Fruit Preservation Research Articles

PCL/soy peptide nanofibers incorporated with riboflavin/HP-β-CD assemblies for improving fruit storage quality

In this study, we first successfully developed functionalized electrospun nanofibers (PCL/SP/ICs) loaded with Riboflavin (RF) for fruit preservation with inclusion complexes (RF/HP-β-CD, IC) formed by encapsulating RF with hydroxypropyl-β-cyclodextrin (HP-β-CD) as a core material and soy peptide-assisted polycaprolactones (PCL/SP) as an overwrap material. Compared to 1 wt% and 5 wt% IC, nanofibers implanted with 3 wt% IC had an acceptable water contact angle (87.40°), good thermal stability, and superior mechanical properties. Also, RF/HP-β-CD integration conferred antimicrobial and antioxidant capabilities to PCL/SP fiber membranes. High-performance liquid chromatography (HPLC) studies revealed that produced films of PCL/SP/ICs could continuously and controllably release RF (within 200 h), hence retarding grape degradation and decreasing mass loss rate and titratable acid content throughout an 8-day storage period. Based on these findings, electrospun nanofiber films may be useful for vitamin loading in active food packaging.

Sustained-release composite films incorporated with cinnamon essential oil: Characterization, release kinetics and application for cherry tomato preservation

Food spoilage waste accelerated the development of bio-based active food packaging. Sustained-release composite films based on oxidized corn starch/ pullulan were prepared by incorporating cinnamon essential oil (CEO) nanoemulsion. The SEM, ATR-FTIR and XRD results showed that CEO was successfully encapsulated in film matrixes. The composite films exhibited the increase of thermal stability, UV-shielding, flexibility and water vapor resistance properties. The films containing CEO nanoemulsion (≥10%) showed excellent antimicrobial activities against S. aureus, E. coli and B. cinerea (the maximum inhibition zones achieving 27.23 ± 2.31 mm). The release kinetics results showed sustained release of CEO from the films with high content of CEO nanoemulsion, and the dominant release mechanism was Fickian diffusion. The composite films effectively maintained cell structure, weight, firmness and total soluble solids content of fruits during storage. Therefore, the sustained-release composite films could be a prospective packaging material for fruits preservation.

Enhancing Clonal Micropropagation of Zarya Alatau Apple

The purpose of this study was to improve the protocol of clonal micropropagation for effective mass production of the Zarya Alatau apple cultivar through the use of axillary buds. In Kazakhstan’s challenging climate, the Zarya Alatau apple thrives because of its unique traits, including fruit preservation until May, cold hardiness, and resistance to scab and powdery mildew. Micropropagation is essential for healthy mother tree establishment, and this research focused on key factors for successful in vitro propagation. The sterilization of explants was optimized: 1.6% solution of sodium hypochlorite effectively sterilized plant materials for 10 minutes. Nutrient media composition was evaluated for efficient shoot regeneration. The study examined axillary bud regeneration on Murashige and Skoog medium with different concentrations of hormones. A combination of 6-benzylaminopurine (0.5 mg/L) and gibberellic acid (0.5 mg/L) yielded optimal results, with shoots reaching 3.5 cm. Root induction was analyzed with varying indole-3-acetic acid (IAA) concentrations, and the best results were achieved with 1.5 mg/L IAA, resulting in an 85% rooting frequency. Adapting in vitro plants to ex vitro conditions is crucial given their sensitivity to environmental changes. Well-developed leaves and a robust root system are essential for successful acclimatization during transplantation into a soil substrate. This research provides valuable insights into the critical parameters for a successful transition of in vitro propagated plants to soil conditions, optimizing micropropagation practices.

The Role of Protein Post-Translational Modifications in Fruit Ripening

Fruit ripening represents a multifaceted biological process intricately controlled by an array of plant hormones, transcription factors, and epigenetic modifications. These regulatory mechanisms are crucial in determining fruit quality and post-harvest shelf life. Recent advancements in proteomics have shifted the focus toward understanding protein post-translational modifications (PTMs), which play a crucial role in modulating protein function. PTMs enhance protein activity and stability by altering their properties after biosynthesis, thereby adding an additional layer of regulation to the ripening process. This paper provides a comprehensive review of the roles of PTMs, including ubiquitination, phosphorylation, redox modifications, and glycosylation in regulating fruit ripening. Emphasis is placed on the intricate interplay between these PTMs and key regulator factors such as plant hormones, transcriptional mechanisms, and epigenetic modifications. By exploring these interactions, this review seeks to enhance our understanding of the complex regulatory network underlying fruit ripening and to offer novel perspectives on strategies for fruit preservation.

Exogenous p-coumaric acid treatment improves phenolic compounds biosynthesis of postharvest cherry tomatoes by regulating physiological metabolism.

To investigate the effect of p-coumaric acid (p-CA) on postharvest cherry tomatoes, breaker stage fruits were treated with p-CA to analyze the physiological metabolism during storage. The results showed that exogenous p-CA treatment improved the sensory quality of tomato fruits. Transcriptomics results indicated that 782 genes (339 up-regulated and 443 down-regulated) were differentially expressed between p-CA treated and control fruits. Results suggested that p-CA treatment regulated the synthesis of phenolic compounds and inhibited the fruit ripening through the pathways of mangiferic acid biosynthesis and phenylalanine metabolism. Key enzymes activities of the phenylpropane metabolic pathway of tomato fruits were increased, including phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H), and 4-coumarate-CoA ligase (4CL). In addition, the total phenols content, flavonoids content and antioxidant capacities of tomato fruits were improved with p-CA treatment. Overall, these findings showed that p-CA treatment could be a potential strategy for fruit and vegetable preservation.

Unveiling the effects of ZnO nanoparticle incorporated chitosan coating on postharvest quality of eggplant (Solanum melongena L.)

Due to rapid moisture loss, eggplant (Solanum melongena L.), a significant economic product, has a short postharvest shelf life. This study examined at 4 °C for 20 days at the effects of chitosan (CH) 1% and CH with micro ZnO (0.25 g/L) on eggplant quality. After 0, 5, 10, 15, and 20 days, coating effects on parameters (weight loss, pH, respiration rate, total acidity, soluble solids, firmness, total anthocyanin, antioxidant, phenolic, antioxidant enzymes superoxide dismutase, peroxidase and malondialdehyde activity), as well as microbiological count (total bacteria and yeast), were examined. When compared to the control, the coatings significantly affected the quality parameters, eggplant fruit coatings with CH (1 %) + nano ZnO (0.25 g/L) had the significantly least respiratory rate, weight loss, firmness, TAC, TPC, TAA and enzyme activity (P < 0.05). The microbial load during fruit preservation was suppressed by nano ZnO treatments (total bacterial and fungal count in control and eggplant treated with nano ZnO were 4.46, 4.33 and 3.96, 3.17 log CFU g−1 respectively). Treatments had little effect on fruit's flavour or aroma, but ZnO-treated fruit had improved texture, colour, and acceptance overall compared to control fruit. Finally, nano ZnO may offer a chance to preserve quality and limit deterioration during extended storage.

On-demand removable hydrogel film derived from gallic acid-phycocyanin and polyvinyl alcohol for fruit preservation

Postharvest spoilage of fruits accounts for significant losses ranging between 20 %–30 %, leading to considerable resource wastage and economic downturns. The development of an effective fresh-keeping packaging material is of paramount importance. This study introduces an innovative on-demand removable active fruit fresh-keeping film (GPP), created by embedding a GP (gallic acid-phycocyanin) fiber mesh hydrogel with functional properties into a polyvinyl alcohol (PVA) matrix. The resultant GPP hydrogel-based film demonstrates outstanding UV and water vapor barrier capabilities, mechanical stability, resistance to external mechanical stress, universal surface adhesion, antibacterial efficacy, and on-demand removal attributes, while being devoid of potential toxicity hazards. Utilizing grapes and blueberries as representative fruits, it is shown that the GPP hydrogel film significantly preserves the fruits' hardness, pH, total soluble solids content (TSS), and minimizes the rate of weight loss, thereby prolonging the shelf life to 13 days for grapes and 20 days for blueberries at ambient temperature. These results underscore the potential of this hydrogel-based film as an invaluable material for fruit preservation within the food industry.

A high-efficiency strategy for fruit preservation using green, natural raw materials

Straw is an abundant renewable biomass resource material. Lignin contained in straw is a unique natural aromatic compound in nature. At present, it is urgent to find ways to realize the higher value of natural lignin resources. In this study, alkali lignin was separated from rice straw by hydrothermal method in NaOH solution, which was prepared lignin nanoparticles by a simple green anti-solvent method. The obtained lignin nanoparticles had excellent anti-tyrosinase activity (IC50 = 0.329 mg mL−1) and anti-oxidation performance (IC50 = 0.0451 mg mL−1). Meanwhile, through the analysis of tyrosinase inhibition kinetics, it is concluded that the tyrosinase inhibition by lignin nanoparticles belongs to mixed inhibition. The affinity of lignin nanoparticles to the free enzyme is greater than that of enzyme and substrate complex. In addition, lignin nanoparticles were added to chitosan solution for compounding, then the composite films for fruit preservation were prepared by casting method. The experimental results show that the composite membrane can effectively extend the shelf life of fruits, which is expected to achieve a broader application in the field of fruit preservation and food packaging.

Fundamentals of Edible Coatings and Combination with Biocontrol Agents: A Strategy to Improve Postharvest Fruit Preservation.

Challenges in global food supply chains include preserving postharvest quality and extending the shelf life of fruits and vegetables. The utilization of edible coatings (ECs) combined with biocontrol agents (BCAs) represents a promising strategy to enhance the postharvest quality and shelf life of these commodities. This review analyzes the most recent developments in EC technologies and their combination with BCAs, highlighting their synergistic effects on postharvest pathogen control and quality maintenance. Various types of ECs, including polysaccharides, proteins, and lipids, are discussed alongside coating fundamentals and the mechanisms through which BCAs contribute to pathogen suppression. The review also highlights the efficacy of these combined approaches in maintaining the physicochemical properties, sensory attributes, and nutritional value of fruits. Key challenges such as regulatory requirements, consumer acceptance, and the scalability of these technologies are addressed. Future research directions are proposed to optimize formulations, improve application techniques, and enhance the overall efficacy of these biocomposite coatings and multifunctional coatings. By synthesizing current knowledge and identifying gaps, this review provides a comprehensive understanding of the potential and limitations of using ECs and BCAs for sustainable postharvest management.

Green-synthesized silver nanoparticles immobilized on graphene oxide for fruit preservation in alginate films

In this study, silver nanoparticles were synthesized by redox method using tea polyphenol as a reducing agent. These nanoparticles were then immobilized within sodium alginate (SA) composite films using graphene oxide (Go), resulting in films with enhanced food preservation capabilities. Initially, the synthesized silver nanoparticles underwent characterization through X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). This characterization affirmed the successful synthesis of silver nanoparticles. Subsequently, the impact of silver nanoparticles and graphene oxide on the properties of the SA composite films was investigated. The SA composite films were analyzed barrier, mechanical, thermal stability, and functional properties. The findings revealed that the inclusion of silver nanoparticles immobilized in Go augmented the tensile strength (23.6 %), degradation temperature of the films, reduced water vapor permeability, and exhibited antioxidant properties (4.16 %–42.09 %), and antimicrobial activities against Escherichia coli and Staphylococcus aureus (19.79–20.37 times). The graphene oxide immobilizes the silver nanoparticles, thereby reducing the release concentration. Packaging blueberry fruits with the SA composite film impregnated with Go-immobilized silver nanoparticles reduced weight loss and wrinkle index and this enhanced blueberry fruit shelf life. Thus, this work presents a novel approach to preparing antimicrobial packaging films for post-harvest fruit preservation.

Practical 1-Methylcyclopropene Technology for Increasing Apple (Malus domestica Borkh) Storability in the Aksu Region.

In recent years, Aksu apple has become popular with consumers because of its unique texture and taste. At present, maintaining quality during storage is the key problem with the apples in the Aksu region. 1-Methylcyclopropene (1-MCP) can delay fruit senescence, so is widely used in fruit preservation. However, many factors affect the preservation effect of 1-MCP. The effects of 1-MCP concentration (0 µL·L-1, 1 µL·L-1, 3 µL·L-1, 5 µL·L-1, and 8 µL·L-1) and postharvest application time (0, 1 and 2 d after harvest) on the quality of stored apple were studied. It was found that 1 µL·L-1 1-MCP was more beneficial in improving the quality of stored apples, reduced the respiration intensity and decay rate, increased the fruit firmness and total soluble solid content, and reduced the relative content of ester volatile aroma components. In addition, 1-MCP treatment applied at different postharvest times also affected the sensory quality and flavor of apples. The effect of 1-MCP treatment immediately after harvest was better.

Buffering moisture variation during cherry tomatoes preservation through deep eutectic solvent films

Moisture plays an important role in fruit preservation. In this study, deep eutectic solvents (DESs) were prepared and DES-based films with the property of buffering moisture variation were fabricated (CG10, CG50). Low-field nuclear magnetic resonance (LF-NMR) analyses and Raman spectra suggested that the water states in DESs and DES-based films transferred from a tight combination to a loose combination during the moisture sorption process. In addition, the moisture sorption capacity (Meq = 2.91) of the film suggested that CG50 possessed water storage capacity and a high effective diffusion coefficient (0.01 mm2 d−1) ensured the easy passing of water molecules through the DES-based films. Furthermore, the fruit preservation experiment using cherry tomatoes as a representative showed that DES-based films as a “buffer pool” not only could inhibit spoilage but also maintain the stable packaging RH, indicating the potential of DES-based films in moisture regulation.

Tannic acid one-step induced quaternized chitin-based edible and easy-cleaning coatings with multifunctional preservation for perishable products

The development of biomass hydrogel coatings is significant for fruit preservation. This paper presents the facile development of a multifunctional polysaccharide-based hydrogel produced from quaternized chitin (QC) and tannic acid (TA) by in situ rapid cross-linking with high-density hydrogen bonding using the sample mixing method. The Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) spectra, and thermogravimetric analysis (TGA) proved that QC-TA hydrogel was formed by physical interactions (hydrogen bonding, electrostatic interaction, etc.). Moreover, the cross-linking density of the QC-TA hydrogels was analyzed by rheological property measurements and scanning electron microscope (SEM) morphology observations. This polysaccharide-based hydrogel, QC-TA, was evaluated as an edible coating for perishable food items, demonstrating significant improvements in physic-chemical properties, oxidation resistance, and antimicrobial activity against key pathogens (E. coli, S. aureus, and C. albicans). Notably, the hydrogel formed a protective film that effectively shields fruits from mechanical damage, maintaining freshness and extending shelf life, and also featuring with easy cleaning. Applied to cherry tomatoes, the QC-TA coating ensured a smooth, uniform surface, reducing dehydration and flavor loss while inhibiting microbial growth. These findings underscore the potential of employing polyphenol induced polysaccharide forming green hydrogel coatings as an economical, efficient strategy for enhancing the quality and safety of perishable foods, representing an advancement in the field of sustainable food packaging.

Alginate-based active and intelligent packaging: Preparation, properties, and applications

Alginate-based packaging materials have emerged as promising alternatives to conventional petroleum-based plastics due to their biodegradability, renewability, and versatile functionalities. This review provides a comprehensive analysis of the recent advances in the development and application of alginate-based films and coatings for food packaging. The composition and fabrication methods of alginate-based packaging materials are discussed, highlighting the incorporation of various functional compounds to enhance their physicochemical properties. The mechanisms of action and the factors influencing the release and migration of active compounds from the alginate matrix are explored. The application of alginate-based packaging materials for the preservation of various food products, including meat, fish, dairy, fruits, and vegetables, is reviewed, demonstrating their effectiveness in extending shelf-life and maintaining quality. The development of alginate-based pH-sensitive indicators for intelligent food packaging is also discussed, focusing on the colorimetric response of natural pigments to spoilage-related pH changes. Furthermore, the review highlights the challenges and future perspectives of alginate-based packaging materials, emphasizing the need for novel strategies to improve their performance, sustainability, and industrial adoption.

Effect of fruit ripeness on electrical impedance spectrum parameters

This study aimed to reveal the mechanisms underlying changes in the electrical parameters of fruit during ripening. Plums and blueberries were selected as research objects, and their electrical parameters, firmness, water state, and microstructure with different maturities were measured. The observed relationships between fruit ripeness and electrical parameters were as follows: as fruit ripeness increased, the cell structure loosened, the number of gaps increased, membrane permeability increased, the distribution of free water became more scattered, and firmness gradually decreased. These factors led to increased cell fluid fluidity, shorter current flow paths, and lower impedance values. This study reveals the changes in various physiological indicators and electrical parameters of fruits during ripening and provides theoretical support for detecting fruit maturity using electrical parameters. These results are significant for the detection and grading of fruit maturity, extending the fruit preservation period, and developing rational fruit storage strategies.

Characterization of the extracellular proteases from Bacillus inaquosorum strain E1-8 and its application in the preparation of hydrolysates from plant and animal proteins with antioxidant, antifreeze and anti-browning properties.

Bacillus inaquosorum strains is widely recognized for their plant-growth-promoting and biocontrol capabilities, yet their roles in protease production remain unclear. The present study aimed to comprehensively assess the protease-producing performance of B. inaquosorum strain E1-8, at the same time as exploring the novel application of agricultural Bacillus proteases in the preparation of protein hydrolysates for fresh-cut fruits preservation. First, genomic sequencing revealed the diversity of E1-8 proteases, indicating 15 putative extracellular proteases. Subsequently, the fermentation conditions for E1-8 protease production were optimized, with sweet potato powder and soybean meal identified as the most suitable carbon and nitrogen sources, respectively, resulting in a maximum protease activity of 321.48 U mL-1. Upon culturing the strain under these optimized conditions, only an S8 family serine protease and an M48 family metalloprotease were revealed by secretomic analysis and protease inhibitor assays. Additionally, the optimal protease conditions for generating protein hydrolysates from soy, pea, fish and porcine proteins were determined. The molecular weight of the hydrolysates primarily ranged from 2000 to 180 Da, with a total of 17 amino acids identified. The application of these hydrolysates demonstrated a 2,2-diphenyl-1-picrylhydrazyl (i.e. DPPH) scavenging activity ranging from 58.64% to 84.12%, significantly reducing of the melting peaks and the freezing points. Furthermore, the browning index of apple slices stored at 4 °C decreased by 14.81% to 22.15% on the second day, and similar effects were observed in fresh-cut banana stored at 4 °C for 7 days. The protein hydrolysates obtained exhibit remarkable antioxidant, antifreeze and anti-browning properties for fresh-cut fruits. © 2024 Society of Chemical Industry.

Incorporation of Silver Nanoparticles for Improvement of Antibacterial and Fruit Preservation Properties of Pectin/Carboxymethyl Cellulose Packaging Film Derived from Grapefruit Peels

AbstractThe study focuses on enhancing the antibacterial properties of packaging films derived from Pectin and Carboxymethyl Cellulose (CMC) by incorporating silver nanoparticles (AgNPs). Pectin and CMC were sourced from grapefruit peels to utilize agricultural by‐products and introduce sustainable alternatives to petroleum‐based packaging films. A comprehensive characterization of the films was conducted to assess their morphology, functionality, and physical/mechanical attributes. The Pectin/CMC/AgNPs composite exhibits superior mechanical properties, achieving a peak tensile strength of 33.01 MPa and an elongation at a break of 22.93 %. The antibacterial efficacy against Escherichia coli (E. coli) and the Bacillus subtilis (B. subtilis) strains of Pectin/CMC and Pectin/CMC/AgNPs films was examined. In addition, the preservation efficacy of green grapes using those films was evaluated over 10 days, focusing on maintaining grape weight, organic acid, and vitamin C content. Results demonstrate that all films possess notable mechanical durability, with the Pectin/CMC/AgNPs film demonstrating superior antibacterial activity. Green grapes preserved with the Pectin/CMC/AgNPs film exhibit the highest fruit weight retention, and the highest maintenance in acid, and vitamin C content, underscoring the remarkable enhancement achieved by incorporating AgNPs.

Fabrication and Application of Tannin Double Quaternary Ammonium Salt/Polyvinyl Alcohol as Efficient Sterilization and Preservation Material for Food Packaging.

Food packaging films play a vital role in preserving and protecting food. The focus has gradually shifted to safety and sustainability in the preparation of functional food packaging materials. In this study, a bisquaternary ammonium salt of tannic acid (BQTA) was synthesized, and the bioplastics based on BQTA and polyvinyl alcohol (PVA) were created for packaging applications. The impact of BQTA on antibacterial effect, antioxidant capacity, opacity, ultraviolet (UV) protective activity, mechanical strength, thermal stability, and anti-fog of the resultant bioplastics was examined. In vitro antibacterial experiments confirmed that BQTA possesses excellent antimicrobial properties, and only a trace amount addition of BQTA in PVA composite film could inhibit about 100% of Escherichia coli and Staphylococcus aureus. Compared to BQTA/PVA bioplastics with pure PVA, the experiment findings demonstrate that BQTA/PVA bioplastics show strong antioxidant and UV protection action and the performance of fruit preservation. It also revealed a small improvement in thermal stability and tensile strength. The small water contact angle, even at low BQTA concentrations, gave BQTA/PVA bioplastics good anti-fog performance. Based on the findings, bioplastics of BQTA/PVA have the potential to be used to create packaging, and they can be applied as the second (inner) layer of the primary packaging to protect food freshness and nutrition due to their antioxidant activity and biocompatibility.

Preparation and Keep-Refreshing Effect of Chitosan/Sea Buckthorn Polysaccharide Composite Film on the Preservation of Yellow Cherry Tomatoes.

In this study, sea buckthorn polysaccharides (SBP) were added as functional substances to chitosan (CS), and chitosan/sea buckthorn polysaccharide (SCS) composite films were prepared using the casting method. The effects of SBP addition on the optical properties, physical properties, mechanical properties, structure, antioxidant activity, and antibacterial activity of the SCS composite films were studied, and the prepared SCS composite films were used to preserve yellow cherry tomatoes. The results showed that SCS composite films exhibited good UV resistance, water solubility, and antioxidant activity, but its apparent structure, hydrophobicity, and mechanical properties needed further improvement. Meanwhile, SBP has inhibitory effects on all 8 experimental strains. In addition, the SCS composite film with the addition of 200 mg/L SBP could reduce the weight loss rate of yellow cherry tomatoes, maintain hardness, delay the decrease of total soluble solids, titratable acid, and Vitamin C content, and inhibit the accumulation of malondialdehyde. SCS composite films are beneficial for enhancing the quality of yellow cherry tomatoes during storage, and their application in fruit and vegetable preservation has development prospects.

Eco-friendly, pH-sensitive curcumin-loaded sodium alginate/hydroxyapatite/quaternary ammonium chitosan microspheres with enhanced antibacterial and antioxidant activities for fruit preservation

The development of intelligent responsive reactive packaging materials with natural polymers shows excellent potential in food preservation. In this study, eco-friendly, pH-sensitive sodium alginate (SA)/hydroxyapatite (HA)/quaternary ammonium chitosan (HACC) composite microspheres loading curcumin (CUR) with excellent antibacterial and antioxidant activities were successfully synthesized. Scanning electron microscopy (SEM) and nitrogen adsorption/desorption tests indicated that the doping of HA substantially increased the specific surface area and pore volume of the microspheres. The loading experiments showed that the efficiency of the microspheres was significantly increased by 49.47 % and 55.10 %, respectively, when HA and HACC were incorporated into the SA network. The release test results suggested that the release rate of SA/HA/HACC microspheres loading CUR (SA/HA/HACC@CUR) increased as the pH decreased, demonstrating notable pH-responsive release characteristics. DPPH free radical scavenging experiments demonstrated that the SA/HA/HACC@CUR had excellent and long-lasting antioxidant capacity. The antibacterial experiments revealed that the SA/HA/HACC@CUR had excellent antibacterial properties, with inhibition rates of 88.73 % and 92.52 % against E. coli and S. aureus, respectively. Making coatings out of microspheres could effectively slow down the rotting and deterioration of cherry tomatoes during storage, suggesting that microspheres with intelligent responses have a broad application prospect in fruit preservation.