Synthesis of Chitosan/Zinc Oxide Nanoparticles Stabilized by Chitosan via Microwave Heating

Nowadays, zinc oxide (ZnO) has attracted attention in research and development because of its remarkable antibacterial properties. Chitosan/ZnO nanoparticles were successfully synthesized via microwave heating. The objectives of this work were to investigate the effect of stabilizer, power heating and time heating on size of chitosan/ZnO nanoparticles and to determine antibacterial activity against pathogenic bacteria, where chitosan was used as a stabilizing agent. Chitosan/ZnO nanoparticles were analyzed  by Fourier Transform Infra Red (FTIR), X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and Zetasizer instrument. The power heating and time heating were varied from 400 to 800 Watt and 4 to 8 minutes, respectively. The presence of chitosan has role on preventing the nanoparticles from agglomeration by producing a milky solution of chitosan/ZnO nanoparticles without any suspensions. The increase of power  and time heating improved the size of nanoparticles. The peak in FTIR spectrum at around 427 cm-1 was confirmed the existence of the ZnO phase. XRD patterns showed that the chitosan/ZnO nanoparticles materials were pure phase with average crystalline size is 130 nm. FESEM revealed that chitosan/ZnO nanoparticles were uniformly distributed with the mean value of size is 70 nm and spherical shaped. Further impact of power and time heating on the size of the chitosan/ZnO nanoparticles can be shown by a nanoparticles size distribution with the average of 30 to 90 nm. The results showed that chitosan/ZnO nanoparticles have displayed an antibacterial inhibition zone against Gram-positive S. aureus and Gram-negative E. coli which 16.0 and 13.3 mm, respectively. Chitosan/ZnO nanoparticles were synthesized in this work presented have potential application to prevent bacterial infections.

Microwave-assisted Synthesis of ZnO Nanoparticles Stabilized with Gum Arabic: Effect of Microwave Irradiation Time on ZnO Nanoparticles Size and Morphology

The conventional heating methods of nanoparticle synthesis regularly depend on the energy inputs from outer heat sources that resulted high energy intake and low reaction competences. In this paper ZnO nanoparticles stabilized with gum arabic are synthesized using precipitating method assisted by simple and cost effective microwave heating technique. The objective of this work is to investigate the effect of microwave irradiation time towards ZnO nanoparticles morphology and size. The effect of microwave irradiation time has been investigated at 2, 4, 6, and 10 minutes. Dynamic Light Scattering (DLS) was employed to measure the size of ZnO nanoparticles. Ultraviolet–Visible spectroscopy (UV-vis), Fourier-Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) were used for the characterization of the ZnO nanoparticles. UV-vis absorption spectrum was found in the range of 350 nm indicating the absorption peak of ZnO nanoparticles. FTIR spectra showed peaks range from 424 to 475 cm–1 which indicating standard of Zn–O stretching. The presence of (100), (002), and (101) planes were apparent in the XRD result, indicating the crystalline phase of ZnO nanoparticles. The increase in the microwave irradiation time affected the processes of nucleation and crystal growth promoted larger ZnO nanoparticles size. Microwave irradiation time at 2 minutes was selected as the best microwave irradiation time for smallest ZnO nanoparticles averaging about 168 nm sizes based on DLS analysis. Copyright © 2019 BCREC Group. All rights reserve

Synthesis of ZnO nanoparticles with chitosan as stabilizing agent and their antibacterial properties against Gram-positive and Gram-negative bacteria

Antibacterial activity of zinc oxide (ZnO) nanoparticles have received significant interest, particularly by the implementation of nanotechnology to synthesize particles in nanometer region. ZnO nanoparticles were successfully synthesized through microwave heating by using chitosan as a stabilizing agent and characterized by UV–vis, FTIR, XRD and FESEM-EDX. The aim of the present study is to determine the antibacterial activity of ZnO nanoparticles against Gram-positive bacterium Staphylococcus aureus (S. aureus) and Gram-negative bacterium Escherichia coli (E. coli). The antibacterial effect of ZnO nanoparticles was investigated for the inhibition zone and inactivation of cell growth. The absorption of ZnO nanoparticles was found to be around 360 nm. FTIR results showed the stretching mode of ZnO nanoparticles at 475 cm−1 of the absorption band. EDX results indicated that ZnO nanoparticles have been successfully formed with an atomic percentage of zinc and oxygen at 23.61 and 46.57% respectively. X-ray diffraction result was confirmed the single-phase formation of ZnO nanoparticles and the particle sizes were observed to be around 50 to 130 nm. The results showed that ZnO nanoparticles have displayed inhibition zone of 16 and 13 mm against S. aureus and E. coli respectively. Gram-negative bacteria seemed to be more resistant to ZnO nanoparticles than Gram-positive bacteria

SYNTHETIC ANTIMICROBIAL AGENT AND ANTIMICROBIAL FABRICS: PROGRESS AND CHALLENGES

ABSTRACT: Recently, there is a strengthening requirement for antimicrobial fabrics that are resistant to pathogens, offer greater hygiene, and are protective in an active lifestyle. Synthetic compounds have been applied to impart antimicrobial properties to the fabrics.  In this paper, synthetic antimicrobial agents, namely quaternary ammonium compounds (QACs), polyhexamethylene biguanide (PHMB), triclosan, and N-halamine are discussed along with their mechanisms of action. Research has been done on synthetic antimicrobial treatment of fabrics; the tested microorganisms used to determine their efficiency and durability are summarized. It is also found that although synthetic antimicrobial agents have excellent strength to kill the microorganisms, some of these antimicrobial agents are harmful and have adverse effects on the environment, safety, and health. Identification of these problems will provide future challenges to overcome and improve the techniques used for antimicrobial treatment of the fabrics. Based on the infromation presented herein, it is recommended that subsequent studies should consider the use of antimicrobial agents that are either obtained from plant sources or from microorganisms. On the other hand, nanotechnlogy should be explored for production of antimicrobial agents in further studies based on its potential to facilitate the production of environmentally benign antimicrobial agents. ABSTRAK: Kebelakangan ini, permintaan terhadap fabrik antimikrobial bagi mencegah jangkitan patogen, penjagaan kebersihan dan perlindungan bagi gaya hidup yang aktif semakin meningkat. Sebatian sintetik telah diguna pakai bagi menambah sifat antimikrobial pada fabrik. Di dalam artikel ini, agen antimikrob sintetik yang dinamakan sebagai sebatian ammonium kuater (QAC), polyhexamethylene biguanide (PHMB), triclosan dan N-halamine serta mekanisma tindak balasnya telah dibincangkan. Penyelidikan telah dijalankan terhadap fabrik yang dirawat menggunakan agen antimikrob sintetik. Mikroorganisma yang digunakan bagi menentukan kecekapan dan daya tahan turut diringkaskan. Keputusan menunjukkan agen antimikrobial sintetik mempunyai tindak balas yang sangat baik untuk membunuh mikroorganisma, namun sebahagian agen antimikrobial ini berbahaya dan mempunyai kesan buruk terhadap alam sekitar, keselamatan dan kesihatan. Melalui kaedah kenal pasti masalah, ia dapat memberi solusi dan membaiki teknik rawatan antimikrobial pada fabrik pada masa hadapan. Hasil keputusan dan perbincangan menunjukkan kajian seterusnya harus menimbang penggunaan agen antimikrobial yang diperoleh dari sumber tumbuhan. Selain itu, nanoteknologi harus diterokai bagi pengeluaran agen antimikrobial berdasarkan potensinya yang mesra alam

Semirefined Carrageenan (SRC) Film Incorporated with α-Tocopherol and Persicaria minor for Meat Patties Application

Semirefined carrageenan (SRC) plasticized with glycerol (G) and incorporated with antioxidants of 0.4% (v/v) of α-tocopherol and Persicaria minor (PM) extract was successfully developed. The objective of this study is to analyze the antioxidant effect of active packaging films from semirefined carrageenan incorporated with α-tocopherol and Persicaria minor on meat patties. Total phenolic content and antioxidant activity of α-tocopherol and PM extract were measured. The effects of α-tocopherol and PM extract incorporated with SRC-based films on meat patties were evaluated using thiobarbituric acid reactive substance (TBARS) assay, metmyoglobin assay, and pH value for 14 days of storage. The films with 0.4% (v/v) of α-tocopherol and PM extract exhibited lower lipid oxidation in meat patties compared to the control (SRC film only, p < 0.05). Also, brown color development of the meat patties of less than 50% was observed at the end of the 14-day storage. Meanwhile, the pH values for all samples decreased throughout the storage period with the SRC+G+α-tocopherol film showed the highest pH value. Hence, the formulation of SRC film with α-tocopherol or PM extract could be used as an alternative packaging for extending the shelf life of food product with high fat conten

Semirefined carrageenan (Src) film incorporated with a-tocopherol and persicaria minor for meat patties application

Semirefined carrageenan (SRC) plasticized with glycerol (G) and incorporated with antioxidants of 0.4% (v/v) of a-tocopherol and Persicaria minor (PM) extract was successfully developed. The objective of this study is to analyze the antioxidant effect of active packaging films from semirefined carrageenan incorporated with a-tocopherol and Persicaria minor on meat patties. Total phenolic content and antioxidant activity of a-tocopherol and PM extract were measured. The effects of a-tocopherol and PM extract incorporated with SRC-based films on meat patties were evaluated using thiobarbituric acid reactive substance (TBARS) assay, metmyoglobin assay, and pH value for 14 days of storage. The films with 0.4% (v/v) of a-tocopherol and PM extract exhibited a lower lipid oxidation in meat patties compared with that of control (SRC film only, p < 0.05). Also, a brown color development of the meat patties of less than 50% was observed at the end of the 14-day storage. Meanwhile, the pH values for all samples decreased throughout the storage period with the SRC+G+a-tocopherol film showed the highest pH value. Hence, the formulation of SRC film with a-tocopherol or PM extract could be used as an alternative packaging for extending the shelf life of food product with high fat contentPeer ReviewedPostprint (published version

Semirefined carrageenan (Src) film incorporated with a-tocopherol and persicaria minor for meat patties application

Semirefined carrageenan (SRC) plasticized with glycerol (G) and incorporated with antioxidants of 0.4% (v/v) of a-tocopherol and Persicaria minor (PM) extract was successfully developed. The objective of this study is to analyze the antioxidant effect of active packaging films from semirefined carrageenan incorporated with a-tocopherol and Persicaria minor on meat patties. Total phenolic content and antioxidant activity of a-tocopherol and PM extract were measured. The effects of a-tocopherol and PM extract incorporated with SRC-based films on meat patties were evaluated using thiobarbituric acid reactive substance (TBARS) assay, metmyoglobin assay, and pH value for 14 days of storage. The films with 0.4% (v/v) of a-tocopherol and PM extract exhibited a lower lipid oxidation in meat patties compared with that of control (SRC film only, p < 0.05). Also, a brown color development of the meat patties of less than 50% was observed at the end of the 14-day storage. Meanwhile, the pH values for all samples decreased throughout the storage period with the SRC+G+a-tocopherol film showed the highest pH value. Hence, the formulation of SRC film with a-tocopherol or PM extract could be used as an alternative packaging for extending the shelf life of food product with high fat contentPeer ReviewedPostprint (published version

Effects of Microwave Power and Carrier Materials on Anthocyanins, Antioxidants, and Total Phenolic Content of Encapsulated Clitoria ternatea Flower Extract

Clitoria ternatea, also famously known as the blue pea flower (local name: bunga telang), has attracted interest among researchers due to its plethora of biological and pharmacological properties. It is rich in anthocyanin and widely used as a natural food colourant. However, the poor stability of active compounds may affect the therapeutic benefits and limit their application in the pharmaceutical and food industries. Hence, this work aims to study the effects of microwave encapsulation on the anthocyanins, antioxidants, and total phenolic content of Clitoria ternatea flower extract (CTFE). Microwave-assisted encapsulation (MAEC) was carried out at three different powers (300, 450, and 600 W) with different formulations of Gum Arabic (GA) and Maltodextrin Dextrose (MD) as carrier materials from 40% to 70% w/v. The total phenolic content (TPC), antioxidant activity, and anthocyanins in encapsulates were analysed for the formulations. The findings showed that increased microwave power increased TPC and antioxidant activity (P<0.05). However, adding carrier materials concentration above 60% reduced TPC and the antioxidant activity of microwave-encapsulated anthocyanin from CTFE. The best microwave-assisted encapsulation conditions of CTFE were found at 600 W microwave power with 50% w/v carrier materials GA/MD (ratio 1:1) concentration. The retention of anthocyanins, antioxidant activity, and TPC increased significantly (P<0.05) with increased microwave power and lower concentration of carrier materials. The MAEC approach to enhance the stability of anthocyanin in CTFE presents a high potential to expand its application as a high-value-added natural colourant

Effects of microwave power and carrier materials on anthocyanins, antioxidants, and total phenolic content of encapsulated Clitoria ternatea flower extract

Clitoria ternatea, also famously known as the blue pea flower (local name: bunga telang), has attracted interest among researchers due to its plethora of biological and pharmacological properties. It is rich in anthocyanin and widely used as a natural food colourant. However, the poor stability of active compounds may affect the therapeutic benefits and limit their application in the pharmaceutical and food industries. Hence, this work aims to study the effects of microwave encapsulation on the anthocyanins, antioxidants, and total phenolic content of Clitoria ternatea flower extract (CTFE). Microwave-assisted encapsulation (MAEC) was carried out at three different powers (300, 450, and 600 W) with different formulations of Gum Arabic (GA) and Maltodextrin Dextrose (MD) as carrier materials from 40% to 70% w/v. The total phenolic content (TPC), antioxidant activity, and anthocyanins in encapsulates were analysed for the formulations. The findings showed that increased microwave power increased TPC and antioxidant activity (P<0.05). However, adding carrier materials concentration above 60% reduced TPC and the antioxidant activity of microwave-encapsulated anthocyanin from CTFE. The best microwave-assisted encapsulation conditions of CTFE were found at 600 W microwave power with 50% w/v carrier materials GA/MD (ratio 1:1) concentration. The retention of anthocyanins, antioxidant activity, and TPC increased significantly (P<0.05) with increased microwave power and lower concentration of carrier materials. The MAEC approach to enhance the stability of anthocyanin in CTFE presents a high potential to expand its application as a high-value-added natural colourant

Concentration influence of different additives on performance of asymmetric polyethersulfone (PES) ultrafiltration flat sheet membranes

This paper reports the effects of additive concentration in the casting solution on performance of asymmetric PES ultrafiltration flat sheet membranes. The membranes were prepared by phase inversion process from the casting solution containing polyethersulfone (PES) as polymer, N, N-dimethylformamide (DMF) as solvent and polyethylene glycol (PEG) of various molecular weights. The concentration of additives were varied from 5 to 25 wt% in the casting solutions. The membranes were characterized in terms of the pure water permeation, solute separation and flux. The results indicated that increased concentration of PEG 400 and PEG 600 in casting solution increased pure water permeation. It is observed that when higher concentration of PEG 200 was added in the casting solution, pure water permeation decreased significantly. As concentration of PEG 400 and PEG 600 in casting solution is increased, solute separation gradually decreases and flux increased. However, when PEG 200 concentration is increased in the casting solution, the solute separation increased significantly while flux decreased. The morphology of the membranes changed with different concentration of additive added. Experimental results revealed that different molecular weights and concentration of additives greatly influenced the performance of PES ultrafiltration flat sheet membranes