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  • Responsive dehydration: sensor-driven optimisation of production cycles in a solar dehydrator
    Publication . Rossi da Silva, Paulo Bruno; Farrero, Bernardo; Silva, Arthur Marangoanha; Babo, Pedro S.; Ribeiro, Luís Frölén
    Drying is an effective method for preserving food. Compared to freezing, it consumes less energy and produces equivalent results. Solar heat is a great way for small farmers to create sustainable and affordable goods since it costs no energy. This article describes and explains how to operate equipment developed to address this issue. The equipment is currently undergoing experimental validation, and real-time monitoring and user notification systems have been installed to improve the production experience and the post-harvest conservation of food products. Additionally, the installed tracking system allows farmers to keep track of their products from the farm to the factory. This article demonstrates how integrated monitoring and tracking systems can enhance small farmer production by optimizing the drying process of acorns.
  • Exploring acorn shells: Phenolic composition and bioactive potential for sustainable valorization
    Publication . Mateus, Cristiano; Alonso-Esteban, José Ignacio; Finimundy, Tiane C.; Mandim, Filipa; Oliveira, Izamara; Babo, Pedro; Ferreira, Isabel C.F.R.; Barros, Lillian
    Pedunculate (Quercus robur L.), holm (Quercus rotundifolia Lam.), and cork (Quercus suber L.) oaks are abundant across the Portuguese landscape. This study aims to evaluate the phenolic composition and bioactivities of acorn shell samples and determine their potential as a functional compound source. In total, five acorn shell samples collected in different locations and from different species were analyzed: Q. rotundifolia (Q. rot-1 and Q. rot-2), Q. suber (Q. sub-1 and Q. sub-2) and Q. robur (Q. rob-1). A total of nine phenolic compounds were tentatively identified, namely gallic and ellagic acids and derivatives. Digalloyl hexoside was the compound detected in higher concentrations in all extracts (2.093 – 8.3 mg/g extract). Q. suber samples exhibited the lowest IC50 values for TBARS assay, lower than the positive control used (Trolox). Overall, the studied samples demonstrated the capacity to inhibit the proliferation of all tumor cell lines tested. Sample Q. sub-1 demonstrated the most promising antibacterial capacity. According to the results, the acorn shell extracts exhibited promising potential, and it may be interesting to conduct a deeper study on the samples of this species.
  • Acorn pre-drying: implications for the food industry
    Publication . Farrero, Bernardo; Ribeiro, Luís Frölén; Famiglietti, Antonio; Babo, Pedro
    In industry, 74% of the energy consumed is used in the form of heat. The food sector is characterised by a high share of processes that rely on industrial heat [1]. However, 90% of this thermal energy currently comes from fossil fuels, and only 9% is supplied by renewable sources [2]. The adoption of solar thermal technologies in the food industry offers multiple benefits that support its viability as an energy alternative to overcome this caveat. Firstly, by relying on a renewable and stable source. Manufacturers can reduce production costs and limit their exposure to the volatility of fossil fuel prices, thereby ensuring greater long-term price stability and predictability [3]. These reductions in energy costs may also be reflected in lower prices for the end consumer. Solar-assisted dehydration enables a decrease in moisture content, thereby limiting microbial growth and food spoilage [3]. In this regard, Solar Heat for Industrial Processes (SHIP) may also address food security concerns as storage losses are estimated to reach up to 20%, posing a critical challenge to food security [4]. The installation of in-situ pre-dehydration systems near harvesting zones provides clear benefits for energy efficiency and product quality. The Iberian Peninsula, notably, benefits from very high solar radiation, with many clear-sky days and extended sunlight periods, making it particularly suitable for solar-based pre-dehydration systems. By lowering produce weight and moisture before transportation, these systems decrease fossil energy demand during both industrial drying and large-scale transport [5]. This approach reduces the final product cost, as demonstrated by an in-situ solar dryer used for acorns in Alentejo holm oak groves. The passive, indirect mobile dryer, fitted with hanging bags, reduces acorn moisture content by 15% after 72 hours of drying, delays fruit spoilage, and cuts large-scale industrial heat input [6,4]. Thermal energy data from a factory case at Landratech, an acorn food producer involved in the MEDACORNET project, indicate that 15% in-situ pre-dehydration cuts thermal energy use by 52% during both initial and final drying stages of acorn flour manufacture [3]. This combined method lowers fossil fuel use, reduces losses, improves energy efficiency, and supports sustainability in the food processing sector.
  • Smart carving of hard-shell fruit with CO2 laser
    Publication . Farrero, Bernardo; Babo, Pedro; Ribeiro, Luís Frölén
    The application of CO₂ laser technology in food processing has gained significant attention due to its precision and adaptability. This study presents an intelligent system for carving hard-shell fruits, specifically acorns, to facilitate their shelling process. The proposed approach integrates real-time control and monitoring technologies to enhance precision and efficiency. A key challenge in acorn processing is the size and shell thickness variability, which complicates mechanical carving. The developed system employs a CO₂ laser to create precise incisions, ensuring optimal shell cracking during dehydration while preventing kernel damage. Experimental tests conducted at the Polytechnic Institute of Bragança identified optimal parameters—6 seconds of laser exposure at 40𝑊 power—for consistent and controlled carving. A thoughtful analysis system was implemented to assess pre- and post-carving conditions, enabling real-time adjustments to laser settings. This self-optimizing process improves the efficiency of the shell carving while reducing waste. The results demonstrate the feasibility of automated acorn carving using CO₂ laser technology, offering a scalable solution for industrial food processing with continuous control of the shell incision. Future research could explore advanced automation techniques to enhance system robustness and adaptability to different fruit types.