Teses de Mestrado ESA
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- Freeze-Dried Nutritious Chestnut Preparation Enriched With Minerals From Thermal WaterPublication . Trad, Hiba; Roriz, Custódio Lobo; Heleno, Sandrina A,; Nassri, RymChestnuts have long been a staple food of rural populations, valued for their high nutritional content, including vitamins such as vitamin C and B6, fiber, minerals and carbohydrates, all while being free of cholesterol. In Portugal, chestnuts are a widely cultivated product, leading to significant waste generation, much of which are often discarded. To address this issue, it is crucial to find sustainable methods for repurposing these by-products into high-value products. In this context, the present work focuses on the valorisation of non- commercial chestnuts to develop a nutritional preparation using the freeze-dried technique. This method involves a dehydration process that removes water from food, preserves the nutritional quality of chestnut, and to extends their shelf life. Additionally, the preparation will be enriched with beneficial minerals derived from the thermal water, further enhancing its nutritional value. This approach aligns with the principals of sustainable food production by reducing waste and contributing to the circular economy. Four Portuguese chestnut varieties (Amarelal, Boa Ventura, Judia and Longal) were characterized regarding their nutritional composition, chemical profile, mineral composition and bioactive properties. Nutritional evaluation was caried out by determining the fat, protein, ash, carbohydrates and energy value. Chemical characterization was performed resorting to different chromatographic techniques, namely High-Performance Liquid Chromatography with refractive index detection (HPLC-RI) for free sugars, High-Performance Liquid Chromatography coupled to fluorescence detection (HPLC-FL) for tocopherols, Ultra-Fast Liquid Chromatography coupled to photodiode array detection (UFLC-PDA) for organic acids, and Gas Chromatography with flame ionization detection (GC-FID) for fatty acid profiling. Mineral composition and bioactive properties, including antimicrobial activity and cytotoxicity, were also evaluated. The results showed that chestnuts presented relevant and functional properties, with carbohydrates representing the major macronutrient and unsaturated fatty acids being predominant in the lipidic fraction. Sucrose was the major free sugar determined, while regarding organic acids, tocopherols and essential minerals presented themselves in considerable amounts. All varieties exhibited moderated to low antimicrobial potential and low cytotoxicity, supporting their potential application in food products. The incorporation of thermal water contributed to the mineral enrichment of the freeze-dried formulation while maintaining their nutritional quality. The final product, rich in vitamins, minerals, and bioactive compounds, demonstrated promising potential as a functional food ingredient for applications such as health drinks, fortified foods, or dietary supplements. Overall, this work highlights the feasibility of valorizing non-commercial chestnuts through sustainable technological approaches, contributing to waste reduction, food innovation, and the development of value-added products with potential industrial applications.
- Natural products as collagenase inhibitors: a molecular modelling approachPublication . Carvalho, Eduardo Miguel Da Costa; Abreu, Rui M.V.; Mateus, CristianoSkin photoaging is a process that involves the degradation of extracellular matrix proteins, including collagen and elastin. These are essential components of the skin, providing sturdiness and elasticity; their degradation leads to the loss of tensile strength, flexibility, and the development of wrinkles. This process is mediated by matrix metalloproteinases (MMPs), including Collagenase (MMP-1). Excessive production of MMP-1 accelerates extrinsic skin ageing, which may be mitigated by applying anti-ageing compounds with anti-collagenase activities. Therefore, there’s interest in discovering better MMP-1 inhibitors, with emphasis on natural compounds, since there’s been a significant shift in market interest towards the usage of natural products in cosmeceutical development. One way to quickly test a wide range of compounds with minimal costs is to rely on in silico methodologies to predict compound bioactivities. This study aimed to explore different molecular modelling approaches to assess the inhibition potential of different natural products against MMP-1, namely molecular docking and quantitative structure-activity relationship (QSAR) modelling. For this purpose, a virtual library of 83 known MMP-1 inhibitors was developed and used to develop QSAR models. QSAR model 2 was selected for further use since it presented solid statistical parameters, with an R² value of 0.96 and a RMSE value of 0.191. A library of natural compounds, with a structure similar to compounds used to develop the QSAR models, was constructed using the COCONUT database of natural compounds. A total of 715 compounds were gathered, and the QSAR model 2 was applied to it. The molecular docking approach was also validated by performing a Re-Docking protocol, and the validated approach was applied in the same library of 715 compounds. Finally, the data from the two methods were combined. Using this data, the tested compounds were ranked according to their combined inhibition probability (%) and the top 10 ranked compounds were analyzed in terms of their structure and binding conformations. In the future, it would be of interest to buy these compounds and test them experimentally to validate these in silico models and confirm the predicted inhibition activity. If this activity is confirmed, then these compounds could be used in cosmeceutical and drug design applications.