Enhancing storage stability of guava with tannic acid-crosslinked zein coatings

Tannic acid as a multifunctional additive in polysaccharide and protein-based films for enhanced food preservation: A comprehensive review

Fossil-based polymers continue to dominate the market for single-use food packaging, despite increasing concerns about their sustainability. In response, natural and renewable polymers, such as proteins and polysaccharides, are gaining attention as potential alternatives due to their biodegradability and biocompatibility. However, their broader adoption is hindered by the need to improve their mechanical, barrier, and thermal properties. Tannic acid (TA) has emerged as a particularly effective additive for biopolymer-based films, offering strong antioxidant and antimicrobial properties. It also enhances mechanical and barrier characteristics through physical and/or covalent crosslinking. As a result, TA shows great potential as an additive for bioplastics, improving food packaging performance and extending product shelf life, while benefiting both the environment and the food industry. Despite the promising applications of TA, comprehensive reviews that focus on recent developments in its performance and bioactive properties remain limited. This review aims to highlight the effectiveness of TA as both an active ingredient and a crosslinking agent in various biopolymer films, offering valuable insights into its role in sustainable food packaging solutions by critically examining the latest advancements.

Construction of efficient ethylene removal and antibacterial cellulose paper-based packaging materials for avocado preservation

Fruits are susceptible to ethylene ripening and microbial infestation, which can lead to spoilage and further significant economic losses. Thus, using functional preservation materials is an effective controlling technology to improve the post-harvest quality and extend the shelf life of fruits. Hence, a dual-function cellulose-based paper with exceptional antibacterial efficiency, favourable ethylene removal performance, improved mechanical and hydrophobic properties was prepared by covalently grafted antibacterial guanidine salt and surface-modified ethylene scavenger. When the amount of guanidine salt grafted and ethylene scavenger is 1.85 wt% and 1.5 g·m-2, respectively, the prepared cellulose paper exhibited about 99 % ethylene conversion and killing efficiency with no leaching, which extending the post-harvest avocado preservation time to 20 days at room temperature. Packaging with the preservation paper effectively reduced hardness and consumption of soluble solids in avocado during storage, maintaining their appearance and nutritional quality. These findings highlight the excellent preservation capabilities of the dual-function paper, making it a promising material for fruit and vegetable preservation in small and medium planting areas and households.

Unfolding bovine serum albumin decorated selenium nanoparticles crosslinking with chitosan: Achieve stabilization of Pickering emulsions gel and enhance resveratrol bioaccessibility

Resveratrol (Res) is a natural polyphenol exhibiting anti-oxidant and anti-inflammatory activity. However, the applications of Res have been limited due to its low stability and water solubility. To enhance the bioaccessibility of Res, unfolding bovine serum albumin-modified selenium nanoparticles (UBSA@SeNPs) encapsulated within chitosan (CS)-coated Pickering emulsions (CS-UBSA@SeNPs-PE) were used to load Res. The results showed that Res-loaded CS(0.06 %)-UBSA@SeNPs-PE has small droplet size (16.13 μm), high gel properties and excellent antioxidant properties. During the simulated digestion process, CS reduced the release rate of Res from Res-loaded CS(0.06 %)-UBSA@SeNPs-PE (42.27 %) to reach a slow release effect. Importantly, Res could quickly release from CS-UBSA@SeNPs-PE within intestinal fluid or in the presence of chitosanase. In simulated absorption experiments, the intestinal permeability of Res in Res-loaded CS(0.06 %)-UBSA@SeNPs-PE were enhanced by 292.31 % compare to Res-loaded CS(0 %)-UBSA@SeNPs-PE. In pharmacokinetic studies, Res-loaded CS(0.06 %)-UBSA@SeNPs-PE had an area under the curve (AUC) up to 3467.99 ± 127.43 ng*h/mL. Furthermore, CS also improved the mucoadhesive nature of UBSA@SeNPs-PE, resulting in a gut-retention time of Res-loaded CS(0.06 %)-UBSA@SeNPs-PE that reached up to 60 h. In conclusion, CS-UBSA@SeNPs-PE can serve as an effective oral delivery system for improving the bioaccessibility of Res.

Plant protein-based edible films and the effect of phenolic additives

The use of protein-based films in food preservation has been investigated as an alternative to synthetic plastics in recent years. Being biodegradable, edible, natural, and upcycling from food waste/by-products are the benefits of protein-based edible films. Their use ensures food safety as an alternative to synthetic plastics, and their film-forming properties can be improved with the addition of bioactive compounds. This review summarizes the studies on the changes in certain quality parameters of plant protein-based films, including mechanical, physicochemical, or morphological properties with the use of different forms of phenolic additives (pure phenolics, phenolic extracts, essential oils) and their application in foods during storage. Phenolics affect protein film matrix formation by acting as plasticizers or cross-linking agents and confer additional health benefits by providing bioactive properties to protein films. On the other hand, the effects were more pronounced with the use of their oxidized forms or higher concentrations. Consequently, phenolic additives have great potential to improve protein films, but further studies are still required to investigate the effects and mechanisms of phenolic addition to the protein-based films.

Postharvest Physiology and Handling of Guava Fruit

Guavas are typical tropical fruit with high nutritional and commercial value. Because of their thin skin and high metabolic rate, guavas are highly susceptible to water loss, physical damage, and spoilage, severely limiting their shelf-life. Guavas can typically only be stored for approximately one week at room temperature, making transportation, storage, and handling difficult, resulting in low profit margins in the industry. This review focuses on the physiological and biochemical changes and their molecular mechanisms which occur in postharvest guavas, and summarizes the various management strategies for extending the shelf-life of these sensitive fruits by means of physical and chemical preservation and their combinations. This review also suggests future directions and reference ideas for the development of safe and efficient shelf-life extension techniques.

Recent advancements in polysaccharides, proteins and lipids based edible coatings to enhance guava fruit shelf-life: A review

Fresh fruits are highly needed for the health benefits of human beings because of the presence of high content of natural nutrition in the form of vitamins, minerals, antioxidants, and other phenolic compounds. However, some nutritional fruits such as guava are climacteric in nature with very less post-harvest shelf-life because of the ripening in a very short period and possibility of microbial infections. Thus security of natural nutrients is a serious concern in order to properly utilize guava without generating a huge amount of waste. Among reported various methods for the enhancement of fruits shelf-life, the application of edible coatings with antimicrobial activities on the outer surface of fruits have attracted significant attention because of their eco-friendly nature, easy applicability, high efficacy, and good durability. In recent years, researchers are paying more and more attention in the development of antimicrobial edible coatings to enhance the post-harvest shelf-life of guava using polysaccharides, protein and lipids. In this review, basic approaches and recent advancements in development of antimicrobial and edible coatings on guava fruit by the application of polysaccharides and protein and lipids along with the combination of nanomaterials are summarized. In addition, improvements in basic properties of edible coatings to significantly control the permeation of gases (O2/CO2) by the optimization of coating components as well as delay in ripening process are reviewed and discussed.

Chitosan coating enriched with biosynthetic CuO NPs: Effects on postharvest decay and quality of mango fruit

A chitosan-based nanocomposite film (CSC) was developed by mixing chitosan (CS, 2 %, v/v) and copper oxide nanoparticles (CuO NPs, 500 μg∙mL-1) synthesized using Alpinia officinarum extract for the safe storage of mango fruit. The effects of CuO NPs on the morphological, mechanical, thermal, physical and antifungal properties of the CS films and postharvest quality of mango fruit were determined. Scanning electron microscopy (SEM) analysis confirmed that CuO NPs were uniformly dispersed into the CS matrix. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) profiles showed that intermolecular H-bondings occurred between CS and CuO NPs, accompanied by decreased crystallinity and increased amorphous structure. In comparison to the pure CS film, addition of CuO NPs obviously improved the morphological, mechanical, thermal, physical and antifungal properties of CSC film. CSC coating treatment obviously delayed the fruit decay and yellowing, as well as reduced losses of weight and firmness of mango (Mangifera indica L.) fruit during the storage, when compared with the control and CS coating treatment. Meanwhile, it significantly decreased the respiration rate and ethylene generation and maintained high level of ascorbic acid (AsA), titratable acid (TA) and soluble sugar content (SSC) of the fruit during the storage. Notably, Cu presented in the CSC film was restrained to the peel, indicating that the CSC coated mango fruit had good edible safety. Principal component analysis (PCA) confirmed that CSC coating played a positive role in mango preservation. Therefore, CSC coating can be considered a potential application for successfully controlling of postharvest disease and prolonging the shelf life for mango fruit.

Tannic Acid and Ca2+ Double-Crosslinked Alginate Films for Passion Fruit Preservation

In this study, the interaction of different concentrations of tannic acid (TA) (10%, 20%, and 30% w/w) and Ca2+ with alginate (SA) was utilized to create double-crosslinked SA films. The resulting films were evaluated for their optical, mechanical, water resistance, and barrier properties, and their microstructure and intermolecular interactions were also characterized. The SA films containing 20% TA showed the best mechanical properties, with an observed increase in tensile strength of 22.54%. In terms of water vapor permeability, the SA film containing 30% TA exhibited the highest barrier property, which was 25.36% higher than that of the pure SA film. Moreover, TA demonstrated a strong UV absorption ability, resulting in a nearly 0% UV transmittance of the SA film at 280 nm. It can be seen that SA films containing 20% TA have excellent barrier and mechanical properties, and the development of such films will be applied to the storage and packaging of fresh food. It is worth noting that this work also investigated the effect of SA coatings containing different concentrations of TA on the preservation of passion fruits for 7 days. The results revealed that passion fruits treated with SA coatings containing a 30% TA concentration maintained a better appearance on the 7th day and had the lowest weight loss and crumpling indices of approximately 8.98% and 2.17, respectively, compared to the other treatment groups. Therefore, based on the overall results, the addition of 30% TA to SA coatings proved to be more effective and can be considered a promising approach for delaying fruit senescence and decay.

Elucidating the insecticidal mechanisms of zein nanoparticles on Anticarsia gemmatalis (Lepidoptera: Erebidae)

Previous research suggested that positively charged zein nanoparticles [(+)ZNP] were toxic to neonates of Anticarsia gemmatalis Hübner and deleterious to noctuid pests. However, specific modes of action for ZNP have not been elucidated. Diet overlay bioassays attempted to rule out the hypothesis that A. gemmatalis mortality was caused by surface charges from component surfactants. Overlay bioassays indicated that negatively charged zein nanoparticles [(-)ZNP] and its anionic surfactant, sodium dodecyl sulfate (SDS), exhibited no toxic effects when compared to the untreated check. Nonionic zein nanoparticles [(N)ZNP] appeared to increase mortality compared to the untreated check, though larval weights were unaffected. Overlay results for (+)ZNP and its cationic surfactant, didodecyldimethylammonium bromide (DDAB), were found to be consistent with former research indicating high mortalities, and thus, dosage response curves were conducted. Concentration response tests found the LC50 for DDAB on A. gemmatalis neonates was 208.82 a.i./ml. To rule out possible antifeedant capabilities, dual choice assays were conducted. Results indicated that neither DDAB nor (+)ZNP were antifeedants, while SDS reduced feeding when compared to other treatment solutions. Oxidative stress was tested as a possible mode of action, with antioxidant levels used as a proxy for reactive oxygen species (ROS) in A. gemmatalis neonates, which were fed diet treated with different concentrations of (+)ZNP and DDAB. Results indicated that both (+)ZNP and DDAB decreased antioxidant levels compared to the untreated check, suggesting that both (+)ZNP and DDAB may inhibit antioxidant levels. This paper adds to the literature on potential modes of action by biopolymeric nanoparticles.

An insight on sources and biodegradation of bioplastics: a review

Durability and affordability are two main reasons for the widespread consumption of plastic in the world. However, the inability of these materials to undergo degradation has become a significant threat to the environment and human health To address this issue, bioplastics have emerged as a promising alternative. Bioplastics are obtained from renewable and sustainable biomass and have a lower carbon footprint and emit fewer greenhouse gases than petroleum-based plastics. The use of these bioplastics sourced from renewable biomass can also reduce the dependency on fossil fuels, which are limited in availability. This review provides an elaborate comparison of biodegradation rates of potential bioplastics in soil from various sources such as biomass, microorganisms, and monomers. These bioplastics show great potential as a replacement for conventional plastics due to their biodegradable and diverse properties.

Beeswax: A review on the recent progress in the development of superhydrophobic films/coatings and their applications in fruits preservation

Recently, the design and fabrication of bio-inspired superhydrophobic materials using natural lipid additives such as beeswax (BW) have aroused great attention in food packaging as they can minimize the transfer rate of water molecules and have effective moisture barriers. This review discusses the recent progress in the design and fabrication of BW-containing edible films/coatings (e.g., emulsion and blend films, bilayer materials, bionanocomposites, and antimicrobial materials) and their potential applications on the postharvest life and quality attributes of various fruits. Incorporation of BW into polysaccharides- and proteins-based emulsion films effectively improved their hydrophobicity, water vapor, and UV/visible light barrier properties, as well as the film tensile properties. The addition of nanoparticles to BW-based polymeric matrices often results in improved physico-mechanical properties. BW coatings have been also applied to prolong the shelf-life of various climacteric fruits, however, optimization of the wax concentration can be further investigated to develop targeted food storage systems.

Recent Advances in Novel Packaging Technologies for Shelf-Life Extension of Guava Fruits for Retaining Health Benefits for Longer Duration

Guava (Psidium guajava L.) fruit is also known as the apple of tropics, belongs to the family of genus Psidium, and is widely cultivated in tropical zones of the world. Recently, the importance of guava fruit has increased due to its inherent nutritional content, pleasant aroma, excellent flavor, and delicious taste. It is considered an excellent source of nutrients and phytochemicals. Guava is a climacteric fruit that continues to mature or ripen even after harvest, showing an increase in the rate of respiration and metabolic activities within a short period, leading to rapid senescence or spoilage of fruit. It has limitations in terms of commercialization due to short storage life after harvest and sensitivity to diseases and chilling injury during the storage period. Many postharvest technologies such as edible packaging, modified atmosphere packaging (MAP), composite packaging, controlled atmosphere packaging (CAP), antimicrobial/antifungal packaging, and nano packaging have been used to retard the chilling injury and enhance the keeping quality of guava fruits during the storage period to control respiration rate, reduce weight loss, minimize lipid oxidation, and maintain organoleptic properties. However, these packaging technologies have varied effects on the internal and external quality attributes of guava fruits. This review, therefore, discusses the physiology, mechanism of ripening, oxidation, and ethylene production of guava fruits. The review also discusses the packaging technologies and their effect on the postharvest characteristics of guava fruits during the storage period.

Edible films and coatings – Not just packaging materials

Edible films and coatings (EFC) are macromolecular-based structures forming thin layers that are usually studied as tools to improve food stability, sometimes being considered as parts of both the packaging system and the food itself. However, EFC are not mere packaging materials, and sometimes they do not even play roles related to those of packaging. This graphical review summarizes possible roles of EFC, including primary packaging, keeping water activity gradients between food components, controlling mass transfer on food processing, carrying active components, or serving as sources of sensory appeal. EFC may even be designed in a way that two or more of those roles may be played simultaneously.

Natural Biocidal Compounds of Plant Origin as Biodegradable Materials Modifiers

The article presents a literature review of the plant origin natural compounds with biocidal properties. These compounds could be used as modifiers of biodegradable materials. Modification of polymer material is one of the basic steps in its manufacturing process. Biodegradable materials play a key role in the current development of materials engineering. Natural modifiers are non-toxic, environmentally friendly, and renewable. The substances contained in natural modifiers exhibit biocidal properties against bacteria and/or fungi. The article discusses polyphenols, selected phenols, naphthoquinones, triterpenoids, and phytoncides that are natural antibiotics. Due to the increasing demand for biodegradable materials and the protection of the natural environment against the negative effects of toxic substances, it is crucial to replace synthetic modifiers with plant ones. This work mentions industries where materials containing natural modifying additives could find potential applications. Moreover, the probable examples of the final products are presented. Additionally, the article points out the current world's pandemic state and the use of materials with biocidal properties considering the epidemiological conditions.

Novel edible coating based on shellac and tannic acid for prolonging postharvest shelf life and improving overall quality of mango

This study aimed to investigate the combined effects of a coating based on shellac and the active agent tannic acid (TA) on the storability and physiological variations of mangoes stored at room temperature. Results showed that TA-shellac prolonged shelf life and improved overall quality of mangoes to a higher extent compared with controls, which was reflected in the extension of shelf life for approximately 10 days, maintaining of tissue firmness and weight loss, slowing down of respiration rate, improvement of physical properties and chemical qualities, suppression of browning, reduction of lipid peroxidation, preservation of aromatic volatiles, and regulation of the related enzymes activities. Addition of TA to shellac coating also improved the antifungal effect of the formulation. The results suggest that a synergistic effect took place between TA and shellac, which demonstrates the high potential for shelf life extension and quality improvement of mangoes of this formulation.

Effect of Kelulut Honey Nanoparticles Coating on the Changes of Respiration Rate, Ascorbic Acid, and Total Phenolic Content of Papaya (Carica papaya L.) during Cold Storage

This study evaluated the respiration rate of coated and uncoated (control) papayas (Carica papaya L.) with 15% of Kelulut honey (KH) nanoparticles (Nps) coating solution during cold storage at 12 ± 1 °C for 21 days. The respiration rate of the papayas significantly changed during storage, with an increase in CO₂ and a decrease in O₂ and C₂H₄, while the ascorbic acid and total phenolic content was maintained. The changes in respiration rate were rather slower for coated papayas when compared to control ones. A kinetic model was established from the experimental data to describe the changes of O₂, CO₂, and C₂H₄ production in papayas throughout the storage period. All O₂, CO₂, and C₂H₄ were experimentally retrieved from a closed system method and then represented by the Peleg model. The outcomes indicated the Peleg constant K₁ and K₂, which were gained from linear regression analysis and coefficients of determination (R²), seemed to fit well with the experimental data, whereby the R² values exceeded 0.85 for both coated and control papayas. The model confirmed both the capability and predictability aspects of the respiration rate displayed by papayas coated with KH Nps throughout the cold storage period. This is supported by the differences in the stomatal aperture of coated and control papaya shown by microstructural images.

Effect of Ginkgo biloba seed exopleura extract and chitosan coating on the postharvest quality of ginkgo seed

BACKGROUND

The effects of Ginkgo biloba seed exopleura extract (GSEE) and chitosan (CH) coating on the preservation of ginkgo seeds were investigated.

RESULTS

Results showed that CH could alleviate the decay rate, and that CH combined with GSEE (CH-GSEE) treatment further inhibited the development of seed decay due to the additional antifungal activity of GSEE. The nutrient contents, including water, starch and soluble protein, were maintained by both CH-GSEE and CH treatments. CH-GSEE treatment led to better restriction on oxidative stress by decreasing superoxide anion production rate, membrane permeability, malondialdehyde content, respiration rate and ethylene production rate. The antioxidant enzyme activities of peroxidase, superoxide dismutase and catalase in ginkgo seeds were maintained by treatment with CH-GSEE at a higher level. These results were consistent with the enhanced visual appearance, qualities and storability of the CH-GSEE-treated seeds. Principal component analysis provided a global view of the internal relations of the ginkgo seeds with different treatments.

CONCLUSIONS

The postharvest qualities of CH-GSEE-treated seeds were better than those of other treatment groups. Therefore, CH-GSEE is an effective and alternative way for inhibiting decay, maintaining quality and extending the postharvest life of ginkgo seeds. © 2018 Society of Chemical Industry.