Percorrer por autor "Teixeira, Raquel"
A mostrar 1 - 8 de 8
Resultados por página
Opções de ordenação
- A flow-based method as a more sustainable tool for total protein monitoring in industrial processesPublication . Teixeira, Raquel; Ribas, Tânia C. F.; Almeida, André; Pintado, Manuela; Rangel, António O. S. S.The growing interest in protein hydrolysates highlights the need for fast and reliable analytical methods to assess their nutritional and functional properties. Total protein quantification is a key parameter for characterizing by-products, monitoring hydrolysis processes, and evaluating hydrolysates. In this work, a sustainable flow-based spectrophotometric method was developed and optimized using the Biuret method [1]. The flow injection analysis (FIA) system employs a double injection strategy in a continuous stream, significantly reducing reagent consumption compared to the conventional procedure, with a 75% decrease in Biuret reagent and an 83% reduction in sodium hydroxide, while maintaining analytical accuracy (Figure 1). Optimization of flow and chemical parameters enabled robust performance across different matrices used during enzymatic hydrolysis. The dynamic range of the method was 0.100 results were in agreement with those obtained with the reference method (<10% deviation). Additionally, the herein proposed method reduced the analysis time from 30 to 3 minutes per sample (triplicate). The proposed protocol offers a faster, greener, and reliable tool for the food industry, supporting sustainability in quality control and nutritional evaluation.
- A flow-based method as a more sustainable tool for total protein monitoring in industrial processesPublication . Teixeira, Raquel; Ribas, Tânia C. F.; Almeida, André; Pintado, Manuela; Rangel, António O. S. S.Introduction: This proposal aims to promote the circular economy, minimizing waste and enhancing environmental sustainability. In collaboration with several companies, the project uses by-products, subjecting them to hydrolysis processes to obtain hydrolysates. Objective: The main objective is to develop a flow spectrophotometric method to quantify the total soluble protein of these by-products, valuing them in the production of new products, such as animal feed, among others. Conclusion: This method is a robust, versatile, and accurate tool for quality control in the food industry, supporting a circular economy.
- Flow-based method for total protein content monitoring in by-products hydrolysatesPublication . Teixeira, Raquel; Ribas, Tânia C. F.; Almeida, André; Pintado, Manuela; Rangel, A. O. S. S.For this purpose, the conventional and reliable Biuret method was used. This method was chosen for its ease of preparation and the use of reagents with associated low toxicity. The flow-based approach consisted of a double injection of the sample and reagent in a continuous stream, resulting in the reduction of the reagent consumption. For the development of the flow injection analysis (FIA) system, essential parameters, including reagent concentration, flow rate and reactor length, were optimized. The method was validated across various matrices, addressing potential interferences, and demonstrated repeatability and reproducibility. This optimized protocol offers a robust, efficient tool for the food industry, enhancing quality control and nutritional assessments.
- Optimized flow-based protein content monitoring in by-products hydrolysates with two merge zones integrationPublication . Teixeira, Raquel; Ribas, Tânia C. F.; Almeida, André; Pintado, Manuela; Rangel, António O. S. S.In the past few years, the interest in protein hydrolysates has been growing exponentially due to their nutritional and functional benefits for both human food and animal feed. In this context, total protein content is a key parameter for characterizing by-products, monitoring the hydrolysis processes, and the hydrolysates. This study aims to develop an accurate and expeditious, revisiting a merging zones flow-based spectrophotometric method for total protein quantification in food samples and hydrolysates. For this purpose, the conventional and reliable Biuret method was used. This method was chosen for its ease of preparation and the use of reagents with associated low toxicity. The flow-based approach consisted of a double injection of the sample and reagent, using a commutator, in a continuous stream, resulting in the reduction of the reagent consumption. For the development of the flow injection analysis (FIA) system, essential parameters, including reagent concentration, flow rate and reactor length, were optimized. The method was validated across various matrices, addressing potential interferences, and demonstrated repeatability and reproducibility. This optimized protocol offers a robust, efficient tool for the food industry, enhancing quality control and nutritional assessments.
- Processing slime from snail (Helix aspersa maxima): a preliminary study on the effect on microbial loadPublication . Teixeira, Raquel; Barbosa, Joana; Albano, Helena; Maciel, Cláudia; Silva, Joana; Saraiva, Jorge A.; Castro, Sónia M.; Teixeira, PaulaSlime from earth snails (Helix aspersa maxima) is a sub-product often used in the cosmetic industry. Due to its origin, a decontamination process ought to be considered. After exposure to UV radiation, no significant (P > 0.05) reduction of the initial microbial load of slime was observed, while treated at 60 °C, a decrease of 4.0 log CFU∙mL-1 was obtained (when compared to non-treated slime). A similar reduction was attained for pressurized (500 MPa) slime. The sequential combination of temperature and pressure treatment had a similar effect (P > 0.05) on the microbial load when compared to 400 MPa (30 min), but the reduction was higher when compared to the less intense treatments (60 °C, 15 min; 400 MPa, 15 min). Overall, the results suggest that pressure ( 400 MPa) is a promising technology for processing snail slime, which can have positive effects on its microbial load, for further use in the cosmetic industry
- Revisiting merging zones in a flow-based approach for the total protein content monitoring in hydrolysatesPublication . Teixeira, Raquel; Ribas, Tânia C. F.; Almeida, André; Pintado, Manuela; Rangel, António O. S. S.In the past few years, the interest in protein hydrolysates has been growing exponentially due to their nutritional and functional benefits for both human food and animal feed. In this context, total protein content is a key parameter for characterizing by-products, monitoring the hydrolysis processes, and hydrolysates. This study aims to develop an expeditious, revisiting a merging zones flow-based spectrophotometric method for total protein quantification in hydrolysates (Fig.1). For this purpose, the conventional and reliable Biuret method was used. The flow-based approach consisted of a double injection of the sample and reagent, using a injector commutator, in a continuous stream, resulting in the reduction of the reagent consumption. For the development of the flow injection analysis (FIA) system, essential parameters, including reagent concentration, flow rate and reactor length, were optimized. The method was validated across various matrices, addressing potential interferences, and demonstrated repeatability and reproducibility. This optimized protocol offers a robust, efficient tool for the food industry, enhancing quality control and nutritional assessments.
- Sequential injection chromatographic system for the expeditious molecular weight screening in hydrolysatesPublication . Teixeira, Raquel; Ribas, Tânia C. F.; Almeida, André; Pintado, Manuela; Rangel, António O. S. S.Introduction and objective: According to European Union regulations, the use of additives in animal feed must be rigorously evaluated to ensure safety, efficacy, and quality. The guidelines highlight the importance of reliable and efficient analytical tools for characterizing bioactive compounds in feed. Currently, protein evaluation is predominantly performed using High-Performance Liquid Chromatography (HPLC). Despite its robustness, presents disadvantages. The main objective is to develop a low-pressure chromatographic flow-based spectrophotometric method for the molecular weight screening of peptides used in animal feed. Method: This work presents a low-pressure chromatographic method based on a sequential injection analysis (SIA) system. A laboratory-made chromatographic column was coupled to the flow system, enabling a rapid molecular weight-based separation and quantification. This method approach provides an expeditious, cost-effective, miniaturized, and automated solution with strong potential for real- time control in industrial production environments. On going work: Optimization of the chromatographic conditions aiming for a higher chromatogram resolution and improved sensitivity through the evaluation of different column sizes, sample volume and flow-rate.
- Sequential injection chromatographic system for the expeditious molecular weight screening in hydrolysatesPublication . Teixeira, Raquel; Ribas, Tânia C. F.; Almeida, André; Pintado, Manuela; Rangel, António O. S. S.According to the regulations of the European Union, the use of additives in animal nutrition must be rigorously assessed to ensure safety, efficacy, and quality. These guidelines emphasize the importance of reliable and efficient analytical tools for characterizing bioactive compounds in feed formulation [1]. Currently, the evaluation of proteins is predominantly performed using high-performance liquid chromatography (HPLC). This is a well-established technique known for its robustness, but on the other hand, it is associated with high operational costs, lengthy analysis times, and complex instrumentation. In response to these limitations, this work presents the development of a sequential injection analysis (SIA) system incorporating a laboratory-made chromatographic column, specifically designed to determine compounds across a range of molecular weights, with particular focus on species below 10 kDa (Figure 1). Integrating the column into the SIA circuit enables selective separation and quantification of low-molecular-weight compounds, significantly enhancing analytical throughput and overall process efficiency. The sequential injection chromatography offers distinct advantages, including improved precision, automation, and reduced reagent consumption [2]. This method approach provides a cost-effective, miniaturized, and automated solution with strong potential for real-time control in industrial production environments. This is particularly relevant in the animal feed manufacturing sector, where accurate monitoring of peptides, amino acids, and other bioactive molecules under 10 kDa is essential to ensure nutritional quality, regulatory compliance, and optimized formulation strategies.