2 resultados para |Aditivo alimentar
em Universidade de Madeira
Resumo:
A indstria agro-alimentar produz anualmente uma grande quantidade de subprodutos, ainda tratados como desperdcio. A indstria cervejeira, em particular, est associada produo de vrios resduos, entre os quais o bagao de malte, tambm designado bagao de cerveja ou dreche. Sendo produzida numa razo de 20 kg por cada 100 litros de cerveja, s na Ilha da Madeira a produo de dreche ultrapassa as 2000 toneladas/ano. O presente trabalho foi realizado com o intuito de estudar a utilizao da dreche como material de partida para a extraco de cido ferlico, um cido hidroxicinmico com elevada bioactividade e aplicaes. A caracterizao fsico-qumica da dreche permitiu determinar um teor de humidade de aproximadamente 70% e um teor de cinzas de cerca de 3,6%. A distribuio granulomtrica da dreche seca, revelou que cerca de 70% das partculas que a constituem tm dimenso entre 1 e 0,25 mm. A extraco com acetona produziu um extracto contendo 5 compostos de natureza fenlica, determinados por LC-MS. A hidrlise alcalina uma das tcnicas que permitem a extraco de compostos como o cido ferlico a partir de matrizes lenhocelulsicas foi estudada em amostras de dreche submetidas a tratamento prvio. O pr-tratamento com cido diludo demonstrou ser eficiente na extraco do cido ferlico a partir da dreche. A extraco em autoclave mostrou ser eficiente na extraco do cido ferlico [0,28% (m/m)] e uma simplificao do procedimento posterior reaco de hidrlise alcalina fez aumentar o rendimento de extraco em cerca de 84%, comparativamente ao procedimento habitual. As condies ptimas de hidrlise alcalina em tubos autopressurizados aconteceram a 120 C, por 1,5 horas, num rcio de 20 mL/g e NaOH (1,5%). O processo de purificao do cido ferlico extrado por adsoro numa resina sinttica resultou em percentagens de adsoro de 90,83% e de dessoro em torno dos 68,70%.
Resumo:
Microalgae are promising microorganisms for the production of food and fine chemicals. Several species of microalgae are used in aquaculture with the purpose of transfer bioactive compounds up to the aquatic food chain. The main objective of this project was to develop a stressinducement strategy in order to enhance the biochemical productivity of Nannochloropsis gaditana, Rhodomonas marina and Isochrysis sp. for aquaculture purposes having in account their growth and organizational differences. In this regard, two experiments were design: the first one consisted on the alteration of overall nutrient availabilities in growth medium; and the second one comprised changes in nitrogen and sulfur concentrations maintaining the concentrations of the other nutrients present in a commercial growth medium (Nutribloom plus), which is frequently used in aquaculture. Microalgae dried biomass was characterized biochemically and elemental analysis was also performed for all samples. In first experimental design: linear trends between nutrient availability in growth media and microalgae protein content were obtained; optimum productivities of eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) were attained for both R. marina and N. gaditana in growth media enriched with 1000 L L-1 of nutrient solution whereas for Isochrysis sp. the double of Nutribloom plus was needed; the decrease of glucans and total monosaccharides with nutrient availability for R. marina and Isochrysis sp. showed the occurrence of a possible depletion of carbohydrates towards lipids and proteins biosynthesis. Second experimental desing: N. gaditana exhibited the highest variation in their biochemical composition against the applied perturbation; variations observed for microalgae in their biochemical composition were reflected in their elemental stoichiometry; in N. gaditana the highest nitrogen concentrations lead to overall maximum productivities of the biochemical parameters. The results of the present work show two stress-inducement strategies for microalgae that may constitute a base for further investigations on their biochemical enhancement.
