Search Results (4)

Recent advancements in analytical strategies have enabled the efficient extraction and characterization of bioactive compounds from agri-food bio-residues, emphasizing green chemistry and circular economy principles. This review highlights the valorization of several agri-food bio-residues for the extraction of high-value-added bioactive compounds, particularly polyphenols, tocopherols, carotenoids, and fatty acids, as a biorefinery approach. To this end, the adoption of environmentally friendly extraction technologies is essential to improve performance, reduce energy consumption, and minimize costs. This study therefore examines emerging methodologies such as supercritical fluid extraction, pressurized liquid extraction, pulsed electric fields, and matrix solid-phase dispersion, highlighting their advantages and limitations. Additionally, the chemical characterization of these bioactive compounds is explored through spectrophotometric and high-resolution chromatographic techniques, crucial for their accurate identification and quantification. This is complemented by an analysis of bioactivity assays evaluating antioxidant, antimicrobial, anticancer, neuroprotective, and anti-inflammatory properties, with a focus on their applications in the food, pharmaceutical, and cosmetic industries. However, the analytical control of toxic compounds, such as alkaloids, in these bio-residues is undoubtedly needed. Ultimately, this approach not only promotes sustainability but also contributes to the development of eco-friendly solutions in various industries. Full article

The aim of this study was to characterize lactic acid bacteria (LAB) isolated from cocoa mucilage and beef and evaluate their inhibitory effect in vitro against pathogenic bacteria, as well as determine their effect on beef quality. For the antagonist assay, 11 strains of LAB were selected and tested against pathogenic strains of Escherichia coli and Salmonella sp. The pathogenic bacteria were cultured in a medium, and a previously reactivated LAB bacterial pellet was added. After incubation, halos were observed around the bacterial colonies of the pathogenic strains, indicating inhibition by the LAB. It was identified that the LAB strains used belonged to the genus Lactobacillus, and the CCN-5 strain showed high percentages of inhibition against Salmonella sp. (58.33%) and E. coli (59%). The effectiveness of LAB application methods (immersion, injection, and spraying) did not present statistical differences. Furthermore, no significant changes in the physicochemical characteristics of beef were observed after the application of LAB. The results obtained demonstrate the potential of cocoa mucilage, as a biological control agent through LAB application, for beef biopreservation due to its ability to inhibit the growth of pathogenic bacteria. Full article

Slope stability is determined by pre-conditioning and triggering factors. The evaluation of the stability by scientific criteria provides crucial input into land-use planning and development. This work aimed to evaluate the slope stability of “Las Cabras” hill (Duran, Ecuador) through geological and geotechnical analysis and a susceptibility assessment that allowed the definition of areas potentially susceptible to landslide and detachment for land planning recommendations. The methodology included (i) analysis of background information about the study area; (ii) fieldwork, sampling and laboratory tests; (iii) assessment of susceptibility to landslides and detachment through a theoretical–practical evaluation (using suggestions by various authors); (iv) a safety factor assessment employing the simplified Bishop method; and (v) analysis of the relationship between susceptibility and stability. Sixteen geomechanical stations were evaluated. Of these, seven stations are characterised as category III (medium susceptibility), six stations as category IV (high susceptibility) and three stations as category V (very high susceptibility). According to the susceptibility zoning map, 58.09% of the total area (36.36 Ha) is in the high to very high susceptibility category. The stability analysis based on 16 critical profiles shows that three of these profiles have safety factor values of less than one (0.86, 0.82 and 0.76, respectively), and two profiles have values close to one (1.02 and 1.00). The northern area is conditioned mainly by a vertical slope with an outcrop of fractured and weathered sandstones, thereby favouring rockfall. The landslide vulnerability in the case of the southern zone is principally conditioned by the fact that the slope and dip are parallel. The described characterisation and susceptibility analysis provide a basis for security measures and territorial planning. Full article

In this paper, we provide a survey on available numerical approaches for solving low-thrust trajectory optimization problems. First, a general mathematical framework based on hybrid optimal control will be presented. This formulation and their elements, namely objective function, continuous and discrete state and controls, and discrete and continuous dynamics, will serve as a basis for discussion throughout the whole manuscript. Thereafter, solution approaches for classical continuous optimal control problems will be briefly introduced and their application to low-thrust trajectory optimization will be discussed. A special emphasis will be placed on the extension of the classical techniques to solve hybrid optimal control problems. Finally, an extensive review of traditional and state-of-the art methodologies and tools will be presented. They will be categorized regarding their solution approach, the objective function, the state variables, the dynamical model, and their application to planetocentric or interplanetary transfers. Full article