António F. S. Silva

Abstract Soybean is a legume with high technological functionality, commonly used by the food industry as an ingredient in different products. However, soybean is an allergenic food whose undeclared presence in processed foods may represent a public health risk. In this work, it was developed an efficient electrochemical immunosensor, targeting the soybean trypsin inhibitor (Gly m TI) allergen using commercial anti-Gly m TI IgG, aiming at detecting/quantifying minute amounts of soybean in different food formulations. For this purpose, model mixtures of different foods (sausages, cooked-hams, biscuits) were prepared to contain known amounts of soybean protein isolate (100,000-0.1 mg kg(-1)) and submitted to specific thermal treatments (autoclaving, oven-cooking, baking). The electrochemical immunosensor allowed quantifying down to 0.1 mg kg(-1) of soybean in the three food matrices, raw and processed (0.0012 mg of Gly m TI/kg of matrix). Accordingly, the immunosensor is suitable for detecting traces of soybean in raw, processed, and complex foods, thus protecting 99 % of soybean-allergic patients.

Abstract Over the last decades, the interface between two immiscible electrolyte solutions (ITIES) attracted considerable attention of the scientific community due to their vast applications, such as extraction, catalysis, partition studies and sensing. The aim of this Review is to highlight the potential of electrochemistry at the ITIES for analytical purposes, focusing on ITIES-based sensors for detection and quantification of chemically and biologically relevant (bio)molecules. We start by addressing the evolution of ITIES in terms of number of publications over the years along with an overview of their main applications (Chapter 1). Then, we provide a general historical perspective about pioneer voltammetric studies at water/oil systems (Chapter 2). After that, we discuss the most impacting improvements on ITIES sensing systems from both perspectives, set-up design (interface stabilization and miniaturization, selection of the organic solvent, etc.) and optimization of experimental conditions to improve selectivity and sensitivity (Chapter 3). In Chapter 4, we discuss the analytical applications of ITIES for electrochemical sensing of several types of analytes, including drugs, pesticides, proteins, among others. Finally, we highlight the present achievements of ITIES as analytical tool and provide future challenges and perspectives for this technology (Chapter 5).

Abstract Biosensors, especially those designed for detecting food allergens like Gly m TI in soybean, play a crucial role in safeguarding individuals who suffer from adverse food allergies, extending to both individual well-being and broader public health considerations. Furthermore, their integration into food production and monitoring processes aids in compliance with regulatory standards, reducing the incidence of allergen-related recalls and protecting vulnerable populations. Technological advancements in biosensor development, such as increased portability, real-time monitoring capabilities, and user-friendly interfaces, have expanded their practical applications, making them indispensable in various settings, including manufacturing plants, food service establishments, and even at-home use by consumers. For the first time, a biosensor targeting the Gly m TI allergen based on molecularly imprinted polymer (MIP) technology was developed to detect/quantify soybean in complex food matrices and effectively address the detection challenges of complex and processed foods. The Gly m TI-MIP underwent a thorough validation process using anti-Gly m TI IgG raised as a polyclonal response to the trypsin inhibitor. Gly m TI-MIP was successfully tested across a range of food matrices, including tree nuts (e.g., peanuts, walnuts, and hazelnuts) and legumes (e.g., lentils, beans, and lupine), presenting minimal cross-reactivity with lupine and walnut. The innovative approach provided a linear response in the 1 ag mL(-1) - 10 mu g mL(-1) range, with a LOD<1 ag mL(-1). Applying the Gly m TI-MIP sensor to complex model foods allowed to detect 0.1 mg kg(-1) (0.00001 %) of soybean protein isolate in biscuits, ham, and sausages before and after the respective thermal treatments. The innovative biosensor can significantly improve food safety protocols by addressing the complexities of tracing allergens in processed and unprocessed food products. By ensuring rigorous allergen control, these biosensors may support global food trade compliance with international safety standards, boost consumer confidence, and promote transparency in food labeling, ultimately contributing to a safer food supply chain.

Abstract The possible fabrication of porous anodic oxide films on aluminium in ionic liquids based on choline dihydrogen citrate eutectic mixtures both with oxalic acid and isopropyl alcohol and ethylene glycol, has been investigated. The anodisation has been carried out in either potentiostatic or galvanostatic regime, at temperatures of 45-80 degrees C, for different process durations. Quite compact, uniform anodic alumina layers have been obtained. Based on AFM and SEM investigations, pore diameters between 50 and 80 nm and interpore distances in the range of 160-200 nm have been estimated, with values influenced by the electrolyte type and anodisation conditions. The highest anodisation rate of about 0.4 mu m min(-1) has been determined by applying operation temperatures of 60 degrees C. The recorded EIS spectra showed a pure capacitive behaviour and high anodic oxide resistances of 10(6)-10(7) omega cm(2) order.

Abstract A plasmonic nanostructure was constructed as a biorecognition element coupled to an optical sensing platform in sandwich format, targeting the hazelnut Cor a 14 allergen-encoding gene. The analytical performance of the genosensor presented a linear dynamic range between 100 amol L-1 and 1 nmol L-1 , a limit of detection (LOD) < 19.9 amol L-1 , and a sensitivity of 13.4 +/- 0.6 m.. The genosensor was successfully hybridized with hazelnut PCR products, tested with model foods, and further validated by real-time PCR. It reached a LOD <0.001% (10 mg kg(-1) ) of hazelnut in wheat material (corresponding to 1.6 mg kg(-1) of protein) and a sensitivity of 17.2 +/- 0.5 m. for a linear range of 0.001%-1%. Herein, a new genosensing approach is proposed as a highly sensitive and specific alternative tool with potential application in monitoring hazelnut as an allergenic food, protecting the health of sensitized/allergic individuals.