Removal of copper(II) using deacetylated konjac glucomannan conjugated soy protein isolate

Highly ordered aggregation of soy protein isolate particles for enhanced gel-related properties through konjac glucomannan addition

This study assessed the effect of konjac glucomannan (KGM) on the aggregation of soy protein isolate (SPI) and its gel-related structure and properties. Raman results showed that KGM promoted the rearrangement of SPI to form more β-sheets, contributing to the formation of an ordered structure. Atomic force microscopy, confocal laser scanning microscopy, and small-angle X-ray scattering results indicated that KGM reduced the size of SPI particles, narrowed their size distribution, and loosened the large aggregates formed by the stacking of SPI particles, improving the uniformity of gel system. As the hydrogen bonding between the KGM and SPI molecules enhanced, a well-developed network structure was obtained, further reducing the immobilized water's content (T22) and increasing the water-holding capacity (WHC) of SPI gel. Furthermore, this gel structure showed improved gel hardness and resistance to both small and large deformations. These findings facilitate the design and production of SPI-based gels with desired performance.

Konjac glucomannan: A comprehensive review of its extraction, health benefits, and pharmaceutical applications

Konjac glucomannan (KG) is a dietary fiber hydrocolloid derived from Amorphophallus konjac tubers and is widely utilized as a food additive and dietary supplement. As a health-conscious choice, purified KG, along with konjac flour and KG-infused diets, have gained widespread acceptance in Asian and European markets. An overview of the chemical composition and structure of KG is given in this review, along with thorough explanations of the processes used in its extraction, production, and purification. KG has been shown to promote health by reducing glucose, cholesterol, triglyceride levels, and blood pressure, thereby offering significant weight loss advantages. Furthermore, this review delves into the extensive health benefits and pharmaceutical applications of KG and its derivatives, emphasizing its prebiotic, anti-inflammatory, and antitumor activities. This study highlights how these natural polysaccharides can positively influence health, underscoring their potential in various biomedical applications.

Turning Food Protein Waste into Sustainable Technologies

For each kilogram of food protein wasted, between 15 and 750 kg of CO2 end up in the atmosphere. With this alarming carbon footprint, food protein waste not only contributes to climate change but also significantly impacts other environmental boundaries, such as nitrogen and phosphorus cycles, global freshwater use, change in land composition, chemical pollution, and biodiversity loss. This contrasts sharply with both the high nutritional value of proteins, as well as their unique chemical and physical versatility, which enable their use in new materials and innovative technologies. In this review, we discuss how food protein waste can be efficiently valorized not only by reintroduction into the food chain supply but also as a template for the development of sustainable technologies by allowing it to exit the food-value chain, thus alleviating some of the most urgent global challenges. We showcase three technologies of immediate significance and environmental impact: biodegradable plastics, water purification, and renewable energy. We discuss, by carefully reviewing the current state of the art, how proteins extracted from food waste can be valorized into key players to facilitate these technologies. We furthermore support analysis of the extant literature by original life cycle assessment (LCA) examples run ad hoc on both plant and animal waste proteins in the context of the technologies considered, and against realistic benchmarks, to quantitatively demonstrate their efficacy and potential. We finally conclude the review with an outlook on how such a comprehensive management of food protein waste is anticipated to transform its carbon footprint from positive to negative and, more generally, have a favorable impact on several other important planetary boundaries.

Konjac Glucomannan Induced Retarding Effects on the Early Hydration of Cement

Customarily, retarders serve as the setting time regulators of cement-based composites to meet the demands of various construction environments. However, the limited ability to adjust the setting time restricts the application of polysaccharides in special environments. In this study, we reported a naturally high-efficiency retarder, konjac glucomannan (KGM), and studied the mechanism of its effect on the hydration of ordinary Portland cement. Incorporating KGM could significantly prolong cement hydration without strength damage. Furthermore, the active hydroxyl group (-OH, rich in KGM) could chelate with Ca²⁺ (released from cement hydration) to form a cross-linking network, which is adsorbed on the surface of cement clinker, thereby being conducive to delaying the process of cement hydration and reducing the heat of hydration. The findings of this study are critical to the ongoing efforts to develop polysaccharide-cement-based composite materials for application in various special environments.

Emerging technologies for the recovery of rare earth elements (REEs) from the end-of-life electronic wastes: a review on progress, challenges, and perspectives

The demand for rare earth elements (REEs) has significantly increased due to their indispensable uses in integrated circuits of modern technology. However, due to the extensive use of high-tech applications in our daily life and the depletion of their primary ores, REE's recovery from secondary sources is today needed. REEs have now attracted attention to policymakers and scientists to develop novel recovery technologies for materials' supply sustainability. This paper summarizes the recent progress for the recovery of REEs using various emerging technologies such as bioleaching, biosorption, cryo-milling, electrochemical processes and nanomaterials, siderophores, hydrometallurgy, pyrometallurgy, and supercritical CO₂. The challenges facing this recovery are discussed comprehensively and some possible improvements are presented. This work also highlights the economic and engineering aspects of the recovery of REE from waste electrical and electronic equipment (WEEE). Finally, this review suggests that greener and low chemical consuming technologies, such as siderophores and electrochemical processes, are promising for the recovery of REEs present in small quantities. These technologies present also a potential for large-scale application.

Soy protein hydrolysate grafted cellulose nanofibrils with bioactive signals for bone repair and regeneration

TEMPO oxidized cellulose nanofibers (T-CNF) were prepared from cellulose pulp which is extracted from bagasse. Soy protein hydrolysate (SPH) was grafted on T-CNF via amidation of carboxylic groups. Biomineralization was, then, assessed via calcium phosphates (CaP) precipitation in twice-simulated body fluid until formation of a new bioactive material. Protein was efficiently grafted without alteration of morphology and nanofibrils packing as reported by Fourier Transform infrared analysis /X Ray Diffraction /Scanning and Transmission Electron Microscopy / Atomic Force Microscopy. Highly crystalline calcium phosphate deposits - ca. 22.1% - were detected, with a Ca/P ratio equal to 1.63, in agreement with native bone apatite composition. In vitro response of human Mesenchymal Stem Cells confirmed the biocompatibility. No significant differences in terms of cell adhesion were recognized while a significant increase in cell proliferation was detected until 7 days. The presence of calcium phosphates tends to cover the nanofibrillar pattern, inducing the inhibition of cell proliferation and promoting the ex-novo precipitation of mineral phases. All the results suggest a promising use of these biomaterials in the repair and/or the regeneration of hard tissues such as bone.

FTIR-based comparative analysis of glucomannan contents in some tuberous orchids, and effects of pre-processing on glucomannan measurement

BACKGROUND

Glucomannan (GM) is a polysaccharide of the mannan family of compounds found in some plant species. The dried and powdered tubers of some orchid species, collectively known as 'salep powder,' are a commercially important crop for human consumption and are one of the primary sources of GM. GM content is the primary indicator for the yield and quality of salep powder. We hypothesized that it would be more practical and accurate to measure GM content within tuber powder directly, prior to any purification or pre-processing. The GM content of tubers of 14 different orchid species was evaluated and compared using Fourier transform infrared (FTIR) spectroscopy and an enzymatic colorimetric method.

RESULTS

Among the analyzed modes, the sum of the peak areas at 873 and 812 cm^-1 , which represent the CH bending attributed to the β-pyranose form of d-glucose and d-mannose, respectively, gave the only confirmation using colorimetric methods. It was found that the tubers of Himantoglossum caprinum and Serapias vomeracea had the highest GM concentrations among the analyzed species. After conducting different pre-processing steps on Serapias vomeracea tubers, it was found that treating the tubers with milk, or high temperature resulted in an apparent increase in GM concentrations.

CONCLUSION

Himantoglossum caprinum and Serapias vomeracea give the highest yields of GM and should be used for commercial horticulture. GM estimation should be made prior to any pre-processing. FTIR spectroscopy is effective and reliable for directly comparing GM content of different orchid species, without the need for any purification or pre-processing. © 2019 Society of Chemical Industry.

High-Pressure Homogenization Pretreatment before Enzymolysis of Soy Protein Isolate: the Effect of Pressure Level on Aggregation and Structural Conformations of the Protein

The high-pressure homogenization (HPH) treatment of soybean protein isolate (SPI) before enzymatic hydrolysis using bromelain was investigated. Homogenization pressure and cycle effects were evaluated on the enzymatic degree of hydrolysis and the antioxidant activity of the hydrolysates generated. The antioxidant activity of SPI hydrolysates was analyzed by 1,1-dipheny-2-picrylhydrazyl (DPPH). The sizes and structures of the SPI-soluble aggregate after HPH treatment were analyzed using dynamic and static laser light scattering. The changes in the secondary structure, as measured by Fourier transform infrared spectroscopy (FTIR) and the macromorphology of SPI, were measured by scanning electron microscope (SEM). These results suggested that the HPH treatment (66.65%) could increase the antioxidant activities of the SPI hydrolysates compared with the control (54.18%). SPI hydrolysates treated at 20 MPa for four cycles obtained higher DPPH radical-scavenging activity than other samples. The control was predicted to be a hard sphere, and SPI treatment at 10 MPa was speculated to be Gaussian coil, polydisperse, and then the high-pressure treated SPI became a hollow sphere. Changes in the secondary structures showed protein aggregate formation and rearrangements. The image of SPI varied from a globular to a clump structure, as observed by the SEM. In conclusion, combining HPH treatment and enzymolysis could be an effective way to improve the antioxidant activity of the SPI.

A Review on Konjac Glucomannan Gels: Microstructure and Application

Konjac glucomannan (KGM) has attracted extensive attention because of its biodegradable, non-toxic, harmless, and biocompatible features. Its gelation performance is one of its most significant characteristics and enables wide applications of KGM gels in food, chemical, pharmaceutical, materials, and other fields. Herein, different preparation methods of KGM gels and their microstructures were reviewed. In addition, KGM applications have been theoretically modeled for future uses.

Characteristics and adsorption study of the activated carbon derived from municipal sewage sludge

Sewage sludge-based activated carbon is proved to be an efficient and low-cost adsorbent in treatment of various industrial wastewaters. The produced carbon had a well-developed pore structure and relatively low Brunauer-Emmett-Teller (BET) surface area. Adsorptive capacity of typical pollutants, i.e. copper Cu(II) and methylene blue (MB) on the carbon was studied. Adsorptions were affected by the initial solution pH, contact time and adsorbent dose. Results showed that adsorption of Cu(II) and MB on the produced carbon could reach equilibrium after 240 min. The average removal rate for Cu(II) on the carbon was high, up to 97% in weak acidic conditions (pH = 4-6) and around 98% for MB in a very wide pH range (pH = 2-12). The adsorption kinetics were well fitted by the pseudo-second order model, and both Langmuir and Freundlich isotherm models could well describe the adsorption process at room temperature. The theoretical maximum adsorption capacities of Cu(II) and MB on sewage sludge-based activated carbon were 114.94 mg/g and 125 mg/g, respectively. Compared with commercial carbon, the sewage sludge-based carbon was more suitable for heavy metal ions' removal than dyes'.

Synergistic effects of ion exchange and complexation processes in cysteine-modified clinoptilolite nanoparticles for removal of Cu(ii) from aqueous solutions in batch and continuous flow systems

In this work, clinoptilolite tuff was pre-treated and converted to microparticles (CMP) and nanoparticles (CNP) by a mechanical method.