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.

Antibacterial Chitosan-Gelatin Microcapsules Modified with Green-Synthesized Silver Nanoparticles for Food Packaging

Silver nanoparticles(Ag NPs)are an effective antibacterial agent,but their application in food packaging is limited due to their easy agglomeration and oxidation.In this study,antibacterial microcapsules were fabricated using Ginkgo biloba essential oil(GBEO)as core material and chitosan and type B gelatin biopolymer as capsule mate-rials.These antibacterial microcapsules were then modified with green-synthesized Ag NPs,blended into the bio-polymer polylactic acid(PLA),and finally formed as films.Physicochemical properties and antibacterial activity against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were evaluated.Results showed that the prepared antibacterial PLA films exhibited excellent antibacterial activity against foodborne pathogens.Its TVC exceeded the limit value of 7 log CFU/g at 7 days compared with the 5 days of pure PLA films.Therefore,these films can extend the shelf life of grass carp fillets by 2–3 days under refrigeration.

Advances in Research of Molded Pulp for Food Packaging

The molded pulp,a product of three-dimensional papermaking technology,is environmentally friendly and has a low environmental impact due to its ability to decompose quickly in the natural environment after disposal.The application of molded pulp for food packaging can replace or reduce the use of plastic food packaging.Researchers extract fibers from plants for the production of safe and hygienic molded pulp for food packaging,and they also study and enhance the qualities of molded pulp to broaden its use in the food industry.This paper reviews the sources and varieties of plant fiber used in molded pulp for food packaging,as well as research on the improvement and optimization of the performance of molded pulp products.Additionally,issues with molded pulp’s actual use for food packaging are reviewed,along with the potential for future research.This work can serve as a reference for molded pulp applications and research in the food industry in the future.

Research Status and Prospects of Bio-based Materials for Grease Barrier Coatings on Paper Food Packaging

Increased environmental and health concerns over the use of plastic packaging or fluorine-containing coatings,in combination with increased market demand for products with a longer shelf life,make bio-based materials one of the most important research candidates for alternative paper packaging materials for oil resistance.These bio-based materials have excellent oxygen and oil barriers,which are critical for food packaging.Moreover,they are biodegradable,naturally renewable,and safe.In this artical,two main groups of bio-based oil repellents for paper food packaging,including polysaccharide-based biopolymers and protein-based biopolymers,are enumerated,and the advantages and weaknesses of bio-based oil repellents are discussed,and effective solutions are proposed.Finally,research status and prospects on the development of bio-based oil-resistant coatings for the food packaging industry are presented.

Analysis of Heavy Metal Lead and Chromium Elements in Food Packaging Bags

[Objectives]This study was conducted to detect the contents of heavy metal lead and chromium in food packaging bags.[Methods]The contents of heavy metal lead and chromium in food packaging bags were determined by microwave digestion-flame atomic absorption spectrophotometer.With concentrated nitric acid and 30%hydrogen peroxide solution as the digestion system,food packaging bags of different materials,plastic packaging bags and paper packaging bags,were ultrasonically digested and then determined for the contents of heavy metal lead and chromium by flame atomic absorption spectrophotometry.[Results]The determination results showed that the linear correlation coefficient of lead was 0.9967,and the linear correlation coefficient of chromium was 0.9977.The method has the characteristics of simplicity,high analysis speed and high sensitivity.[Conclusions]This study provides a theoretical basis for the safety of food packaging bags.

High-strength collagen/delphinidin film incorporated with Vaccinium oxycoccus pigment for active and intelligent food packaging

This study developed an active and intelligent collagen-based packaging film with high strength for visually monitoring the freshness of fish.The results of scanning electron microscopy and atomic force microscopy showed that the film based on cross-linked collagen/delphinidin catalyzed by laccase exhibited a denser layer structure and a rougher surface.The dry and wet tensile strengths of the laccase-catalyzed collagen/delphinidin film(Col/Dp-LA film)increased by 41.74 MPa and 13.13 MPa in comparison with that of the pure collagen film,respectively.Moreover,the Col/Dp-LA film presented good antioxidant and barrier properties demonstrated by the results of free radical scavenging rate,light transmission rate,and water vapor permeability.The intelligent collagen-based film was obtained by incorporating Vaccinium oxycoccus pigment into the Col/Dp-LA film,which could change color under different pH values.When applied to the preservation offish fillets,the film could release Dp to minimize oxidative rancidity and prolong the shelf life of the fish for 2 days.Meanwhile,the film showed visual color changes from purplish-red to greyish-blue after the fish spoilage.These results indicated that the collagen film treated with delphinidin,laccase,and Vaccinium oxycoccus pigment has potential application value in the field of active and intelligent food packaging.

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.

Biobased materials for food packaging

Consumers prefer foods that are healthier with high quality and safety.Food packaging are de-manded to effectively extend the shelf-life,preserve the nutrients and decrease the microbial contamination during the transport and storage of food.With the increasing concern on the envi-ronmental impacts caused by food packaging wastes,sustainable and green packaging are highly demanded to minimize the harmful effects of food packaging waste on the environment.Bio-based materials are derived from sustainable and renewable biomass,instead of finite petrochemicals.The applications of bio-based materials for food packaging are highlighted in this review.The emphasis is placed on the categories of related biobased materials,their characteristics and ad-vantages for food packaging,as well as the strategies used to improve their performances.Though a lot of trials have been done on biobased materials for food packaging,further attempts to im-prove their performances,understand the functioning mechanisms and develop greener methods for the production,processing and destiny of these bio-based materials are still highly needed for the future research.

Effect of PLA/ZnO Packaging and Gamma Radiation on the Content of Listeria innocua, Escherichia coil and Salmonella enterica on Ham during Storage at 4℃

The effect of ZnO and low y-radiation on PLA based-films was investigated to be used for food packaging application. Ham slices were inoculated with E. coli, L. innocua and S. enterica and then covered with PLA and PLA/5% ZnO films. The samples were irradiated with a y-radiation dose of 0.3 kGy at dose rate of 13.5 kGy/h. Microbiological analysis was performed at 0, 1 and 5 days on samples stored at 4 ℃. Results showed that no consistent reduction of bacteria was obtained, even at the fifth day of storage, when the ham was covered with PLA/5% ZnO film and no γ-radiation was performed. The use of γ-radiation results necessary to reduce the bacteria growth. In fact E. coli and S. enterica were not detected after 5 days of storage; whereas in the case of test with L. innocua a reduction of 1.3 log CFU/g was observed after 5 days of storage. The antibacterial results indicate that the presence of ZnO in PLA film is effective only for E. coll. The differences of the results obtained here with those reported in literature （where ZnO particles are reported to be very effective as antimicrobial material） are accounted for the different methodologies used. In conclusion considering the positive results, even if small, obtained here at least only for the E. Coli and considering that PLA/5% ZnO film shows, compared to plain PLA film, good tensile properties （especially Young＇s modulus and stress at yielding） and good permeability （to O2 and CO2） induce to consider the PLA/5% ZnO composite film usable for food packaging when long shelf life and food safety are required, considering also that it is biodegradable and compostable.

The Use of Zinc Oxide Nanoparticles in Eva to Obtain Food Packing Films

The increasing demand for new packages with increased shelf life properties has stimulated the increase of research in the active packaging sector. The use of antimicrobial agents requires an in-depth study of their properties to avoid loss of efficiency of the polymer processing. In this context, the objective of this work was to evaluate the preparation of an 18% ethylene vinyl acetate copolymer (EVA) nanocomposite and zinc oxide (ZnO) as microbicidal nanoparticle, prepared in a monosulfon extruder. The nanoparticle was modified with octadecylamine and EVA 18 nanocomposite films were prepared and compared to the systems containing modified nanoparticle. These new materials were characterized by thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), Dynamic Mechanical Analysis (DMA), Time Domain Nuclear Magnetic Resonance (NMR) to investigate the effect of zinc oxide nanoparticles on thermal properties, EVA crystallinity and antimicrobial effect. The TGA showed a tendency of increase of the thermal stability in different proportions of ZnO. DSC results did not show significant changes in thermal parameters. The XRD analysis showed an increase in the degree of crystallinity of the nanocomposites in relation to the EVA matrix and change in the crystallinity with the increase of ZnO percentages. DMA analysis indicates change in structural organization through the variation of storage modulus, loss, and tan delta. Time domain NMR data corroborate with XRD data through the change in molecular mobility.

Development of African Earthenware Container Imbedded with Nanosilver Particles for Food Preservation

With the aim of ameliorating its preservation capacity, silver nanoparticles (0 - 100nm) with 99.9% purity and 35nm average particle size, were used as building material for earthenware jar, an extremely old container which is still used in rural African villages specifically in North Cameroon. Earth material was dissolved in water at the weight ratio of 5% to 10%. Silver nanoparticles were then added to the mixture and stirred to prepare 1% to 5% Ag/Earth paste (1 to 5 ppm). A grounded metal rotating drum was used to prepare earth embedded nanosilver plates. An n-order mathematic expression was used to evaluate the shelf-live quality and deterioration rate of sorghum porridge preserved in this African earthenware container imbedded with nanosilver particles. Accelerated shelf-life testing was used to predict the shelf life of the product at usual rural storage conditions. The used Arrhenius model indicated that the shelf life of the sorghum porridge stored in African earthenware container imbedded with nanosilver particles can be extended to 14 days at 4&degC ± 1&degC, 6 days at 15&degC ± 5&degC, and 4 days at 30&degC ± 2&degC. The calculated Q10 values were found to be in the range of 1.5 - 2.0.

Packaging Design and the Changing Needs of End Consumers

With the rapid development of China’s economy,the society has entered the era of big data intelligence,leading to tremendous changes in people’s shopping methods.From the original way of shopping via traditional channels from street vendors and farmer’s markets to shopping via WeChat,Douyin,Taobao,Pinduoduo,and other digital e-commerce channels,online shopping has become the norm and an integral part of people’s life in the post-pandemic era.The shift from traditional offline shopping to online shopping calls for a change in design thinking,integrating food packaging design,consumer needs,and brand stories,reflecting individual characters and regional cultures,as well as incorporating traditional Chinese style and cultural elements.

Real-Time Anomaly Detection in Packaged Food X-Ray Images Using Supervised Learning

Physical contamination of food occurs when it comes into contact with foreign objects.Foreign objects can be introduced to food at any time during food delivery and packaging and can cause serious concerns such as broken teeth or choking.Therefore,a preventive method that can detect and remove foreign objects in advance is required.Several studies have attempted to detect defective products using deep learning networks.Because it is difficult to obtain foreign object-containing food data from industry,most studies on industrial anomaly detection have used unsupervised learning methods.This paper proposes a new method for real-time anomaly detection in packaged food products using a supervised learning network.In this study,a realistic X-ray image training dataset was constructed by augmenting foreign objects with normal product images in a cut-paste manner.Based on the augmented training dataset,we trained YOLOv4,a real-time object detection network,and detected foreign objects in the test data.We evaluated this method on images of pasta,snacks,pistachios,and red beans under the same conditions.The results show that the normal and defective products were classified with an accuracy of at least 94%for all packaged foods.For detecting foreign objects that are typically difficult to detect using the unsupervised learning and traditional methods,the proposed method achieved high-performance realtime anomaly detection.In addition,to eliminate the loss in high-resolution X-ray images,the false positive rate and accuracy could be lowered to 5%with patch-based training and a new post-processing algorithm.

Technological Development on Layered Products for Foods and/or Foodstuff-Evaluation by Patenting Documents

Packaging is one of the most important methods of keeping the quality of food products for storage, transportation and end-use. The price of materials employed for packaging food has traditionally been high and used to be more expensive than the food itself. Technological innovations made possible to produce packaging materials cheaply. One of these processes is known as co-extrusion. This technique makes a film with two or more layers with different plastics not laminating the layers together with an adhesive, eliminating the use of solvents and producing a film in just one step instead multiple steps. In this background, our paper relates to the evolution on packaging for foods by using patenting documents. A search for patent documents was performed on free patent databases using keywords and International Patent Classification （IPC） codes related to this technology. As results： （a） 17% of the 21,472 documents found are focused on multilayer packaging for food; （b） 12 countries hold more than 90% of patents （38% Japan; 23% The United States of America; 7% Canada and 6% Germany）; and, （c） two peaks were perceived in the period of 1992-1994 and 2003, and matches, respectively, the Persian Gulf （1990-1991） and Iraq Wars （2003-invasion of Iraq）, so the historical tendency is confirmed： ＂wars also generate scientific and technological innovations＂.

Active packaging for lipid foods and development challenges for marketing

Consumer demand for natural products with low concentration of additives and controlled environmental impact has been a major challenge for the lipid food packaging industry.Because of this fact,active packaging such as oxygen absorbers and antioxidant releasers are trends in the industry.In this work,research developed on oxygen absorbing packaging and antioxidant-releasing packaging will be discussed.This work will also reveal the challenges to commercialization.Packaging that slows down lipid oxidation in food presents satisfactory results and greater efficacy than vacuum packaging.The challenges for the development of active packaging that consist of biopolymers and natural additives are related to the physical and mechanical properties of the materials.Future research should develop biodegradable active packaging that are resistant to industrial processing.Furthermore,there are plenty of natural resources not yet studied and that may be applicable for the development of active oxygen-absorbing and antioxidant active packaging for food.

Consumer Response to the Product Carbon Footprint （PCF）

A survey of 277 German participants demonstrates that a Product Carbon Footprint （PCF） label is not yet a suitable instrument for communication with consumers because of the lack of standardized PCF calculation within Europe. Most consumers do not understand either the PCF statement or the PCF calculation. The public message of a PCF label does not conform to the terms of sustainability. At first sight, PCF seems to be an opportunity to communicate the sustainability aspects of food to consumers, but too many different approaches to defining PCF exist in Europe. Additionally, the use of a ＂green＂ PCF label may distort trading conditions because of the lack of PCF-issuing authorities in accordance with World Trade Organization （WTO） standards. Hence, PCF may ultimately deceive consumers through its misapplication if the PCF calculation is not aligned to internationally accepted standards.

ENVIRONMENTAL ATTITUDES AND CONSUMER PREFERENCE FOR ENVIRONMENTALLY-FRIENDLY BEVERAGE PACKAGING:THE ROLE OF INFORMATION PROVISION AND IDENTITY LABELING IN INFLUENCING CONSUMER BEHAVIOR

This study examined whether urban Chinese consumers with stronger environmental values have higher valuations for plastic beverage bottles that are made of post-consumer recycled material(rPET)or that come in large sizes that use plastic more efficiently.It also assesses the effectiveness of environmental information provision and green identity labeling in increasing consumer willingness to pay for environmentally-friendly packaging.The results suggest that urban Chinese consumers are willing to pay a premium for rPET bottles,indicating that there is a potential market for rPET food and beverage packaging in China that calls for manufacturing guidelines,safety standards,or regulations.Providing environmental information and attaching green identity labels increases consumer valuations of rPET bottles,with their joint use exerting the largest effect.Pro-environmental consumers are more responsive to environmental information and green identity labeling and thus are willing to pay a higher premium for rPET bottles.However,in terms of choosing large bottles as a means to reduce plastic use in product packaging,consumers were found to be indifferent about plastic bottle sizes even after receiving environmental information.It is suggested that the inconvenience of carrying or storing large bottles might have offset their perceived environmental benefits.

Biodegradable,strong,and clear wood package for plastic alternative

Using biodegradable material derived from renewable resources as petroleum-based plastics replacement is a promising way towards sustainable development.However,the insufficient mechanical properties and complex manufacturing process of bioplastics still need to be improved for high-quality food packages.Herein,we report a top-down strategy to transform natural wood into a clear wood packaging film through scalable delignification and polyvinyl alcohol(PVA)infiltration.The wood packaging film demonstrates a laminated structure with completely collapsed cell walls and PVA intertwined together after energy-saving air drying,resulting in high light transmittance with low haze,good mechanical performance,and high barrier performance for oxygen and water vapor.Molecular dynamics simulations reveal the underlying fracture mechanism between cellulose and PVA,which effectively enhances the Young’s modulus and strength of the wood packaging film.These findings contribute to the development of biodegradable and strong packaging materials,as well as other food-related applications,using sustainable wood.

Generation of Tough Poly(glycolic acid)(PGA)/Poly(butylene succinate-co-butylene adipate)(PBSA)Films with High Gas Barrier Performance through In situ Nanofibrillation of PBSA under an Elongational Flow Field

Poly(glycolic acid)(PGA)is derived from glycolide obtained by fermenting pineapples or sugarcane,which has excellent gas barrier properties and a small carbon footprint.PGA is a potential substitute for the current aluminum-plastic composite films used in high barrier packaging applications.However,its poor ductility and narrow processing window limit its application in food packaging.Herein,poly(butylene succinate-co-butylene adipate)(PBSA)was used to fabricate PGA/PBSA blend films through an in situ fibrillation technique and blown film extrusion.Under the elongational flow field used during the extrusion process,a unique hierarchical structure based on the PBSA nanofibrils and interfacially oriented PGA crystals was obtained.This structure enhances the strength,ductility and gas barrier properties of the PGA/PBSA blend film.In addition,an epoxy chain extender(ADR4468)was used as a compatibilizer to further enhance the interfacial adhesion between PGA and PBSA.70PGA/0.7ADR exhibited a very low oxygen permeability(2.34×10^(-4)Barrer)with significantly high elongating at break(604.4%),tensile strength(47.4 MPa),and transparency,which were superior to those of petroleum-based polymers.Thus,the 70PGA/0.7ADR blown films could satisfy the requirements for most instant foods such as coffee,peanuts,and fresh meat.

Applications of chitosan-based biomaterials:a focus on dependent antimicrobial properties

Marine-derived chitosan has been widely examined for its use in developing biomedical materials.Not only is it non-toxic,biocompatible,and degradable,it has also shown unique antimicrobial properties.The antimicrobial properties of chitosan are restricted by neutral and physiological conditions because it is insoluble in water and its pKa values is 6.5.One solution to this problem is to graft chemically modified groups onto the backbone of chitosan.The aim of this paper is to review the mode of antimicrobial action of chitosan and chitosan derivatives.Using chitosan alone may not meet the demands of various applications.However,the introduction of additional polymers and antimicrobial agents is commonly used to enhance the antimicrobial potential of chitosan-based biomaterials.Chitosan-based composite biomaterials have been developed that allow diversified formulations to broaden applications,including nanoparticles,hydrogels,films,sponges,fibers,or even microspheres.These along with recent advances on chitosan-based composite biomaterials used for wound healing,food packaging,textile sector,3D printing and dental materials,were reviewed in detail.