Effects of incorporation with clove (Eugenia caryophyllata) essential oil (CEO) on overall performance of chitosan as active coating

A frontier exploration of ancient craftsmanship: Effects of various tea products in traditional Chinese cuisine "tea flavored beef"

Modern science often overlooks to reveal the scientific essence of traditional crafts to promote their inheritance and development. In this work, five different types of tea products were prepared using the same variety of tea leaves referring to traditional methods. The analysis of their components and activities indicated that the processing reduced total catechin contents (from 172.8 mg/g to 48.2 mg/g) and promoted the synthesis of theaflavins (from 17.9 mg/g to 43.4 mg/g), reducing antioxidant and antimicrobial abilities of the resulting tea products. On this basis, the tea products were applied to "tea flavored beef" to reveal long-term effects. Within 15 days of storage, tea treatment showed remarkable antimicrobial and antioxidant activities on the beef. Also, the declines of sensory scores and texture of the treated beef were significantly suppressed. Meanwhile, protein degradation in the beef was inhibited, limiting the contents of various biogenic amines within relatively low levels.

Metal-organic frameworks-based moisture responsive essential oil hydrogel beads for fresh-cut pineapple preservation

The preservation of fresh-cut fruits and vegetables has attracted attention to the shelf-life reduction caused by high humidity. Herein, alginate/copper ions cross-linking, in-situ growth and self-assembly techniques of metal-organic frameworks (MOFs) were utilized to prepare a moisture responsive hydrogel bead (HKUST-1@ALG). As the multistage porous structure formation, tea tree essential oil (TTO) load capacity in hydrogel bead (TTO-HKUST-1@ALG) was increased from 6.1% to 21.6%. TTO-HKUST-1@ALG had excellent moisture response performance, and the release rates of TTO increased from 33.89% to 70.98% with moisture increasing from 45% to 95%. Besides, TTO-HKUST-1@ALG exhibited excellent antimicrobial, antioxidant capacity, and biocompatibility. During storage, TTO-HKUST-1@ALG effectively improved the cell membrane integrity by maintaining the balance of reactive oxygen species metabolism. The degradation of cell wall structure and tissue softening were delayed by inhibiting the cell wall-degrading enzymes activity. Briefly, TTO-HKUST-1@ALG improved the storage quality and extended shelf-life of fresh-cut pineapple, which was a promising preservative.

Clove Essential Oil: Chemical Profile, Biological Activities, Encapsulation Strategies, and Food Applications

Plants have proven to be important sources for discovering new compounds that are useful in the treatment of various diseases due to their phytoconstituents. Clove (Syzygium aromaticum L.), an aromatic plant widely cultivated around the world, has been traditionally used for food preservation and medicinal purposes. In particular, clove essential oil (CEO) has attracted attention for containing various bioactive compounds, such as phenolics (eugenol and eugenol acetate), terpenes (β-caryophyllene and α-humulene), and hydrocarbons. These constituents have found applications in cosmetics, food, and medicine industries due to their bioactivity. Pharmacologically, CEO has been tested against a variety of parasites and pathogenic microorganisms, demonstrating antibacterial and antifungal properties. Additionally, many studies have also demonstrated the analgesic, antioxidant, anticancer, antiseptic, and anti-inflammatory effects of this essential oil. However, CEO could degrade for different reasons, impacting its quality and bioactivity. To address this challenge, encapsulation is viewed as a promising strategy that could prolong the shelf life of CEO, improving its physicochemical stability and application in various areas. This review examines the phytochemical composition and biological activities of CEO and its constituents, as well as extraction methods to obtain it. Moreover, encapsulation strategies for CEO and numerous applications in different food fields are also highlighted.

Design of equilibrium modified atmosphere packaging for postharvest cabbages preservation based on introducing available active sites into film materials as gas transport channels

This work aims to explore an available avenue to design an equilibrium modified atmosphere packaging (EMAP) by the modification of gas permeability of material. In this work, the introduction of available active sites endowed materials with adjustable gas permeability properties. With varying concentrations of the resulting materials with various gas permeability, the CO2 and O2 gas permeability of the blending films were modified at the range of 3.92 ∼ 17.84 barrier and 0.65 ∼ 3.46 barrier, respectively. On this basis, the films were used as EMAP to preserve postharvest cabbages. The results indicated that each EMAP achieved an equilibrium atmosphere containing 6.8 % ∼ 3.8 % CO2 and 2.1 % ∼ 5.2 % O2 within 15 h and maintained it continuously. In these atmosphere, the respiratory rate of the preserved cabbages was significantly inhibited, thereby delaying the deterioration of their storage quality. As the results, sensory scores of the preserved samples were maximally maintained. Declines of color indexes and texture indexes were obviously inhibited. Chemical variations in chlorophyll content, total phenolics content, total flavonoids content, ascorbic acid and nitrite content were significantly suppressed. The overall findings revealed that this method is suitable and promising to develop EMAP for the postharvest vegetables.

Application of chitosan and other biopolymers based edible coatings containing essential oils as green and innovative strategy for preservation of perishable food products: A review

Deterioration of perishable foods due to fungal contamination and lipid peroxidation are the most threatened concern to food industry. Different chemical preservatives have been used to overcome these constrains; however their repetitive use has been cautioned owing to their negative impact after consumption. Therefore, attention has been paid to essential oils (EOs) because of their natural origin and proven antifungal and antioxidant activities. Many EO-based formulations have been in use but their industrial-scale application is still limited, possibly due to its poor solubility, vulnerability towards oxidation, and aroma effect on treated foods. In this sense, active food packaging using biopolymers could be considered as promising approach. The biopolymers can enhance the stability and effectiveness of EOs through controlled release, thus minimizes the deterioration of foods caused by fungal pathogens and oxidation without compromising their sensory properties. This review gives a concise appraisal on latest advances in active food packaging, particularly developed from natural polymers (chitosan, cellulose, cyclodextrins etc.), characteristics of biopolymers, and current status of EOs. Then, different packaging and their effectiveness against fungal pathogens, lipid-oxidation, and sensory properties with recent previous works has been discussed. Finally, effort was made to highlights their safety and commercialization aspects towards market solutions.

Preparation and Characterization of Eugenol Incorporated Pullulan-Gelatin Based Edible Film of Pickering Emulsion and Its Application in Chilled Beef Preservation

The purpose of this study was to develop a composite film composed of eugenol Pickering emulsion and pullulan-gelatin, and to evaluate its preservation effect on chilled beef. The prepared composite film was comprehensively evaluated in terms of the stability of emulsion, the physical properties of the film, and an analysis of freshness preservation for chilled beef. The emulsion size (296.0 ± 10.2 nm), polydispersity index (0.457 ± 0.039), and potential (20.1 ± 0.9 mV) proved the success of emulsion. At the same time, the films displayed good mechanical and barrier properties. The index of beef preservation also indicated that eugenol was a better active ingredient than clove essence oil, which led to the rise of potential of hydrogen, chroma and water content, and effectively inhibited microbial propagation, protein degradation and lipid oxidation. These results suggest that the prepared composites can be used as promising materials for chilled beef preservation.

Effect of Edible Coatings of Cassava Starch Incorporated with Clove and Cinnamon Essential Oils on the Shelf Life of Papaya

Applying edible coatings added with plant essential oils is a strategy used to delay ripening processes in climacteric fruits such as papaya. Formulations comprising 3% or 4% cassava starch (w/v), added with clove or cinnamon essential oils (2 mL/L), were tested for microbial inhibition (in vitro) purposes. Moreover, these fruits' physicochemical and microbiological aspects were assessed at 25 °C, for 12 days. Slight variations in pH and Brix values were observed during storage. On the other hand, there were no significant variations in carotenoid contents over storage time. The papaya fruits' coating contributed to reducing their weight loss from 40.66% (uncoated sample) to 24.10% on the 12th storage day, as well as delayed changes often observed during the ripening process. The 4% cassava starch coatings added with essential oils were more efficient in reducing microbiological levels. The herein proposed treatments reduced aerobic mesophilic bacteria, as well as molds and yeast counts, by 1.48 and 1.95 log CFU/g, on average, respectively, in comparison to the control sample. The assessed microorganism counts were higher in the uncoated sample than in the coated papaya fruits, after 12 days of storage. Thus, the tested coatings can potentially delay the emergence of post-harvest changes; consequently, they can help improve the quality of papaya fruits and extend their shelf life.

Fortification of polysaccharide-based packaging films and coatings with essential oils: A review of their preparation and use in meat preservation

As the demand for botanical food additives and eco-friendly food packaging materials grows, the use of essential oils, edible biodegradable films and coatings are becoming more popular in packaging. In this review, we discussed the recent research trends in the use of natural essential oils, as well as polysaccharide-based coatings and films: from the composition of the substrates to preparing formulations for the production of film-forming technologies. Our review emphasized the functional properties of polysaccharide-based edible films that contain plant essential oils. The interactions between essential oils and other ingredients in edible films and coatings including polysaccharides, lipids, and proteins were discussed along with effects on film physical properties, essential oil release, their active role in meat preservation. We presented the opportunities and challenges related to edible films and coatings including essential oils to increase their industrial value and inform the development of edible biodegradable packaging, bio-based functional materials, and innovative food preservation technologies.

Essential oil from the leaves of Eugenia pohliana DC. (Myrtaceae) alleviate nociception and acute inflammation in mice

Eugenia pohliana DC.(Myrtaceae) is used in folk medicine by communities in Brazil. However, there are no reports on its biological activity. This is the first study to identify the components of E. pohliana essential oil (EpEO) and evaluate their antinociceptive and anti-inflammatory activities in an in vivo model at doses of 25, 50, and 100 mg/kg. The essential oil (EO) was obtained by hydrodistillation, and the analysis was performed by gas chromatography coupled with mass spectrometry. Antinociceptive activity was evaluated by writhing tests, tail movement, and formalin (neurogenic and inflammatory pain); naloxone was used to determine the nociception mechanism. Anti-inflammatory activity was assessed by oedema and peritonitis tests. We found that (E)-β-caryophyllene (BCP) (15.56%), δ-cadinene (11.24%) and α-cadinol (10.89%) were the major components. In the writhing test, there was a decrease in writing by 42.95-70.70%, in the tail movement, an increase in latency time by 69.12-86.63%, and in the formalin test, there was a reduction in pain neurogenic by 29.54-61.74%, and inflammatory pain by 37.42-64.87%. The antinociceptive effect of EpEO occurs through the activation of opioid receptors. In addition, a reduction in inflammation by 74.93‒81.41% was observed in the paw edema test and inhibition of the influx of leukocytes by 51.86‒70.38% and neutrophils by 37.74‒54.72% in the peritonitis test. It was concluded that EpEO has antinociceptive effect by the opioid pathway, as shown by the inhibitory effect of naloxone, and anti-inflammatory actions, and that its use does not cause hemolytic damage or behavioral change.

Eco-friendly 'ochratoxin A' control in stored licorice roots - quality assurance perspective

According to toxicity data, ochratoxin A (OTA) is the second most important mycotoxin and is produced by Aspergillus and Penicillium. As a natural antifungal agent, clove essential oil (CEO) is a substance generally recognised as safe (GRAS) and shows strong activity against fungal pathogens. Here, we aimed to investigate the control efficacy of CEO in nano-emulsions (CEN) against OTA production in licorice roots and rhizomes during storage. The experiments were performed under simulated conditions of all four seasons (i.e. Spring, Summer, Autumn and Winter). Relative humidity (RH) and temperature were simulated in desiccators along with various salt solutions in incubators. Fresh licorice roots were immersed in CEN at various concentrations (150, 300, 600, 1200 and 2400 µl/l). Before utilising the nano-emulsions, we measured their polydispersity index and mean droplet size by the dynamic light scattering (DLS) technique. Also, the chemical composition of the CEO was determined using GC and GC-MS analyses. Sampling was carried out to monitor OTA once every five days. The samples were dried immediately and analysed by high-performance liquid chromatography (HPLC). Results showed that various concentrations of CEN inhibited the growth of fungi and OTA production. The most effective CEN concentrations were 1200 and 2400 µl/l, which reduced OTA production to 19 and 20 ppb under Winter and Autumn conditions, respectively. These results suggest an effective eco-friendly method for the storage of licorice to reduce postharvest fungal decay.

Preparation of an Antimicrobial and Antioxidant Bio-Polymer Film and Its Application as Glazing Shell for Postharvest Quality of Fresh-Cut Apple

The aim of this work is to glazing a modified bio-polymer shell as substitute of peel to keep the postharvest quality of fresh-cut fruits. In this study, chitosan as backbone of the shell was modified by addition of the functional extracts obtained from Zanthoxylum, in which 12 kinds of main identified bio-active components consisted of over 55% of the total extracts. The introduction of the extracts improved physic and mechanical properties of the shell, and endowed it with significant antimicrobial and antioxidant activity. Accordingly, the modified chitosan was used as the substitute of peel to preserve fresh-cut apples. Results exhibited that such treatments obviously delayed the decline process of overall postharvest quality of the preserved apple samples throughout all the storage period, represented by the variations in physical, chemical, and microbial properties of the apple samples were significantly inhibited. The overall observations revealed promising potential of the bio-polymer shell in food application.

Bioactive Edible Films and Coatings Based in Gums and Starch: Phenolic Enrichment and Foods Application

Edible films and coatings allow preserving fresh and processed food, maintaining quality, preventing microbial contamination and/or oxidation reactions and increasing the shelf life of food products. The structural matrix of edible films and coatings is mainly constituted by proteins, lipids or polysaccharides. However, it is possible to increase the bioactive potential of these polymeric matrices by adding phenolic compounds obtained from plant extracts. Phenolic compounds are known to possess several biological properties such as antioxidant and antimicrobial properties. Incorporating phenolic compounds enriched plant extracts in edible films and coatings contribute to preventing food spoilage/deterioration and the extension of shelf life. This review is focused on edible films and coatings based on gums and starch. Special attention is given to bioactive edible films and coatings incorporating plant extracts enriched in phenolic compounds.

Carrageenan/agar-based functional film integrated with zinc sulfide nanoparticles and Pickering emulsion of tea tree essential oil for active packaging applications

A functional carrageenan/agar-based film was prepared by combining tea tree oil Pickering emulsion (PET) and zinc sulfide nanoparticles (ZnSNP). PET was formulated using tea tree essential oil stabilized with nanocellulose fibers. PET and ZnSNPs were uniformly dispersed in the binary polymer matrix and formed compatible films. The incorporation of ZnSNPs improved the mechanical strength, whereas PET slightly decreased the strength, but the combined addition of ZnSNP and PET maintained the mechanical strength with slightly improved flexibility. The addition of ZnSNP and PET, alone or in combination, slightly improved the water vapor barrier, water resistance, and thermal stability of the film. In addition, the carrageenan/agar-based composite membrane showed distinct antioxidant and antibacterial activity. The ZnSNP and PET incorporated binary composite films with enhanced physical and functional properties are likely to be used in active food packaging applications.

Physically cross-linked chitosan/dextrin cryogels entrapping Thymus vulgaris essential oil with enhanced mechanical, antioxidant and antifungal properties

Herein, we entrapped Thymus vulgaris essential oil (EO) within the physically cross-linked sponge-like architecture of cryogels by ice template-assisted freeze-drying. Their 3D cryogenically-structured network was built through hydrogen bonding formed by blending two naturally-derived polysaccharides, chitosan and dextrin. The embedment of EOs within the cryogel matrix generates porous films with an increased elasticity that allows their fast shape recovery after full compression. Thus, the swollen EOs-loaded cryogel films exhibited an elastic modulus of 3.00 MPa, which is more than 40 times higher than that of polysaccharide films without EOs (an elastic modulus of only 0.07 MPa). In addition, the encapsulation of bioactive compounds endows the bio-based films with both antioxidant and antifungal properties, showing a radical scavenging activity of 65% and a zone inhibition diameter of 40 mm for Candida parapsilosis fungi. Our results recommend the entrapment of EOs into bio-based cryogel carriers as a straightforward approach to provide 'green' polysaccharide-based films having both improved physicochemical properties and remarkable antifungal activity.

Effects of cinnamon essential oil and Persian gum on preservation of pomegranate arils

Given the high perishability of pomegranate arils, edible antimicrobial coating will enhance their shelf life and maintain their marketability. An antimicrobial coating was prepared using 1% (w/v) soluble part of Persian gum (PG) and different concentrations (0.25%, 0.50%, and 0.75% (v/v)) of cinnamon essential oil (CEO) to extend the shelf life of pomegranate arils. Microbiological, chemical, physical, and sensorial characteristics of coated and uncoated samples were evaluated at 7-day intervals. Total anthocyanin (TAN), titrable acidity (TA), and ascorbic acid showed a decreasing trend, during the whole period of the storage. TAN, TA, and ascorbic acid decreased from 119.8 to 44.5 mg/L, 1.6% to 1.37%, and 682 to 140 mg/L, respectively. Firmness increased during the storage time, while total soluble solids (TSS, around 17.4 °Brix) and total phenolic compounds (TP, around 14.21 mg/100 ml) showed no significant changes with CEO concentrations. Coatings containing 0.5% and 0.75% CEO significantly prevented fungal growth on the samples at least for 3 weeks and 3 months, respectively. Optimization proved that 1-week cold storage and 0.43% CEO could dramatically meet 80% of the research targets including maximum nutritional quality and freshness, as well preventing microbial spoilage. It was concluded that coating the pomegranate arils by PG and selecting an appropriate concentration of the CEO could considerably increase shelf life, marketability, and nutritional quality of pomegranate arils at a suitable and acceptable level.

Preparation and characterization of clove essential oil loaded nanoemulsion and pickering emulsion activated pullulan-gelatin based edible film

The clove essential oil (CEO) loaded nano and pickering emulsions prepared with Tween 80 and whey protein isolate/inulin mixture, respectively were incorporated into pullulan-gelatin film base fluid at three levels (0.2%, 0.4%, and 0.6%). The droplet sizes of NE and PE loaded with CEO were 15.93 nm and 266.9 nm, respectively. The PDI of CEOs with stable NE and PE were 0.262 and 0.259, respectively. Our results showed the improved compatibility between pullulan-gelatin and essential oil-loaded nanocarriers. The active film composed of PE carrier had the structural characteristics of high density, low water content, and low permeability, thus exhibiting excellent mechanical properties, water barrier properties, and appreciable antioxidant activities. Compared with NE, it was found that the CEO-loaded PE showed slow-release profile in the film sample. The prepared active film containing PE possessed a great potential to be used as effective and natural alternatives for active food packaging.