1,721,046 research outputs found
Water Activity Prediction in Sugar and Polyol Systems Using Theoretical Molecular Descriptors
Full text linkWater activity is a key factor in the development of pharmaceutical, cosmetic, and food products. In aqueous solutions of nonelectrolytes, the Norrish model provides a simple and effective way to evaluate this quantity. However, it contains a parameter, known as the Norrish constant, that must be estimated from experimental data. In this study, a new strategy is proposed for the prediction of water activity in the absence of experimental information, based on the use of theoretical molecular descriptors for characterizing the effects of a solute. This approach was applied to the evaluation of water activity in the presence of sugars (glucose, fructose, xylose, sucrose) and polyols (sorbitol, xylitol, glycerol, erythritol). The use of two descriptors related to the constitutional and connectivity properties of the solutes was first investigated. Subsequently, a new theoretical descriptor, named the global information index (G), was developed. By using this index, the water activity curves in the binary systems were reconstructed. The positive results obtained support the proposed strategy, as well as the possibility of including, in a single information index, the main molecular features of a solute that determine its effects on water activity
Enhanced lycopene extraction from tomato peels by optimized mixed-polarity solvent mixtures
Full text linkMounting evidence from clinical and epidemiological studies suggests that lycopene, the most abundant carotenoid in tomatoes, may be beneficial in the prevention or treatment of some important diseases. Ripe tomato peels are the richest source of lycopene, but the use of conventional solvent extraction methods without pretreatment of the plant material results in very poor recovery. The reason lies in the localization of lycopene in the plant tissue and the low permeability of the latter to solvent molecules. In this paper, a mixture design procedure was used to formulate solvent mixtures allowing the recovery of lycopene from non-pretreated tomato peels. Two ternary systems were investigated: (a) n-hexane–ethanol–acetone and (b) ethyl lactate–ethanol–acetone. Optimization of the ternary mixture composition led to a recovery of over 90% of the lycopene present in the peels. The high extraction efficiency was explained in terms of lycopene affinity combined with the ability to swell the plant material. A tomato oleoresin with high antioxidant activity and a lycopene content of about 13% (w/w) was also produced. Overall, the results indicate that highly effective solvents for direct recovery of lycopene from tomato peels can be easily prepared by a mixture design approach
Economic evaluation and techno-economic sensitivity analysis of a mass integrated shrimp biorefinery in North Colombia
Full text linkThe high freshwater consumption requirements in shrimp biorefinery approaches represents one of the major drawbacks of implementing these technologies within the shrimp processing industry. This also affects the costs associated with the plant operation, and consequently, the overall economic performance of the project. The application of mass integration tools such as water pinch analysis can reduce frewshwater consumption by up to 80%, contributing to shrimp biorefinery sustainability. In this work, the economic evaluation and the techno-economic sensitivity analysis for a mass integrated approach for shrimp biorefinery were performed to determine the economic feasibility of the project when located in the North-Colombia region and to identify the critical techno-economic variables affecting the profitability of the process. The integrated approach designed to process 4113.09 tons of fresh shrimp in Colombia reaches a return on investment (%ROI) at 65.88% and a net present value (NPV) at 10.40 MM USD. The process supports decreases of up to 28% in capacity of production and increases of 12% and 11% in the cost of raw materials and variable operating costs without incurring losses, respectively. These findings suggest that the proposed design of the water recycling network coupled to a shrimp biorefinery approach is attractive from an economic point of view
Recovery of natural antioxidants from spent coffee grounds
No full textSpent coffee grounds (SCG) were extracted with an environmentally friendly procedure and analyzed to evaluate the recovery of relevant natural antioxidants for use as nutritional supplements, foods, or cosmetic additives. SCG were characterized in terms of their total phenolic content by the Folin-Ciocalteu procedure and antioxidant activity by the DPPH scavenging assay. Flavonoid content was also determined by a colorimetric assay. The total phenolic content was strongly correlated with the DPPH scavenging activity, suggesting that phenolic compounds are mainly responsible for the antioxidant activity of SCG. An UHPLC-PDA-TOF-MS system was used to separate, identify, and quantify phenolic and nonphenolic compounds in the SCG extracts. Important amounts of chlorogenic acids (CGA) and related compounds as well as caffeine (CAF) evidenced the high potential of SCG, a waste material that is widely available in the world, as a source of natural phenolic antioxidants. © 2013 American Chemical Society
The application of catalytic processes on the production of algae-based biofuels. A review
Full text linkOver the last decades, microalgal biomass has gained a significant role in the development of different high-end (nutraceuticals, colorants, food supplements, and pharmaceuticals) and low-end products (biodiesel, bioethanol, and biogas) due to its rapid growth and high carbon-fixing efficiency. Therefore, microalgae are considered a useful and sustainable resource to attain energy security while reducing our current reliance on fossil fuels. From the technologies available for obtaining biofuels using microalgae biomass, thermochemical processes (pyrolysis, Hydrothermal Liquefaction (HTL), gasification) have proven to be processed with higher viability, because they use all biomass. However, due to the complex structure of the biomass (lipids, carbohydrates, and proteins), the obtained biofuels from direct thermochemical conversion have large amounts of heteroatoms (oxygen, nitrogen, and sulfur). As a solution, catalyst-based processes have emerged as a sustainable solution for the increase in biocrude production. This paper’s objective is to present a comprehensive review of recent developments on the catalyst-mediated conversion of algal biomass. Special attention will be given to operating conditions, strains evaluated, and challenges for the optimal yield of algal-based biofuels through pyrolysis and HTL
Sewage sludge derived biochar and its potential for sustainable environment in circular economy: Advantages and challenges
No full textWith the increase in population and wastewater generation, the management of solid by-products, including sewage sludge (SS), has become a challenge. This article reviews various advantages and challenges associated with the use of sewage sludge-derived biochar (SSDB) and its potential for application in environmental improvement toward the attainment of circular economy. SS is a semi-solid mixture of various components, including potentially toxic elements (PTEs), generated as a by-product from wastewater treatment plants. The economic feasibility associated with SS management is a primary challenge for wastewater treatment plants. The utilization of bio-waste after conversion into biochar is gaining impetus considering its application potential in various fields. Biochar is rich in organic matter and nutrients. Its highly porous structure makes it an attractive alternative to traditional waste management methods. The properties of biochar, especially sludge-derived biochar, are greatly affected by various factors such as residence time, moisture content, pyrolysis temperature, heating rate, etc. This paper reviews recent emerging fields of application for SSDB, including water and wastewater treatment, soil amelioration, air pollution control, and carbon sequestration. The barriers of sludge-derived biochar application and possible strategies to overcome them have also been presented. This review article will promote further research, facilitate the advancement required for the sustainable management of SS and promote the circular economy
The effect of the complex processing of Microalgae Chlorella vulgaris on the intensification of the lipid extraction process
Full text linkMicroalgae are considered a promising source of lipids. However, the existing technologies of their extraction necessitate a massive improvement. In the course of the study optimal parameters of microwave radiation and of enzyme mixture "Cellolux A" and "Protosubtilin G3x" were experimentally selected and theoretically proved so as to allow increasing the yield of lipids 5.75 times to 23 % in comparison with the control sample (5 %). Moreover, the ratio and type of polar and non-polar solvents in the extraction stage for the maximum extraction of lipids was determined taking into account the necessity to process protein-lipid complexes
Inherent safety analysis and sustainability evaluation of chitosan production from shrimp exoskeleton in Colombia
Full text linkWaste valorization strategies are key to achieve more sustainable production within the shrimp industry. The crustacean exoskeletons can be potentially used to obtain value-added products such as chitosan. A comprehensive analysis including both safety and sustainability aspects of chitosan production from shrimp shells is presented in this study. The inherent safety analysis and sustainability evaluation was performed using the Inherent Safety Index (ISI) methodology and the Sustainable Weighted Return on Investment Metric (SWROIM), respectively. The process was designed for a processing capacity of 57,000 t/year. The return on investment (%ROI), potential environmental impact (PEI output), exergy efficiency, and the total inherent safety index (ITI) were used as indicators to evaluate process sustainability. The total inherent safety index was estimated at 25 indicating that the process is inherently unsafe. The main process risks were given by handling of flammable substances, reactivity, and inventory subindices. The overall sustainability evaluation showed a SWROIM of 36.33% indicating that the case study showed higher weighted performance compared to the return on investment metric of 18.08%
Green synthesis of gold nanoparticles using Kiwifruit juice
Full text linkThe use of kiwifruit juice as a source of metal-reducing and stabilizing agents for the production of gold nanoparticles (AuNPs) was investigated. The reaction was carried out in batch by mixing appropriate amounts of kiwifruit juice and gold(III) chloride solution. The formation of AuNPs was monitored by measuring the intensity of the surface plasmon resonance (SPR) band of gold. The effects of temperature (20-60 °C), pH (8-12) and gold-to-polyphenol ratio (GPR) were investigated. Characterisation of AuNPs by XRD, DLS and zeta-potential measurements showed that they were highly crystalline, with an average hydrodynamic diameter of about 50 nm and a zeta-potential ranging between -29.2 and -21.7 mV. Under the best reaction conditions (60 °C, pH 9, GPR = 5 mol Au3+/mol GAE), AuNPs with an average size of about 30 nm were produced. The results obtained suggest that kiwifruit juice is a suitable medium for the production of small-sized and stable AuNPs
AI in Agriculture for Sustainable and Economic Management
No full textThis book explains the best practices and their respective outcomes in artificial intelligence (AI) to meet sustainable development goals and demands. It examines the practices, technologies, and innovations at the core of various research issues to meet the sustainable development demands in agriculture to balance social, economic, and environmental sustainability with AI. AI in Agriculture for Sustainable and Economic Management discusses AI-driven nanotechnology approaches for precision agriculture and solutions for the optimization of farming resources and their management. The authors examine the impact of AI in agriculture and how technology-driven sustainable farming with smart waste-water treatment for zero waste for the circular economy can extend crop shelf-life. It discusses how AI expertise can be advantageous to envisage and evaluate the increasing demands of productivity, and to help to maintain ecosystems and strengthen the capacity for crop adaptation in response to drastic changes in climate and weather, natural disasters, and other significant factors. These findings and practices are also useful to emphasize how an agricultural ecosystem can be advanced and industrialized so that it can aid not only large commercial farms but also smaller farmlands. Finally, it also discusses how AI practices will help to find a balance between the volume of food manufactured and the proper maintenance of the ecosystem. This book is intended for researchers and upper graduate students interested in artificial intelligence in agricultural engineering, AI advances in crop science and technology for sustainable development
- …
