Percorrer por autor "Dias, Sara"
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- Advancing circular nutrition: the development of a freeze-dried snack based on broccoli stalk powderPublication . Soares, Inês; Machado, Daniela; Vedor, Rita; Sousa, Sérgio; Orvalho, Telma; Dias, Sara; Alves, Marco; Gomes, Ana MariaAim: The upcycling of agri-food by-products presents a sustainable strategy for reducing waste and creating value-added products. This study aimed to develop a freeze-dried snack incorporating broccoli stalks, an often discarded by-product, and to characterise its nutritional composition, microbiological quality, physicochemical properties and bioactive potential. Method: Broccoli stalks were freeze-dried, milled into a powder, and incorporated into a snack formulation that was subsequently lyophilised. Nutritional profile (moisture, total protein, total fats, ash, total carbohydrates and dietary fibre) was determined using AOAC methods. Microbiological quality was assessed by enumerating mesophiles in Plate Count Agar, yeasts and molds in Potato Dextrose Agar, and enterobacteria in Violet Red Bile Glucose Agar. Physicochemical properties (pH, water activity, texture and colour) were analysed over 4-months of storage. Bioactive potential was evaluated by quantifying total phenolic content (using Folin–Ciocalteu method) and measuring antioxidant activity (via ABTS assay) and antidiabetic activity (through ?-glucosidase inhibition assay). Results: The developed snack demonstrated high dietary fibre content (33.73 g/100 g) and substantially high protein levels (24.30 g/100 g). Microbial loads remained below 10? CFU/g, indicating adequate microbiological safety. Over four months of storage, a gradual decrease in pH was observed (from 6.39 to 5.90), accompanied by an increase in water activity (from 0.21 to 0.32). Texture analysis indicated an increase in both hardness (from 11.33 kg to 14.72 kg) and crispiness (from 43.75 kg·s to 45.54 kg·s), measured by texturometer (Texture Profile Analysis). Despite the slight increase in water activity, the product became firmer and crunchier over time. The reported colour variations (0 vs. 4 months) — ?E of 15.20 on the exterior and 14.42 on the interior — were not sufficient to significantly affect the product's visual appeal. Furthermore, the snack exhibited notable total phenolic content (2.121 mg gallic acid equivalents/g), along with substantial antioxidant (6.088 ?mol Trolox equivalents/g) and antidiabetic activity (73.95% ?-glucosidase inhibition). Conclusion: The lyophilised snack developed from broccoli stalks demonstrated a favourable nutritional profile, with adequate microbiological quality and promising antioxidant and antidiabetic properties. These findings support the incorporation of vegetable by-products in the formulation of sustainable, functional foods aligned with circular economy principles.
- Development of a new beetroot snack: impact of pulsed electric fields (PEF) pretreatment on the physicochemical and bioactive propertiesPublication . Orvalho, Telma; Dias, Sara; Machado, Daniela; Soares, Inês; Vedor, Rita; Gomes, Ana; Alves, MarcoIntroduction: Low-caliber vegetables are used to produce juices, flours and dried snacks. The valorization of non-marketable products through the development of new high value-added food products is aligned with current trends and contributes for a more sustainable and circular food sector. PEF is an emerging and promising technology with the potential to reduce freeze-drying time and improve the quality characteristics of processed fruit and vegetables. Objectives: This study evaluated the impact of PEF pretreatment on the physicochemical and bioactive properties of a freeze-dried snack made from low-caliber beetroot.
- Porto Solidário – Diagnóstico Social do PortoPublication . Azevedo, Joaquim; Baptista, Isabel; Vieira, Ilídia; Azevedo, Ana Sofia; Magalhães, Paulo; Dias, Sara; Martins, FranciscoRespondendo à solicitação do Conselho Local de Acção Social do Porto, formulada pela Fundação Porto Social e visando satisfazer os requisitos legalmente previstos para as redes sociais concelhias, a Universidade Católica Portuguesa - Porto, através da sua Faculdade de Educação e Psicologia, levou a cabo um processo de estudo, de auscultação e de participação cívica, desenvolvido ao longo de um período de dez meses (Setembro 2008 – Junho 2009) sob o enquadramento do projecto «Porto Solidário».
- Reimagining waste: exploring the nutritional and biological power of a freeze-dried snack based on broccoli stalk powderPublication . Soares, Inês; Vedor, Rita; Orvalho, Telma; Dias, Sara; Alves, Marco; Machado, Daniela; Gomes, Ana MariaIntroduction: The global food industry is progressively adopting closed-loop systems to promote sustainability and resource efficiency. Upcycling of food by-products has emerged as a critical strategy within this paradigm, with the aim of minimising waste while maximising the use of nutrient-rich residues. Broccoli stalks, which are often discarded during processing, are rich in dietary fibre and bioactive compounds, making them an ideal candidate for upcycling. Objectives: Investigate the nutritional composition of a freeze-dried snack based on broccoli stalk powder, determining its suitability for upcycling. Evaluate the bioactive properties of this novel food, focusing on the total phenolic content, antioxidant and antidiabetic activities. Conclusion: The freeze-dried snack based on broccoli stalk powder demonstrated multifunctional potential supported by an interesting nutritional profile, noteworthy phenolic content and valuable antioxidant and antidiabetic properties. Incorporating broccoli stalk powder into food formulations not only supports sustainability goals by reducing food waste, but also meets growing consumer demand for nutrient-enriched, health-oriented products. This approach exemplifies the dual role of up-cycled ingredients in driving nutritional innovation and environmental sustainability in the food industry.