Biodegradable Alginate Films with ZnO Nanoparticles and Citronella Essential Oil—A Novel Antimicrobial Structure

Abstract

The petroleum-based materials could be replaced, at least partially, by biodegradable packaging. Adding antimicrobial activity to the new packaging materials can also help improve the shelf life of food and diminish the spoilage. The objective of this research was to obtain a novel antibacterial packaging, based on alginate as biodegradable polymer. The antibacterial activity was induced to the alginate films by adding various amounts of ZnO nanoparticles loaded with citronella (lemongrass) essential oil (CEO). The obtained films were characterized, and antibacterial activity was tested against two Gram-negative (Escherichia coli and Salmonella Typhi) and two Gram-positive (Bacillus cereus and Staphylococcus aureus) bacterial strains. The results suggest the existence of synergy between antibacterial activities of ZnO and CEO against all tested bacterial strains. The obtained films have a good antibacterial coverage, being efficient against several pathogens, the best results being obtained against Bacillus cereus. In addition, the films presented better UV light barrier properties and lower water vapor permeability (WVP) when compared with a simple alginate film. The preliminary tests indicate that the alginate films with ZnO nanoparticles and CEO can be used to successfully preserve the cheese. Therefore, our research evidences the feasibility of using alginate/ZnO/CEO films as antibacterial packaging for cheese in order to extend its shelf life.

Antibacterial Biodegradable Films Based on Alginate with Silver Nanoparticles and Lemongrass Essential Oil–Innovative Packaging for Cheese

“…This can be attributed to the existence of local Ag NPs agglomerations (as seen in ESEM images), which promotes Ag-Ag interactions, either directly or mediated by moieties of alginate. A similar effect of nanoparticles on alginate fluorescence was reported in [4].…”

“…When it is not salted, uncontrolled and extensive development of microorganisms is contributing to cheese's short shelf life. Different cheese varieties need some bacterial cultures to be produced, and this creates an infection hazard from the cheese-borne species such as Escherichia coli, Salmonella enterica, or Staphylococcus aureus [4]. Samples of soft cheese of approximatively 10.00-13.00 g were weighed and packed in alginate or AAg1-Aag4 films.…”

“…The majority of food packaging materials used at present are based on petrochemical products or cellulose, due to historical factors such as low cost or mechanical and barrier properties [1,2]. The pressure of environmental concerns will phase out the petroleumbased materials, which will increase the need for innovative, biodegradable polymeric packaging materials such as chitosan [3], alginate [4], cellulose [5], starch [6], pullulan [7], polylactic acid [8], etc. The need to decrease the food waste, and the desire to increase the food safety and to prolong the shelf life creates pressure on the food packaging industry to develop and adopt new antimicrobial materials [9][10][11].…”

Zinc Oxide Nanoparticles for Water Purification

“…Moreover, zinc oxide has numerous applications in diverse fields, such as drug delivery [ 19 , 20 ], cosmetics [ 16 , 21 ], paints [ 5 ], medical devices [ 22 ], dentistry [ 23 ], and the textile industry [ 24 ]. The applicability of zinc oxide is not limited to sunscreens [ 15 ]; it is also important in other industries such as rubber, pharmaceuticals [ 25 ], and food [ 26 ].…”

Synergistic Effect of Glycyrrhizic Acid and ZnO/Palygorskite on Improving Chitosan-Based Films and Their Potential Application in Wound Healing

“…Films with a greater opacity value are less transparent. The opacity values of the films were calculated by Equation (4) [35].…”