Browsing by Issue Date, starting with "2021-07-26"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- Dietary intake and tailored fermentation towards the development of functional cereal fibre-rich food products : bridge between Africa and EuropePublication . Vila Real, Catarina Pereira de Melo; Pinto, Elisabete Cristina Bastos; Gomes, Ana Maria PereiraDiets rich in high-sugar and -fat foods and poor in vegetable food products have been leading to the promotion or worsening of non-communicable diseases, whereas the consumption of vegetable products, namely whole grains, has been associated with beneficial effects on consumers’ health, with high fibre content being one of the main factors involved. In addition to the undeniable importance that the assessment of the dietary intake has in the design of strategies for the promotion of more balanced eating habits, the food industry is also a key player in this context. The development of food products with beneficial health properties is the first step for an effective consumption. Therefore, it is necessary to invest research efforts towards the development of innovative, functional food products, with a high-quality nutritional profile and tailored to consumers’ needs. In this sense, this Ph.D. thesis responds to these two research areas in the fields of food science and nutrition, proposing a two-fold strategy based on the following objectives: to study the dietary intake of adult urban Kenyans, and further comparison with Portuguese data; and, to develop and characterize an innovative fermented gluten-free whole grain-based product, with functional properties and an improved nutritional profile, expecting a positive impact on the nutritional deficits of the populations under study. Regarding the first objective outlined within this research work, a semi-quantitative food frequency questionnaire (FFQ) was firstly designed and developed, towards its further application in the target population. Once developed, this FFQ was validated (against three non-consecutive twenty-four hours recalls) and studied for its reproducibility (test-retest method). The developed FFQ presented higher nutrient intakes compared to the multiple recalls (median for total energy: 2998 kcal vs. 2032 kcal), thus showing moderate agreement between the classification of intake quartiles; nevertheless, it was shown to be a valid and reproducible (total energy median: 2978 kcal vs. 2506 kcal) tool for ranking Kenyan urban adults according to their dietary intake. This validated FFQ was then used for the study of the dietary intake of a wider heterogeneous and representative sample of urban adult Kenyans. Macronutrients’ intake ranges were within the WHO/FAO dietary guidelines. Cereals and grain products (34.0 %), sugar, syrups, sweets, and snacks (9.8 %), fruits (9.7 %), and meat and eggs (8.8 %) were the major contributors to total energy. Individual characteristics such as gender, age and level of education seemed to have implications on the choice of food groups. When compared to the Portuguese diet, the Kenyan diet was similar in terms of contributors to energy, but with some differences regarding food sources. Responding to the second objective, several bacterial strains (indigenous exopolysaccharides (EPS)-producing strains and commercial probiotics), in plain and combined cultures, were studied for fermentation of three different whole grain African flours, Sorghum, Pearl millet and Finger millet, expecting the selection of a bacterial consortium which would reveal fermentative capacity and after all show a positive impact on the physicochemical, nutritional, sensorial, biological profiles, and also on the human gut microbiota of the product under study. The selected bacterial consortium included the Lactiplantibacillus plantarum 299v probiotic strain and the EPS-producing Weissella confusa 2LABPT05 indigenous strain, inoculated in a 1:1 ratio (v/v), in finger millet suspended in an aqueous sucrose-based solution at 10 %, fermented at 30 ºC, 200 rpm, for 8 h. The final product obtained, hereinafter referred to as fermented yoghurt-like beverage (YLB), was shown to promote a significant growth of both strains (>108 colony-forming unit (CFU)/mL), and to have higher viscosity (35 vs. 12 mPa.s), significant EPS content (16 % vs. 0.3 %) contributing to matrix texturization and essential and non-essential amino acids (threonine, arginine, GABA, and glutamine), increased protein digestibility (64 % vs. 25 %) and high fibre content (4 g/100 g) comparatively to the native cereal prior fermentation. It was organoleptically acceptable, both per si and combined with a dairy matrix, an unsweetened plain yogurt. In terms of biological activity, antidiabetic activity (21 % vs. 14 %) and total phenolics (244 vs. 181 mg of gallic acid equivalents (GAE)/kg YLB) increased with fermentation. The digested fermented YLB contributed to the increase, during the first 6 h of feacal fermentation, of the Bifidobacterium’s number of copies of the 16S rRNA gene, which results were supported by the acidification, concomitant with an expressive metabolic activity reflected in the significant production of lactic acid and the acetic, propionic and butyric short chain fatty acids. In conclusion, this research work has created useful nutritional epidemiology tools that can be applied in future studies carried out in Kenya. In addition, it has increased food alternatives in the area of fermented probiotic products, specifically with the development of a novel synbiotic functional fermented African gluten-free cereal-based product. Thus, the work developed in this thesis brought increased scientific knowledge and pioneering novelty in several areas of research.
- Caracterização e avaliação da satisfação dos utentes da Clínica Dentária UniversitáriaPublication . Ramos, Ricardo Edgar Nogueira; Ribeiro, Paulo Alexandre de Oliveira Castro; Veiga, Nélio Jorge; Moura, Anna Carolina Volpi Mello deObjetivo: Estudar a satisfação dos utentes da Clínica Dentária Universitária da Universidade Católica Portuguesa - Centro Regional Viseu. Materiais e Métodos: Foi realizado um estudo quantitativo descritivo, correlacional com foco transversal. O instrumento de recolha de dados foi a Escala da Satisfação do Utente com a Medicina Dentária de autoria de Frade (10) , que contém 6 componente de avaliação da satisfação: obtenção de consulta; secretariado; sala de espera; clínica; médico dentista; custo. O estudo de confiabilidade, de validade de conteúdo e de validade da Escala revela um alfa de Cronbach global de 0,800. O item 3 da categoria “Clínica”, “Existe um grande Tempo de espera para fazer testes/raio”, foi eliminado por apresentar um alfa de Cronbach abaixo dos valores aceitáveis e que fazia baixar o alfa de Cronbach global, ficando a escala constituída por 30 itens. Resultados: A amostra é constituída por 116 utentes, maioritariamente feminina (56,0%), com uma média etária de 46,53±18,53 anos (variância de 19 e 80 anos), prevalecendo os pacientes que vão à consulta de 6 em 6 meses (38,8%) e 1 vez por ano (31,9%). Os dados descritivos das 6 componentes da satisfação indicam um grau mais elevado para a componente Médico Dentista, com uma média de 55,28±7,53 (variação de 36-65), seguindo-se a satisfação em relação à obtenção de consulta, com uma média de 18,51±1,69 (variação de 14-20). Constatou-se diferença estatisticamente significativa na componente custo (p=0,005), sendo os pacientes cujo propósito da consulta foi a destartarização que pontuaram mais. Conclusões: Decorrente do estudo efetuado constatou-se, na globalidade, que os pacientes revelam satisfação em relação à Medicina Dentária, tendo em conta as variações registadas.
- Acinetobacter and public health : risks posed by strains isolated from foodsPublication . Carvalheira, Ana Isabel Teixeira; Teixeira, Paula Cristina Maia; Silva, Joana Gabriela Laranjeira daAcinetobacter spp. has emerged as a pathogen of a major public health concern due to their increased resistance to antibiotics and their association with a wide range of nosocomial infections. The aim of this work was to gain insight into the food-related ecology and epidemiology of Acinetobacter spp. and to compare food and clinical strains regarding biofilm production, resistance to desiccation and disinfectant susceptibility. As there is no standard procedure to recover Acinetobacter spp. from food, two selective enrichment media were evaluated for the recovery of low levels of these organisms. Enrichment in Dijkshoorn enrichment medium followed by plating on CHROMagarTM Acinetobacter medium was shown to be a reliable method. Using this procedure, Acinetobacter spp. were isolated from 77.9% of fruit (35/50) and vegetables (39/45) samples and from all the meat analysed (50). A high genetic diversity established by pulsed-field gel electrophoresis (PFGE) was observed among the isolates and based on the analysis of the partial sequence of rpoB,181 strains ecovered from fruits and vegetables and 156 strains recovered from meat samples were identified as members of eighteen and thirteen distinct species, respectively. Acinetobacter calcoaceticus and Acinetobacter johnsonii were the most common species (both with the frequency of 26.5%) recovered from fruit and vegetables, while Acinetobacter guillouiae (34.9%), A. johnsonii (15%) and A. bereziniae (12%) were the most common species recovered from meats. Acinetobacter spp. belonging to the A. baumannii group (11.0% from fuit and vegetables, 18.7% from meats), which is most frequently associated with nosocomial infections worldwide, were also recovered. Most of these strains were resistant to some of the antimicrobials recommended to treat Acinetobacter infections such as piperacillin¬tazobactam, ceftadidime, ciprofloxacin, as well as to colistin and polymyxin B, the last-resort drugs to treat infections caused by multidrug-resistant Acinetobacter. Overall, 29.8% of the isolates from fruit and lettuces, and 51.2% of the isolates from meats were classified as multidrug¬resistant (MDR), and 4.4% and 9.6% as extensively drug-resistant (XDR), respectively. The taxonomic status of six strains of Acinetobacter obtained from meats, was investigated, using a polyphasic analysis, since their partial rpoB sequence similarities to other Acinetobacter species with validly published names were lower than 95%. The species status of two groups was confirmed by comparative multilocus sequence analysis, including also the gyrB, recA and 16S rRNA genes, low (below 95%) whole-genome sequence (WGS) average nucleotide identity (ANI) values and low (below 70%) digital DNA¬DNA hybridization (dDDH) similarities between the WGS of the proposed type strains of each novel species and the representatives of the known Acinetobacter species. Phylogenomic treeing from core genome analysis supported these results as well as, the coherence of each new species¬lineage was supported by matrix-assisted laser desorption/ionization time¬of-flight mass spectrometry, differentiation of the species at the protein level by cellular fatty acids profiles and by unique and differential combinations of metabolic and physiological properties shared by each novel species. These strains represented two coherent lineages that were distinct from each other and from all known species, and the names Acinetobacter portensis sp. nov. (four strains: AC 877T = CCUG 68672T = CCM 8789T as type strain), and Acinetobacter guerrae sp. nov. (two strains: AC 1271T = CCUG 68674T = CCM 8791T as type strain) were proposed for these novel species. Control the dissemination of A. baumannii is challenging mainly due to its high adaptability to adverse environmental conditions. The biofilm formation ability in silicon and stainless steel, the resistance to desiccation on a stainless steel surface and the susceptibility to eleven commercial antimicrobial products was compared between food (10) and clinical strains (10). The clinical strains were selected based on their presumptive persistent and non-persistent status among 104 isolates recovered from patients in Hospital de São Marcos, Braga. Predominant clones of MDR A. baumannii repeatedly isolated in different years (2004 to 2007) or in different months (isolates recovered in 2014) were defined as persistent and strains recovered sporadically (with a PFGE pattern observed only once among all isolates) were defined as non-persistent. There were no significant differences between clinical and food strains since all the strains were able to form biofilm on silicon and stainless steel surfaces, exhibited desiccation resistance capacity ranging from 14 to 77 days and were susceptible to disinfectants at the recommended use concentrations. However, the biofiom-forming capacity of persistent strains was significantly higher than the non-persistant strains on both surfaces. The resistance to desiccation of persistent strains (mean survival time: 65.8 days) was also significantly longer than that of the non-persistent strains (mean survival time: 35.8 days). Therefore, these factors may contribute to their maintenance in the hospital setting. A high intra¬species variability in susceptibility to disinfectants was observed for A. baumannii and there was no correlation between the efficiency of disinfectants and the origin of the isolates. Moreover, no correlation between antibiotic resistance and biofilm production, resistance to desiccation and disinfectant susceptibility was found. Therefore, food products may be a potential vehicle of spread in the community and clinical environments of Acinetobacter strains resistant to several antibiotics, able to produce biofilm and to survive to desiccation, which may led to nosocomial and community¬acquired infections in susceptible individuals.