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Browsing by Author "Chouikh, Ali Seif"

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  • Breakfast snacks made from extruded leguminous flour
    Publication . Chouikh, Ali Seif; Caleja, Cristina; Rocha, Luís; Charfi, Ichrak
    Although legumes are recognized as nutritionally richer than cereal grains, contributing a higher content of protein, dietary fiber, complex carbohydrates, and bioactive compounds, their global consumption often remains below recommended levels. Many countries, particularly in Europe, do not meet the suggested intake targets. In this regard, it becomes crucial to address alternatives that allow for offering nutritionally more attractive, convenient, and healthy foods that can be included in the daily diet and contribute to the maintenance of consumer health. From this perspective, the present study aims to address the need for highly nutritious snacks, leveraging extrusion technology to enrich corn semolina flour and rice flour with chickpea flour in order to obtain protein-enriched ready-to-eat snacks. The specific objectives encompassed defining the optimized extrusion parameters as well as the proportions of each flour in the mixture to ensure not only the improvement of the protein content but also the organoleptic and texture characteristics expected by the consumer of this type of product. Additionally, the study intended to characterize the resulting snacks physically and nutritionally (fat, ash, protein, carbohydrates, and energy value) as well as to determine the chemical composition, and evaluate the bioactive properties, specifically antibacterial and antifungal activities. The extrusion process was achieved using a twin-screw extruder to combine chickpea flour with rice flour or corn semolina. The process parameters, including screw speed, water flow, and a multi-zone temperature profile, were meticulously recorded to correlate with the resulting product characteristics, such as desirable color, crunchy texture, homogeneous flow, particle diameter, and protein content. For the Rice:Chickpea (AGE) flour mixture, the optimized characteristics (white color, crunchy texture, homogeneous flow, and good particle diameter) were achieved using a high screw speed of 600 rpm and a die temperature of 180°C (AGE4). In turn, the Corn Semolina:Chickpea (SGE1) flour mixture achieved optimized physical attributes (golden color, crunchy texture, homogeneous flow, and medium particle diameter) at a lower screw speed of 400 rpm and a relatively lower die temperature of 120°C. Protein content was evaluated using the Kjeldahl method. Among all tested conditions, measured protein levels ranged from 10.23 g/100 g PS (DW) to a maximum of 13.39 g/100 g PS (AGE 4). Specifically, the Corn Semolina:Chickpea (50:50) mixtures reached up to 12.58 g/100 g PS (SGE 1). The two formulations with the best performance in terms of physical characteristics and protein content were selected for complete nutritional and chemical characterization: SGE1 (Corn Semolina:Chickpea, 50:50) and AGE4 (Rice:Chickpea, 50:50). Both SGE and AGE are classified as ready-to-eat snacks with low fat content, high carbohydrate content, and high protein content. They exhibited very low moisture (SGE:3.97%; AGE: 3.63%) and very low fat content (SGE: 0.048 g/100 g fresh weight; AGE: 0.043g/100 g fresh weight), which are desirable attributes for shelf stability and health. The AGE formulation demonstrated a statistically higher protein content (13.39 ± 0.01 g/100 g dry weight) compared to SGE (12.58 ± 0.10 g/100 g dry weight), suggesting that the Rice:Chickpea mixture offers a more protein-rich snack option. Carbohydrates were the main macronutriente (SGE: 83.28 g/100 g fresh weight; AGE: 82.81 g/100 g fresh weight), resulting in similar overall energy values (AGE: 385 Kcal/100 g; SGE: 384 Kcal/100 g). Chemical analysis of free sugars revealed sucrose as the only free sugar present in both snacks. The low free sugar contente is favorably aligned with public health recommendations. The fatty acid profiles were distinct: SGE exhibited a lipid profile rich in saturated fatty acids (AGS: 55.3 ± 0.1%), with palmitic acid (C16:0) being the most abundant (45.287 ± 0.42%). Meanwhile, AGE demonstrated a profile rich in polyunsaturated fatty acids (AGPI: 48.4 ± 0.1%), predominantly linoleic acid (C18:2n6c: 48.438 ± 0.07%). Regarding bioactive properties, the evaluation of the extracts showed limited antibacterial activity against most tested foodborne pathogens (including Gram-negative E. coli and Gram-positive S. aureus). Minimum Inhibitory Concentrations (MICs) generally exceeded the maximum concentration tested (> 10 mg/mL). However, both SGE and AGE extracts showed fungistatic activity against Aspergillus species. The MIC values for fungal inhibition against A. brasiliensis and A. fumigatus ranged between 5 mg/mL and 10 mg/mL, although neither reached a fungicidal concentration (MFC > 10 mg/mL). This study successfully demonstrated that extrusion technology can be effectively applied in the development of ready-to-eat snacks, rich in protein, low in fat, and with energy balance, by combining chickpea flour with rice and semolina flours. The rice and chickpea formulation (AGE) showed the highest protein content and a favorable fatty acid profile, confirming the potential of legumes to increase the nutritional value of extruded products. These findings highlight the relevance of legume mixtures in formulating healthy, protein-rich snacks that meet modern consumer demands for nutritious and practical plant-based foods, while also supporting strategies to improve global protein intake and diet quality.
    2025Master thesis Open access Show more