scholarly journals Antibacterial and Freshness-Preserving Mechanisms of Chitosan-Nano-TiO2-Nano-Ag Composite Materials

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 914
Author(s):  
Zihao Dong ◽  
Ran Li ◽  
Yan Gong
Keyword(s):  
Composite Materials ◽  
Fruits And Vegetables ◽  
Raw Materials ◽  
Composite Films ◽  
Film Coating ◽  
Coating Films ◽  
Nano Tio2 ◽  
E Coli ◽  
Blending Method ◽  
Ensure Product Quality

With chitosan, nano-TiO2 and nano-Ag as raw materials, nano-TiO2 and nano-TiO2-Ag were modified by a surface modifier-sodium laurate. Chitosan (CTS), chitosan-nano-TiO2 (CTS-TiO2), and chitosan-nano-TiO2-nano-Ag (CTS-TiO2-Ag) composite materials and corresponding films were prepared by a solution co-blending method. Then, the antibacterial performances of the above three types of materials against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis were compared. Moreover, potato and strawberry weight loss rates, peroxidase activity, and vitamin C contents after different film coating treatments were measured. Compared with CTS films, the CTS-TiO2-Ag and CTS-TiO2 composite films both showed better physical properties, and both demonstrated higher antibacterial effects, especially for E. coli. Measurement of physiological indices in fruits and vegetables showed that the freshness-preserving effect of CTS-TiO2-Ag coating films was the most significant. In all, the CTS-TiO2-Ag coating films can actively contribute to the storage of fruits and vegetables at room temperature, and better ensure product quality. Thus, such films are meaningful for research and development of new fruit freshness-keeping techniques and materials.

Bamboo Waste-based Bio-composite Substance: An application for Low-cost Construction Materials

2020 ◽  
Vol 4 (1) ◽  
pp. 41-48
Author(s):  
Teodoro Astorga Amatosa ◽  
Michael E. Loretero
Keyword(s):  
Composite Materials ◽  
Sea Water ◽  
Raw Materials ◽  
Low Cost ◽  
Construction Materials ◽  
Single Layer ◽  
High Strength ◽  
Green Technology ◽  
Experimental Medium ◽  
Natural Treatment

Bamboo is a lightweight and high-strength raw materials that encouraged researchers to investigate and explore, especially in the field of biocomposite and declared as one of the green-technology on the environment as fully accountable as eco-products. This research was to assess the technical feasibility of making single-layer experimental Medium-Density Particleboard panels from the bamboo waste of a three-year-old (Dendrocalamus asper). Waste materials were performed to produce composite materials using epoxy resin (C21H25C105) from a natural treatment by soaking with an average of pH 7.6 level of sea-water. Three different types of MDP produced, i.e., bamboo waste strip MDP (SMDP), bamboo waste chips MDP (CMDP) and bamboo waste mixed strip-chips MDP (MMDP) by following the same process. The experimental panels tested for their physical-mechanical properties according to the procedures defined by ASTM D1037-12. Conclusively, even the present study shows properties of MDP with higher and comparable to other composite materials; further research must be given better attention as potential substitute to be used as hardwood materials, especially in the production, design, and construction usage.

Impact of Raw Materials and Processing Techniques on The Microbiological Quality of Egyptian Domiati Cheese

2020 ◽  
Keyword(s):  
Raw Materials ◽  
Microbiological Quality ◽  
Raw Milk ◽  
Plate Count ◽  
E Coli ◽  
Fresh Cheese ◽  
Processing Techniques ◽  
The Impact ◽  
Total Yeast

Domiati cheese is the most popular brand of cheese ripened in brine in the Middle East in terms of consumed quantities. This study was performed to investigate the impact of the microbiological quality of the used raw materials, the applied traditional processing techniques and ripening period on the quality and safety of the produced cheese. Three hundred random composite samples were collected from three factories at Fayoum Governorate, Egypt. Collected samples represent twenty-five each of: raw milk, table salt, calf rennet, microbial rennet, water, environmental air, whey, fresh cheese, ripened cheese & swabs from: worker hands; cheese molds and utensils; tanks. All samples were examined microbiologically for Standard Plate Count (SPC), coliforms count, Staphylococcus aureus (S. aureus) count, total yeast & mould count, presence of E. coli, Salmonellae and Listeria monocytogenes (L. monocytogenes). The mean value of SPC, coliforms, S. aureus and total yeast & mould counts ranged from (79×102 CFU/m3 for air to 13×108 CFU/g for fresh cheese), (7×102 MPN/ cm2 for tank swabs to 80×106 MPN/ml for raw milk), (9×102 CFU/g for salt to 69×106 CFU/g for fresh cheese) and (2×102 CFU/cm2 for hand swabs to 60×104 CFU/g for fresh cheese), respectively. Whereas, E. coli, Salmonella and L. monocytogenes failed to be detected in all examined samples. There were significant differences in all determined microbiological parameters (p ≤0.05) between fresh and ripened cheese which may be attributed to different adverse conditions such as water activity, pH, salt content and temperature carried out to improve the quality of the product.

scholarly journals 3D-Printed Nanocellulose-Based Cushioning–Antibacterial Dual-Function Food Packaging Aerogel

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3543
Author(s):  
Wei Zhou ◽  
Jiawei Fang ◽  
Shuwei Tang ◽  
Zhengguo Wu ◽  
Xiaoying Wang
Keyword(s):  
3D Printing ◽  
Food Packaging ◽  
Fruits And Vegetables ◽  
Antibacterial Effect ◽  
Dual Function ◽  
Printing Technology ◽  
E Coli ◽  
3D Printing Technology ◽  
The Core ◽  
3D Printed

Cushioning and antibacterial packaging are the requirements of the storage and transportation of fruits and vegetables, which are essential for reducing the irreversible quality loss during the process. Herein, the composite of carboxymethyl nanocellulose, glycerin, and acrylamide derivatives acted as the shell and chitosan/AgNPs were immobilized in the core by using coaxial 3D-printing technology. Thus, the 3D-printed cushioning–antibacterial dual-function packaging aerogel with a shell–core structure (CNGA/C–AgNPs) was obtained. The CNGA/C–AgNPs packaging aerogel had good cushioning and resilience performance, and the average compression resilience rate was more than 90%. Although AgNPs was slowly released, CNGA/C–AgNPs packaging aerogel had an obvious antibacterial effect on E. coli and S. aureus. Moreover, the CNGA/C–AgNPs packaging aerogel was biodegradable. Due to the customization capabilities of 3D-printing technology, the prepared packaging aerogel can be adapted to more application scenarios by accurately designing and regulating the microstructure of aerogels, which provides a new idea for the development of food intelligent packaging.

Effect of temperature on composite films made with activated carbon, graphite, or graphene oxide (GO) in a gelatin matrix

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 77-95
Author(s):  
Siqiao Yang ◽  
Haichao Li
Keyword(s):  
Contact Angle ◽  
Activated Carbon ◽  
Water Absorption ◽  
Composite Films ◽  
Effect Of Temperature ◽  
Gelatin Matrix ◽  
Vapour Permeability ◽  
Blending Method ◽  
The Matrix ◽  
Different Temperatures

Activated carbon, graphite, and GO/gelatin composite films were prepared by the blending method. The properties of composites were characterized by tensile strength (TS), elongation at break (EB), water vapour permeability (WVP), water-absorption ability, contact angle, scanning electron microscopy (SEM), and moisture at different temperatures. The properties of GO/gelatin composite films were better when each of three kinds of carbon materials were used as reinforcement phases and added into the matrix gelatin. The results showed that EB and TS of GO/gelatin composite films were both excellent. The moisture of GO/gelatin composite films was greater than the others. SEM micrographs showed that GO had better compatibility and dispersibility with gelatin than activated carbon and graphite. The water absorption of GO/gelatin composite films were low, at 15 °C and 25 °C, and the WVP was low at 35 °C. The WVP of GO/gelatin composite films was lower than the others at different temperatures. The contact angle of GO/gelatin composite films was larger than the others.

Preparation and disinfection properties of graphene oxide/trichloroisocyanuric acid disinfectant

2021 ◽  
Author(s):  
li li jiang ◽  
Su Xu ◽  
Haitao Yu ◽  
Qi Cui ◽  
Rui Cao
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Kinetic Curve ◽  
X Ray ◽  
Bacterial Inhibition ◽  
E Coli ◽  
Blending Method ◽  
Trichloroisocyanuric Acid

Abstract In this study, graphene oxide (GO) was first prepared by the modified Hummer method. Then, the GO/trichloroisocyanuric acid (TCCA) composite was prepared by loading TCCA into GO with the blending method. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and atomic force microscopy were used to characterize the composite. The results showed that TCCA was successfully loaded on the surface of GO or intercalated among GO layers. Next, the antibacterial performance of the composite against Escherichia coli and Staphylococcus aureus was tested by the 96-well plate assay. A bactericidal kinetic curve, bacterial inhibition tests, and the mechanism of bacterial inhibition is discussed. The results showed that the minimum inhibitory concentration of the GO/TCCA composite (GO:TCCA ratio = 1:50) was 327.5 µg/mL against E. coli and 655 µg/mL against S. aureus. At the minimum inhibitory concentration, the inhibition rate of the GO/TCCA composite exceeded 99.46% against E. coli and 99.17% against S. aureus. The bactericidal kinetic curves indicate that the GO/TCCA composite has an excellent bactericidal effect against E. coli and S. aureus.

scholarly journals Effect of High Pressure Treatment on Poly(lactic acid)/Nano–TiO2 Composite Films

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2621 ◽  
Author(s):  
Hai Chi ◽  
Wenhui Li ◽  
Chunli Fan ◽  
Cheng Zhang ◽  
Lin Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Lactic Acid ◽  
Composite Film ◽  
Composite Films ◽  
Barrier Properties ◽  
Poly Lactic Acid ◽  
Pressure Treatment ◽  
Nano Tio2 ◽  
High Pressure Treatment

The microstructure, thermal properties, mechanical properties and oxygen and water vapor barrier properties of a poly(lactic acid) (PLA)/nano-TiO2 composite film before and after high pressure treatment were studied. Structural analysis showed that the functional group structure of the high pressure treated composite film did not change. It was found that the high pressure treatment did not form new chemical bonds between the nanoparticles and the PLA. The micro-section of the composite film after high pressure treatment became very rough, and the structure was depressed. Through the analysis of thermal and mechanical properties, high pressure treatment can not only increase the strength and stiffness of the composite film, but also increase the crystallinity of the composite film. Through the analysis of barrier properties, it is found that the barrier properties of composite films after high pressure treatment were been improved by the applied high pressure treatment.

Development of green nanocomposites reinforced by cellulose nanofibers extracted from paper sludge

2015 ◽  
Vol 29 (06n07) ◽  
pp. 1540025 ◽  
Author(s):  
Hitoshi Takagi ◽  
Antonio N. Nakagaito ◽  
Kazuya Kusaka ◽  
Yuya Muneta
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Mechanical Treatment ◽  
Raw Materials ◽  
Cellulose Nanofibers ◽  
Tensile Tests ◽  
Cellulose Nanofiber ◽  
Paper Sludge ◽  
Reinforcing Effect ◽  
Mechanical And Physical Properties

Cellulose nanofibers have been showing much greater potential to enhance the mechanical and physical properties of polymer-based composite materials. The purpose of this study is to extract the cellulose nanofibers from waste bio-resources; such as waste newspaper and paper sludge. The cellulosic raw materials were treated chemically and physically in order to extract individualized cellulose nanofiber. The combination of acid hydrolysis and following mechanical treatment resulted in the extraction of cellulose nanofibers having diameter of about 40 nm. In order to examine the reinforcing effect of the extracted cellulose nanofibers, fully biodegradable green nanocomposites were fabricated by composing polyvinyl alcohol (PVA) resin with the extracted cellulose nanofibers, and then the tensile tests were conducted. The results showed that the enhancement in mechanical properties was successfully obtained in the cellulose nanofiber/PVA green nanocomposites.

Investigation of Magnetorheological Suspensions by Optical Methods

2009 ◽  
Vol 152-153 ◽  
pp. 151-154
Author(s):  
L.V. Nikitin ◽  
D.N. Kudryavcev ◽  
I.V. Shashkov ◽  
A.P. Kazakov
Keyword(s):  
Magnetic Field ◽  
Composite Materials ◽  
Uniform Magnetic Field ◽  
Magnetic Particles ◽  
Raw Materials ◽  
Optical Methods ◽  
Magnetic Clusters ◽  
Liquid Polymer ◽  
Synthetic Rubber ◽  
Magnetorheological Suspensions

In this work we studied magnetorheological suspensions, which are produced by dispersion of magnetic particles in liquid polymer matrix, based on natural and synthetic rubber. Such suspensions are the raw materials for creation of new high-elastic magneto-controlled composite materials (magnitoelastics[1-4]). Processes of aggregation and structurization of magnetic particles in suspension are also examined. We discovered that motion of magnetic clusters in oligomer solution has interrupted character. Such behavior can be explained by interaction of magnetic clusters moving in not uniform magnetic field with polymer net fragments. Evaluation of polymer net’s elastic properties was calculated.

Microbial Survey of Selected Ontario-Grown Fresh Fruits and Vegetables

2007 ◽  
Vol 70 (12) ◽  
pp. 2864-2867 ◽  
Author(s):  
LINDSAY ARTHUR ◽  
SANDRA JONES ◽  
MARTHA FABRI ◽  
JOSEPH ODUMERU
Keyword(s):  
Food Safety ◽  
Media Coverage ◽  
Microbial Contamination ◽  
Fruits And Vegetables ◽  
Risk Mitigation ◽  
Fresh Market ◽  
E Coli ◽  
Safety Research ◽  
Potential Risks ◽  
Leaf Lettuce

Recent produce-related outbreaks have been receiving heightened media coverage, which has increased public concern toward the safety of fresh fruits and vegetables. In response, the microbial contamination of Ontario-grown fresh fruits and vegetables was evaluated by the Ontario Ministry of Agriculture, Food and Rural Affairs during the summer of 2004. Prior to this survey, information specific to the microbial contamination of Ontario-produced fruits and vegetables was limited. This nonregulatory survey had two objectives: (i) to obtain a general microbiological profile of selected fruits and vegetables produced in Ontario and (ii) to use the information and knowledge gained from this survey to direct and support future on-farm food safety research and food safety programs to manage potential risks. In all, 1,183 samples, including muskmelon (151), scallions and green onions (173), leaf lettuce (263), organic leaf lettuce (112), head lettuce (155), parsley (127), cilantro (61), and fresh market tomatoes (141), were collected and analyzed. Samples were analyzed for Salmonella, Shigella, and generic E. coli. Enrichment cultures positive for E. coli were further assessed for verotoxigenicity. One sample each of Roma tomato and organic leaf lettuce were positive for Salmonella, with no samples yielding Shigella or verotoxigenic E. coli. The E. coli prevalence was highest in parsley (13.4%), followed by organic leaf lettuce (11.6%), leaf lettuce (6.5%), scallions (6.4%), cilantro (4.9%), muskmelon (1.3%), head lettuce (0%), and fresh market tomatoes (0%). These findings, in combination with foodborne illness data, will help target those commodities that require more focused risk mitigation efforts.

scholarly journals SRAVNITEL'NYY ANALIZ MIKROBIOLOGICHESKIKH POKAZATELEY KACHESTVA POVERKHNOSTI PLODOVOOVOSHCHNYKH PRODUKTOV, OBRABOTANNYKH VODOY I ELEKTROKHIMICHESKI AKTIVIROVANNYM VODNYM RASTVOROM COMPARATIVE ANALYSIS OF MICROBIOLOGICAL QUALITY INDICATORS SURFACES OF FRUIT AND VEGETABLE PRODUCTS PROCESSED WITH WATER AND ELECTROCHEMICALLY ACTIVATED AQUEOUS SOLUTION

2020 ◽  
Vol 2 (3(72)) ◽  
pp. 4-8
Author(s):  
O.A. Suvorov ◽  
K.V. Prohorova ◽  
D.I. Polyakova
Keyword(s):  
Comparative Analysis ◽  
Fruits And Vegetables ◽  
Raw Materials ◽  
Tap Water ◽  
Microbiological Quality ◽  
Food Products ◽  
Microbiological Safety ◽  
Highly Active ◽  
Physical Processing ◽  
Positive Effect

The method of improving the microbiological safety of food products based on the use of an electrochemically activated solution of chlorine-oxygen and hydroperoxide compounds was researched. The issue of food products cleaning is very relevant in catering. It’s usually used tap water for cleaning of vegetables and fruits, not disinfectant solutions or physical processing methods. During the analysis of this problem, several experiments were conducted with the «Анолит АНК СУПЕР» (anolyte) as a disinfectant for food products. The active agents of this solution are represented by a mixture of highly active metastable chlorine-oxygen and hydroperoxide compounds. To study the action of the anolyte, a research was conducted to determine the total microbial number (QMAFAnM) and the presence of yeast and fungi on the surfaces of the selected raw materials. It was used microbiological rapid tests «Петритест». Samples were: fresh carrots, fresh celery (leaf), fresh apples. During the research of raw materials treated with water supplied by a centralized drinking water supply system, it was determined that its level of contamination is large. When the samples treated with a disinfectant solution, a positive effect was observed: no seeds were found on the test materials. Anolyte’s using did not affect the organoleptic Евразийский Союз Ученых (ЕСУ) # 3(72), 2020 5 indicators: freshly squeezed juice was made from the processed raw materials and tasted and smelled like the drink which was made from fruits and vegetables and treated by tap water. A comparative analysis of the results was carried out and it was found that the use of the test solution had a positive effect on the microbiological safety of raw materials

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