Antimicrobial packaging based on starch, poly(3-hydroxybutyrate) and poly(lactic-co-glycolide) materials and application challenges

This research article published by Elsevier Ltd., 2018Background In recent years, food packaging has focused on two scientific pillars; adopting the biodegradable packaging materials and development of antimicrobial packaging for extended shelf life, quality and safety of food products. The bioplastic materials provide a promising application in the packaging industry to substitute environmentally deleterious petrochemical-based plastics. Scope and approach This paper gives insights to very recent progress on the antimicrobial application of starch, polyhydroxybutyrate (PHB) and poly (lactic-co-glycolide) (PLGA) as well as their blends and nanocomposites in food packaging research. It also presents an overview of the antimicrobial application of these materials particularly in food and biomedical industry. Key findings and conclusions PHB, starch and PLGA materials have unique properties towards novel application in foods, cosmetics, medicines as well as various composites. The materials necessitate critical studies to improve their industrial performance both for processing engineering and antimicrobial packaging due to functional and technical limitations

Optimized Preparation of Silver Nanoparticles from Polyethylene Glycol and Formaldehyde

Research Article published by International Research Journal of Pure & Applied ChemistryThe purpose of this work was to study the effect of various process and formulation parameters on size and shapes of silver nanoparticles (AgNPs) based on surface plasmon resonance (SPR). AgNPs were prepared by chemical reduction using formaldehyde (HCHO) as reducing agent and capped by polyethylene glycol (PEG). Effect of several processing variables including the concentration and volume of capping agent and reaction time is reported. The size of monodispersed nanoparticles was between 30-100 nm and was stable for three months at both room temperature and 4°C

Release Kinetic Models of Vanillin and Physicomechanical Properties of Thermoplastic Starch and Chitosan Nanocomposite Films: Effects of Mixing Order

This research article published by Springer Nature Switzerland AG., 2020The effects of mixing sequence of starch–chitosan nanocomposite films on antimicrobial properties of vanillin, the release kinetics of vanillin, and physicomechanical changes of films have been reported. Four types of films were prepared based on the order of mixing. SC1: starch–glycerol–MMT–vanillin; SC2: starch–glycerol–chitosan–MMT–vanillin; SC3: starch–MMT–glycerol–vanillin–chitosan and SC4: starch–chitosan–glycerol–vanillin–MMT. All formulation exhibited high antimicrobial activity against E. coli, S. enterica, and Z. bailii, except P. aeruginosa, which showed lower sensitivity. Migration dynamics of vanillin from films into simulants showed high vanillin migrated into water and 10% ethanol at 25 and 40 °C as analyzed by high-performance liquid chromatography (HPLC). The diffusion coefficients of vanillin in water ranged between 0.38 × 10−13m2 s−1 and 4.30 × 10−13m2 s−1 and in 10% ethanol between 1.38 × 10−13m2 s−1 and 5.16 × 10−13m2 s−1 following the Fickian diffusion mechanism and first-order kinetics. The diffusion was temperature-dependent following the Arrhenius equation with high activation energies of 15.00–52.80 kJmol−1 in water and 35.80–56.50 kJ mol−1 in 10% ethanol. The plot of the mass fraction of mt/m∞ against time for each sample shows the burst release of vanillin in between 30 min and 1 h and then attained the steady-state migration over 48 h. The plasticization effect of vanillin reduced the tensile strength and elastic modulus of films, while it increased the elongation at the break by 154% that was reversed after the addition of chitosan. These nanostructured starch films showed promising applications in the antimicrobial packaging industry

Antimicrobial dependence of silver nanoparticles on surface plasmon resonance bands against Escherichia coli

Nichrous G Mlalila,1,2 Hulda Shaidi Swai,1 Askwar Hilonga,3 Dattatreya M Kadam2 1School of Life Sciences and Bioengineering, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania; 2ICAR-Central Institute of Post-Harvest Engineering and Technology (ICAR-CIPHET), Ludhiana, Punjab, India; 3Department of Materials Science and Engineering, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania Abstract: This study presents a simple and trouble-free method for determining the antimicrobial properties of silver nanoparticles (AgNPs) based on the surface plasmon resonance (SPR) bands. AgNPs were prepared by chemical reduction method using silver nitrates as a metallic precursor and formaldehyde (HCHO) as a reducing agent and capped by polyethylene glycol. Effects of several processing variables on the size and shape of AgNPs were monitored using an ultraviolet–visible spectrophotometer based on their SPR bands. The formed particles showing various particle shapes and full width at half maximum (FWHM) were tested against Escherichia coli by surface spreading using agar plates containing equal amounts of selected AgNPs samples. The NPs exhibited higher antimicrobial properties; however, monodispersed spherical NPs with narrow FWHM were more effective against E. coli growth. The NPs prepared are promising candidates in diverse applications such as antimicrobial agents in the food and biomedical industries. Keywords: antimicrobial agent, bandwidth, full width at half maximum, nanoparticles, particle siz

Transformation of food packaging from passive to innovative via nanotechnology: concepts and critiques

This research article was published by Springer, 2016In recent decades, there is a global advancement in manufacturing industry due to increased applications of nanotechnology. Food industry also has been tremendously changing from passive packaging to innovative packaging, to cope with global trends, technological advancements, and consumer preferences. Active research is taking place in food industry and other scientific fields to develop innovative packages including smart, intelligent and active food packaging for more effective and efficient packaging materials with balanced environmental issues. However, in food industry the features behind smart packaging are narrowly defined to be distinguished from intelligent packaging as in other scientific fields, where smart materials are under critical investigations. This review presents some scientific concepts and features pertaining innovative food packaging. The review opens new research window in innovative food packaging to cover the existing disparities for further precise research and development of food packaging industry

Human food safety and environmental hazards associated with the use of methyltestosterone and other steroids in production of all-male tilapia

Research Article published by Springer Volume 22, Issue 7, April 2015In recent years, all-male cultures of Nile tilapia (Oreochromis niloticus) have been the most preferred mode of production in aquaculture industry. All-male individuals achieve higher somatic growth rate and shut high energy losses associated with gonadal development and reproduction. The economic advantages of culturing all-male tilapia have led to the development of procedures for producing unisex cultures, using 17α-methyltestosterone (MT). Despite widespread use of the MT in tilapia farming, the implications of hormone treatment in relation to human health and the environment have raised a number of concerns in the scientific community. In this review, the hormonal application processes, economic and ecological significance of MT, food safety and residual MT, comparative uses of steroids in aquaculture, animal husbandry, and medicine have been briefly reviewed for regulatory guidelines, and finally, future research perspectives have been addressed. The review can be used as policy-making guidelines in aquaculture framework development as can be emphasized in African continent, among others. The most important conclusion to draw is that the quantity of MT used in conventional practice is large compared to the actual dose required for sex reversal, fish produced are safe for human consumptions, and the environmental hazards should be further emphasized

Effects of spray-drying on w/o/w multiple emulsions prepared from a stearic acid matrix

Nichrous Mlalila,1 Hulda Swai,2 Lonji Kalombo,2 Askwar Hilonga3 1School of Life Sciences and Bioengineering, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania; 2Materials Science and Manufacturing, Council for Scientific and Industrial Research, Pretoria, South Africa; 3Department of Materials Science and Engineering, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania Abstract: The goal of this study was to explore the effects of spray-drying on w/o/w double emulsions of methyltestosterone (MT) loaded in a stearic acid matrix. MT-loaded nanoparticles were formulated by a water-in-oil-in-water emulsion technique using 50, 75, and 100 mg of stearic acid, 2% and 3% w/v polyvinyl alcohol, 5% w/v lactose, and 0.2% w/v chitosan. The emulsions were immediately spray-dried based on an optimized model of inlet temperature and pump rate, and characterized for optimized responses with regard to particle size, polydispersity index, and zeta potential, for both emulsion and powder samples. Dynamic light scattering analysis shown that the nanoparticles increased in size with increasing concentrations of polyvinyl alcohol and stearic acid. Scanning electron microscopy indicated that the MT-loaded nanoparticles were spherical in shape, had a smooth surface, and were in an amorphous state, which was confirmed by differential scanning calorimetry. These MT-loaded nanoparticles are a promising candidate carrier for the delivery of MT; however, further studies are needed in order to establish the stability of the system and the cargo release profile under normal conditions of use. Keywords: double emulsions, nanoparticles, pump rate, spray-drying, testosteron

Effects of spray-drying on w/o/w multiple emulsions prepared from a stearic acid matrix

Research Article published by Devo Press JournalThe goal of this study was to explore the effects of spray-drying on w/o/w double emulsions of methyltestosterone (MT) loaded in a stearic acid matrix. MT-loaded nanoparticles were formulated by a water-in-oil-in-water emulsion technique using 50, 75, and 100 mg of stearic acid, 2% and 3% w/v polyvinyl alcohol, 5% w/v lactose, and 0.2% w/v chitosan. The emulsions were immediately spray-dried based on an optimized model of inlet temperature and pump rate, and characterized for optimized responses with regard to particle size, polydispersity index, and zeta potential, for both emulsion and powder samples. Dynamic light scattering analysis shown that the nanoparticles increased in size with increasing concentrations of polyvinyl alcohol and stearic acid. Scanning electron microscopy indicated that the MT-loaded nanoparticles were spherical in shape, had a smooth surface, and were in an amorphous state, which was confirmed by differential scanning calorimetry. These MT-loaded nanoparticles are a promising candidate carrier for the delivery of MT; however, further studies are needed in order to establish the stability of the system and the cargo release profile under normal conditions of use

Antimicrobial dependence of silver nanoparticles on surface plasmon resonance bands against Escherichia coli

Research Article published by Dove Press JournalThis study presents a simple and trouble-free method for determining the antimicrobial properties of silver nanoparticles (AgNPs) based on the surface plasmon resonance (SPR) bands. AgNPs were prepared by chemical reduction method using silver nitrates as a metallic precursor and formaldehyde (HCHO) as a reducing agent and capped by polyethylene glycol. Effects of several processing variables on the size and shape of AgNPs were monitored using an ultraviolet–visible spectrophotometer based on their SPR bands. The formed particles showing various particle shapes and full width at half maximum (FWHM) were tested against Escherichia coli by surface spreading using agar plates containing equal amounts of selected AgNPs samples. The NPs exhibited higher antimicrobial properties; however, monodispersed spherical NPs with narrow FWHM were more effective against E. coli growth. The NPs prepared are promising candidates in diverse applications such as antimicrobial agents in the food and biomedical industries