Shelf Life Of Strawberries Research Articles

Application of a Multi-Component Composite Edible Coating for the Preservation of Strawberry Fruit

The rapid perishability of strawberries due to factors such as fungal decay, mechanical damage, and respiration significantly limits their shelf life. In this study, a novel multi-component edible coating composed of bacterial cellulose, chitosan, and gellan gum (BChG) was developed to enhance the postharvest quality and extend the shelf life of strawberries. The coated fruits were evaluated over a 15-day storage period for key parameters such as weight loss, total soluble solids (TSS), titratable acidity (TA), enzymatic activity, color retention, antioxidant activity, and microbiological analysis. The results demonstrated that coated strawberries exhibited significantly lower weight loss, reduced cellulase activity, and higher retention of TSS and TA compared to uncoated controls. The evaluation of microbial quality indicated that coatings, particularly those with higher concentrations of chitosan, control the growth of total mesophilic aerobic bacteria (TMAB) and molds and yeasts (MY), due to the antimicrobial properties of chitosan. This contributed to extending the shelf life of the fruit by preventing spoilage and reducing the risk of toxic compound formation. Additionally, the BChG coatings also preserved the characteristic red color of the fruit and maintained higher antioxidant activity, with BChG-4 being the most effective formulation. The inclusion of chitosan in the coatings was found to play a crucial role in reducing respiration, delaying ripening, and enhancing the fruit’s resistance to oxidative damage. Overall, multi-component coatings, particularly those with higher chitosan concentrations, offer a promising method for extending the shelf life of strawberries, reducing postharvest losses, and preserving fruit quality under ambient storage conditions.

Xyloglucan based edible coating in combination with Borassus flabellifer seed coat extract for extending strawberry postharvest shelf life

In this study, xyloglucan (XG) based edible coatings were developed and combined with a bioactive compound, Borassus flabellifer seed coat extract (BFE). The effect of designed edible coatings on the quality of strawberry fruits was investigated over an 8-day storage under ambient conditions. The results revealed the preservation effects in intrinsic properties of coated strawberries that the XG/BFE coated strawberries showed superior maintenance of qualitative parameters over uncoated strawberries, showing delayed weight loss, pH, and total soluble solids, tritratable acidity, retained firmness and lightness, as well as minimized the total color difference at the end of storage. Furthermore, the inclusion of BFE significantly enhanced the antimicrobial properties of developed edible coatings, evidenced by reduced microbial load. These results paved a solid way for designing the active edible XG/BFE coating for maintaining the postharvest quality and extending the shelf life of strawberries under ambient conditions.

Pengaruh Aplikasi Edible Coating Gel Lidah Buaya dan Kitosan terhadap Mutu Buah Stroberi pada Penyimpanan Suhu Ruang dan Suhu Rendah

Strawberries are nonclimateric fruits harvested in the final stages of ripening, so they are highly damaged due to cellular fragility, high respiration rate, and susceptibility to fungal growth. This study aims to test the effectiveness of edible coating of aloe vera gel and chitosan to maintain the quality and shelf life of strawberries. The study was carried out by experimental method with split plot by group random design. Storage temperature treatment as the main plot consists of two treatment levels, namely 25±2o C and 4±1o C, while the concentration of edible coating combination as a plot consists of five treatment levels, namely control without edible coating, aloe vera gel 40%, chitosan 2%, aloe vera gel 40% + chitosan 2%, and aloe vera gel 20% + chitosan 1%. Quality attributes including weight loss, fruit hardness, total dissolved solids, decay index, and shelf life are observed until total deterioration occurs. The results showed that at a storage temperature of 25±2° C, chitosan 2% treatment was more able to maintain the quality attributes of strawberries compared to other treatments. Meanwhile, at a storage temperature of 4±1°C, edible coating treatment of 40% aloe vera gel and 40% aloe vera gel + 2% chitosan which more effectively maintains the quality attributes of strawberries. However, for shelf life parameters, only the temperature factor of the storage room affects the length of shelf life of strawberries. The longest shelf life is achieved at low temperature storage (4±1°C) with edible coating treatment of 40% aloe vera gel + 2% chitosan (13.33 days). However, according to the LSD test at a real level of 5%, this value was not significantly different from other edible coating treatments stored at low temperatures, including the lowest shelf life that occurred in controls without edible coatings (10.67 days).

Enhancing Strawberry Freshness: Multifunction Sustainable Films Utilizing Two Types of Modified Carbon Nanotubes for Photothermal Food Packaging.

Currently, antimicrobial films with stable and efficient antibacterial activities are receiving considerable attention in the food packaging industry. Herein, a chemically/physically linked konjac glucomannan-sodium alginate (KGM-SA)@carbon nanotubes (CNTs)/Fe3+ composite film with outstanding resistance to ultraviolet radiation, oxidation, and bacteria, as well as excellent photothermal effects and mechanical properties, was successfully prepared using a solvent flow method. Tannic acid-modified carboxyl-functionalized CNTs (TCCNTs), l-cysteine-modified carboxyl-functionalized CNTs (LCCNTs), and Fe3+ were incorporated into the prepared film. The film structure of KGM-SA@CNTs/Fe3+ was characterized using various methods, confirming the formation of a dual-cross-linked network through metal-coordination bonds and hydrogen bonding. This unique structure endowed the film with excellent water vapor permeability (3.58 g mm/m2 day kPa), water resistance (water contact angle = 93.66°), and thermal stability. Further, the film exhibited outstanding photothermal conversion efficiency and stability under near-infrared irradiation (300 mW/cm2) as well as excellent bactericidal properties against Staphylococcus aureus and Escherichia coli, achieving a bacterial inhibition rate of >99%. In a strawberry preservation experiment, the KGM-SA@CNTs/Fe3+ composite film exhibited remarkable preservation effects, extending the shelf life of strawberries by 4-6 d. Thus, this photothermal antibacterial film offers a new approach for the application of CNTs in food packaging.

Fabrication and characterization of double-layer active intelligent film based on chitosan, polyvinyl alcohol, grape skin anthocyanin and selenium nanoparticle

This study involved the fabrication of double-layer intelligent films using chitosan (CS), polyvinyl alcohol (PVA), grape skin anthocyanin (GSA), gellan gum (GG) and selenium nanoparticles (SeNPs). The CS/PVA/GSA layer functioned as the internal indicator layer, and the GG/SeNPs layer acted as the external layer for antioxidant and antimicrobial purposes. SEM, FTIR, XRD, and TGA results confirmed the successful fabrication of double-layer films as well as the presence of hydrogen bonding interaction between the two layers. The tensile strength of double-layer films (8.06 MPa–9.61 MPa) fallen between that of single-layer CS/PVA/GSA film (12.51 MPa) and GG/SeNPs film (1.50 MPa–7.67 MPa). The double-layer films demonstrated good UV-blocking abilities, as well as outstanding antioxidant (ABTS scavenging rate can be up to ∼80 %) and antimicrobial properties. Compared with single-layer CS/PVA/GSA film, the double-layer film incorporated with 6.6 wt% SeNPs (CPG/GS2 film) possessed a more rapid and stronger response towards NH3/acetic acid as well as enhanced storage stability. Furthermore, the CPG/GS2 film can increase the shelf life of strawberries at 25 °C by 4 days, and its visible color change showed strong correlation with the weight loss rate (R2 = 0.99) and hardness (R2 = 0.98) of strawberries.

Effect of Edible Coatings on Morphological Characters of Strawberry Fruits

Strawberry (Fragaria × ananassa Duch.) a member of rosaceae family, is a monoecious, short day, succulent, thalamus, perennial herb and quick growing fruit plant. Strawberries are processed into various value-added products such as canned strawberry, jam, jelly, ice cream, wine and other soft drinks. Strawberry is a delicious but delicate fruit with 2-4 days shelf life on ambient condition. Fruit of strawberry are very delicate and highly perishable in nature which resulted very short life span and considerable postharvest loss. The use of edible coating improved the shelf life of strawberry in general compared to untreated control. Significant difference was observed for effect of edible coating on strawberry for all the quality parameter during storage. The fruit weight, width and length decreased in all edible coating treatment. The minimum decrease in fruit weight, Width and length was recorded in treatment T7 (EC + Aloe vera gel 20%) while, the minimum decrease in volume and specific gravity of fruit in the same edible coating.

Physicochemical characterization of bioactive polysaccharides from three seaweed and application of functional fruit packaging films

Seaweed polysaccharides show tremendous research and application value because of their significant and unique biological activities. However, reports on seaweed polysaccharides usually focus on in-depth studies of a specific biological activity, which severely limits their further development. Herein, three seaweed polysaccharides were isolated from Undaria pinnatifida (UPPS), Sargassum pallidum (SPPS), and Ulva lactuca (ULPS), respectively. The physicochemical properties, structure, rheological properties, antioxidant activities, antibacterial activities, and anti-glycation activities of UPPS, ULPS, and SPPS were comprehensively studied. It was first demonstrated that SPPS and UPPS had triple prominent biological activities. SPPS exhibited the best biological activities in antioxidation (IC50 in the ABTS test: 0.4616 ± 0.0134 mg/mL), antibacterial effect, and anti-glycation activity (inhibitory rate: 84.74 ± 0.07 %). Additionally, UPPS films (UPPSF) demonstrated superior ultraviolet shielding performance, lower water vapor permeability (1.78 ± 0.01 g/m·s·Pa × 10−11), higher hydrophobicity (water contact angle: 96.91 ± 2.52°), and higher antioxidant activity compared to ULPS films (ULPSF). UPPSF and ULPSF effectively prolonged the shelf life of strawberries to six days, and UPPSF showed better preservation properties. This work provides novel theoretical insights into the use of polysaccharides as medicinal nutraceuticals, bioactive agents, and food packaging films.

Preparation and characterization of a novel green cinnamon essential oil nanoemulsion for the enhancement of safety and shelf-life of strawberries

This study aimed to optimize a novel green CEO nanoemulsions (CEO NEs) and explore its physicochemical properties and the effect on the shelf-life of strawberries during storage at environmental temperature (20–25 °C). We used CEO as oil phase and tea saponin (TS) as a natural surfactant to formulate the novel green CEO NEs, and its potential as an antimicrobial agent was also investigated. The results showed that CEO NEs had a droplet size about 170 nm with uniform distribution and regularly spherical. These CEO NEs exhibited excellent storage stability, thermal stability, pH stability and centrifugal stability. The antimicrobial test indicated that the minimal inhibitory concentration and the minimal bactericidal (fungicidal) concentration of CEO NEs against Escherichia coli, Botrytis cinerea and Aspergillus flavus were 17.81 μg/mL and 35.62 μg/mL, 35.62 μg/mL and 71.25 μg/mL, 2.23 μg/mL and 4.45 μg/mL, respectively, which were significantly lower than those of pure CEO (333.75 μg/mL and 667.5 μg/mL, 667.5 μg/mL and 1335 μg/mL, 41.72 μg/mL and 83.44 μg/mL). More interestingly, after soaking strawberries in CEO NEs for 2 min, the shelf-life of strawberries can be extended to 7 days at environmental temperature, and a lower rate of weight loss and mildew were showed in the group of CEO NEs than other control groups, especially the strawberries in ultrapure water group went bad first, obviously shranked, and contaminated by molds after 3 days. The above results indicate that CEO NEs prepared in this study has great potential as a new green antimicrobial agent in fruit preservation.

Photo-responsive Cu-tannic acid nanoparticle-mediated antibacterial film for efficient preservation of strawberries

The existing films used for fruit preservation suffer from insufficient preservation abilities. This study introduces Cu-tannic acid (Cu-TA) nanoparticles, synthesized from tannic acid (TA) and Cu2+, to enhance food packaging properties. Integrated into a chitosan-gelatin (CG) matrix, the resultant Cu-TA nanocomposite films exhibit superior antibacterial efficacy and killing rates of Escherichia coli and Staphylococcus aureus more than 99 %, and double the shelf life of strawberries, underscoring the exceptional freshness preservation capabilities of film. Additionally, the tensile strength of the Cu-TA nanocomposite films increased by 1.75 times, the DPPH radical scavenging percentage increased from 29.4 % to 68.4 %, and the water vapor permeability (WVP) decreased by about 60 % compared to the pure CG films. Comprehensive cytotoxicity and migration assessments confirm the safety of film, paving the way for their application in food packaging. The excellent performance of the Cu-TA nanocomposite films positions them as a formidable solution for protecting perishable food items.

A biodegradable bi‐layer nano fibrous membrane fabricated by centrifugal spinning for active food packaging

AbstractTo solve the problem of cytotoxicity for most antimicrobial agents loaded in packaging materials, we developed a novel bi‐layer fibrous membrane by using centrifugal spinning, which of the outer layer was submicron native potato starch/polyvinyl alcohol (ST/PVA) composite fibers loaded with ZnO nanoparticles (ZnO NPs) for providing high antibacterial activity. The inner layer was nano‐based calcium alginate/polyethylene oxide (CA/PEO) fiber for providing excellent biocompatibility. The addition of ZnO caused the semicrystalline structures of ST/PVA fibers, while the CA/PEO fibers were shown semicrystalline structures due to the PEO. Fourier transform infrared indicated that posttreatment had not effect on the structures of ST/PVA/ZnO fiber, but the structure of CA/PEO fibers were affected by interaction between COO groups of alginate and Ca2+ ions. The results of mechanical property demonstrated that CA/PEO fibers showed highest stress of 3.83 ± 0.25 MPa and helpful for improving the stress of bi‐layer fibrous membrane. The obtained fibrous membrane had excellent antibacterial property with diameters of bacteriostatic zone against E. coli and S. aureus of 20.5 and 21.5 mm, respectively. On this basis, the shelf life of strawberry was improved up to 6th day by inhibit the growth of microorganisms, which indicated that the obtained fibrous membrane showed great potential for food packaging.

Effects of Hexanal Based Formulation on Shelf Life of Strawberry (Fragaria x ananassaDuch.)

We evaluated the role of ‘Enhanced Freshness Formulation’ (EFF) having hexanal as the main component on shelf life enhancement of strawberry (Fragaria x ananassa) cv. Sweet Charlie. Hexanal based Enhanced Freshness Formulation was sourced from Centre for Agricultural Nanotechnology, Tamil Nadu Agricultural University, Coimbatore. After crop harvest, a laboratory experiment in completely randomized design was done at ambient temperature (about 22-30°C) with 5-treatments (dipping of freshly harvested berries in hexanal of varying strengths)viz., 1 % hexanal for 2.5 min (V1), 1% hexanal for 5 min (V2), 2% hexanal for 2.5 min (V3) and 2% hexanal for 5 min (V4). Undipped berries were considered as control treatment (V5). Fruit firmness, shelf life, physiological loss in weight, decay loss and anthocyanin content were studied. The study revealed that dipping the berries in 2% hexanal for 2.5 min proved most effective to prolong the shelf life of strawberry. Maximum shelf life (5.90 days) and fruit firmness (5.88 N mm-1) were obtained in the most efficacious treatment, thereby extending the marketing period.

Curcumin-mediated photodynamic treatment to extend the postharvest shelf-life of strawberries.

This study investigated the potential use of curcumin-mediated photodynamic treatment as a postharvest decontamination technique to reduce microbial load and growth and therefore extend the shelf life of strawberries. Curcumin was applied on strawberries, followed by illumination and storage at 4°C for 16 days. Strawberries were evaluated for decay, microbial load, and physicochemical properties such as weight loss, color, and firmness during storage. The findings revealed that curcumin-mediated photodynamic treatment effectively reduced the decay incidence and severity in strawberries, with 20% less decay occurrence compared to untreated fruits, which was shown to be dependent on curcumin concentration. While a complete reduction in microbial load was observed upon treatment, microbial growth remained unaffected throughout storage. Moreover, photodynamic treatment did not show any adverse impact on color properties and firmness of strawberries. This eco-friendly technique presents potential for fruit's shelf-life extension, although optimization of treatment parameters and photodynamic unit design seems to be essential.

Preparation of chitosan/polyvinyl alcohol antibacterial indicator composite film loaded with AgNPs and purple sweet potato anthocyanins and its application in strawberry preservation

This study incorporated purple sweet potato anthocyanin (PSPA) and silver-nanoparticles (AgNPs) into the chitosan/polyvinyl alcohol film matrix (PVA/CS) to successfully prepare a composite film, which effectively inhibited bacterial growth and indicated product freshness. The addition of AgNPs and PSPA led to a dense structure of the film, which effectively enhanced its physical properties, barrier properties and functional properties. The incorporation of PSPA made the composite film highly pH-sensitive, which exhibited distinct color changes in varying pH solutions. The PVA/CS-AgNPs-PSPA10 composite film with PSPA and AgNPs resulted the shelf life of strawberries to 13 days at 4 °C, which effectively reduced strawberry breathing during storage. Additionally, such composite film changed color from purple to yellow-purple, indicating the deterioration of strawberries. It also showed an antibacterial indication through its excellent antibacterial property and freshness indication performance, which demonstrated its significance in developing antibacterial indicator composite packaging materials for fruits and vegetables preservation.

Biocompatible Pickering emulsions and films: Unlocking the chitosan-polyvinyl alcohol synergy for multifaceted capabilities

The exciting potential of harnessing the synergy between polysaccharides and bioactive components is attracting significant scientific interest. This research paves the way for the development of novel materials that can improve human health. Therefore, current research is conducted to explore the innovative use of chitosan, polyvinyl alcohol (PVA) complex (CHN-PVA), olive oil-stabilized Pickering emulsions (PEs), and films with multifaceted applications. The sonication stabilized Pickering emulsions (PEs at different pH values 3, 5, 7, 9, and 11) exhibited decrease in particle size compared to control PEs. The pH significantly impacted the zeta potential of PEs. Fourier-transform infrared spectroscopy (FTIR) confirmed the non-covalent linkages. The antibacterial activity of the PEs revealed greater efficacy against gram-positive bacteria than gram-negative bacteria. The CHN-PVA synergy greatly impacted the mechanical properties of films, resulting in tremendous increase of tensile strength and elongation at break compared to CHN film. The PEs efficiently delivered quercetin at neutral pH. The electro spraying of PEs significantly extended strawberry shelf life. Finally, the films exhibited promising properties of adsorbent and the results depicted that pH had a significant impact on methylene blue removal. Conclusively, this investigation underscores the potential of CHN-PVA films in food, health, and environmental fields.

Effects of Cultivar Factors on Fermentation Characteristics and Volatile Organic Components of Strawberry Wine.

Strawberry wine production is a considerable approach to solve the problem of the Chinese concentrated harvesting period and the short shelf life of strawberries, but the appropriative strawberry cultivars for fermentation are still undecided. In this study, the strawberry juice and wines of four typical strawberry cultivars named Akihime (ZJ), Sweet Charlie (TCL), Snow White (BX), and Tongzhougongzhu (TZ) were thoroughly characterized for their physicochemical indicators, bioactive compounds, and volatile organic components (VOCs) to determine the optimal strawberry cultivars for winemaking. The results showed that there were significant differences in the total sugar content, pH, total acid, and other physicochemical indexes in the strawberry juice of different cultivars, which further affected the physicochemical indexes of fermented strawberry wine. Moreover, the content of polyphenols, total flavonoids, vitamin C, and color varied among the four strawberry cultivars. A total of 42 VOCs were detected in the strawberry juice and wines using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), and 3-methyl-1-butanol, linalool, trans-2-pinanol, hexanoic acid, and hexanoic acid ethyl ester were the differential VOCs to identify the strawberry wine samples of different cultivars. Overall, strawberry cultivar ZJ had a relatively high VOC and bioactive compound content, indicating that it is the most suitable cultivar for strawberry wine fermentation. In addition to determining the relatively superior fermentation characteristics of cultivar ZJ, the results may provide a theoretical basis for the raw material quality control and quality improvement of strawberry wine.

Evaluating the shelf life of strawberries using a portable Vis-NIR spectrophotometer and a Reflectance Quality Index (RQI)

This study aimed to develop a postharvest quality index for strawberry (Fragaria ananassa Duch.) based on Vis-NIR reflectance, using a portable handset spectrometer to assess fruit quality and establish maximum shelf life. Fresh strawberries were stored at different temperatures (5, 15, 25 and 35 °C) and at 60 % relative humidity for up to 15 days. Various quality parameters were evaluated, including colour, firmness, weight loss, appearance, and microbial quality, every three days during storage. Kinetic models were used to describe the changes in weight loss, appearance, colour, and firmness of strawberries during storage under different temperatures. Vis-NIR spectroscopy was employed to establish a Reflectance Quality Index (RQI) for determining fruit quality during storage. This index helped to reduce the high number of wavelengths to a lower set of representative independent variables. Calibration and prediction models were created using the partial least squares (PLS) regression method, incorporating cross-validation, to predict quality indicators of strawberries. These models were developed for predicting appearance, weight loss, L*, a*, b* colour parameters, and firmness. A very good fit was obtained (R2 = 0.95), demonstrating the feasibility of both the RQI and PLS for evaluating strawberry quality. This study presents a novel approach for assessing the shelf life of strawberries based on storage time and temperature using a portable spectrophotometer. This method can be a valuable tool for the food industry to ensure optimal fruit quality and minimize food losses.

Eryngo essential oil nanoemulsion stabilized by sonicated-insect protein isolate: An innovative edible coating for strawberry quality and shelf-life extension

New bioactive coatings with eryngo essential oil (EEO) nanoemulsions stabilized by ultrasonically-treated lesser mealworm protein isolate (LMPI) were developed to extend strawberry shelf life and quality. EEO due to high carvone (43.03 %), phenolics (87.45 mg gallic acid equivalent/g), flavonoids (13.56 mg quercetin equivalent/g), and carotenoids (635.07 mg/kg) contents exhibited a significant antioxidant activity comparable to ascorbic acid (AA) and BHT. Nanoemulsions stabilized with 9 % sonicated LMPI showed smaller droplet size, higher negative ζ-potential, and greater stability, turbidity, and encapsulation efficiency of EEO compared to those stabilized with native LMPI. The FTIR spectra showed that sonicated LMPI had structural changes enhancing its emulsifying activity, with key peaks indicating the presence of hydrogen bonds, carbonyl groups, and protein conformations in both EEO and LMPI. Strawberries coated with optimal EEO-loaded nanoemulsions showed superior quality with minimal storage-dependent physicochemical, textural, color, and sensory changes compared to control samples. This edible coating also maintained higher total monomeric anthocyanin and AA contents with lower peroxidase activity during storage than EEO-based coatings. However, no significant difference in superoxide dismutase activity between samples covered by EEO and EEO-loaded nanoemulsions over 14 days of storage was found. Bioactive nanoemulsions stabilized by insect proteins would be an eco-friendly and safe approach to upholding quality standards in stored fruits and vegetables.

Foliar spraying of boron prolongs preservation period of strawberry fruits by altering boron form and boron distribution in cell.

Boron (B), an essential micronutrient for fruit development, also plays a crucial role in maintaining the shelf life of strawberries (Fragaria ananassa Duch.) by affecting cell wall structure and components. We investigated the distribution pattern of B within cells and cell walls in strawberry fruits under different B levels and revealed the relationship between the B distribution in cell walls and fruit firmness after harvesting. Foliar spraying of 0.1% H3BO3 promoted the growth of strawberry seedlings and improved fruit yield and flesh firmness by 45.7% and 25.6%. During the fruit softening and decay process, the content of bound B and cell wall-B decreased while more B was allocated to the protoplast and apoplast. The changes in B distribution in cells were attributed to cell damage during fruit decay, and B extended the freshness period of the fruits by alleviating the decrease of B distribution in cell walls. After leaving the fruits at room temperature for 10 h, the B content in different cell wall components significantly decreased, while foliar spraying of B alleviated the reduction of B content in covalently bound pectin (CBP), cellulose, and hemicellulose. Meanwhile, B spraying on fruit decreased the activity of cell wall degradation enzymes, including polygalacturonase (PG) and pectin lyase (PL), by 20.2% and 38.1%, while enhancing the demethylation of pectin by increasing pectin methylesterase (PME) activity from 21.6 U/g to 25.7 U/g. Thus, foliar spraying of 0.1% H3BO3 enhances the cross-linking of B with cell wall components and maintains cell wall structure, thereby prolonging the shelf life of strawberry fruits.

Highly stable and multifunctional intelligent film based on grape skin anthocyanin, polyvinyl alcohol, chitosan and selenopeptide: Preparation, characterization and application

Highly stable and multifunctional intelligent films were fabricated using a combination of grape skin anthocyanin, polyvinyl alcohol, chitosan and selenopeptide, and the influence of selenopeptide concentration on films' properties and their effectiveness in strawberry preservation and freshness monitoring was investigated. The results showed that the incorporated selenopeptide could interact with polyvinyl alcohol and grape skin anthocyanin via hydrogen bonding, improving the hydrophobic, UV-blocking, and mechanical characteristics of the films. In particular, the introduction of 0.4% selenopeptide into the film notably boosted its tensile strength from 11.91 MPa to 26.91 MPa. More importantly, the films incorporated with selenopeptide showed decent antioxidant and antibacterial properties, along with high storage stability and thermal stability. Adding 0.4% selenopeptide to the film can increase the shelf life of strawberries at 25 °C by 3 days, and a distinct color change showing fair good linear relationship with the freshness indexes of the strawberry (hardness and weight loss rate) was observed. Overall, anthocyanin-infused films combined with selenopeptide have demonstrated promising results in preserving food and monitoring freshness, opening up new opportunities for preparing stable, smart and active films.

Development, characterization and application of chitosan/locust bean gum based multifunctional green food packaging containing Koelreuteria paniculata Laxm. bracts extract and Ti-carbon dots

Multifunctional green food packaging films were developed by incorporating Koelreuteria paniculata Laxm. bract extract (KBE) and bio-waste-derived Ti-doped carbon dots (Ti-CDs) into a chitosan/locust bean gum (CG) matrix for the first time. Results from FTIR and XRD demonstrated the precise bonding of Ti-CDs to CG through a Schiff base reaction and hydrogen bonding, while KBE was effectively immobilized within the film matrix via hydrogen bonding. SEM and TGA analysis demonstrated enhanced thermal stability and density of the films. Addition of Ti-CDs synergistically improved the barrier properties and mechanical strength of the films through enhanced hydrogen bonding and Schiff base reactions. Specifically, the incorporation of 3 wt% Ti-CDs increased the oxygen barrier properties, tensile strength, water resistance, and vapor permeability of CG films by approximately 1.18, 0.75, and 1.51 times, respectively. Furthermore, the antimicrobial and antioxidant capabilities were significantly improved with the addition of KBE to films. The CG-3%CDs-KBE film coating effectively prolonged the shelf life of strawberries. Additionally, these films exhibited superior pH responsiveness and ammonia-sensitivity, enabling visual monitoring of shrimp freshness during storage. Importantly, CG-3%CDs-KBE films exhibited biodegradability in soil and displayed good biosafety. Overall, these findings underscore the promising potential of CG-3%CDs-KBE films as multifunctional green food packaging materials.