Renato Souza Cruz

Bio: Renato Souza Cruz is an academic researcher from State University of Feira de Santana. The author has contributed to research in topics: Starch & Amylose. The author has an hindex of 14, co-authored 45 publications receiving 1597 citations. Previous affiliations of Renato Souza Cruz include Federal University of Bahia & Federal Fluminense University.

Zinc Oxide Nanoparticles: Synthesis, Antimicrobial Activity and Food Packaging Applications

Abstract: Zinc oxide (ZnO) is an inorganic compound widely used in everyday applications. ZnO is currently listed as a generally recognized as safe (GRAS) material by the Food and Drug Administration and is used as food additive. The advent of nanotechnology has led the development of materials with new properties for use as antimicrobial agents. Thus, ZnO in nanoscale has shown antimicrobial properties and potential applications in food preservation. ZnO nanoparticles have been incorporated in polymeric matrices in order to provide antimicrobial activity to the packaging material and improve packaging properties. This review presents the main synthesis methods of ZnO nanoparticles, principal characteristics and mechanisms of antimicrobial action as well as the effect of their incorporation in polymeric matrices. Safety issues such as exposure routes and migration studies are also discussed.

Bioactive Peptides: Synthesis, Properties, and Applications in the Packaging and Preservation of Food

Abstract: Bioactive peptides are protein fragments which have a positive impact on the functions and conditions of living beings. Peptides have shown several useful properties for human health, including antimicrobial, antifungal, antiviral, and antitumor activities. These compounds are produced by almost all species of life. However, they are produced in limited quantities in nature. As a result, researchers have tried to synthesize bioactive peptides to study their properties and applications in various areas. Among their applications in food preservation, peptides have been incorporated into packaging materials. This review begins with a brief description of the methods used for the synthesis, purification, and characterization of peptides. Also, the main bioproperties and mechanisms of action of peptides are discussed. Finally, some applications of peptides are presented, especially their use in active packaging, their effects on the polymeric matrix, and peptide migration.

Mercury-selenium relationships in liver of Guiana dolphin: the possible role of Kupffer cells in the detoxification process by tiemannite formation.

Abstract: Top marine predators present high mercury concentrations in their tissues as consequence of biomagnification of the most toxic form of this metal, methylmercury (MeHg). The present study concerns mercury accumulation by Guiana dolphins (Sotalia guianensis), highlighting the selenium-mediated methylmercury detoxification process. Liver samples from 19 dolphins incidentally captured within Guanabara Bay (Rio de Janeiro State, Brazil) from 1994 to 2006 were analyzed for total mercury (THg), methylmercury (MeHg), total organic mercury (TOrgHg) and selenium (Se). X-ray microanalyses were also performed. The specimens, including from fetuses to 30-year-old dolphins, comprising 8 females and 11 males, presented high THg (0.53–132 µg/g wet wt.) and Se concentrations (0.17–74.8 µg/g wet wt.). Correlations between THg, MeHg, TOrgHg and Se were verified with age (p<0.05), as well as a high and positive correlation was observed between molar concentrations of Hg and Se (p<0.05). Negative correlations were observed between THg and the percentage of MeHg contribution to THg (p<0.05), which represents a consequence of the selenium-mediated methylmercury detoxification process. Accumulation of Se-Hg amorphous crystals in Kupffer Cells was demonstrated through ultra-structural analysis, which shows that Guiana dolphin is capable of carrying out the demethylation process via mercury selenide formation.

Acetate cellulose film with bacteriophages for potential antimicrobial use in food packaging

Abstract: The search for new technologies that guarantee the safety and quality of food has intensified, as has concern for consumer health, leading to the adoption of measures to reduce food-related risks. The purpose of the study was to evaluate the efficiency of active biodegradable films incorporated with bacteriophage for future application in packaging materials. Cellulose acetate films incorporated with solution of bacteriophages showed antimicrobial activity against Salmonella Typhimurium ATCC 14028 displayed the formation of inhibition zones in Muller-Hinton agar, and a growth curve, using the diffusion method in liquid medium. There was an increase in the lag phase and slower growth of microorganisms in the environment containing bacteriophages with the films, compared to control. The mechanical and physical properties of films, such as thickness, elongation and puncture resistance showed no significant effects. However, tensile resistance was different between control and treatments. The addition of bacteriophage altered the film surface, as observed by atomic force microscopy. There was a higher porosity of the films containing the bacteriophage solution compared to control. The acetate films may be incorporated with bacteriophages, since the physical and mechanical properties of the films were not changed drastically and there was an effect of the antimicrobial film.

Review on Zinc Oxide Nanoparticles: Antibacterial Activity and Toxicity Mechanism.

Abstract: Antibacterial activity of zinc oxide nanoparticles (ZnO-NPs) has received significant interest worldwide particularly by the implementation of nanotechnology to synthesize particles in the nanometer region. Many microorganisms exist in the range from hundreds of nanometers to tens of micrometers. ZnO-NPs exhibit attractive antibacterial properties due to increased specific surface area as the reduced particle size leading to enhanced particle surface reactivity. ZnO is a bio-safe material that possesses photo-oxidizing and photocatalysis impacts on chemical and biological species. This review covered ZnO-NPs antibacterial activity including testing methods, impact of UV illumination, ZnO particle properties (size, concentration, morphology, and defects), particle surface modification, and minimum inhibitory concentration. Particular emphasize was given to bactericidal and bacteriostatic mechanisms with focus on generation of reactive oxygen species (ROS) including hydrogen peroxide (H2O2), OH− (hydroxyl radicals), and O2 −2 (peroxide). ROS has been a major factor for several mechanisms including cell wall damage due to ZnO-localized interaction, enhanced membrane permeability, internalization of NPs due to loss of proton motive force and uptake of toxic dissolved zinc ions. These have led to mitochondria weakness, intracellular outflow, and release in gene expression of oxidative stress which caused eventual cell growth inhibition and cell death. In some cases, enhanced antibacterial activity can be attributed to surface defects on ZnO abrasive surface texture. One functional application of the ZnO antibacterial bioactivity was discussed in food packaging industry where ZnO-NPs are used as an antibacterial agent toward foodborne diseases. Proper incorporation of ZnO-NPs into packaging materials can cause interaction with foodborne pathogens, thereby releasing NPs onto food surface where they come in contact with bad bacteria and cause the bacterial death and/or inhibition.

Zinc Oxide-From Synthesis to Application: A Review.

Abstract: Zinc oxide can be called a multifunctional material thanks to its unique physical and chemical properties. The first part of this paper presents the most important methods of preparation of ZnO divided into metallurgical and chemical methods. The mechanochemical process, controlled precipitation, sol-gel method, solvothermal and hydrothermal method, method using emulsion and microemulsion enviroment and other methods of obtaining zinc oxide were classified as chemical methods. In the next part of this review, the modification methods of ZnO were characterized. The modification with organic (carboxylic acid, silanes) and inroganic (metal oxides) compounds, and polymer matrices were mainly described. Finally, we present possible applications in various branches of industry: rubber, pharmaceutical, cosmetics, textile, electronic and electrotechnology, photocatalysis were introduced. This review provides useful information for specialist dealings with zinc oxide.

Green Synthesis of Metallic Nanoparticles via Biological Entities

Abstract: Nanotechnology is the creation, manipulation and use of materials at the nanometre size scale (1 to 100 nm). At this size scale there are significant differences in many material properties that are normally not seen in the same materials at larger scales. Although nanoscale materials can be produced using a variety of traditional physical and chemical processes, it is now possible to biologically synthesize materials via environment-friendly green chemistry based techniques. In recent years, the convergence between nanotechnology and biology has created the new field of nanobiotechnology that incorporates the use of biological entities such as actinomycetes algae, bacteria, fungi, viruses, yeasts, and plants in a number of biochemical and biophysical processes. The biological synthesis via nanobiotechnology processes have a significant potential to boost nanoparticles production without the use of harsh, toxic, and expensive chemicals commonly used in conventional physical and chemical processes. The aim of this review is to provide an overview of recent trends in synthesizing nanoparticles via biological entities and their potential applications.