chelating ability
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2021 ◽  
Vol 9 (12) ◽  
pp. 2544
Author(s):  
Haicui Wu ◽  
Tim-Fat Shum ◽  
Jiachi Chiou

Background: There are several potential healthy or nutritional benefits from the use of lactic acid bacteria (LAB) in foods. This study aimed to characterize the LAB isolates from kimchi, yogurt, and baby feces in the Hong Kong area and evaluate their performance in fermented soymilk, which allowed us to assess their potential use in future experiments. Methods: General characteristics including tolerance to acid, NaCl, bile salts and phenol, antimicrobial activity to various pathogens, and adhesive ability to Caco-2 cells were evaluated using 18 LAB in this study. To further demonstrate the influence of such isolates in soymilk fermentation, we measured viability by plating and noting changes in pH, amino acid content, aglyconic isoflavones content and antioxidant capacities in vitro, such as scavenging ability, and iron chelating ability. Results: In this study, various LAB isolates belonging to Lactobacillusrhamnosus, Lactobacillus sakei, Lactiplantibacillus plantarum, andLeuconostocmesenteroides isolated in Hong Kong were evaluated. L. plantarum isolates R7, AC12, and AC14.1, and L. rhamnosus AC1 showed higher tolerance to acid, NaCl, bile salts, and phenol as compared to the other isolates tested. L. plantarum isolates AC12, AC13 and AC14.1, and L. rhamnosus AC1 harbored strong antimicrobial activity. L. plantarum isolates R7, AC12, AC13 and AC14.1, and L. paracasei isolates R6 and R8 showed higher adhesive ability than the other tested isolates. In soymilk, the viable numbers of L. paracasei R5, L. plantarum R7, L. rhamnosus AC1, L. sakei AC2, and Leu. mesenteroides AC5 were much higher than the other tested isolates after 48 h of fermentation. The pH value measuring the lactic acid level in soymilk fermented by L. plantarum AC14.1 was the lowest in comparison to those in soymilk fermented by other isolates. In addition, the levels of free amino acids and isoflavones in the aglycone forms of L. rhamnosus AC1-fermented soymilk were the highest. L. rhamnosus AC1-fermented soymilk also showed the highest antioxidant potential, including DPPH scavenging ability and iron chelating ability. Conclusions: In general, L. plantarum isolates R7 and AC14.1 and L. rhamnosus AC1 exhibited higher tolerance to challenging conditions as compared to the other isolates. Moreover, L. rhamnosus AC1 exhibited superior performance in soymilk fermentation and potential as a starter and probiotic culture.


Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2780
Author(s):  
Juanjuan Tian ◽  
Qingyan Mao ◽  
Mingsheng Dong ◽  
Xiaomeng Wang ◽  
Xin Rui ◽  
...  

Soybean whey is a high-yield but low-utilization agricultural by-product in China. In this study, soybean whey was used as a substrate of fermentation by Lacticaseibacillus plantarum 70810 strains. An exopolysaccharide (LPEPS-1) was isolated from soybean whey fermentation by L. plantarum 70810 and purified by ion-exchange chromatography. Its preliminary structural characteristics and antioxidant activity were investigated. Results show that LPEPS-1 was composed of mannose, glucose, and galactose with molar ratios of 1.49:1.67:1.00. The chemical structure of LPEPS-1 consisted of →4)-α-D-Glcp-(1→, →3)-α-D-Galp-(1→ and →2)-α-D-Manp-(1→. Scanning electron microscopy (SEM) revealed that LPEPS-1 had a relatively rough surface. In addition, LPPES-1 exhibited strong scavenging activity against DPPH and superoxide radicals and chelating ability on ferrous ion. This study demonstrated that soybean whey was a feasible fermentation substrate for the production of polysaccharide from L. plantarum 70810 and that the polysaccharide could be used as a promising ingredient for health-beneficial functional foods.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hojat Veisi ◽  
Mozhdeh Abrifam ◽  
Sheida Ahany Kamangar ◽  
Mozhgan Pirhayati ◽  
Shokoufeh Ghahri Saremi ◽  
...  

AbstractIn recent days, nanohybrid metal organic frameworks (MOF) have been considered as next generation catalysts due to their unique features like large surface to volume ratio, tailorable geometry, uniform pore sizes and homogeneous distribution of active sites. In this report, we address the biguanidine modified 3D Zr-centred MOF UiO-66-NH2 following a post synthetic modification approach. Utilizing the excellent chelating ability of biguanidine, Pd ions are immobilized over the host matrix MOF. The as-synthesized material was physicochemically characterized using a broad range of analytical techniques like FT-IR, electron microscopy, EDS, elemental mapping, XRD and ICP-OES. Subsequently the material has been catalytically employed in the classical Suzuki–Miyaura coupling towards the synthesis of diverse biphenyl derivatives at sustainable conditions. There are very few reports on the covalently modified MOFs towards the organic coupling reactions. The catalyst has been isolated by centrifugation and recycled in 9 consecutive runs with almost insignificant leaching and minute decrease in reactivity.


Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6639
Author(s):  
Joanna Izabela Lachowicz ◽  
Luigi Isaia Lecca ◽  
Federico Meloni ◽  
Marcello Campagna

An increasing number of pathologies correlates with both toxic and essential metal ions dyshomeostasis. Next to known genetic disorders (e.g., Wilson’s Disease and β-Thalassemia) other pathological states such as neurodegeneration and diabetes are characterized by an imbalance of essential metal ions. Metal ions can enter the human body from the surrounding environment in the form of free metal ions or metal-nanoparticles, and successively translocate to different tissues, where they are accumulated and develop distinct pathologies. There are no characteristic symptoms of metal intoxication, and the exact diagnosis is still difficult. In this review, we present metal-related pathologies with the most common onsets, biomarkers of metal intoxication, and proper techniques of metal qualitative and quantitative analysis. We discuss the possible role of drugs with metal-chelating ability in metal dyshomeostasis, and present recent advances in therapies of metal-related diseases.


SPE Journal ◽  
2021 ◽  
pp. 1-11
Author(s):  
Tao Song ◽  
Qi Feng ◽  
Thomas Schuman ◽  
Jie Cao ◽  
Baojun Bai

Summary Excessive water production from oil reservoirs not only affects the economical production of oil, but it also results in serious environmental concerns. Polymer gels have been widely applied to decrease water production and thus improve oil production. However, traditional polymer gels such as partially hydrolyzed polyacrylamide (HPAM)/chromium (III) gel systems usually have a short gelation time and cannot meet the requirement of some conformance control projects. This paper introduces a novel polymer gel system of which crosslinking time can be significantly delayed. A branched polymer grafted from arginine by the surface initiation method is synthesized as the backbone, chromium acetate is used as the crosslinker, and no additional additives are used for the gel system. The results show that the gelation time of this system can be delayed to 61 days at 45°C and 20 days at 65°C because of the rigid structure of the branched polymer and the excellent chromium (III) chelating ability of arginine. The polymer gels have been stable for more than 150 days at 45 and 65°C. Coreflooding and rheology tests have demonstrated that this branched polymer has good injectivity and shear resistance in high-permeabilityrocks.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
George H. R. Northover ◽  
Yiru Mao ◽  
Haris Ahmed ◽  
Salvador Blasco ◽  
Ramon Vilar ◽  
...  

AbstractBacteria, fungi and grasses use siderophores to access micronutrients. Hence, the metal binding efficiency of siderophores is directly related to ecosystem productivity. Salinization of natural solutions, linked to climate change induced sea level rise and changing precipitation patterns, is a serious ecological threat. In this study, we investigate the impact of salinization on the zinc(II) binding efficiency of the major siderophore functional groups, namely the catecholate (for bacterial siderophores), α-hydroxycarboxylate (for plant siderophores; phytosiderophores) and hydroxamate (for fungal siderophores) bidentate motifs. Our analysis suggests that the order of increasing susceptibility of siderophore classes to salinity in terms of their zinc(II) chelating ability is: hydroxamate < catecholate < α-hydroxycarboxylate. Based on this ordering, we predict that plant productivity is more sensitive to salinization than either bacterial or fungal productivity. Finally, we show that previously observed increases in phytosiderophore release by barley plants grown under salt stress in a medium without initial micronutrient deficiencies, are in line with the reduced zinc(II) binding efficiency of the α-hydroxycarboxylate ligand and hence important for the salinity tolerance of whole-plant zinc(II) status.


2021 ◽  
Author(s):  
Tereza Varnali ◽  
Mert Bozoflu ◽  
Hüseyin Şengönül ◽  
Seher İ. Kurt

Abstract Mycosporine-like amino acids (MAAs) are low molecular-weight (<400 Da) water soluble secondary metabolites that are attributed many functions such as antioxidants, compatible solutes, nitrogen reservoirs and especially, photostable UV-protectants. Recently, they are attracting attention due to their biotechnological and industrial potential for anti-aging and wound healing properties as well. In this study, we explored the metal chelating capacity of selected MAAs ( 4-deoxygadusol, mycosporine-glycine, mycosporine-taurine, palythine, poryphyra-334, shinorine, mycosporine-2-glycine and euhalothece-362) making use of dft calculations. We report model structures of ferrous and ferric ion-MAA complexes and their binding affinities in relation to their structural differences and multiple sites available for chelation on the MAAs. We also investigated calcium ion complexes for mycosporine-glycine, shinorine, porphyra-334 and mycosporine-2-glycine. Our findings support previous suggestions made to explain some experimental results obtained in earlier studies on MAAs. Lastly, we briefly mention the findings in the context of early life and hence relevance to astrobiology.


2021 ◽  
Vol 13 (1) ◽  
pp. 19-25
Author(s):  
Babalola Taiwo ◽  
Akanbi Charles ◽  
Omobuwajo Taiwo

Two lesser known indigenous vegetables: netlespurge (Jatropha tanjorensis) and black nightshade (Solanum nigrium) were each processed into flour samples and were incorporated into wheat flour in coating peanut. These veggie peanut burgers were analysed for their antioxidant properties such as DPPH, FRAP and Metal Chelating ability assay and their linoleic acid inhibition. Veggie peanut burger with netlespurge vegetable had values between 44.62 to 68.32%, 0.0106 to 0.0253 mg AAE/g sample and 49.03 to 63.30% for DPPH, FRAP and Metal chelating assay, respectively, while veggie peanut burger with black nightshade had values between 54.97 to 72.70%, 0.0105 to 0.0173 mg AAE/g sample and 47.13 to 64.01% for DPPH, FRAP and Metal chelating assay respectively. The result of the inhibition of linoleic acid of the peanut burger incorporated with vegetables revealed the abilities of the vegetables to inhibit propagation of peroxides up till the fourth day. Netlespurge vegetable had absorbance values of 2.3220 µm initially rising to 2.6845 µm on the fourth day and a fall absorbance value of 1.1845 µm on the sixth day while Black Nightshade vegetable had absorbance values of 2.3670 µm initially rising to 2.7490 µm on the fourth day and a fall absorbance value of 1.2355 µm on the sixth day. This study concluded that processing methods does not eliminate the antioxidative properties of vegetables and the inclusion of vegetables into peanut burgers increased their antioxidative properties.


2021 ◽  
Vol 41 ◽  
pp. 100985
Author(s):  
Ziye Wang ◽  
Shuzhen Cheng ◽  
Di Wu ◽  
Zhe Xu ◽  
Shiqi Xu ◽  
...  

2021 ◽  
pp. 8-12
Author(s):  
Елизавета Владимировна Залисская

Полноценное и здоровое питание является неотъемлемым фактором, прямо влияющим на развитие организма и общего здоровья человека. В мире все больший интерес представляет разработка и производство функциональных продуктов питания. Среди них сегмент молочных продуктов считается одним из самых быстрорастущих и перспективных. Особый интерес для научного сообщества представляют природные ассоциации, нашедшие применение в пищевой промышленности. Кефирный грибок - естественная спонтанная ассоциация нескольких видов микроорганизмов, широко используемая для производства кисломолочного продукта кефир. В состав кефира входят более 50 видов различных молочнокислых бактерий и дрожжей, что отличает его от других пробиотических продуктов. Исследователи, занимающиеся изучением кефира, открывают новые, ранее неизвестные его свойства. Большое количество исследований проводится по пробиотическим свойствам кефира, в частности широко изучаются его антимикробные, противоопухолевые, иммуномодулирующие, противовоспалительные и ранозаживляющие действия. Подобные пробиотические свойства кефира связывают в основном с присутствием лактобацилл в составе кефирных грибков. Также в ряде исследований указывается, что кефир обладает более выраженной антиоксидантной активностью, чем известный антиоксидант витамин Е. В статье описаны такие механизмы антиоксидантной активности бактерий, входящих в состав кефира, как ферментативная защита клеток, хелатирующая способность лактобактерий и иные механизмы, нейтрализующие действия свободных радикалов. Также собраны и представлены наиболее популярные методы определения антиоксидантной активности, такие как ABTS, DPPH, ORAC, FRAP. Приведены результаты исследований кефира, приготовленного с использованием молока различных сельскохозяйственных животных. A complete and healthy diet is an integral factor that directly affects the development of the body and general human health. The development and production of functional food products are of increasing interest in the world. Among them, the segment of dairy products is considered one of the fastest-growing and most promising. Natural associations that have found application in the food industry are of particular interest to the scientific community. Kefir grains are a natural spontaneous association of several types of microorganisms, widely used for the production of the fermented milk product kefir. Kefir contains more than 50 different species of lactic acid bacteria and yeast, which distinguishes it from other probiotic products. Researchers studying kefir are finding new and hitherto unknown properties. A large number of studies are carried out on the probiotic properties of kefir, in particular, its antimicrobial, antitumor, immunomodulating, anti-inflammatory, and wound-healing effects are widely studied. Such probiotic properties of kefir are mainly associated with the presence of lactobacilli in kefir grains. Several studies indicate that kefir has a more pronounced antioxidant activity than the well-known antioxidant vitamin E. The article describes mechanisms of the antioxidant activity of bacteria that make up kefir, such as enzymatic antioxidant protection of cells, the chelating ability of lactobacilli, and other mechanisms of antioxidant activity. Also collected and presented the most popular methods for determining antioxidant activity, such as ABTS, DPPH, ORAC, FRAP. The results of studies of kefir prepared using milk from various farm animals are presented.


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