Characterization of natural gums via elemental and chemometric analyses, synthesis of silver nanoparticles, and biological and catalytic applications

Physicochemical and Emulsifying Properties of Melia azedarach Gum

Naturally occurring hydrophilic colloids are versatile excipients in drug delivery systems. They are often used as coating materials, disintegrating agents, binders, emulsion stabilizers, and other applications. This study sought to investigate the physicochemical and emulsifying properties of gum extracted from Melia azedarach (MA). The gum was harvested, authenticated, and purified using ethanol precipitation. Physicochemical, microbial, and proximate analyses were performed on the purified gum. Oil of olive emulsions containing different amounts (5-15%w/v) of the gum as emulsifiers were prepared by homogenization. The zeta potential, creaming index, and average droplet size of products were assessed. The effects of pH changes, temperature, and monovalent and divalent electrolytes on the stability of the emulsions were also investigated. The yield of the gum after purification was 68.3%w/w. The gum has low moisture content and good swelling properties. Lead, copper, cadmium, and mercury were not detected. Emulsions containing 15%w/v of acacia or MA gum had the smallest average (Z-average) droplet size (acacia: 1.837 ± 0.420 μm; MA gum: 2.791 ± 0.694 μm) and the highest zeta potential (acacia: -30.45 mV; MA gum: -32.867 mV). Increasing the concentration of the gums increased the emulsion viscosity with MA gum emulsions being more viscous than corresponding acacia emulsions. MA gum emulsions had higher emulsion capacity and stability but lower creaming index relative to acacia gum emulsions of similar concentrations. Potassium chloride (KCl) reduced zeta potential but increased Z-average for emulsions prepared with either gum. Calcium chloride (CaCl2) produced a similar but more pronounced effect. When the pH was decreased from 10 to 2, the zeta potential of the droplets was reduced, but the droplet size of emulsions prepared from either gum was increased. Increasing temperature from 25 to 90°C produced no significant (p value >0.9999) change in droplet size. These findings suggest that MA gum is a capable emulsifying agent at 15%w/v.

Biogenic Salvia species synthesized silver nanoparticles with catalytic, sensing, antimicrobial, and antioxidant properties

Salvia (Lamiaceae family) is used as a brain tonic to improve cognitive function. The species including S. plebeia and S. moorcroftiana are locally used to cure hepatitis, cough, tumours, hemorrhoids, diarrhoea, common cold, flu, and asthma. To the best of authors' knowledge, no previous study has been conducted on synthesis of S. plebeia and S. moorcroftiana silver nanoparticles (SPAgNPs and SMAgNPs). The study was aimed to synthesize AgNPs from the subject species aqueous and ethanol extracts, and assess catalytic potential in degradation of standard and extracted (from yums, candies, and snacks) dyes, nitrophenols, and antibiotics. The study also aimed at AgNPs as probe in sensing metalloids and heavy metal ions including Pb2+, Cu2+, Fe3+, Ni2+, and Zn2+. From the results, it was found that Salvia aqueous extract afforded stable AgNPs in 1:9 and 1:15 (quantity of aqueous extract and silver nitrate solution concentration) whereas ethanol extract yielded AgNPs in 1:10 (quantity of ethanol extract and silver nitrate solution concentration) reacted in sunlight. The size of SPAgNPs and SMAgNPs determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were 21.7 nm and 19.9 nm, with spherical, cylindrical, and deep hollow morphology. The synthesized AgNPs demonstrated significant potential as catalyst in dyes; Congo red (85 %), methylene blue (75 %), Rhodamine B (<50 %), nitrophenols; ortho-nitrophenol (95-98 %) and para-nitrophenol (95-98 %), dyes extracted from food samples including yums, candies, and snacks. The antibiotics (amoxicillin, doxycycline, levofloxacin) degraded up to 80 %-95 % degradation. Furthermore, the synthesized AgNPs as probe in sensing of Pb2+, Cu2+, and Fe3+ in Kabul river water, due to agglomeration, caused a significant decrease and bathochromic shift of SPR band (430 nm) when analyzed after 30 min. The Pb2+ ions was comparatively more agglomerated and chelated. Thus, the practical applicability of AgNPs in Pb2+ sensing was significant. Based on the results of this research study, the synthesized AgNPs could provide promising efficiency in wastewater treatment containing organic dyes, antibiotics, and heavy metals.

Replacement of polyethylene oxide by peach gum to produce an active film using Litsea cubeba essential oil and its application in beef

This study evaluated the effects of adding various concentrations (0 %, 1 %, 2 %, and 3 %) of peach gum (PG) to films made from polyethylene oxide (PEO) combined with Litsea cubeba essential oil (LCEO) to be utilized as active packaging for food in the future. The findings showed that the film containing PG 2 % concentration had the best physic-mechanical properties. In films made with PG, the glass transition temperature was significantly improved. Combining PG and PEO resulted in films that were brighter in color, had lower WVP values, and had the lowest water activity. Furthermore, XRD demonstrated that PG additions were compatible with the film of PEO blended with LCEO. The PG films formulated with PG presented high antioxidant and antibacterial activity against Staphylococcus aureus and E. coli. Wrapping beef with P2G2 film led to maintaining its quality with suitable levels of pH, TBARS, and TVB-N. This also decreased the number of E. coli and S. aureus in beef throughout the storage period. The results indicate that adding PG to PEO films enhances their suitability for food preservation.

Classification, processing, and applications of bioink and 3D bioprinting: A detailed review

With the advancement in 3D bioprinting technology, cell culture methods can design 3D environments which are both, complex and physiologically relevant. The main component in 3D bioprinting, bioink, can be split into various categories depending on the criterion of categorization. Although the choice of bioink and bioprinting process will vary greatly depending on the application, general features such as material properties, biological interaction, gelation, and viscosity are always important to consider. The foundation of 3D bioprinting is the exact layer-by-layer implantation of biological elements, biochemicals, and living cells with the spatial control of the implantation of functional elements onto the biofabricated 3D structure. Three basic strategies underlie the 3D bioprinting process: autonomous self-assembly, micro tissue building blocks, and biomimicry or biomimetics. Tissue engineering can benefit from 3D bioprinting in many ways, but there are still numerous obstacles to overcome before functional tissues can be produced and used in clinical settings. A better comprehension of the physiological characteristics of bioink materials and a higher level of ability to reproduce the intricate biologically mimicked and physiologically relevant 3D structures would be a significant improvement for 3D bioprinting to overcome the limitations.

A review on peach gum polysaccharide: Hydrolysis, structure, properties and applications

To achieve sustainable development, increasing attention has been paid to the utilization of renewable polysaccharides extracted from plant gum instead of synthetic materials. Peach gum polysaccharide (PGP) is a typical polysaccharide, which can be readily obtained by hydrolysis of peach gum, one of the abundant plant gums in the world. In the past decade, the research on the hydrolysis, structure, properties and applications of PGP has aroused great interest. The PGP with highly branched macromolecular structure shows remarkable merits of numerous functional groups, excellent water solubility, good biocompatibility, favorable emulsifying property, fine antioxidant and antibacterial activity, and low cost. The application of PGP has expanded from the pharmaceutical field to the fields of food, adsorbents, functional carbon materials, binders and gel materials. This review systematically introduces the research progress of PGP, as well as the opportunities and challenges faced by PGP in scientific research and practical application.

Wood Waste from Fruit Trees: Biomolecules and Their Applications in Agri-Food Industry

In the European Union (EU), a total of 11,301,345 hectares are dedicated to the cultivation of fruit trees, mainly olive orchards, grapevines, nut trees (almond, walnut, chestnut, hazelnut, and pistachio), apple and pear trees, stone fruit trees (peach, nectarine, apricot, cherry, and plum), and citrus fruit trees (orange, clementine, satsuma, mandarin, lemon, grapefruit, and pomelo). Pruning these trees, together with plantation removal to a lesser extent, produces a huge amount of wood waste. A theoretical calculation of the wood waste in the European Union estimates approximately 2 and 25 million tons from wood plantation removal and pruning, respectively, per year. This wood waste is usually destroyed by in-field burning or crushing into the soil, which result in no direct economic benefits. However, wood from tree pruning, which is enriched in high added-value molecules, offers a wide spectrum of possibilities for its valorization. This review focuses on the contribution of wood waste to both sustainability and the circular economy, considering its use not only as biomass but also as a potential source of bioactive compounds. The main bioactive compounds found in wood are polyphenols, terpenes, polysaccharides, organic compounds, fatty acids, and alkaloids. Polyphenols are the most ubiquitous compounds in wood. Large amounts of hydroxytyrosol (up to 25 g/kg dw), resveratrol (up to 66 g/kg dw), protocatechuic acid (up to 16.4 g/kg), and proanthocyanins (8.5 g/kg dw) have been found in the wood from olive trees, grapevines, almond trees and plum trees, respectively. The bioactivity of these compounds has been demonstrated at lower concentrations, mainly in vitro studies. Bioactive compounds present antioxidant, antimicrobial, antifungal, biostimulant, anti-inflammatory, cardioprotective, and anticarcinogenic properties, among others. Therefore, wood extracts might have several applications in agriculture, medicine, and the food, pharmaceutical, nutraceutical, and cosmetics industries. For example, olive tree wood extract reduced thrombin-induced platelet aggregation in vitro; grapevine tree wood extract acts a preservative in wine, replacing SO2; chestnut tree wood extract has antifungal properties on postharvest pathogens in vitro; and stone tree wood extracts are used for aging both wines and brandies. Moreover, the use of wood waste contributes to the move towards both a more sustainable development and a circular economy.

Evaluation of natural gum-based cryogels for soft tissue engineering

In this study, three natural biomaterials, Locust bean gum (LBG), Xanthan gum (XG), and Mastic gum (MG), were combined to form cryogel scaffolds. Thermal and chemical characterizations revealed the successful blend formation from LBG-XG (LX) and LBG-XG-MG (LXM) polymers. All blends resulted in macro-porous scaffolds with interconnected pore structures under the size of 400 μm. The swollen cryogels had similar mechanical properties compared with other polysaccharide-based cryogels. The mean tensile and compressive modulus values of the wet cryogels were in the range of 3.5-11.6 kPa and 82-398 kPa, respectively. The sustained release of the small molecule Kartogenin from varying concentrations and ratios of cryogels was in between 32 and 66% through 21 days of incubation. Physical, mechanical, and chemical properties make LX and LXM polysaccharide-based cryogels promising candidates for cartilage and other soft tissue engineering, and drug delivery applications.

Prunus armeniaca gum exudates: An overview on purification, structure, physicochemical properties, and applications

Prunus armeniaca gum exudate (PAGE) is obtained from the trunk branches of apricot trees. PAGE is a high-molecular-weight polysaccharide with arabinogalactan structure. The physicochemical and rheological characteristics of this gum have been investigated in various researches. PAGE offers a good potential for use as an emulsifying, binding, and stabilizing agent in food and pharmaceutical industries. It also can be used as an organic additive in tissue culture media, synthesizing of metallic nanoparticles, binding potential in tablets, antioxidant agent, and corrosion inhibitor. For desirable emulsifying, stabilizing, shelf life-enhancing properties, and antioxidant activity of PAGE, it can be used as additive in many foods. We present here a comprehensive review on the existing literatures on characterization of this source of polysaccharide to explore its potential applications in various systems.