Synergism of Zinc Oxide/Organoclay-Loaded Poly(lactic acid) Hybrid Nanocomposite Plasticized by Triacetin for Sustainable Active Food Packaging

The synergistic effect of organoclay(OC)and zinc oxide(ZnO)nanoparticles on the crucial properties of poly(lactic acid)(PLA)nanocompositefilms was systematically investigated herein.After their incorporation into PLA via the solvent casting technique,the water vapor barrier property of the PLA/OC/ZnOfilm improved by a maximum of 86%compared to the neat PLAfilm without the deterioration of Young’s modulus or the tensile strength.Moreover,thefilm’s self-antibacterial activity against foodborne pathogens,including gram-negative(Escherichia coli,E.coli)and gram-positive(Staphylococcus aureus,S.aureus)bacteria,was enhanced by a max-imum of approximately 98–99%compared to the neat PLAfilm.Furthermore,SEM images revealed the homo-geneous dispersion of both nano-fillers in the PLA matrix.However,the thermal stability of thefilm decreased slightly after the addition of the OC and ZnO.Thefilm exhibited notable light barrier properties in the UV-Vis range.Moreover,the incorporation of a suitable biodegradable plasticizer significantly decreased the Tg and notably enhanced theflexibility of the nanocompositefilm by increasing the elongation at break approxi-mately 1.5-fold compared to that of the neat PLAfilm.This contributes to its feasibility as an active food packa-ging material.

Electrospun gelatin/chitosan nanofibers containing curcumin for multifunctional food packaging

Recently,food grade nanofiber-based materials have received growing attentions in food packaging.In this work,novel active and intelligent packaging nanofibers based on gelatin/chitosan with curcumin(GA/CS/CUR)were developed via electrospinning technique.Effects of the incorporation of CUR content(0.1%-0.3%,m/m)on the microstructure and functional properties of the electrospun nanofibers were investigated.Morphological studies using scanning electron microscopy indicated that loading CUR can affect the average diameter of nanofiber mats,which remained around 160-180 nm.The addition of an appropriate level CUR(0.2%,m/m)led to a stronger intermolecular interaction,and thus enhanced the thermal stability and tensile strength of the obtained nanofibers.Meanwhile,the incorporation of CUR significantly improved antioxidant activity and the antimicrobial activity of GA/CS/CUR nanofibers.Moreover,the sensitivity of nanofibers to ammonia results indicated that GA/CS nanofibers containing 0.2%CUR(GA/CS/CURⅡ)presented high sensitivity of colorimetric behavior to ammonia(within 3 min).These results suggest GA/CS/CURⅡnanofibers has great potential as a multifunctional packaging to protect and monitor the freshness of proteinrich animal foods,such as meat and seafood.

Anthocyanins/chitosan films doped by nano zinc oxide for active and intelligent packaging:comparison of anthocyanins source from purple tomato or black wolfberry

The multifunctional films was prepared by blending chitosan and nano-ZnO with purple tomato anthocyanins or black wolfberry anthocyanins.The properties of films functioned by anthocyanins source and nano-ZnO content were studied.It was found purple tomato anthocyanins showed more significant color change against pH than black wolfberry anthocyanins.The nano-ZnO were widely dispersed in matrix and enhanced the compatibility of anthocyanins with chitosan.However,the anthocyanins source influenced the properties of the films more slightly than nano-ZnO addition.The tensile strength,antioxidant and antibacterial effects of the chitosan films dramatically increased after cooperated by nano-ZnO and anthocyanins,which also enhanced with increase of nano-ZnO content,whereas the elongation at break of the composite films decreased.Especially,the anthocyanin and nano-ZnO promoted the antibacterial activity of films synergistically.Composite films made from black wolfberry anthocyanins exhibited higher mechanical performance than those made from purple tomato anthocyanins but weaker antibacterial effects.The purple tomato anthocyanins/chitosan and nano-ZnO/purple tomato anthocyanins/chitosan films effectively reflected pork spoilage,changing their colors from dark green to brown,indicating the potential for applications in active and intelligent food packaging.

The interaction of nanostructured antimicrobials with biological systems:Cellular uptake,trafficking and potential toxicity

Nanomaterials have been found increasing applications in the food sector.Nanostructured antimicrobials can be incorporated either to food matrix of food packaging or to provide extended safety and quality.However,the interactions and effects of nanomaterials with biological systems are still poorly understood.Nanoparticles can enter the organism by oral,dermal and inhalation routes and distributed to different tissues by the circulatory system.Increasing evidence indicate that targeting to specific tissues,cellular uptake and intracellular fate of nanoparticles are strongly influenced by size,shape and surface properties.The specific characteristics of nanomaterials are also determinant for their toxicity in higher organisms.The dose,exposure time and administration route are important aspects influencing toxicity of nanoparticles as well.Both in vitro and in vivo evaluation studies on different types of nanostructures have providing information to support a better understanding about the interactions of nanoscale materials with biological systems.

Antioxidant Migration Studies in Chitosan Films Incorporated with Plant Extracts

The aim of this work was to develop an active biopolymer based on chitosan by incorporating natural antioxidants.Five essential oils(ginger,rosemary,sage,tea tree and thyme)and six hydro-alcoholic extracts(from ginger,green and black tea,kenaf leaves,rosemary and sage plants)were tested.Migration assays were carried out to evaluate the films’activity,and total phenolic content and antioxidant activity were monitored in the simulant during storage.Interaction between natural compounds and polymeric matrix was evaluated by FTIR spectroscopy.The diffusion of the phenolic compounds was not detected in the films incorporated with hydro-alcoholic extracts(HAEs),indicating their entrapment in the chitosan.Migration was observed in the films with essential oils(EOs),and biobased films incorporated with ginger,sage or rosemary essential oils,presented the highest diffusion and antioxidant activity in the simulant,highlighting their functionality and potential to be used as food active packaging material.

Development of Ficus carica Linn leaves extract incorporated chitosan films for active food packaging materials and investigation of their properties

The serious problems caused by extensive usage of petroleum-based plastic materials led to investigating the comprehensive studies and developing active food packaging materials.Even if the chitosan-based films are considered an attractive source,they exhibit some practical difficulties in developing active food packaging applications.Hence,Ficus carica Linn leaves extract(FLE),with the features of its cheapness,easy accessibility and superoxide anion radical scavenging activity,was incorporated into chitosan(CS)film at various concentrations(2%-6%w/w).To the best of our knowledge,this was the first time that FLE was utilized as a bioactive substance incorporated into chitosan films to develop eco-friendly,biodegradable,active food packaging material.The results obtained revealed that FLE incorporation into chitosan films significantly improved the swelling,water solubility and opacity of neat chitosan films.FTIR and morphological analysis indicated that the films produced exhibited smooth structure with homogenous dispersion of FLE.In mechanically,the addition of FLE resulted in a significant reduction in tensile strength while the elasticity of the films was improved.Additionally,the antioxidant and biodegradability properties of neat chitosan films were enhanced significantly.It was concluded that CS-FLE films appeared to be a capable and enhanced option for synthetic polymer-based food packaging materials.Based on the analyses performed,further studies are suggested on the packaging application for various foods and to evaluate the possible interaction of packaging film materials with the compounds of the food products,to avoid possible negative effects.

Ethylene scavenging film based on corn starch-gum acacia impregnated with sepiolite clay and its effect on quality of fresh broccoli florets

Barley(Hordeum vulgare L.)grasses(BG)have attracted considerable interest due to their multiple physiological activities and health benefits.In this paper,eight BG at four different growth stages were collected:seedling,tillering,stem elongation,and heading,and their product qualities and biological activities were examined and studied.Results demonstrated that harvest time obviously influenced proximate composition,surface color,and amino acid profile.Z21 and Z23 harvested at the seedling and early tillering stages,respectively,had higher total phenolic content(TPC)and total flavonoid content(TFC)than the other BG.Moreover,Z21 and Z23 possessed better DPPH radical-scavenging ability,antioxidant capacity,andα-glucosidase inhibitory activity,which were positively correlated with TPC,TFC,and protein and total amino acid contents.Our findings suggested that the early tillering stages were the preferable harvest times for BG with good product quality and biological properties.

Evidence on antimicrobial activity of essential oils and herbal extracts against Yersinia enterocolitica - A review

Yersinia enterocolitica is a very common food-borne pathogen which causes gastrointestinal infections (yersiniosis) in humans and a wide array of animals (e.g.cattle,deer,pigs,and birds).Due to the increasing interest in innovative plant-based substances as common food preservatives,several essential oils and herbal extracts have been investigated deeply that resulted in the emergence of novel anti-Yersinia additives.We reviewed relevant work done by 53 researchers covering literature from the year 2002 to till date.Some species such as Origanum vulgare ,Rosmarinus officinalis ,Thymus vulgaris ,Ocimum basilicum have been extensively investigated and identified that 1,8-cineole,linalool and γ-terpinene as compounds found in the essential oils of these plants have anti-Yersinia activity active food packaging agents.In the same direction,some promising results have been mentioned about the herbal extracts of Murrya koenigii ,Tanacetum vulgare and Tanacetum balsamita,but further investigations are needed for their sustainable implications.According to hierarchical cluster analysis,we found that Lamiaceae and Lauracea as the most significant families with anti-Yersinia activity.Towards the end,we proposed new research trends in order to enhance a global knowledge about the use of natural products against Y.enterocolitica .