furthermore, yield and cubature shrubs. Vitamin C, dry matter and refractometric dry matter values were determined. Sensory properties of products were assessed.