Active packaging for table grapes: Evaluation of antimicrobial performances of packaging for shelf life of the grapes under thermal stress

Pedalium murex plant-based bioplasticizer reinforced polylactic acid films: A promising approach for biodegradable fruit packaging applications

The most likely materials for use in packaging are plastics. A lot of synthetic polymers are harming the environment. A plasticizer is required for all polymers to improve their characteristics and workability. The plasticizers come in liquid form and are also derived from fossil fuels, which are harmful to the environment. Producing functional and affordable biopolymer for packaging applications is a difficult task nowadays. The preparation of biofilm for packaging using biopolymer and bioplasticizer is the main aim of this work. The biopolymer poly L-lactic acid (PLA) is used, and the bio plasticizer is extracted from Pedalium murex plant. Chemical and mechanical methods are used to extract the plasticizer. Plasticization of polylactic acid biopolymer was done using the extracted plasticizer at additions of 1 %, 2 %, 3 %, 4 %, and 5 %. FT-IR spectroscopy, X-ray diffraction spectroscopy, and surface roughness values are used to characterise the prepared biofilms. Scanning electron spectroscopy pictures are utilised to evaluate the morphological orientation of the biofilms. Strawberries packed with biofilms are used to evaluate the barrier properties of biofilms using UV spectroscopy analysis. Thermal degradation behaviour is investigated using thermo gravimetric analysis. We examined the mechanical characteristics, such as tensile strength, elongation modulus, and elongation break percentage. The plasticizing effect of the plasticizer raises the elongation break percentage while decreasing the tensile strength and modulus. For 2 % plasticizer addition the elongation break increases and the tensile not much affected. To demonstrate biodegradability and microbial resistance, the soil degradation behaviour and antimicrobial activities were examined.

Carboxymethyl cellulose/poly (vinyl alcohol) based active film incorporated with tamarind seed coat waste extract for food packaging application

Incorporating a bioactive food waste extract into biodegradable polymers is a promising green approach to producing active films with antioxidant and antibacterial activity for food packaging. Active packaging films from carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA) incorporated with tamarind seed coat waste extract (TS) were prepared by solvent casting method using citric acid as a crosslinking agent. The effect of TS content on the film properties was determined by measuring the optical, morphology, mechanical, water vapor transmission rate (WVTR), antioxidant, and antimicrobial attributes. The CMC/PVA-TS films were also tested on fresh pork. The addition of TS did not significantly affect the film structure and WVTR but it improved the mechanical and UV barrier properties. The films possessed antioxidant and antimicrobial ability against bacteria (S. aureus and E. coli). Thus, CMC/PVA packaging was successfully prepared, and the incorporation of TS enhanced the antioxidant and antimicrobial properties of the film, which extended the shelf-life of fresh pork.

New Functional Bionanocomposites by Combining Hybrid Host-Guest Systems with a Fully Biobased Poly(lactic acid)/Poly(butylene succinate-co-adipate) (PLA/PBSA) Binary Blend

In this study, we have developed innovative polymer nanocomposites by integrating magnesium-aluminum layered double hydroxide (LDH)-based nanocarriers modified with functional molecules into a fully biobased poly(lactic acid)/poly(butylene succinate-co-adipate) (PLA/PBSA) matrix. These LDH-based hybrid host-guest systems contain bioactive compounds like rosmarinic acid, ferulic acid, and glycyrrhetinic acid, known for their antioxidant, antimicrobial, and anti-inflammatory properties. The bioactive molecules can be gradually released from the nanocarriers over time, allowing for sustained and controlled delivery in various applications, such as active packaging or cosmetics. The morphological analysis of the polymer composites, prepared using a discontinuous mechanical mixer, revealed the presence of macroaggregates and nano-lamellae at the polymer interface. This resulted in an enhanced water vapor permeability compared to the original blend. Furthermore, the migration kinetics of active molecules from the thin films confirmed a controlled release mechanism based on their immobilization within the lamellar system. Scaling-up experiments evaluated the materials' morphology and mechanical and thermal properties. Remarkably, stretching deformation and a higher shear rate during the mixing process enhanced the dispersion and distribution of the nanocarriers, as confirmed by the favorable mechanical properties of the materials.

Evaluation of the Antioxidant and Antimicrobial Potential of SiO2 Modified with Cinnamon Essential Oil (Cinnamomum Verum) for Its Use as a Nanofiller in Active Packaging PLA Films

One of the main causes of food spoilage is the lipid oxidation of its components, which generates the loss of nutrients and color, together with the invasion of pathogenic microorganisms. In order to minimize these effects, active packaging has played an important role in preservation in recent years. Therefore, in the present study, an active packaging film was developed using polylactic acid (PLA) and silicon dioxide (SiO₂) nanoparticles (NPs) (0.1% w/w) chemically modified with cinnamon essential oil (CEO). For the modification of the NPs, two methods (M1 and M2) were tested, and their effects on the chemical, mechanical, and physical properties of the polymer matrix were evaluated. The results showed that CEO conferred to SiO₂ NPs had a high percentage of 2,2-diphenyl-l-picrylhydrazyl (DPPH) free radical inhibition (>70%), cell viability (>80%), and strong inhibition to E. coli, at 45 and 11 µg/mL for M1 and M2, respectively, and thermal stability. Films were prepared with these NPs, and characterizations and evaluations on apple storage were performed for 21 days. The results show that the films with pristine SiO₂ improved tensile strength (28.06 MPa), as well as Young's modulus (0.368 MPa) since PLA films only presented values of 27.06 MPa and 0.324 MPa, respectively; however, films with modified NPs decreased tensile strength values (26.22 and 25.13 MPa), but increased elongation at break (from 5.05% to 10.32-8.32%). The water solubility decreased from 15% to 6-8% for the films with NPs, as well as the contact angle, from 90.21° to 73° for the M2 film. The water vapor permeability increased for the M2 film, presenting a value of 9.50 × 10^-8 g Pa^-1 h^-1 m^-2. FTIR analysis indicated that the addition of NPs with and without CEO did not modify the molecular structure of pure PLA; however, DSC analysis indicated that the crystallinity of the films was improved. The packaging prepared with M1 (without Tween 80) showed good results at the end of storage: lower values in color difference (5.59), organic acid degradation (0.042), weight loss (24.24%), and pH (4.02), making CEO-SiO₂ a good component to produce active packaging.

A Hydrotalcite-Based PET Composites with Enhanced Properties for Liquid Milk Packaging Applications

In the present work, the two-phase mixture (HTLc) of hydrotalcite and its oxide were used to improve the barrier properties, UV resistance and antimicrobial activity of Poly(ethylene terephthalate) (PET) for their application in liquid milk packaging. Firstly, CaZnAl-CO₃-LDHs with a two-dimensional layered structure were synthesized by hydrothermal method. CaZnAl-CO₃-LDHs precursors were characterized by XRD, TEM, ICP and dynamic light scattering. A series of PET/HTLc composite films were then prepared, characterized by XRD, FTIR and SEM, and a possible mechanism of the composite films with hydrotalcite was proposed. Barrier properties to water vapor and oxygen have been studied in PET nanocomposites, as well as their antibacterial efficacy by the colony technique and their mechanical properties after exposure to UV irradiation for 24 h. By the presence of 1.5 wt% HTLc in the PET composite film, the oxygen transmission rate (OTR) was reduced by 95.27%, the water vapor transmission rate was reduced by 72.58% and the inhibition against Staphylococcus aureus and Escherichia coli was 83.19% and 52.75%. Moreover, a simulation of the migration process in dairy products was used to prove the relative safety. This research first proposes a safe technique for fabricating hydrotalcite-based polymer composites with a high gas barrier, UV resistance and effective antibacterial activity.

What is the role of active packaging in the future of food sustainability? A systematic review

Nowadays, the strong increase in products consumption, the purchase of products on online platforms as well as the requirements for greater safety and food protection are a concern for food and packaging industries. Active packaging brings huge advances in the extension of product shelf-life and food degradation and losses reduction. This systematic work aims to collect and evaluate all existing strategies and technologies of active packaging that can be applied in food products, with a global view of new possibilities for food preservation. Oxygen scavengers, carbon dioxide emitters/absorbers, ethylene scavengers, antimicrobial and antioxidant active packaging, and other active systems and technologies are summarized including the products commercially available and the respective mechanisms of action. © 2022 Society of Chemical Industry.

Rosmarinic and Glycyrrhetinic Acid-Modified Layered Double Hydroxides as Functional Additives for Poly(Lactic Acid)/Poly(Butylene Succinate) Blends

Immobilizing natural antioxidant and biologically active molecules in layered double hydroxides (LDHs) is an excellent method to retain and release these substances in a controlled manner, as well as protect them from thermal and photochemical degradation. Herein, we describe the preparation of host-guest systems based on LDHs and rosmarinic and glycyrrhetinic acids, two molecules obtained from the extraction of herbs and licorice root, respectively, with antioxidant, antimicrobial, and anti-inflammatory properties. Intercalation between the lamellae of the mono-deprotonated anions of rosmarinic and glycyrrhetinic acid (RA and GA), alone or in the presence of an alkyl surfactant, allows for readily dispersible systems in biobased polymer matrices such as poly(lactic acid) (PLA), poly(butylene succinate) (PBS), and a 60/40 wt./wt. PLA/PBS blend. The composites based on the PLA/PBS blend showed better interphase compatibility than the neat blend, correlated with increased adhesion at the interface and a decreased dispersed phase size. In addition, we proved that the active species migrate slowly from thin films of the composite materials in a hydroalcoholic solvent, confirming the optimization of the release process. Finally, both host-guest systems and polymeric composites showed antioxidant capacity and, in the case of the PLA composite containing LDH-RA, excellent inhibitory capacity against E. coli and S. aureus.

Effect of Gaseous Citral on Table Grapes Contaminated by Rhizopus oryzae ITEM 18876

Rhizopus oryzae is responsible for rapidly producing a deliquescent appearance in grape berries, generally favoured by cold chain interruptions. To counteract fruit spoilage and to meet consumer acceptance, innovative strategies based on the application of natural compounds are ongoing. Due to their biological activities, including antimicrobial ones, natural flavour compounds extend the shelf life and improve the nutritional value as well as the organoleptic properties of foods. Thus, in this work, the application of the antimicrobial citral, a flavor component of monoterpenes identified in plant and fruit essential oils, was developed and validated against one spoiler of R. oryzae. Citral, as pure compound, was first investigated in vitro against R. oryzae ITEM 18876; then, concentrations equal to the minimal inhibitory concentration (MIC) and 4-fold MIC (4MIC) value were applied on the table grape cv Italia infected with this strain and stored. The MIC value was equal to 0.0125 μL/cm3; both citral concentrations (0.0125 and 0.05 µL/cm3) were effective in counteracting the microbial decay of infected table grapes over the storage period. The HS-SPME/GC-MS method showed citral persistence in the head space of plastic trays with the infected samples; as expected, a higher content of citral isomers was found in the sample treated with 4MIC value. In conclusion, citral revealed its efficacy to counteract the onset of soft rot by R. oryzae ITEM 18876 under storage conditions. Thus, it could be successfully exploited to develop an active packaging or natural preservatives to extend table grape shelf life without affecting its quality and sensory characteristics, whilst also satisfying the consumer demand for natural preservative agents.

Effect of Active Packaging Material Fortified with Clove Essential Oil on Fungal Growth and Post-Harvest Quality Changes in Table Grape during Cold Storage

Fungal growth in table grapes (Vitis vinifera cv. beauty seedless) is triggered by Botrytis cinerea, Penicillium sp., Aspergillus sp., and Rhizopus stolonifera during post-harvest storage. Due to the safety aspects, this research aimed to develop antifungal packaging embedded with essential oils (EOs) to alleviate the fungal decay of table grapes (TG). The various levels of EOs (0.5–5%, v/v) from clove, cinnamon, thyme, peppermint, lemon, bergamot, ginger, spearmint, and lemongrass were tested against Aspergillus sp. The results attained in radial growth, disk diffusion method, minimal inhibitory concentration, and minimal fungicidal concentration revealed that 1% clove essential oil (CEO) showed higher efficacy against Aspergillus sp. compared to the untreated control and other treatments. CEO at the 1% level exhibited a pleasant odor intensity in TG than the other EOs. The active polyvinyl alcohol (7% PVA) film with 1% CEO resulted in lower weight loss, disease severity, and TG berry drop than the control and other treated samples. Additionally, the acceptance score in the TG sample wrapped with a PVA film containing 1% CEO was augmented. Therefore, the PVA film with 1% CEO retarded the fungal growth and prolonged the shelf life of TG during storage of 21 days at 13 °C and 75% relative humidity (RH).

Active Packaging Based on Coupled Nylon/PE Pouches Filled with Active Nano-Hybrid: Effect on the Shelf Life of Fresh Milk

The study reports on the preparation and characterization of an active packaging based on pouches composed of a coupled system nylon/polyethylene (PE). The PE layer was filled with and active nano-hybrid of layered double hydroxide (LDH) on which it was anchored salicylate, as antimicrobial molecule. The release of the salicylate anchored to the LDH was compared to the release of the molecule free dispersed into the PE and resulted much slower. It was evaluated the efficiency of the active packaging to inhibit Pseudomonas aeruginosa, Escherichia coli, Listeria monocytogenes, Salmonella typhimurium, and Campylobacter. Global migration tests on the PE active layer, using ethanol (50% v/v) as food simulant, demonstrated the possibility of such active nanocomposite to be used for food contact being the migration limits in compliance with those imposed from the EU regulation. Fresh milk was packed into the active pouches and pouches with unfilled PE layer, as control. The pH reduction as function of the time, due to the production of lactic acid, resulted much slower in the active packaging. Total bacterial count (TBC) was evaluated on the milk, either packed into the active packaging or the control, up to 50 days of storage at 4 °C. Shelf life of the milk was evaluated using the Gompertz model. It was demonstrated an increasing of the shelf life of milk packaged in active pouches from 6 days up to 10 days.

Essential oils as additives in active starch-based food packaging films: A review

The production of sustainable food packaging from renewable sources represents a prominent alternative to the use of petrochemical-based plastics. For example, starch remains one of the more closely studied replacement options due to its broad availability, low cost and significant advances in improving properties. In this context, essential oils as additives fulfil a key role in the manufacture of renewable active packaging with superior performances. In this review, a comprehensive summary of the impact of adding essential oils to the starch-based films is provided. After a brief introduction to the fundamental concepts related to starch and essential oils, details on the most recent advances in obtaining active starch-based films are presented. Subsequently, the effects of essential oils addition on the structure-property relationships (from physicochemical to antimicrobial ones) are thoroughly addressed. Finally, applications and challenges to the widespread use of essential oils are critically discussed.

Evaluation of Quality and Storability of "Italia" Table Grapes Kept on the Vine in Comparison to Cold Storage Techniques

The aim of the study was to compare the quality of table grapes (cv. Italia) held on the vine compared to grapes stored in cold rooms with or without modified-atmosphere packaging (MAP). The grapes were harvested from 12 plants in 2 vineyards in the same area, differing for the age of the plant. Four- and a fourteen-year-old vines were cultivated with the “Apulia tendone” system. After the first harvest, grapes were divided into small clusters and used for storage treatments in air and in MAP. Samples of 400 g were packaged in polypropylene (PP) trays sealed with a polypropylene/polyamide (PP/PA) film with 20% CO₂ in air. MAP and control samples were then stored in the same cold room at 0 °C. Initially and after 8, 21, and 28 days, grapes stored in air and MAP were compared to fresh harvested grapes, stored on the plants. Quality attributes included color, texture, maturity index, phenols, antioxidant activity, sugars, organic acids, sensory parameters, and volatile compounds. The results obtained demonstrated that grapes held on the plant and in MAP showed better quality in terms of appearance scores compared to grapes stored in air. In particular, the application of high CO₂ contributed to reduce the deterioration rate of the clusters, minimizing weight loss, and delaying degradation processes, and this particularly for grapes from the 14-year-old vine, where grapes held on the plant degraded faster than grapes in the younger vines. Most volatile compounds did not change their concentration with the storage treatment, except for ethyl acetate and ethanol, which increased in MAP at the end of storage, and to some compound responsible for green odor. In conclusion, keeping the grapes on the plant can be considered a good agronomic practice to preserve the quality, whereas MAP can be applied to better maintain postharvest quality of the product throughout storage and distribution.

Innovative Preservation Technology for the Fresh Fruit and Vegetables

The preservation of the freshness of fruits and vegetables until their consumption is the aim of many research activities. Quality losses of fresh fruit and vegetables during cold chain are frequently attributable to an inappropriate use of postharvest technologies. Moreover, especially when fresh produce is transported to distant markets, it is necessary to adopt proper postharvest preservation technologies in order to preserve the initial quality and limit microbial decay. Nowadays, for each step of supply chain (packing house, cold storage rooms, precooling center, refrigerate transport and distribution), are available innovative preservation technologies that, alone or in combination, could improve the fresh products in order to maintain the principal quality and nutritional characteristics. The issue groups five original studies and two comprehensive reviews within the topic of preservation technologies related to innovative packaging and postharvest operation and treatments, highlighting their effect on quality keeping.

Combined Effect of Active Packaging of Polyethylene Filled with a Nano-Carrier of Salicylate and Modified Atmosphere to Improve the Shelf Life of Fresh Blueberries

Blueberries are popular among consumers for their high nutritional value but are highly perishable due to the microbial decay. The use of active packaging that is able to interact with the food through releasing or absorbing substances can be a valid approach to preserve the quality and increase the fruit’s shelf-life. In this paper, an active packaging based on polyethylene (PE) filled with a nano-carrier of salicylate was prepared and characterized. Fresh blueberries were packaged in passive modified atmosphere packaging (pMA) for 13 days at 8 °C. The combination of the active filler in bulk and pMA showed a significant inhibition of mold development and a reduction of the respiration rate of fruits. Moreover, the release of salicylate on blueberries did not alter the fruits’ sensory traits and preserved the firmness and the nutritional quality. Finally, the combination of active packaging and pMA resulted a valid solution to extend blueberries’ shelf-life up to 13 days.

Formulation of a Bio-Packaging Based on Pure Cellulose Coupled with Cellulose Acetate Treated with Active Coating: Evaluation of Shelf Life of Pasta Ready to Eat

An active packaging based on pure cellulose coupled with cellulose acetate coated with layered double hydroxide (LDH), hosting 4-hydroxybenzoate (listed in EC-Directive 10/2011) as an antimicrobial agent, was formulated and realized. The release of 4-hydroxybenzoate ionically bonded to the LDH layers was much slower than the molecule freely dispersed into the coating. The capability of the active packaging to inhibit Pseudomonas, Escherichia coli, Salmonella and Lactic Bacteria was evaluated, as well as the global migration with three different food simulant (i.e., acetic acid at 3% (v/v), ethanol at 50% (v/v) and vegetable oil) that demonstrated, in compliance with the migration limits of the EU regulation, the suitability of the prepared packaging to be employed as food contact material. Ready to east cooked tomato pasta was packaged into the active trays and in uncoated, as control, up to 30 days at 4 °C. Organoleptic characteristics, mold evolution, total mesophilic aerobic counts (TBC), Enterobacteriaceae, Lactic Bacteria and Pseudomonas, and in colony forming unit per gram (CFU/g), showed a significant activity of 4-hydroxybenzoate in increasing the shelf life of the pasta ready to eat.

Botrytis cinerea and Table Grapes: A Review of the Main Physical, Chemical, and Bio-Based Control Treatments in Post-Harvest

Consumers highly appreciate table grapes for their pleasant sensory attributes and as good sources of nutritional and functional compounds. This explains the rising market and global interest in this product. Along with other fruits and vegetables, table grapes are considerably perishable post-harvest due to the growth of undesired microorganisms. Among the microbial spoilers, Botrytis cinerea represents a model organism because of its degrading potential and the huge economic losses caused by its infection. The present review provides an overview of the recent primary physical, chemical, and biological control treatments adopted against the development of B. cinerea in table grapes to extend shelf life. These treatments preserve product quality and safety. This article also focuses on the compliance of different approaches with organic and sustainable production processes. Tailored approaches include those that rely on controlled atmosphere and the application of edible coating and packaging, as well as microbial-based activities. These strategies, applied alone or in combination, are among the most promising solutions in order to prolong table grape quality during cold storage. In general, the innovative design of applications dealing with hurdle technologies holds great promise for future improvements.