Effects of chitosan based coatings enriched with procyanidin by-product on quality of fresh blueberries during storage

Azadirachta indica derived copper oxide nanoparticles: A sustainable approach for reducing post-harvest losses and enhancing mango quality

In this study, the green synthesis of copper oxide nanoparticles (CuO NPs) mediated by Azadirachta indica is reported, along with an evaluation of their antifungal activity against post-harvest anthracnose and their effects on the storage behaviour (shelf life) and physico-chemical properties of 'Kesar' mangoes, particularly those associated with the ripening process. The CuO NPs were initially synthesized using neem leaf extract and characterized through UV- Visible spectroscopy, SEM, EDX, HR-TEM, FT-IR, XRD, XPS, DLS and zeta potential. Characterization confirmed their monoclinic crystalline structure, spherical morphology, high purity, and stability, with a mean size of 50.93 nm and a zeta potential of -32.50 mV. The antifungal activities of synthesized CuO NPs against the fungus Colletotrichum gloeosporioides were assessed using poisoned food technique in which 1000 ppm CuO NPs showed lowest colony diameter (20.70 mm) and highest per cent growth inhibition (77.00 %). Subsequently in a dipping treatment lowest per cent disease incidence (00.00 %) were recorded in fruit treated with CuO NPs @ 200 ppm and 250 ppm, respectively. While, highest shelf life (18.23 days) were recorded in fruit treated with CuO NPs @ 250 ppm. Untreated control fruit exhibited increased per cent weight loss, total sugar, reducing sugar, non-reducing sugar and total soluble solids (TSS) over the storage period which responsible for early and rapid ripening. Post-harvest treatments of CuO NPs improved mango quality by reducing weight loss, retaining firmness, and delaying ripening through maintaining peel thickness, lower sugar levels, and higher titratable acidity and ascorbic acid. The 250 ppm concentration was most effective, ensuring safety with copper levels below toxicity thresholds. Therefore, A. indica-CuO NPs treatment is an eco-friendly and safe alternative to preserve fruit quality, reducing post-harvest disease/losses and extending the storage period (shelf life) of mango by delayed the ripening process.

Synthesis of New Copolymer and Genotoxic Effects on Triticum aestivum L. (Wheat) Root Tip Cells

In the present study, a copolymer of poly(N,N-dimethylacrylamide) and sodium acrylate was synthesized with the Solution Polymerization Technique. The purpose was to uncover the cytotoxic and genotoxic effects on root tip cells of the Triticum aestivum L. plant germinated with this polymer at different concentrations (25, 50, 100, and 200 ppm). The deposition of poly(DMAA-co-NaAc) copolymer in the study sample T. aestivum was demonstrated with the FTIR, UV-VIS spectroscopy analysis, X-Ray Diffraction (XRD) Spectroscopy, Scanning Electron Microscopy (SEM), SEM Element Map, and Energy Dispersive Spectroscopy (EDS) Spectrum. All concentrations of the poly(DMAA-co-NaAc) copolymer caused a decrease in the Mitotic Index (MI). The poly(DMAA-co-NaAc) copolymer caused various mitotic abnormalities such as loss of genetic material, deconstructed prophase, adhesion, chromosome groupings in metaphase, deconstructed metaphase, C-metaphase, chromosomal loss, chromosomal fracture, deconstructed anaphase, lagging chromosome, fragment, polar aberration, bridge, advancing, star anaphase, multipolarity, and deconstructed telophase. Study results show that poly(DMAA-co-NaAc) copolymer will cause abnormalities in mitosis as a result of its uptake by plants. These results also show that the poly(DMAA-co-NaAc) polymer, which affects organisms, must be produced in a controlled setting to reduce its accumulation in nature and ultimately disposed of in a way that will not harm the environment.

Effects of burdock oligosaccharide preventing membrane lipid peroxidation in postharvest blueberry fruit

The aim of this study was to evaluate the influence of burdock fructooligosaccharide (BFO) treatment on postharvest blueberries, specifically focusing on the influence of membrane lipid metabolism on overall quality. Our findings revealed that BFO treatment effectively suppressed decay index and preserved firmness in blueberry fruit. At the same time, BFO treatment effectively mitigated the production of H2O2 and malondialdehyde (MDA), while reinforcing the activities of antioxidant enzymes and enhancing the expression level. Moreover, BFO treatment preserved high amounts of unsaturated fatty acids while suppressing the gene expression and enzyme activity of phospholipase D (PLD), lipase, and lipoxygenase (LOX). In summary, the application of BFO effectively retards the metabolism of membrane lipids and preserves the integrity of cell membranes, thereby delaying blueberry senescence.

Emerging chitosan systems incorporated with polyphenols: Their applications in intelligent packaging, active packaging, and nutraceutical systems - A comprehensive review

Chitosan, a biodegradable anionic polysaccharide, has been increasingly investigated for food packaging and nutraceutical applications. In recent years, chitosan has been combined with polyphenols, a group of health promoting bioactive compounds, to enhance their physicochemical, functional, and biological properties. The synergistic functional attributes of chitosan and polyphenols have led to the development of several novel food packaging materials and nutraceuticals. Despite, several investigations being conducted on chitosan-polyphenol materials (e.g., films, coating, nanoparticles, complexes, emulsion gels), currently there is a lack of studies that comprehensively evaluate the combined effect of chitosan and polyphenol in development of both food packaging materials and nutraceuticals. Therefore, in this review, novel packaging materials and nutraceuticals developed employing chitosan-polyphenol in recent years (2018-2024) are thoroughly investigated. This review initiates with the source, production strategies, and techniques employed to improve the functionality of chitosan. Secondly, the findings associated with important intelligent packaging materials, including pH indicator, time-temperature indicator, and freshness indicator, developed using chitosan-polyphenol is investigated. Following that, the applications of chitosan-polyphenol materials in active food packaging (i.e., antimicrobial, antioxidant, oxygen scavenger, ethylene scavenger, and moisture scavenger) are explored. Notably, chitosan-based delivery systems that are employed to improve the chemical stability, bioaccessibility, and biological properties of polyphenols for nutraceutical applications are summarized. Finally, the challenges associated with the industrial application of chitosan-polyphenol materials are addressed. Overall, this review would benefit a wide range of scientists from food packaging to ingredient sectors by providing the current knowledge associated with chitosan-polyphenol materials.

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.

Effect of preharvest biofilm application regimes on cracking and fruit quality traits in '0900 Ziraat' sweet cherry cultivar

BACKGROUND

Fruit cracking impacts the quality of sweet cherry, significantly affecting its marketability due to increased susceptibility to injury, aesthetic flaws, and susceptibility to pathogens. The effect of 1% biofilm (Parka™) application regimes on fruit cracking and other quality parameters in the '0900 Ziraat' cherry cultivar was investigated in this study. Fruit sprayed with water were served as control (U1). Fruit treated only once with biofilm three, two and one week before the commercial harvest were considered as U2, U3 and U4, respectively. Fruit treated with biofilm three, two, and one week before harvest were considered as U5; three and two week before harvest as U6; two and one week before harvest as U7; and fruit treated three and one week before harvest as U8.

RESULTS

In both measurement periods, the lower cracking index was obtained in biofilm-treated sweet cherry fruit. However, the firmness of biofilm-treated fruit was higher than that of the control fruit. The lowest respiration rate was observed in U7, while the highest weight was recorded in U4 and U5 than the control. The biofilm application decreased fruit coloration. The biofilm application also increased the soluble solids content of the fruit. The U2, U3 and U4 applications at harvest showed higher titratable acidity than the control. In both measurement periods, the vitamin C content of the U2, U5, U6, U7 and U8 applications was found to be higher than that of the control. The total monomeric anthocyanin of the U3 and U8 applications was higher than that of the control. Furthermore, the antioxidant activity of the U2, U3 and U5 in the DPPH, and the U7 and U8 in FRAP were measured higher thanthat of the control.

CONCLUSIONS

The application of biofilms has the potential to mitigate fruit cracking, prolong postharvest life of sweet cherries, and enhance fruit firmness.

Comparison of Polylactide-Based Active Films Containing Berberine and Quercetin as Systems for Maintaining the Quality and Safety of Blueberries

Polymeric thin films based on polylactide with an addition of poly(ethylene glycol) as a plasticizer and flavonoids in the form of quercetin and berberine were subjected to tests that were particularly relevant from the point of view of contact with food. A comparative analysis of the effect of individual flavonoids on the antioxidative properties of tested films and blueberry storage was carried out. The influence of active compounds on the water vapor permeability, as well as UV protection, of the obtained materials was investigated. Also, the specific migration of individual flavonoids from obtained materials to food simulants in the form of acetic acid and ethyl alcohol was determined. The crucial point of this study is the storage of blueberries. The obtained results indicate that the selection of packaging, containing individual active compounds, depends on the purpose and requirements that the packaging must meet for particular types of food.

Biopolymer-based intelligent packaging integrated with natural colourimetric sensors for food safety and sustainability

Increasing concerns about global food safety and security demands innovative solutions, particularly in food packaging technologies. This review paper investigates the advanced integration of natural colourimetric sensors with biopolymer-based packaging materials, with a focus on developments over the past 5 years. These sensors change colour in response to environmental stimuli such as oxygen, temperature, pH and relative humidity, intuitively indicating food freshness and safety. The paper emphasizes the recent advancements in using natural colourants, such as alizarin, anthocyanins, betacyanins, chlorophyll, curcumin and shikonin. When combined with either natural or synthetic biopolymers, these colourants contribute to a sustainable and eco-friendly approach to food packaging. Such technological advances could notably decrease the incidence of foodborne illnesses by signaling potential spoilage or contamination, while also addressing food wastage by providing clear indications of edibility. Although challenges remain in sensor longevity and widespread adoption, the prospects for biopolymer-based food packaging with embedded natural colourimetric sensors are promising.

Chitosan derivatives act as a bio-stimulants in plants: A review

Chitosan has been considered an eco-friendly biopolymer. Chitosan is a natural polycationic linear polysaccharide composed of D-glucosamine and N-acetyl-D-glucosamine linked by β-1,4-glycosidic bonds. Chitosan has been used as an eco-friendly biopolymer for so many agricultural applications. Unfortunately, the relatively poor solubility and poor antimicrobial properties limit its widespread applications in agriculture sciences. Hence, chitosan derivatives are produced via various chemical approaches such as cross-linking, carboxylation, ionic binding, and so on. As an alternative to chemical fertilizers, chitosan derivatives, chitosan conjugates, nanostructures, semisynthetic derivatives, oligo mixes, chitosan nanoparticles, and chitosan nano-carriers are synthesized for various agricultural applications. Its several chemical and physical properties such as biocompatibility, biodegradability, permeability, cost-effectiveness, low toxicity, and environmental friendliness make it useful for many agricultural applications. Hence, popularizing its use as an elicitor molecule for different host-pathogen interaction studies. Thus, the versatile and plethora of chitosan derivatives are gaining momentum in agricultural sciences. Bio-stimulant properties and multifunctional benefits are associated with further prospective research. Therefore, in the present review, we decipher the potential pros and cons of chitosan derivatives in plants.

Preparation and application of chlorine dioxide gas slow-release fresh-keeping card based on polylactic acid

Blueberries are highly perishable after harvest, so a simple preservation method is needed to extend the shelf life of blueberries. In this study, sodium chlorite-loaded sepiolite was added to polylactide solution with tartaric acid to create a ClO2 gas slow-release fresh-keeping card. The fresh-keeping card absorbs moisture in the air, which causes tartaric acid to enter the sepiolite and react with sodium chlorite to release ClO2 gas slowly. The study investigated the impact of fresh-keeping cards on the quality attributes of blueberries, including appearance, decay rate, ethylene release rate, respiration rate, hardness, ascorbic acid content, and anthocyanin concentration. Low-field nuclear magnetic technology was used to analyze the water state and distribution of blueberries during storage. The results showed that the ClO2 gas released by the fresh-keeping card can destroy ethylene in the air and kill microorganisms in blueberries, thereby delaying fruit decay.

Incorporation of cellulose nanocrystals to improve the physicochemical and bioactive properties of pectin-konjac glucomannan composite films containing clove essential oil

This study aimed to investigate the effectiveness of cellulose nanocrystals (CNC) isolated from cotton in augmenting pectin (PEC)/konjac glucomannan (KGM) composite films containing clove essential oil (CEO) for food packaging application. The effects of CNC dosage on film properties were examined by analyzing the rheology of film-forming solutions and the mechanical, barrier, antimicrobial, and CEO-release properties of the films. Rheological and FTIR analysis revealed the enhanced interactions among the film components after CNC incorporation due to its high aspect ratio and abundant hydroxyl groups, which can also prevent CEO droplet aggregation, contributing to form a compact microstructure as confirmed by SEM and 3D surface topography observations. Consequently, the addition of CNC reinforced the polysaccharide matrix, increasing the tensile strength of the films and improving their barrier properties to water vapor. More importantly, antibacterial, controlled release and kinetic simulation experiments proved that the addition of CNC could further slow down the release rate of CEO, prolonging the antimicrobial properties of the films. PEC/KGM/CEO composite films with 15 wt% CNC was found to have relatively best comprehensive properties, which was also most effective in delaying deterioration of grape quality during the storage of 9 days at 25 °C.

Potential use of cold plasma treatment for disinfection and quality preservation of grape inoculated with Botrytis cinerea

Gray mold caused by Botrytis cinerea is a serious disease of grape (Vitis vinifera) during storage. The aim of this study is to evaluate the effect of atmosphere cold plasma (a novel and nonthermal technology) on inactivation of B. cinerea and preservation of chemical, physical, and mechanical characteristics of grape inoculated with B. cinerea. Herein, different time of cold plasma (0, 10, 20, and 40 s) was firstly considered to be the main factors, besides different storage time (1, 2, 3, 4, and 5 weeks) at 4°C. According to the results, plasma treatment exhibited inhibitory effect on gray mold percentage and microbial load of B. cinerea (log CFU g-1) during postharvest storage. So, in the last week, the gray mold percentage and microbial load in the control were 100% and 3.6 log CFU g-1, and in 40-s plasma were 4.5% and 2.53 log CFU g-1, respectively. Although the minimum infection and microbial load were observed in 40-s plasma, better postharvest quality preservation was observed in short-time cold plasma treatment (≤20 s). Forty-second plasma caused fruit tissue destruction and negatively decreased mechanical indices (Emod: 0.0028, Fmax = 1.78, and W = 3.18) and weight loss (91.9) in comparison with ≤20-s plasma, in which mechanical indices (Emod =0.0077, Fmax = 3.6, and W = 10.06) and weight loss (1/1) were higher. The long-time cold plasma treatment (40 s) had also maximum effects on color changes (10) and surface temperature (2.8°C). Although the highest TSS and TA were observed in 40-s Plasma, but different time of plasma treatments had no effect on pH. Altogether, these results indicate that the short-time cold plasma treatment can inactivate B. cinerea on grape berries and preserve crop quality properties.

Phenolic acid-chitosan derivatives: An effective strategy to cope with food preservation problems

Chitosan, a cost-effective and eco-friendly natural polymeric material, possesses excellent film-forming properties. However, it has low solubility and biological activity, which hinders its widespread applications. To overcome these limitations, researchers have developed phenolic acid-chitosan derivatives that greatly enhance the mechanical, antibacterial and antioxidant properties of chitosan, expanding its potential application, particularly in food preservation. This review aims to provide an in-depth understanding of the structure and biological activity of chitosan and phenolic acid, as well as various synthetic techniques employed in their modification. Phenolic acid-chitosan derivatives exhibit improved physicochemical properties, such as enhanced water solubility, thermal stability, rheological properties, and crystallinity, through grafting techniques. Moreover, these derivatives demonstrate significantly enhanced antibacterial and antioxidant activities. Through graft modification, phenolic acid-chitosan derivatives offer promising applications in food preservation for diverse food products, including fruits, vegetables, meat, and aquatic products. Their ability to improve the preservation and quality of these food items makes them an appealing option for the food industry. This review intends to provide a deeper understanding of phenolic acid-chitosan derivatives by delving into their synthetic technology, characterization, and application in the realm of food preservation.

Development of mussel-inspired chitosan-derived edible coating for fruit preservation

Fruit rotting at the postharvest stage severely limits their marketing supply chains and shelf-life. Thus, developing a green and cost-effective approach to extend the shelf-life of perishable foods is highly desired. In this study, inspired by the mussel-adhesion strategy, a multifunctional fruit coating material has been developed using a quaternized catechol-functionalized chitosan (CQ-CS) grafted with 2, 3-epoxypropyl trimethyl ammonium chloride and 3, 4-dihydroxy benzaldehyde. The as-prepared CQ-CS coating exhibited excellent mechanical properties, universal surface adhesion abilities, antimicrobial and antioxidant capacities without any potential toxicity effects. Using strawberry and banana as model fruits, we showed that the CQ-CS coating could effectively maintain the fruit's firmness and color, decrease the weight loss rate, and prevent microbial growth, thus finally extending their shelf- life when compared to uncoated samples, indicating the universal application of the as-prepared CQ-CS coating. These findings demonstrated that this novel conformal coating of CQ-CS has great potential for fruit preservation in the food industry.

l-Arginine treatment maintains postharvest quality in blueberry fruit by enhancing antioxidant capacity during storage

The postharvest quality of blueberry fruit is largely limited by deterioration. l-arginine (Arg) is a functional nontoxic amino acid with high biological activities. This study investigated the positive effects and the underlying mechanism of Arg treatment on the quality of postharvest blueberries. Arg effectively mitigated fruit decay and improved the quality of blueberries, including weight loss, firmness, and soluble solid content. Mechanistically, Arg-mediated activation of the anti-oxidative defense system reduced reactive oxygen species-mediated oxidative damage. Moreover, Arg treatment decreased the activities and gene expression of phospholipase D, lipoxygenase, and lipase-inhibiting membrane lipid peroxidation during the prolonged storage of blueberries. Meanwhile, Arg treatment increased nitric oxide (NO) content and NO synthase activity. Furthermore, correlation and principal component analyses revealed the enhancement of Arg treatment on antioxidant capacity. This study suggests that Arg treatment can maintain the postharvest quality of blueberries by improving antioxidant capacity.

Effectiveness of aloe vera gel coating and paraffin wax-coated paperboard packaging on post-harvest quality of hog plum (Spondius mangifera L.)

In this research work, hog plum (Spondius mangifera L.) was treated with Aloe vera gel (AVG) coating and paraffin wax-coated box (PWB) packaging and stored at ambient condition (25 ± 3 °C and 80-85% relative humidity) for 12 d to evaluate their impact on postharvest quality and storability. The physicochemical properties, microbiological analysis, and decay evaluation were analyzed throughout the storage period. The AVG and PWB coating treatments both demonstrated a significant effect on the quality of fruits during storage. The results showed that fruits with AVG coating and PWB packaging exhibited lower decay rates, weight loss, color difference, total microbial population, total soluble solids, titratable acidity, and higher fruit firmness and pH than uncoated (control) fruits. The AVG coating was the most effective treatment, followed by the PWB packaging treatment. Our findings show that the AVG coating and PWB packaging treatment can be a promising solution for preserving the quality of hog plums and also helps in increasing the lifetime of hog plums during storage.

Impact of Postharvest Putrescine Treatments on Phenolic Compounds, Antioxidant Capacity, Organic Acid Contents and Some Quality Characteristics of Fresh Fig Fruits during Cold Storage

The storage and shelf life of the fig, which has a sensitive fruit structure, is short, and this results in excessive economic losses. In a study carried out to contribute to the solution of this problem, the effect of postharvest putrescine application at different doses (0, 0.5, 1.0, 2.0, and 4.0 mM) on fruit quality characteristics and biochemical content during cold storage in figs was determined. At the end of the cold storage, the decay rate and weight loss in the fruit were in the ranges of 1.0-1.6% and 1.0-5.0 %, respectively. The decay rate and weight loss were lower in putrescine-applied fruit during cold storage. Putrescine application had a positive effect on the changes in fruit flesh firmness values. The SSC rate of fruit varied between 14 and 20%, while significant differences in the SSC rate occurred depending on storage time and putrescine application dose. With putrescine application, the decrease in the acidity rate of the fig fruit during cold storage was smaller. At the end of the cold storage, the acidity rate was between 1.5-2.5% and 1.0-5.0. Putrescine treatments affected total antioxidant activity values and changes occurred in total antioxidant activity depending on the application dose. In the study, it was observed that the amount of phenolic acid in fig fruit decreased during storage and putrescine doses prevented this decrease. Putrescine treatment affected the changes in the quantity of organic acids during cold storage, and this effect varied depending on the type of organic acid and the length of the cold storage period. As a result, it was revealed that putrescine treatments can be used as an effective method to maintain postharvest fruit quality in figs.

Apple polyphenols delay postharvest senescence and quality deterioration of 'Jinshayou' pummelo fruit during storage

INTRODUCTION

Apple polyphenols (AP), derived from the peel of mature-green apples, are widely used as natural plant-derived preservatives in the postharvest preservation of numerous horticultural products.

METHODS

The goal of this research was to investigate how AP (at 0.5% and 1.0%) influences senescence-related physiological parameters and antioxidant capacity of 'Jinshayou' pummelo fruits stored at 20°C for 90 d.

RESULTS

The treating pummelo fruit with AP could effectively retard the loss of green color and internal nutritional quality, resulting in higher levels of total soluble solid (TSS) content, titratable acidity (TA) content and pericarp firmness, thus maintaining the overall quality. Concurrently, AP treatment promoted the increases in ascorbic acid, reduced glutathione, total phenols (TP) and total flavonoids (TF) contents, increased the scavenging rates of 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and hydroxyl radical (•OH), and enhanced the activities of superoxide dismutase (SOD), catalase, peroxidase, ascorbate peroxidase (APX), and glutathione reductase (GR) as well as their encoding genes expression (CmSOD, CmCAT, CmPOD, CmAPX, and CmGR), reducing the increases in electrolyte leakage, malondialdehyde content and hydrogen peroxide level, resulting in lower fruit decay rate and weight loss rate. The storage quality of 'Jinshayou' pummelo fruit was found to be maintained best with a 1.0% AP concentration.

CONCLUSION

AP treatment can be regarded as a promising and effective preservative of delaying quality deterioration and improving antioxidant capacity of 'Jinshayou' pummelo fruit during storage at room temperature.

Chitosan Edible Films and Coatings with Added Bioactive Compounds: Antibacterial and Antioxidant Properties and Their Application to Food Products: A Review

Chitosan is the deacetylated form of chitin regarded as one of the most abundant polymers and due to its properties, both chitosan alone or in combination with bioactive substances for the production of biodegradable films and coatings is gaining attention in terms of applications in the food industry. To enhance the antimicrobial and antioxidant properties of chitosan, a vast variety of plant extracts have been incorporated to meet consumer demands for more environmentally friendly and synthetic preservative-free foods. This review provides knowledge about the antioxidant and antibacterial properties of chitosan films and coatings enriched with natural extracts as well as their applications in various food products and the effects they had on them. In a nutshell, it has been demonstrated that chitosan can act as a coating or packaging material with excellent antimicrobial and antioxidant properties in addition to its biodegradability, biocompatibility, and non-toxicity. However, further research should be carried out to widen the applications of bioactive chitosan coatings to more foods and industries as well was their industrial scale-up, thus helping to minimize the use of plastic materials.

Preparation of zein/chitosan/eugenol/curcumin active films for blueberry preservation

This study aimed to develop zein/chitosan-based films formulated with curcumin and eugenol to improve the quality of postharvest blueberries. First, the film-forming solutions were characterized (rheological property and water distribution), and the mechanical, structural properties and bioactivity of active films fabricated by casting were evaluated. Further, the active film was coated with blueberry stored at 4 °C, and physicochemical properties (weight loss, hardness, microbial counts, and appearance changes) were measured. The film-forming solutions exhibited non-Newtonian behavior. The incorporation of curcumin and eugenol improved the tensile strength and elongation at the break of films, reaching 17.86 MPa and 92.80 %, respectively. The antioxidant capacity was enhanced, and DPPH and ABTS radical scavenging rates were up to 90.60 ± 0.06 % and 86.34 ± 0.39 %, respectively. Meanwhile, the prepared active films possessed good anti-UV and sensitive pH-response color-shifting ability. Compared to the uncoated blueberry, blueberry coated with zein/chitosan/curcumin/eugenol showed lower weight loss and higher hardness, indicating that the prepared active films played a vital role in delaying the deterioration of blueberry and extending its shelf life. Overall, the zein-chitosan incorporated with curcumin and eugenol films could be a promising candidate to prolong the shelf life of food products due to their excellent bioactive capacity.

Investigations into Determinants of Blueberry Coating Effectiveness

Coatings have been investigated as a means of slowing weight loss and helping to preserve quality in blueberries but reported results have been inconsistent with the inadequate presentation of the impact of coatings on blueberry appearance. In this study, we compare the ability to limit weight loss, along with the effect on appearance, of several previously studied coatings for blueberries and attempt to identify reasons why coatings have not been more successful in limiting weight loss in blueberries. In a two-year study, coatings were applied either as a spray or a dip, depending on the nature of the coating, and included 1% chitosan (CH) with and without either 1% or 2% oleic acid (OA), 1% Semperfresh (SF), 2% sodium caseinate (SC), and carnauba wax (CAR). None of the coatings reduced weight loss in either year of the study and sometimes enhanced it. CH, CH + OA, CAR, and SF greatly altered the appearance of the berries by removing all or a part of the waxy bloom. SC also did this to some degree but was generally better at maintaining the natural appearance. It was found that coating application did not effectively limit weight loss through either the cuticle or stem end of the blueberries. Loss of the bloom on the blueberry surface, confirmed visually and by scanning electron microscopy, occurred during coating application, but was found to not influence coating effectiveness. Using CH + OA as an example, it was found that increasing the amount of handling during the drying process significantly increased subsequent weight loss relative to blueberries with minimal handling. This indicates that careful handling during the coating process is important for coating success.

Bioactivities and mechanisms of dietary proanthocyanidins on blood pressure lowering: A critical review of in vivo and clinical studies

Proanthocyanidins, widespread in natural plant sources, are bioactive substances that exhibit broad benefits to human health. Of note, proanthocyanidins have been reported to lower blood pressure and prevent hypertension, but a critical review of this is lacking. In this review, information on the basic structures and absorption of dietary proanthocyanidins as well as their bioactivities and related mechanisms on the lowering of blood pressure derived via in vivo and clinical studies are summarized. Clinical studies have shown that proanthocyanidins have a pronounced blood pressure-lowering effect, effectively preventing hypertension and reducing the occurrence of cardiovascular and cerebrovascular diseases. The potential mechanisms, which are herein reviewed in detail, involve the improvement of vascular function, reduction of oxidative stress and inflammation, and modulation of lipid metabolism. Taken together, this work provides information for a better understanding of the antihypertensive effects of proanthocyanidins, which may promote their use to reduce the risk of developing hypertension.

Melatonin treatment reduces qualitative decay and improves antioxidant system in highbush blueberry fruit during cold storage

BACKGROUND

Blueberry is considered as a 'functional food' because it contains bioactive compounds such as flavonoids, phenolic acids, tannins and anthocyanins. The blueberry is one of the most consumed berries in the world and is highly appreciated by consumers because of its unique taste and sensory properties. Fresh blueberries decay rapidly because of mould and water loss. To preserve the qualitative and nutraceutical traits of fresh highbush blueberries during storage, the efficacy of 1 mm melatonin treatment was investigated at 5 °C for 3 weeks.

RESULTS

The results demonstrated that melatonin treatment reduced weight loss and delayed postharvest ripening. Compared to the control, melatonin treatment induced an overproduction of polyphenols, flavonoids, anthocyanins and ascorbic acid, consequently increasing antioxidant activity. The enzymatic antioxidant system was also affected by the treatment. An increase in the activity of catalase, superoxide dismutase and ascorbate peroxidase was observed in treated fruit compared to that in control fruit. Enzymatic browning, controlled by assaying the content of malondialdehyde and hydrogen peroxide, polyphenol oxidase, guaiacol peroxidase and lipoxygenase activities, appeared to slow down under melatonin treatment.

CONCLUSION

Melatonin coating is a valid tool for delaying the perishability and qualitative decay of highbush blueberry fruit during cold storage. Furthermore, this treatment increases the production of secondary metabolites such as polyphenols, flavonoids, anthocyanins and ascorbic acid, improving the nutraceutical traits of this fruit during storage. Melatonin treatment can be considered as an environmentally sustainable, non-harmful-to-human-health alternative for the postharvest preservation of highbush blueberry fruit. © 2022 Society of Chemical Industry.

Influence of guar gum and chitosan enriched with lemon peel essential oil coatings on the quality of pears

Pear is a typically climacteric fruit and highly perishable with a low shelf life owing to extreme metabolic activity after harvesting. The present study aimed to reduce weight loss and improve the firmness of pear during storage. The lemon peel essential oil (LPEO) has gained considerable attention due to being the richest source of bioactive compounds that behaved as a natural antioxidant agent, being cost-effective, and being generally recognized as safe. Edible coatings equipped with a natural antioxidant agent and renewable biopolymers have gained more research fame owing to their involvement in the direction of biodegradability and food safety. In this work, edible skin coating materials (ESCMs) embedded by chitosan (1%) and guar gum (2%) were fabricated, and afterward, five concentrations of LPEO (1, 1.5, 2, 2.5, and 3.0%) were incorporated individually into the ESCMs. Findings revealed that LPEO-ESCMs significantly reduced the weight loss and improved the firmness of pear up to 45 days of storage at 4 ± 2°C. Furthermore, the LPEO-ESCMs have enhanced the antioxidant capacity, antibacterial efficiency, and malondialdehyde level of pear during storage time. It was concluded that 3% of LPEO-ESCMs improved the overall acceptability of pear fruits. Taken together, the novel insights of guar gum and chitosan-based ESCMs entrapped with LPEO will remain a subject of research interest for researchers in the future.

Recent Advances in pH-Responsive Freshness Indicators Using Natural Food Colorants to Monitor Food Freshness

Recently, due to the enhancement in consumer awareness of food safety, considerable attention has been paid to intelligent packaging that displays the quality status of food through color changes. Natural food colorants show useful functionalities (antibacterial and antioxidant activities) and obvious color changes due to their structural changes in different acid and alkali environments, which could be applied to detect these acid and alkali environments, especially in the preparation of intelligent packaging. This review introduces the latest research on the progress of pH-responsive freshness indicators based on natural food colorants and biodegradable polymers for monitoring packaged food quality. Additionally, the current methods of detecting food freshness, the preparation methods for pH-responsive freshness indicators, and their applications for detecting the freshness of perishable food are highlighted. Subsequently, this review addresses the challenges and prospects of pH-responsive freshness indicators in food packaging, to assist in promoting their commercial application.

Extraction and Characterization of Pectin from Jerusalem ArtiChoke Residue and Its Application in Blueberry Preservation

To prolong the storage period of blueberry and improve its shelf-life quality, an edible coating based on chitosan was developed, and different contents of pectin were added to the coating. In this study, Jerusalem artichoke residue was used as a source of pectin, which is a byproduct of the processing of inulin. The extracted pectin has a low cost and high quality, which is very suitable for the preservation of coating. The coating was prepared and the chemical properties of the coating were characterized by SEM, XRD, TG, and FTIR. The barrier properties of the coating were analyzed by thickness, water content, solubility, and water vapor permeability. The results showed that the pectin coating exhibited excellent performance in blueberry preservation. Following 16 days of storage, the decay and weight loss rates of blueberry treated with 0.2% pectin coating decreased by 33 and 22%, respectively. Moreover, the organic acid consumption of the coated blueberry slowed and the anthocyanins were better preserved. As a low-cost, safe, and efficient technology, the pectin chitosan composite coating has significant potential in the berries preservation industry.

Delayed Senescence and Marketability Index Preservation of Blackberry Fruit by Preharvest Application of Chitosan and Salicylic Acid

Blackberry fruits are appreciated as a source of nutrients and compounds related to benefit human health. However, they are highly perishable and very susceptible to decay factors. Current methods to improve and maintain blackberry quality are limited in use because of the fruit's fragile physical properties. Regarding these properties, it has been reported that the activities of certain enzymes are linked to senescence and fruit softening processes. This study was aimed to assess the effect of salicylic acid (SA) and chitosan (COS) as preharvest treatments on the physiology related to improving fruit conservation and preserving the marketability index of blackberry fruit. The preharvest treatments were foliar sprayed on blackberry plants at different concentrations. The activities of enzymes superoxide dismutase (SOD), catalase (CAT), phenylalanine ammonia-lyase (PAL), and polygalacturonase (PG) were measured. Total soluble solids (TSS), titratable acidity (TA), TSS/TA ratio, and marketability index (MI) were analyzed after 144 h of storage. The application of 3 mM of SA and 0.25% of COS treatments preserved the MI of blackberries by reducing leakage, red drupelet reversion (RDR), and mycelium presence in the fruit. SA application increased SOD, CAT, and PAL activities. Our results also showed that SA and COS preharvest treatments modified the activity of the cell wall degrading enzyme PG, which might play a role in improving the shelf life and resistance to decay factors of blackberry fruit without any significant effects on physicochemical properties like TSS, TA, and the TSS/TA ratio.

Preparation of acylated chitosan with caffeic acid in non-enzymatic and enzymatic systems: Characterization and application in pork preservation

To further improve the performance of chitosan in food processing and preservation, this study investigated the grafting of the caffeic acid onto the chitosan in non-enzymatic and enzymatic systems. Result suggested that the caffeic acid was successfully incorporated into the chitosan in the non-enzymatic system, and the grafting ratio of modified chitosan (CA@CTS-N) was 7.49%. Moreover, lipase had a significant positive effect on the grafting reaction of the chitosan, and the modified chitosan prepared in enzymatic system (CA@CTS-E) obtained a higher grafting ratio, which was 11.82%. In both systems, the carboxyl of the caffeic acid was bonded to the amino of the chitosan and formed carbonyl ammonia. After the introduction of foreign group, many changes occurred in the functional properties of the modified chitosan. First, the water solubility of the chitosan was significantly improved from 0.00285 (native chitosan, CTS) to 0.221 (CA@CTS-N) and 0.774 g/100 mL (CA@CTS-E). The caffeoyl had a significant impact on the emulsifying properties of the chitosan. Compared with those of CTS, the modified chitosan had stronger antioxidation and antibacterial activities against Escherichia coli, Staphylococcus aureus, and Candida albicans. Finally, the pork treated with the modified chitosan exhibited longer shelf life than that treated with CTS.

Effects of konjac glucomannan/pomegranate peel extract composite coating on the quality and nutritional properties of fresh-cut kiwifruit and green bell pepper

The effects of an edible coating, based on konjac glucomannan (KG) incorporated with pomegranate peel extracts (PE), on the physicochemical and nutritional properties of fresh-cut kiwifruit and green bell pepper during storage were investigated. The optimal extract time (40.6 min), temperature (54.5 °C), and ultrasound power (255.5 W) with response surface method, provided a high total antioxidant activity (TAA) of (92.31 ± 1.43)%. Fresh-cut kiwifruit and green bell pepper were coated by dipping using five treatments (distilled water, ascorbic acid, KG, PE, KG + PE), packed into polymeric film and stored for 8 days at 10 °C. Distilled water treatment was used as control. KG + PE treatment resulted in the highest total soluble solid and titratable acidity in fresh-cut kiwifruit, while the maximum firmness in fresh-cut green bell pepper. The weight loss was both effectively decreased in samples treated with KG or KG + PE. All samples treated with KG + PE had significantly higher contents of chlorophyll, ascorbic acid, total phenolic and TAA than others. Moreover, the KG + PE group had the lowest counts of microorganisms in all samples. KG coating incorporated with PE was proved to be efficient in maintaining the physico-chemical and nutritional properties of fresh-cut kiwifruit and green bell pepper during low temperature storage compared with control.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-021-05006-7.

Dextran-Based Edible Coatings to Prolong the Shelf Life of Blueberries

The development of edible films and coatings in the food packaging industry presents one of the modern strategies for protecting food products and ensuring their freshness and quality during their shelf lives. The application of microbial polysaccharides to the development of food package materials, as an alternative option to the commonly used plastic materials, is both economic and environmentally favorable. New edible films were developed using dextran from lactic acid bacterium Leuconostoc mesenteroides T3, and additionally plasticized by different concentrations of polyglycerol. The best tensile strength of the films was obtained using a formulation that contained 10 wt% of polyglycerol, which corresponded to a value of 4.6 MPa. The most flexible formulation, with elongation at break of 602%, was obtained with 30 wt% of polyglycerol. Water vapor permeability values of the films synthesized in this study were in the range of (3.45–8.81) ∗ 10⁻¹² g/m s Pa. Such low values indicated that they could be efficient in preventing fruit from drying out during storage. Thus, the film formulations were used to coat blueberries in order to assess their quality during a storage time of 21 days at 8 °C. The results showed that dextran/polyglycerol films could be efficient in extending the shelf life of blueberries, which was evidenced by lower weight loss and total sugar solids values, as well as a delay in titratable acidity, in comparison to the uncoated blueberries.

Latest Developments in Edible Coatings on Minimally Processed Fruits and Vegetables: A Review

The food industry nowadays is facing new challenges in terms of sustainability and health implications of packaging and processing techniques. Due to their desire for new and natural products coupled with changes in lifestyle, consumers are looking for food products that have been less processed but possess longer shelf life and maintain nutritional and sensorial proprieties during storage. These requirements represent real challenges when dealing with highly perishable food products, such as fruits and vegetables. Thus, in recent years, edible coatings have been intensively developed and studied because of their capacity to improve the quality, shelf life, safety, and functionality of the treated products. Edible coatings can be applied through different techniques, like dipping, spraying, or coating, in order to control moisture transfer, gas exchange, or oxidative processes. Furthermore, some functional ingredients can be incorporated into an edible matrix and applied on the surface of foods, thus enhancing safety or even nutritional and sensory attributes. In the case of coated fruits and vegetables, their quality parameters, such as color, firmness, microbial load, decay ratio, weight loss, sensorial attributes, and nutritional parameters, which are very specific to the type of products and their storage conditions, should be carefully monitored. This review attempts to summarize recent studies of different edible coatings (polysaccharides, proteins, lipids, and composites) as carriers of functional ingredients (antimicrobials, texture enhancers, and nutraceuticals) applied on different minimally processed fruits and vegetables, highlighting the coating ingredients, the application methods and the effects on food shelf life and quality.

Effects of Peroxyacetic Acid on Postharvest Diseases and Quality of Blueberries

Postharvest diseases are a limiting factor in the storage of fresh blueberries. Gray mold caused by Botrytis cinerea and Alternaria rot caused by Alternaria spp. are important postharvest diseases in blueberries grown in California. Control of these fungal pathogens is generally dependent on preharvest sprays of synthetic fungicides, but in California multiple fungicide resistance has already developed in those pathogens, leading to the failure of disease control. Therefore, alternatives to synthetic fungicides are needed for the control of postharvest diseases. Peroxyacetic acid (PAA) is a disinfectant agent that poses low risk to human health. In this study, we evaluated the effects of postharvest use of PAA at 24 µl liter^-1 and 85 µl liter^-1 on fruit decay caused by fungal pathogens and quality of stored blueberry fruit. PAA treatment was applied to four cultivars over three seasons using two methods, dipping or spraying. Dipping blueberries compared with spraying them with PAA and its application at 85 µl liter^-1 were the most effective treatments. For example, when applied to 'Snowchaser' blueberries, this combination reduced naturally occurring decay after 4 weeks of storage at 0 to 1°C from 14.3% among water-treated controls to 2.7% in 2018, and from 25.7% among water-treated controls to 8.6% in 2020. In general, PAA did not adversely affect fruit quality or sensory quality of blueberries. Postharvest use of PAA appears to be a promising means to reduce postharvest decay of blueberries. To reliably obtain an acceptable level of disease control, the best use of PAA may be in combination with other practices rather than using it alone.

Prospects of Nanotechnology in Improving the Productivity and Quality of Horticultural Crops

Nanotechnology shows high promise in the improvement of agricultural productivity thus aiding future food security. In horticulture, maintaining quality as well as limiting the spoilage of harvested fruit and vegetables is a very challenging task. Various kinds of nanomaterials have shown high potential for increasing productivity, enhancing shelf-life, reducing post-harvest damage and improving the quality of horticultural crops. Antimicrobial nanomaterials as nanofilm on harvested products and/or on packaging materials are suitable for the storage and transportation of vegetables and fruits. Nanomaterials also increase the vitality of the cut flower. Nanofertilizers are target-specific, slow releasing and highly efficient in increasing vegetative growth, pollination and fertility in flowers, resulting in increased yield and improved product quality for fruit trees and vegetables. Formulated nanopesticides are target-specific, eco-friendly and highly efficient. Nanosensors facilitate up-to-date monitoring of growth, plant disease, and pest attack in crop plants under field conditions. These novel sensors are used to precisely identify the soil moisture, humidity, population of crop pests, pesticide residues and figure out nutrient requirements. This review aimed to provide an update on the recent advancement of nanomaterials and their potential uses for enhancing productivity, quality of products, protection from pests and reduction of the postharvest losses of the horticultural crops. This study reveals that nanotechnology could be used to generate cutting-edge techniques towards promoting productivity and quality of horticultural crops to ensure food and nutritional security of ever-increasing population of the world.

A visual bi-layer indicator based on roselle anthocyanins with high hydrophobic property for monitoring griskin freshness

This study designed a new type indicator with hydrophobic Polyvinylidene Fluoride (PVDF) film as a moisture prevent-layer. And the sensor layer was provided based on polyvinyl alcohol/Sodium alginate (PS) and Roselle anthocyanins (RAs). Physical properties, microstructure, and color stability of the bi-layer indicator have been investigated. The Water contact angle (WCA) of PS/RAs/ PVDF film (PSRF) was 108.85°, which can be considered as an excellent hydrophobic surface. The lowest Water Vapor Permeability (WVP) value of PSRF exhibited a good barrier property for moisture. Therefore, PSRF film was used to monitor the griskin freshness. The Total volatile basic nitrogen (TVB-N) level was increased to 18.02 mg/100 g at 72 h, and the color of the indicator presented visible color changes. The acquired results revealed a good correlation between TVB-N, pH and color change of the indicator. The research indicated that PSRF indicator has increasing potential application on food intelligent packaging.

Biodegradable film for raisins packaging application: Evaluation of physico-chemical characteristics and antioxidant potential

The objective of this study was to evaluate the application of a biodegradable film, based on grape seed flour extract, for raisin packaging. Physico-chemical characteristics (moisture, total soluble solids, total acidity, pH), total phenolic content and antioxidant activity were evaluated during 182 days of storage at 20 °C, compared to a poly(ethylene) film packaging. After 182 days, the use of biodegradable film increased raisin moisture and pH, decreased total soluble solids and total acidity of raisin compared to the use of poly(ethylene) film. The total phenolic content and antioxidant activity of raisin packed in the biodegradable film were 60.0 and 51.8% higher, respectively, than in poly(ethylene) film. The results showed that the biodegradable film based on seed flour extract is a potential material for active packaging due its contribution to the maintenance of the antioxidant activity of raisin and can be used for their conservation.

Curcumin doped functionalized cellulose nanofibers based edible chitosan coating on kiwifruits

The developed edible coating with curcumin facilitated iron functionalized cellulose nanofiber (f-CNF) reinforced chitosan (CS) were applied on kiwifruits for maintaining the quality during storage life. The f-CNF was fabricated via anchoring iron particles onto the surface of CNF as evident by FESEM, FETEM, and XRD analysis. The inclusion of f-CNF and curcumin as a component of edible coating can provide a synergistic effect in maintaining the quality of kiwifruits. The f-CNF (1.5 wt%) dispersed CS edible coating assisted by curcumin provided a lamellar and heterogonous surface morphology with a hazy appearance. The used edible coating materials were effective in reducing mass loss, firmness loss, respiration rate, and microbial count of the kiwifruits during storage life (10 days at 10 °C). Additionally, color, and physiological properties of kiwifruits can be modified by using the addressed edible coating materials.

Effect of Chitosan/Nano-TiO2 Composite Coating on the Postharvest Quality of Blueberry Fruit

Blueberries are a rich source of health-promoting compounds such as vitamins and anthocyanins and show a high antioxidant capacity. Thus, considerable commercial and scientific interest exists in prolonging its postharvest life to meet the year-round demand for this fruit. In this investigation, the effect of a chitosan-based edible coating, as well as a chitosan-based edible coating containing nanosized titanium dioxide particles (CTS-TiO2), on the postharvest quality of blueberry fruit quality was evaluated during storage at 0 °C. The blueberries were treated with a chitosan coating (CTS) and a CTS-TiO2 composite, respectively. The most suitable chitosan and nano-TiO2 fraction concentrations to be incorporated in the coating formulation were prepared based on the wettability of the corresponding coating solutions. Changes in firmness, total soluble solids (TSS), titratable acidity (TA), ascorbic acid (VC), malondialdehyde (MDA), polyphenol oxidase (PPO), and peroxidase (POD) activities, anthocyanins, flavonoids, total phenolic content, and microbiological analysis were measured and compared. This combined treatment prevented product corruption. Compared with CTS, the CTS-TiO2 composite coating application effectively slowed down the decrease in firmness, TSS, VC, and TA in the blueberries. Additionally, changes in the total polyphenol, anthocyanin, and flavonoid contents and the antioxidant capacity of CTS-TiO2 composite coating blueberry fruits were delayed. Therefore, these results indicated that the chitosan/nano-TiO2 composite coating could maintain the nutrient composition of blueberries while playing a significant role in preserving the quality of fruit at 0 °C.