Microgel particle formation: Influence of mechanical properties of pectin-based gels on microgel particle size distribution

Biopolymer-based beads for the adsorptive removal of organic pollutants from wastewater: Current state and future perspectives

Among biopolymer-based adsorbents, composites in the form of beads have shown promising results in terms of high adsorption capacity and ease of separation from the effluents. This review addresses the potential of biopolymer-based beads to remediate wastewaters polluted with emerging organic contaminants, for instance dyes, active pharmaceutical ingredients, pesticides, phenols, oils, polyaromatic hydrocarbons, and polychlorinated biphenyls. High adsorption capacities up to 2541.76 mg g-1 for dyes, 392 mg g-1 for pesticides and phenols, 1890.3 mg g-1 for pharmaceuticals, and 537 g g-1 for oils and organic solvents have been reported. The review also attempted to convey to its readers the significance of wastewater treatment through adsorption by providing an overview on decontamination technologies of organic water contaminants. Various preparation methods of biopolymer-based gel beads and adsorption mechanisms involved in the process of decontamination have been summarized and analyzed. Therefore, we believe there is an urge to discuss the current state of the application of biopolymer-based gel beads for the adsorption of organic pollutants from wastewater and future perspectives in this regard since it is imperative to treat wastewater before releasing into freshwater bodies.

Sucrose and Ca2+ synergistically regulate the rheological properties of apple high-methoxyl pectin

The thickening and gelling mechanism of high-methoxyl pectins (HMPs) with different degree of esterification (DE) values (60.6 %, 66.1 %, and 72.4 %) synergistically affected by calcium ion (Ca2+) and sucrose was investigated using several technical methods. Rheological measurements, including steady-shear flow, thixotropy and dynamic viscoelasticity tests, texture analysis, water-holding capacity (WHC), thermal analyses (TG), and microstructure observation (TEM), were all systemically conducted. The results showed that the main thickening and gelling mechanism of Ca2+ on different HMPs was complex and the presence of sucrose had a synergistic effect on structure formation in HMP systems. Ca2+ was not always conducive to structure formation, and excessive Ca2+ addition may hinder structure formation. HMP systems with lower DE values had higher gel strengths due to the presence of more binding domains. The results of the texture properties, WHC, and thermal characteristics coincided with those obtained from the rheological measurements, which reflect the variations in HMPs affected by Ca2+ and DE. All of these results showed that Ca2+ addition at an appropriate concentration in the presence of sucrose favors HMP gelation even in the absence of acid. The results obtained here are expected to broaden the application of HMPs in acid-free gel food products.

Using waste biomass to produce 3D-printed artificial biodegradable structures for coastal ecosystem restoration

The loss of ecosystem functions and services caused by rapidly declining coastal marine ecosystems, including corals and bivalve reefs and wetlands, around the world has sparked significant interest in interdisciplinary methods to restore these ecologically and socially important ecosystems. In recent years, 3D-printed artificial biodegradable structures that mimic natural life stages or habitat have emerged as a promising method for coastal marine restoration. The effectiveness of this method relies on the availability of low-cost biodegradable printing polymers and the development of 3D-printed biomimetic structures that efficiently support the growth of plant and sessile animal species without harming the surrounding ecosystem. In this context, we present the potential and pathway for utilizing low-cost biodegradable biopolymers from waste biomass as printing materials to fabricate 3D-printed biodegradable artificial structures for restoring coastal marine ecosystems. Various waste biomass sources can be used to produce inexpensive biopolymers, particularly those with the higher mechanical rigidity required for 3D-printed artificial structures intended to restore marine ecosystems. Advancements in 3D printing methods, as well as biopolymer modifications and blending to address challenges like biopolymer solubility, rheology, chemical composition, crystallinity, plasticity, and heat stability, have enabled the fabrication of robust structures. The ability of 3D-printed structures to support species colonization and protection was found to be greatly influenced by their biopolymer type, surface topography, structure design, and complexity. Considering limited studies on biodegradability and the effect of biodegradation products on marine ecosystems, we highlight the need for investigating the biodegradability of biopolymers in marine conditions as well as the ecotoxicity of the degraded products. Finally, we present the challenges, considerations, and future perspectives for designing tunable biomimetic 3D-printed artificial biodegradable structures from waste biomass biopolymers for large-scale coastal marine restoration.

Stability of yerba mate extract, evaluation of its microencapsulation by ionic gelation and fluidized bed drying

Studies show that yerba mate (Ilex paraguariensis) has high antioxidant capacity occasioned by its high contents of total phenolic compounds. Microencapsulation, specifically ionic gelation, since it does not use heating during process, is considered as an alternative for preserving and applying the extract. The purpose of this study was to evaluate general characteristics and stability of hydroalcoholic extract of yerba mate, conduct the extract microencapsulation by ionic gelation followed by microparticle fluidized bed drying. The extract was evaluated for color stability, total phenolic compounds, and antioxidant activity for nine weeks and at three temperatures (5, 15, and 25 °C). From the extract, a double emulsion (W/O/W), generation of microparticles (ionic gelation by dripping), and fluidized bed drying were conducted. The extract had 32912.55 mg GAE/100 g of phenolic compounds and 2379.49 μmol TE/g of antioxidant activity. The main compound observed was chlorogenic acid (5-CQA) with 0.35 ± 0.01 g/100 mL. In the stability study, the temperature was observed to influence in phenolic compounds reduction, as well as in total color difference of the extract. Double emulsion has shown to be stable and appropriate for use. The values of microparticles total phenolic compounds and antioxidant activity were 423.18 ± 8.60 mg GAE/100 g and 21.17 ± 0.24 μmol TE/g, respectively. After drying, the moisture of microparticles was reduced from 79.2% to 19%. The extract had high total phenolic compound content and high antioxidant activity. Storage at the lowest temperature (5 °C) assured better preservation of extract total phenolic compounds. The dried microparticles showed content of total phenolic compounds and antioxidant activity with potential for commercialization and future application in food matrices.

Linear and non-linear rheological properties of water–ethanol hybrid pectin gels for aroma enhancement

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Linear to non-linear rheological responses of WEPGs were characterized.

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Gel rheological properties can be tuned by changing ethanol concentration.

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Non-linear viscoelasticity should be considered for aroma enhancement of WEPGs.

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The most relevant indicator to aroma release is e₃/e₁ under critical strain.

Whereas water–ethanol hybrid gels present an opportunity to realize aroma enhancement, translating hypothesis into practice is limited by poorly defined viscoelastic characteristics of those gels. In this work, the linear and non-linear rheological properties of water–ethanol hybrid pectin gels (WEPGs) were studied. Those WEPGs are physical gels in nature and the WEPG of 28.6% v/v ethanol differs basically from those of higher ethanol concentrations in the gel strength, resistance to deformation and non-linear properties. The retention of isopentyl acetate of WEPGs is dramatically improved by increasing the ethanol concentration to 33.3% v/v in the co-solvent system, but it is not further improved at 37.5% v/v. The cluster analysis reveals strong positive correlations between the isopentyl acetate release concentration and v₃/v₁ and absolute value of S/T ratio under 100% strain, suggesting the non-linear rheological responses of WEPGs have to be taken into account for which the enhancement of aroma is desired.