Due to the environmental pollution problems caused by plastic-based packaging, the development of edible food packaging films is imminent. However, the performance of most edible packaging films is ...insufficient to meet practical applications, so recent studies have focused on the research of various fillers to improve film properties. This article reviews recent applications of cellulose nanocrystals (CNC) and cellulose nanofiber (CNF) in edible food packaging films including the effect on thickness, optical properties, barrier properties, water sensitivity, mechanical properties, antioxidant and antimicrobial properties. The main conclusion of this review is that the incorporation of CNC and CNF could significantly improve the performance of edible food packaging films. Particular finding is that although CNC and CNF can be used as excellent addition to improve the performance of edible food packaging films, there is a key “optimum” concentration. In addition, we also found that CNC and CNF as excellent controlled release agents and stabilizers significantly increased the antioxidant and antibacterial properties of edible food packaging films.
Display omitted
•Recent developments of nanocellulose incorporated edible food packaging (EFP) films.•Nanocellulose is excellent enhancer in EFP films.•There exist an “optimum” concentration of added nanocellulose in EFP film.•Nanocellulose crystals are more functionally stable than nanocellulose fibers.•Nanocellulose is excellent controlled release agent and stabilizer in EFP films.
•Postharvest UV-C treatment effectively controlled brown rot in nectarine fruit.•UV-C treatment enhanced antioxidant system in nectarine fruit.•UV-C treatment enhanced activities of defense-related ...enzymes in nectarine fruit.•UV-C promoted phenylpropane metabolic pathway and anthocyanin biosynthesis.
UV-C is a no residual environmentally friendly physical treatment that could activate the fruit defense system and induce resistance to control the postharvest disease. Herein, the study was performed to investigate the effect of UV-C on disease occurrence, antioxidant system, disease-resistant defense enzymes, and phenylpropane metabolic pathway, and anthocyanin biosynthesis in nectarine fruit inoculated with Rhizopus stolonifer. Compared with the fruit without treatment, the results showed 3 kJ m−2 UV-C treatment decreased lesion diameter as well as disease index. UV-C treatment increased the activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) and the contents of ascorbic acid (ASA) as well as glutathione (GSH). UV-C treatment activated the phenylpropane metabolic pathway and anthocyanin biosynthesis, thereby increasing the content of phenolic compounds, total flavonoids, anthocyanins, and lignin. Besides, UV-C treatment also promoted the activities of chitinase (CHI) and β-1,3-glucanase (GLU). These data demonstrated that UV-C treatment could promote the antioxidant system, stimulate phenylpropane metabolic pathway and anthocyanin biosynthesis, thus alleviate disease severity in R. stolonifer-inoculated nectarine during storage. This work concluded that UV-C was an eco-friendly treatment to control disease occurrence of postharvest nectarine fruit.
This study determined the total phenolic and flavonoid contents, ascorbic acid and phenolic composition and evaluated antioxidant properties and metal chelating activity of five peach cultivars, ...separately for pulp and peel. Identification and quantification of ascorbic acid and phenolic compounds were performed using HPLC method. The antioxidant and metal chelating activities are evaluated by means of several in vitro methods, such as the β-carotene/linoleate model system, radical scavenging, reducing power, and iron and copper ion chelation. The results showed that the peach peels have the highest antioxidant capacities, reflecting their highest content of total phenolics, flavonoids, ascorbic acid and phenolic compounds. In addition, the predominant phenolic compounds in peaches was found to be chlorogenic acid, followed by neo-chlorogenic acid, (+)-catechin, quercetin-3-rutinoside and protocatechuic acid. The results indicated that peach peels are good sources of bioactive and antioxidant compounds, and can be explored for their health promoting values in food products.
•Five representative peaches from China were analyzed separately for peel and pulp.•Peel contained higher contents of TPs, TFs, ascorbic acid and phenolics than pulp.•Peel presented higher antioxidant capacity and metal chelating capacity than pulp.•Antioxidant and metal chelating properties were correlated both to TPs, TFs and ascorbic acid.
Display omitted
•Near-freezing temperature storage (NFTS) delayed senescence in sweet cherry fruit.•NFTS improved quality and bioactive compound content of sweet cherry fruit.•NFTS reduced ROS ...accumulation and inhibited membrane damage.•NFTS induced antioxidant enzymes activities and enhanced antioxidant capacity.
Near-freezing temperature storage (NFTS) is a novel method to inhibit quality loss of fresh fruit. However, little information is available on NFTS delaying the onset of senescence in sweet cherry (Prunus avium L.) fruit and regulating the changes on antioxidative enzymes participated in the balancing of reactive oxygen system (ROS). Fruits were stored at NFT (between super-cooling point and freezing point), 0 °C and 5 °C, respectively, until fruits exhibited visually rot (sampled every twenty days). NFTS effectively slowed senescence process in sweet cherry fruit, as indicated by extending storage duration and improving the changes of firmness, anthocyanins, ion leakage, peel color and sugars content. Moreover, fruit stored at NFT had higher levels of ascorbic acid, phenolics and organic acids and lower accumulation of carotenoids, malondiadehyde, hydrogen peroxide (H2O2) and superoxide radical (O2•¯). Additionally, NFTS maintained membrane integrity and prevented fresh browning of fruit by enhancing the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and gluta thione reductase (GR) and inhibiting the activities of guaiacol peroxidase (POD), polyphenol oxidase (PPO) and lipoxygenase (LOX). Furthermore, NFTS fruit exhibited higher level of antioxidant capacity as measured by radical scavenging activity and reducing power at the end of storage. These results indicate that the activities of antioxidant enzymes to scavenge superoxide anions and H2O2 during NFTS was implicated in the maintenance of membrane integrity, which might be a part of the mechanism associated with the delay of senescence in sweet cherry fruit.
•1-MCP treatment can offset the ineffectiveness of intermittent warming.•The combination of 1-MCP plus intermittent warming treatment was most effective in alleviating chilling injury.•The ...combination of 1-MCP plus intermittent warming treatment maintained highest phenolics as well as antioxidant activity.•Phenolics increased firstly and then decreased during storage time.•Antioxidant activity had a similar change pattern as phenolics.
Peach (Prunus persica L. cv. Yuhualu) fruit were picked at their physiologically mature stage and treated with 5μLL−1 1-methylcyclopropene (1-MCP), intermittent warming (IW) and a combination of 1-MCP and IW (1-MCP+IW). Severity of chilling injury (CI), quality characters, phenolic composition as well as antioxidant properties were measured during refrigerate storage at 2°C plus three days of shelf-life at 20°C. These results showed that all applied treatments dramatically prevented the degree of flesh browning for ‘Yuhualu’ peach fruit. Furthermore, 1-MCP treatment was able to alleviate the negative impact of IW, and the combination of 1-MCP and IW possessed the lowest CI index and the highest fruit qualities. Additionally, treatment with 1-MCP alone or combined with IW effectively delayed and elevated the accumulation of phenolics and antioxidant capacities for peach fruit during entire cold storage and subsequent shelf-life period. The application of 1-MCP plus IW could be a favorable practice for preventing chilling injury and maintaining fruit quality for peach fruit during refrigerate storage.
Display omitted
•Post-storage ethylene treatment can improve sensory quality of cold-stored apricot.•Post-storage ethylene accelerates sugar, acid metabolism and ripening process.•Post-storage 1-MCP ...treatment delay fruit softening and pectin degradation.•Post-storage 1-MCP treatment inhibit pectin related enzymes and gene expressions.•TEM and pectin immunolabeling prove that 1-MCP delay middle lamella dissolution.
Post-storage applications of exogenous ethylene and 1-methylcyclopropene (1-MCP) were performed in cold-stored apricot to regulate the ripening and softening process during shelf life. The results showed that post-storage ethylene treatment could accelerate SSC accumulation, organic acids degradation, color change and ripening process of cold-stored apricot, and could effectively improve the consumer acceptability of the fruit. Post-storage 1-MCP treatment strongly suppressed ethylene production in apricot during shelf life, causing the suppression of expression levels of pectin related genes encoding for pectin degraded enzymes, including polygalacturonase, β-galactosidase and pectin methyl esterase. Microscopic observation provided a direct evidence that post-storage treatment of 1-MCP delayed pectin degradation and middle lamella dissolution of apricot, and delayed the softening process during shelf life. The regulation of ripening and softening process of apricot with post-storage treatment of ethylene or 1-MCP could be effective for improving consumer acceptability or delaying fruit softening of the fruit.
Display omitted
•NFT storage, in minus non-frozen temperature, is a novel storage method.•We developed a NFT storage method for preservation of nectarines.•NFT prolonged storage period and improved ...the postharvest quality of nectarines.•NFT storage improved health-promoting compounds and antioxidant capacity.
To avoid postharvest quality loss of nectarine fruits during storage, the method of near freezing temperature (NFT) storage was established and applied. This study evaluated the postharvest characteristics, nutritional quality and antioxidant potential of nrctarines fruits after NFT storage. Nectarines were stored at NFT (−1.5°C to −1.2°C), 0°C or 5°C, until the fruits visually spoiled. NFT showed the longest storage period (70d) and reduced ethylene production, softening, delay rate, titratable acidity loss and accumulation of malondiadehyde and anthocyanins. NFT storage also retarded peel discoloration and improved the content of soluble solids, ascorbic acid, phenolics and flavonoids in the nectarines. The antioxidant properties of nectarines were also improved by NFT storage. The radical scavenging activity, reducing power, antioxidant activity and metal-chelating ability of the pulp were significantly enhanced by NFT storage at the end of storage. These results suggested that NFT storage could prolong the storage period and improve the postharvest quality and antioxidant capacity of nectarines.
Anti-programmed death 1/programmed death ligand 1 (anti-PD-1/PD-L1) antibodies exert significant antitumor effects by overcoming tumor cell immune evasion and reversing T-cell exhaustion. However, ...the emergence of drug resistance causes most patients to respond poorly to these immune checkpoint inhibitors (ICIs). Studies have shown that insufficient T-cell infiltration, lack of PD-1 expression, deficient interferon signaling, loss of tumor antigen presentation, and abnormal lipid metabolism are all considered to be closely associated with immunotherapy resistance. To address drug resistance in tumor immunotherapy, a lot of research has concentrated on developing combination therapy strategies. Currently, ICIs such as anti-PD-1 /PD-L1 antibody combined with chemotherapy and targeted therapy have been approved for clinical treatment. In this review, we analyze the mechanisms of resistance to anti-PD-1/PD-L1 therapy in terms of the tumor microenvironment, gut microbiota, epigenetic regulation, and co-inhibitory immune checkpoint receptors. We also discuss various promising combination therapeutic strategies to address resistance to anti-PD-1/PD-L1 drugs, including combining these therapies with traditional Chinese medicine, non-coding RNAs, targeted therapy, other ICIs, and personalized cancer vaccines. Moreover, we focus on biomarkers that predict resistance to anti-PD-1/PD-L1 therapy as well as combination therapy efficacy. Finally, we suggest ways to further expand the application of immunotherapy through personalized combination strategies using biomarker systems.
To study how chlorogenic acid affects changes of reactive oxygen species (ROS) and the proteins involved in ROS scavenging of nectarine during storage time, the fruits were treated with chlorogenic ...acid (CHA) then stored at 25°C for further studies. The CHA-treatment significantly reduced O2-· production rate, H2O2 content, and membrane permeability of nectarine fruit during storage. The key proteins related the nectarine fruit senescence during storage were identified by two-dimensional electrophoresis and MALDI-TOF/TOF. Level and enzymatic activity of peroxidase were reduced, while both the protein levels and the enzymatic activities of superoxide dismutase, glutathione reductase, glutathione-s-transferase and monodehydroascorbate reductase were enhanced in nectarine fruit treated with CHA. In addition, levels of several pathogen-related proteins were also enhanced by CHA-treatment. Taking together, the present study showed that CHA could influence changes in defense related proteins and reduced oxidative damage in nectarine fruit during postharvest ripening.
In the present study, the antioxidant and antibacterial chitosan/tea polyphenols-silver nanoparticles composite film (CS/TP-AgNPs) was developed via a novel one-pot method. The TP was added to the CS ...film not only as the reducing agent of AgNPs but also as the cross-linking agent and antioxidant. The AgNPs and nanocomposite films developed were characterized by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Besides, the physical, mechanical, antioxidant and antibacterial properties of the nanocomposite films were also analyzed. As the content of TP-AgNPs incorporation increased, the color of CS/TP-AgNPs nanocomposite film gradually shifted to brown, accompanied by an increase in opacity and thickness. The decrease in moisture contents and water vapor permeability of CS/TP-AgNPs nanocomposite film indicated that the TP-AgNPs varied the original bond between the CS-CS and CS-water. The denser cross-section of CS/TP-AgNPs nanocomposite film confirmed the enhanced mechanical properties. It is worth noting that CS/TP-AgNPs nanocomposite film exhibited more excellent antioxidant and antibacterial activity than CS film. This study developed the multi-functionality chitosan film by the simultaneous incorporation of AgNPs and TP and revealed the multiple effects of TP acting as reducing agent for AgNPs, cross-linking agent and antioxidant on chitosan film.
Display omitted
PDF