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The spontaneous emulsification method was used to produce nanoemulsions loaded with grumixama leaves extracts (GLE) to protect and improve its functionality as a natural additive in food. Nanoemulsions were characterized for physicochemical stability, morphology, thermal analyses, antioxidant capacity, and antimicrobial activity. The formulations showed encapsulation efficiency (EE%) >89%, sizes between 182 and 290 nm, low polydispersity, and zeta potential near -30 mV. The formulations were kinetically stable since these parameters remained constant for up to 180 days at 4°C. The nanoemulsion with 125 mg GLE exhibited better droplet structure, which favored greater phenolic compounds protection and thermal resistance. The antioxidant capacity of all formulations remained stable over 30 days. The nanoemulsions acted as a bactericidal agent (MBC/MIC ratio ≤ 4) against Staphylococcus aureus, Bacillus cereus, and Listeria monocytogenes strains. However, GLE-loaded nanoemulsions offer a sustainable and functional alternative for use as a natural additive to meet trends such as a clean label. [ABSTRACT FROM AUTHOR]

The control of biodeterioration has led to the development of new additives for the application in coating formulations. Antimicrobial nanoparticles obtained from aqueous plant extracts are promising; it is accessible, effective, low cost and eco-friendly. The aims of this research were to assess, for the first time, the use of aqueous extracts from three Argentine native plants: Schinus molle, Equisetum giganteum, and Ilex paraguariensis Saint Hilaire , for the synthesis of silver nanoparticles to be applied to antimicrobial coating formulations. The particles were identified and characterized by UV–vis spectroscopy, Fourier transformed infrared spectroscopy, Transmission electron microscopy and Scanning electron microscopy. The antimicrobial activity assays were carried on against bacterial and fungal strains: Escherichia coli (ATCC 11229), Staphylococcus aureus (ATCC 6538), Chaetomium globosum (KU936228) and Alternaria alternata (KU936229). Quasy-spherical nanoparticles obtained from Equisetum giganteum with an average size of 20 nm showed the higher antimicrobial activity. MIC (Minimum inhibitory concentration) range between 3.3 and 67.5 μg/mL with the different test strains and were integrated to an indoor acrylic waterborne paint formulation. The paint formulated with a silver concentration of 0.015 wt% proved to be more effective to inhibit the development of fungal and bacterial biofilms. Image 1 • The control of biodeterioration has led to the development of new additives. • Indoor coatings with antimicrobial functionality could prevent infections. • Nanoparticles obtained from aqueous plant extracts are low cost and eco-friendly. • Nanoparticles suspensions with antimicrobial activity are applicable to coatings. [ABSTRACT FROM AUTHOR]

Keropok lekor is a popular and highly savoured fish product in Malaysia. Keropok lekor has a short shelf life whereby it can be stored at room temperature for only one day. The aim of this study was to develop keropok lekor incorporated with lemongrass oil as an antimicrobial additive. In this study, keropok lekor were incorporated with lemongrass oil at different formulations: 0.8%, 1.2%, and 0% (control). The microbiological analysis (total plate count, yeast and mould, and coliform count) were conducted for samples stored at room temperature (25±2°C) for four days. The moisture content and sensory analysis were also evaluated. The results showed that the keropok lekor made using 1.2% lemongrass oil had significantly longer shelf life (4 days) when compared to control (1 day). In addition, significant reduction in total plate count, yeast and mould count, and moisture content were observed in this formulation (p<0.05). There were no coliforms detected in all samples. For sensory analysis, all samples recorded the same score for overall acceptability. Overall, keropok lekor made using 1.2% lemongrass oil was the best formulation. The results obtained support the use of lemongrass oil as a potential antimicrobial additive in keropok lekor. [ABSTRACT FROM AUTHOR]

It is well known that microbiological spoilage in indoor surfaces has a negative impact on human health. Antimicrobial functionalized materials are intensely studied. The present work seeks the synthesis of eco-friendly and cheap bioactive hybrid filler from diatomaceous earth (DE). The activation method used proved to be efficient to enhance the amount of quaternary ammonium groups supported by DE which was corroborated by spectroscopic methods and the thermogravimetry analysis. Zeta potential measurements reviled a bilayer arrangement of the ammonium groups on the functionalized solids and the bioassays showed their antimicrobial activity. [ABSTRACT FROM AUTHOR]

An array of quaternary ammonium functionalized-polyhedral oligomeric silsesquioxane (Q-POSS) compounds with different alkyl chain lengths and counter ions were synthesized using a two-step process. First, octasilane POSS was functionalized with dimethylamino groups by hydrosilylation with allyldimethylamine. Next, partial quaternization of the tertiaryamino-functional POSS was achieved using an alkyl halide to produce the Q-POSS. Alkyl chain length of the Q-POSS compounds varied from -CH to -CH and the counter ions varied between chlorine, bromine, and iodine. Moisture-cured polysiloxane coatings were prepared by dispersing Q-POSS molecules into a solution blend of silanol-terminated polydimethylsiloxane, methylacetoxysilane, and a catalyst. To evaluate the utility of the Q-POSS molecules as a broad-spectrum antimicrobial additive, the antimicrobial activity of the coatings toward the Gram-negative bacterium, Escherichia coli, the Gram-positive bacterium, Staphylococcus aureus, and the opportunistic fungal pathogen, Candida albicans, was determined using an agar plating method. The results obtained showed that both the composition of the Q-POSS and the composition of the polysiloxane matrix affected antimicrobial properties. Compositions were identified that inhibited the growth of all three microorganisms on the coating surface. Surface Raman spectroscopic analysis was performed on selected set of coatings to understand the relative concentration of Q-POSS molecules at the coating surface. [ABSTRACT FROM AUTHOR]

Biofouling on the membrane surface leads to performance deficiencies in membrane filtration. In this study, the application of ginger extract as a bio-based additive to enhance membrane antibiofouling properties was investigated. The extract was dispersed in a dimethyl acetamide (DMAc) solvent together with polyvinylidene fluoride (PVDF) to enhance biofouling resistance of the resulting membrane due to its antibiotic property. The concentrations of the ginger extract in the dope solution were varied in the range of 0–0.1 wt %. The antibacterial property of the resulting membranes was assessed using the Kirby Bauer disc diffusion method. The results show an inhibition zone formed around the PVDF/ginger membrane against Escherichia coli and Staphylococcus aureus demonstrating the efficacy of the residual ginger extract in the membrane matrix to impose the antibiofouling property. The addition of the ginger extract also enhanced the hydrophilicity in the membrane surface by lowering the contact angle from 93° to 85°, which was in good agreement with the increase in the pure water flux of up to 62%. [ABSTRACT FROM AUTHOR]