Changes of Sensory Quality, Flavor-Related Metabolites and Gene Expression in Peach Fruit Treated by Controlled Atmosphere (CA) under Cold Storage.

Controlled atmosphere (CA) has been used to alleviate chilling injury (CI) of horticultural crops caused by cold storage. However, the effects of CA treatment on peach fruit sensory quality and flavor-related chemicals suffering from CI remain largely unknown. Here, we stored peach fruit under CA with 5% O2 and 10% CO2 at 0 °C up to 28 d followed by a subsequent 3 d shelf-life at 20 °C (28S3). CA significantly reduced flesh browning and improved sensory quality at 28S3. Though total volatiles declined during extended cold storage, CA accumulated higher content of volatile esters and lactones than control at 28S3. A total of 14 volatiles were positively correlated with consumer acceptability, mainly including three C6 compounds, three esters and four lactones derived from the fatty acid lipoxygenase (LOX) pathway. Correspondingly, the expression levels of genes including PpLOX1, hyperoxide lyase PpHPL1 and alcohol acyltransferase PpAAT1 were positively correlated with the change of esters and lactones. CA elevated the sucrose content and the degree of fatty acids unsaturation under cold storage, which gave us clues to clarify the mechanism of resistance to cold stress. The results suggested that CA treatment improved sensory quality by alleviating CI of peach fruits under cold storage.

Genome-Wide Analysis of Calmodulin Binding Transcription Activator (CAMTA) Gene Family in Peach (Prunus persica L. Batsch) and Ectopic Expression of PpCAMTA1 in Arabidopsis camta2,3 Mutant Restore Plant Development.

Calmodulin-binding transcription activator (CAMTA) is a transcription factor family containing calmodulin (CaM) binding sites and is involved in plant development. Although CAMTAs in Arabidopsis have been extensively investigated, the functions of CAMTAs remain largely unclear in peaches. In this study, we identified five peach CAMTAs which contained conserved CG-1 box, ANK repeats, CaM binding domain (CaMBD) and IQ motifs. Overexpression in tobacco showed that PpCAMTA1/2/3 were located in the nucleus, while PpCAMTA4 and PpCAMTA5 were located in the plasma membrane. Increased expression levels were observed for PpCAMTA1 and PpCAMTA3 during peach fruit ripening. Expression of PpCAMTA1 was induced by cold treatment and was inhibited by ultraviolet B irradiation (UV-B). Driven by AtCAMTA3 promoter, PpCAMTA1/2/3 were overexpressed in Arabidopsis mutant. Here, we characterized peach PpCAMTA1, representing an ortholog of AtCAMTA3. PpCAMTA1 expression in Arabidopsis complements the developmental deficiencies of the camta2,3 mutant, and restored the plant size to the wild type level. Moreover, overexpressing PpCAMTA1 in camta2,3 mutant inhibited salicylic acid (SA) biosynthesis and expression of SA-related genes, resulting in a susceptibility phenotype to Pst DC3000. Taken together, our results provide new insights for CAMTAs in peach fruit and indicate that PpCAMTA1 is associated with response to stresses during development.

Synthesis of flavour-related linalool is regulated by PpbHLH1 and associated with changes in DNA methylation during peach fruit ripening.

Linalool is one of the common flavour-related volatiles across the plant kingdom and plays an essential role in determining consumer liking of plant foods. Although great process has been made in identifying terpene synthase (TPS) genes associated with linalool synthesis, much less is known about regulation of this pathway. We initiated study by identifying PpTPS3 encoding protein catalysing enantiomer (S)-(+)-linalool synthesis, which is a major linalool component (˜70%) observed in ripe peach fruit. Overexpression of PpTPS3 led to linalool accumulation, while virus-induced gene silencing of PpTPS3 led to a 66.5% reduction in linalool content in peach fruit. We next identified transcription factor (TF) PpbHLH1 directly binds to E-box (CACATG) in the PpTPS3 promoter and activates its expression based on yeast one-hybrid assay and EMSA analysis. Significantly positive correlation was also observed between PpbHLH1 expression and linalool production across peach cultivars. Peach fruit accumulated more linalool after overexpressing PpbHLH1 in peach fruit and reduced approximately 54.4% linalool production after silencing this TF. DNA methylation analysis showed increased PpTPS3 expression was associated with decreased 5 mC level in its promoter during peach fruit ripening, but no reverse pattern was observed for PpbHLH1. Arabidopsis and tomato fruits transgenic for peach PpbHLH1 synthesize and accumulate higher levels of linalool compared with wild-type controls. Taken together, these results would greatly facilitate efforts to enhance linalool production and thus improve flavour of fruits.

Involvement of the R2R3-MYB transcription factor MYB21 and its homologs in regulating flavonol accumulation in Arabidopsis stamen.

Commonly found flavonols in plants are synthesized from dihydroflavonols by flavonol synthase (FLS). The genome of Arabidopsis thaliana contains six FLS genes, among which FLS1 encodes a functional enzyme. Previous work has demonstrated that the R2R3-MYB subgroup 7 transcription factors MYB11, MYB12, and MYB111 redundantly regulate flavonol biosynthesis. However, flavonol accumulation in pollen grains was unaffected in the myb11myb12myb111 triple mutant. Here we show that MYB21 and its homologs MYB24 and MYB57, which belong to subgroup 19, promote flavonol biosynthesis through regulation of FLS1 gene expression. We used a combination of genetic and metabolite analysis to identify the role of MYB21 in regulating flavonol biosynthesis through direct binding to the GARE cis-element in the FLS1 promoter. Treatment with kaempferol or overexpression of FLS1 rescued stamen defects in the myb21 mutant. We also observed that excess reactive oxygen species (ROS) accumulated in the myb21 stamen, and that treatment with the ROS inhibitor diphenyleneiodonium chloride partly rescued the reduced fertility of the myb21 mutant. Furthermore, drought increased ROS abundance and impaired fertility in myb21, myb21myb24myb57, and chs, but not in the wild type or myb11myb12myb111, suggesting that pollen-specific flavonol accumulation contributes to drought-induced male fertility by ROS scavenging in Arabidopsis.

UDP-glucosyltransferase PpUGT85A2 controls volatile glycosylation in peach.

The monoterpene linalool is a major contributor to aroma and flavor in peach (Prunus persica) fruit. It accumulates during fruit ripening, where up to ~40% of the compound is present in a non-volatile glycosylated form, which affects flavor quality and consumer perception by retronasal perception during tasting. Despite the importance of this sequestration to flavor, the UDP-glycosyltransferase (UGT) responsible for linalool glycosylation has not been identified in peach. UGT gene expression during peach fruit ripening and among different peach cultivars was analyzed using RNA sequencing, and transcripts correlated with linalyl-ß-d-glucoside were selected as candidates for functional analysis. Kinetic resolution of a racemic mixture of R,S-linalool was shown for PpUGT85A2, with a slight preference for S-(+)-linalool. PpUGT85A2 was shown to catalyze synthesis of linalyl-ß-d-glucoside in vitro, although it did not exhibit the highest enzyme activity between tested substrates. Subcellular localization of PpUGT85A2 in the cytoplasm and nucleus was detected. Application of linalool to peach leaf disks promoted PpUGT85A2 expression and linalyl-ß-d-glucoside generation. Transient expression in peach fruit and stable overexpression in tobacco and Arabidopsis resulted in significant accumulation of linalyl-ß-d-glucoside in vivo. Taken together, the results indicate that PpUGT85A2 expression is a major control point predicting linalyl-ß-d-glucoside content.

E-Nose and GC-MS Reveal a Difference in the Volatile Profiles of White- and Red-Fleshed Peach Fruit.

First purchases of fruit are mainly dependent on aspects of appearance such as color. However, repeat buys of fruit are determined by internal quality traits such as flavor-related volatiles. Differences in volatile profiles in white- and red-fleshed peach fruit are not well understood. In the present study, peach cultivars with white- and red-fleshed fruit were subjected to sensory analysis using electronic nose (e-nose) to evaluate overview volatile profiles. Approximately 97.3% of the total variation in peach color-volatiles was explained by the first principle component 1 (PC1) and PC2. After analyzing sensory differences between peach fruit samples, 50 volatile compounds were characterized based on GC-MS. Multivariate analysis such as partial least squares discriminant analysis (PLS-DA) was applied to identify volatile compounds that contribute to difference in white- and red-fleshed peach fruit cultivars. A total of 18 volatiles that could separate peach fruit cultivars with different colors in flesh during ripening were identified based on variable importance in projection (VIP) score. Fruity note latone γ-hexalactone had higher contents in red-fleshed cultivars, while grassy note C6 compounds such as hexanal, 2-hexenal, (E)-2-hexenal, 1-hexanol, and (Z)-2-hexen-1-ol showed great accumulation in white-fleshed peach fruit.

UV-B irradiation differentially regulates terpene synthases and terpene content of peach.

Plants generate protective molecules in response to ultraviolet (UV) light. In laboratory experiments, 48 h UV-B irradiation of peach fruits and leaves reduced the flavour-related monoterpene linalool by 60%. No isoprene was detected, but other terpenoids increased significantly, including a threefold accumulation of the sesquiterpene (E,E)-α-farnesene, which was also increased by jasmonic acid treatment. RNA sequencing revealed altered transcript levels for two terpene synthases (TPSs): PpTPS1, a TPS-g subfamily member, decreased by 86% and PpTPS2, a TPS-b subfamily member, increased 80-fold. Heterologous expression in Escherichia coli and transient overexpression in tobacco and peach fruits showed PpTPS1 was localized in plastids and associated with production of linalool, while PpTPS2 was responsible for (E,E)-α-farnesene biosynthesis in the cytoplasm. Candidate regulatory genes for these responses were identified. Commercial peach production in Asia involves fruit bagging to maintain marketable yield and quality. TPS gene expression and volatile terpenoid production in field experiments, using bags transmitting high UV-B radiation, showed similar effects on peach volatiles to those from laboratory experiments. Bags transmitting less UV-B light ameliorated the reduction in the flavour volatile linalool, indicating that flavour components of peach fruits can be modulated by selecting an appropriate source of environmental screening material.

Two ω-3 FADs Are Associated with Peach Fruit Volatile Formation.

Aroma-related volatiles, together with sugars and acids, play an important role in determining fruit flavor quality. Characteristic volatiles of peach fruit are mainly derived from fatty acids such as linoleic acid (18:2) and linolenic acid (18:3). In the present study, six genes encoding fatty acid desaturases (FAD) were cloned, including two ω-6 FAD genes (PpFAD2, PpFAD6) and four ω-3 FAD genes (PpFAD3-1, PpFAD3-2, PpFAD7 and PpFAD8). Heterologous expression of peach FADs in tobacco plants showed that PpFAD3-1, and PpFAD3-2 significantly reduced contents of 18:2, and accumulated significant higher levels of 18:3. In the case of volatiles, transgenic plants produced lower concentrations of hexanal and higher levels of (E)-2-hexenal. Consequently, the ratio of the (E)-2-hexenal and hexanal was about 5- and 3-fold higher than that of wild type (WT) in PpFAD3-1 and PpFAD3-2 transformants, respectively. No significant changes in volatile profiles were observed in transgenic plants overexpressing the four other peach FAD genes. Real-time quantitative polymerase chain reaction (qPCR) analysis showed that ripe fruit had high PpFAD3-1 and low PpFAD3-2 transcript levels. In contrast, high PpFAD3-2 and low PpFAD3-1 transcript levels were observed in young fruit. These results indicate a temporal regulation of these two ω-3 FADs during development and ripening, influencing peach fruit volatile formation.

Bagging treatment influences production of C6 aldehydes and biosynthesis-related gene expression in peach fruit skin.

Bagging is a useful method to improve fruit quality by altering its exposure to light, whereas its effect on fruit volatiles production is inconsistent, and the genes responsible for the observed changes remain unknown. In the present study, single-layer yellow paper bags were used to study the effects of bagging treatment on the formation of C6 aldehydes in peach fruit (Prunus persica L. Batsch, cv. Yulu) over two succeeding seasons. Higher concentrations of n-hexanal and (E)-2-hexenal, which are characteristic aroma volatiles of peach fruit, were induced by bagging treatment. After bagging treatment, peach fruit had significantly higher LOX and HPL enzyme activities, accompanying increased contents of C6 aldehydes. The gene expression data obtained through real-time PCR showed that no consistent significant differences in transcript levels of LOX genes were observed over the two seasons, but significantly up-regulated expression was found for PpHPL1 after bagging treatment In addition, bagging-treated fruit produced more (E)-2-hexenal and had higher expression levels of PpHPL1 during postharvest ripening at room temperature. The regulatory role of the LOX-HPL pathway on the biosynthesis of n-hexanal and (E)-2-hexenal in response to bagging treatment during peach fruit development is discussed in the text.

Chronic exposure to polystyrene microplastics induced LHR reduction and decreased testosterone levels through NF-κB pathway.

The extensive utilization of plastic products in recent years has resulted in a significant contamination of microplastics (MPs). The ingestion of MPs by aquatic and terrestrial organisms facilitates their transmission to mammals through the food chain. Therefore, the toxicity of MPs has attracted widespread attention from researchers. Previous studies have shown a connection between being exposed to polystyrene MPs (PS-MPs) and issues with male reproductive function. Testosterone, a hormone essential for male reproductive function, is produced and secreted by specialized cells known as Leydig cells, which found in the testicular interstitium. In our prior research, we confirmed that exposure to PS-MPs caused a reduction in testosterone levels by interfering with the LH-mediated LHR/cAMP/PKA/StAR pathway, with LHR being pivotal in this mechanism. However, the molecular mechanism underlying PS-MPs-induced reduction of LHR remains unclear. In this study, mice were respectively given drinking water containing 1000 µg/L PS-MPs characterized by diameters of 0.5 µm, 4 µm, and 10 µm for a period of 180 days. Our findings indicated that exposure to PS-MPs resulted in the proliferation of macrophages as well as their polarization towards the M1 phenotype. Additionally, the presence of PS-MPs triggered the release of tumor necrosis factor alpha (TNF-α) from macrophages, thereby activating nuclear factor-κB (NF-κB) signaling pathway within Leydig cells. The translocation of NF-κB into nucleus facilitated its binding to the promoter region of LHR, which consequently led to the repression of LHR transcription. This transcriptional inhibition resulted in a subsequent suppression of testosterone synthesis and secretion. Overall, this study elucidates a theoretical basis for explaining the interference of PS-MPs on the testosterone synthesis and secretion in Leydig cells from the perspective of the interaction between cells in the testicular interstitium.

Effects of slightly acidic electrolyzed water on the quality and antioxidant capacity of fresh red waxy corn during postharvest cold storage.

Fresh red waxy corn is consumed worldwide because of its unique flavor and rich nutrients, but it is susceptible to deterioration with a short shelf life. This study explored the effect of slightly acidic electrolyzed water (SAEW) treatment on the quality and antioxidant capacity of fresh red waxy corn during postharvest cold storage up to 40 d. The SAEW treatment exhibited lower weight loss, softer firmness, and higher total soluble solids (TSS) and moisture content than the control group. Correspondingly, the SAEW maintained the microstructure of endosperm cell wall and starch granules of fresh red waxy corn kernels well, contributing to good sensory quality. Furthermore, SAEW effectively reduced the accumulation of H2O2 content, elevated the O2 -· scavenging ability, maintained higher CAT and APX activities, and decreased the decline of the flavonoids and anthocyanin during the storage. These results revealed that the SAEW treatment could be a promising preservation method to maintain higher-quality attributes and the antioxidant capacity of fresh red waxy corn during postharvest cold storage.

Development and Characterization of an Antioxidant and Antimicrobial Film Composited by Hydroxyethyl Cellulose and Sulfated Rice Bran Polysaccharides for Food Packaging.

The nonantimicrobial properties and relatively poor mechanical properties of hydroxyethyl cellulose (HEC) limit its use in packaging. Sulfated rice bran polysaccharides (SRBP) possess significant antioxidant and antimicrobial activities. The purpose of this study was to investigate the effect of different concentrations of SRBP on the physical and mechanical properties and the functional characteristics of HEC/SRBP films. The physical properties of the HEC/20% SRBP films, such as water resistance, water vapor barrier, light barrier, and tensile strength, improved significantly (p < 0.05) compared with those of the HEC films. Scanning electron microscopy and Fourier transform infrared spectrometry showed that HEC formed hydrogen bonds with SRBP and exhibited better compatibility. Thermogravimetric analysis revealed that the addition of SRBP was beneficial to the thermal stability of the films. In addition, the antioxidant and bacteriostatic properties of the films were enhanced by the addition of SRBP to HEC, with the 20% SRBP films showing the most significant enhancement in activity. Therefore, the HEC/20% SRBP films show potential for development for use as active food packaging.

Identification, in silico selection, and mechanistic investigation of antioxidant peptides from corn gluten meal hydrolysate.

Seven novel antioxidant peptides (AWF, LWQ, WIY, YLW, LAYW, LPWG, and LYFY) exhibiting a superior activity compared to trolox were identified through in silico screening. Among these, the four peptides (WIY, YLW, LAYW, and LYFY) displayed notably enhanced performance, with ABTS activity 2.58-3.26 times and ORAC activity 5.19-8.63 times higher than trolox. Quantum chemical calculations revealed that the phenolic hydroxyl group in tyrosine and the nitrogen-hydrogen bond in the indole ring of tryptophan serve as the critical sites for antioxidant activity. These findings likely account for the potent chemical antioxidant activity. The corn peptides also exerted a protective effect against AAPH-induced cytomorphologic changes in human erythrocytes by modulating the antioxidant system. Notably, LAYW exhibited the most pronounced cytoprotective effects, potentially due to its high content of hydrophobic amino acids.

Pulsed laser deposition of hexagonal GaN-on-Si(100) template for MOCVD applications.

Growth of hexagonal GaN on Si(100) templates via pulsed laser deposition (PLD) was investigated for the further development of GaN-on-Si technology. The evolution of the GaN growth mechanism at various growth times was monitored by SEM and TEM, which indicated that the GaN growth mode changes gradually from island growth to layer growth as the growth time increases up to 2 hours. Moreover, the high-temperature operation (1000 °C) of the PLD meant no significant GaN meltback occurred on the GaN template surface. The completed GaN templates were subjected to MOCVD treatment to regrow a GaN layer. The results of X-ray diffraction analysis and photoluminescence measurements show not only the reliability of the GaN template, but also the promise of the PLD technique for the development of GaN-on-Si technology.

On the impacts of agricultural subsidies on agricultural carbon emissions in China: empirical evidence from microdata of rice production.

China's agricultural subsidy system has increased the investment on the agricultural production factors such as energy and chemistry, which caused an increase of agricultural carbon emissions. Based on the Thousand-Village Survey data from Shanghai University of Finance and Economics in 2013, the focal paper uses ordinary and two-stage least squares (OLS and 2SLS) to systematically investigate the impact and mechanism of agricultural subsidies on agricultural carbon emissions in China. Results show that China's current agricultural subsidy system has a promoting effect on agricultural carbon emissions. Four types of agricultural subsidies, namely, direct grain subsidies, subsidies for improved varieties, comprehensive subsidies for agricultural materials, and agricultural machinery purchase subsidies, impact the agricultural carbon emissions in ascending order. The agricultural subsidies increase the agricultural carbon emissions directly and indirectly. The findings indicate that a new type of agricultural subsidy system should be constructed, which mainly includes subsidies for farmers' out-migrating for work and land transfer, direct subsidies for grain, and subsidies for improved seed varieties. Among them, the direct grain subsidies should be implemented on the size of planting area and subsidies for improved seed varieties on the size of farmland to reduce the agricultural carbon emissions.

Comprehensive analysis of the progression mechanisms of CRPC and its inhibitor discovery based on machine learning algorithms.

Background: Almost all patients treated with androgen deprivation therapy (ADT) eventually develop castration-resistant prostate cancer (CRPC). Our research aims to elucidate the potential biomarkers and molecular mechanisms that underlie the transformation of primary prostate cancer into CRPC. Methods: We collected three microarray datasets (GSE32269, GSE74367, and GSE66187) from the Gene Expression Omnibus (GEO) database for CRPC. Differentially expressed genes (DEGs) in CRPC were identified for further analyses, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and gene set enrichment analysis (GSEA). Weighted gene coexpression network analysis (WGCNA) and two machine learning algorithms were employed to identify potential biomarkers for CRPC. The diagnostic efficiency of the selected biomarkers was evaluated based on gene expression level and receiver operating characteristic (ROC) curve analyses. We conducted virtual screening of drugs using AutoDock Vina. In vitro experiments were performed using the Cell Counting Kit-8 (CCK-8) assay to evaluate the inhibitory effects of the drugs on CRPC cell viability. Scratch and transwell invasion assays were employed to assess the effects of the drugs on the migration and invasion abilities of prostate cancer cells. Results: Overall, a total of 719 DEGs, consisting of 513 upregulated and 206 downregulated genes, were identified. The biological functional enrichment analysis indicated that DEGs were mainly enriched in pathways related to the cell cycle and metabolism. CCNA2 and CKS2 were identified as promising biomarkers using a combination of WGCNA, LASSO logistic regression, SVM-RFE, and Venn diagram analyses. These potential biomarkers were further validated and exhibited a strong predictive ability. The results of the virtual screening revealed Aprepitant and Dolutegravir as the optimal targeted drugs for CCNA2 and CKS2, respectively. In vitro experiments demonstrated that both Aprepitant and Dolutegravir exerted significant inhibitory effects on CRPC cells (p < 0.05), with Aprepitant displaying a superior inhibitory effect compared to Dolutegravir. Discussion: The expression of CCNA2 and CKS2 increases with the progression of prostate cancer, which may be one of the driving factors for the progression of prostate cancer and can serve as diagnostic biomarkers and therapeutic targets for CRPC. Additionally, Aprepitant and Dolutegravir show potential as anti-tumor drugs for CRPC.

Co-exposure to polystyrene microplastics and microcystin-LR aggravated male reproductive toxicity in mice.

Microplastics (MPs) are plastic pollutants with a diameter of less than 5 mm and microcystins (MCs) are natural toxins produced by cyanobacteria. In recent years, the pollution of MPs and MCs attracted widespread attention. However, our understanding about the toxic effects of co-exposure of MPs and MCs on male reproduction is limited. Mice were continuously exposed to 0.04mg/(kg*bw) microcystin-leucine-arginine (MC-LR) or 45 mg/(kg*bw) polystyrene microplastics (PS-MPs) or a mixed solution of 0.04mg/(kg*bw) MC-LR and 45 mg/(kg*bw) PS-MPs by gavage for 28 days in this study. The results showed that PS-MPs could absorb MC-LR in ddH2O and MC-LR content in testis was increased in the group with combined exposure when compared to the group only exposed to MC-LR. Exposure to PS-MPs or MC-LR individually could destroy testis structure, increase the level of tissue apoptosis and decrease the quality of sperm, while the co-exposure enhanced the toxic effects. Furthermore, PS-MPs could carry MC-LR into testis Leydig cells, reduce testosterone levels and mRNA expression levels of key molecules involved in testosterone synthesis (StAR, P450scc, P450c17,3ß-HSD and 17ß-HSD). Among them, the combined effect of PS-MPs-MC-LR was the most severe. In summary, this study provides new insights into the toxicity of MPs and MCs in mammals.

Hot Water Treatment Improves Date Drying and Maintains Phytochemicals and Fruit Quality Characteristics of Date Palm (Phoenix dactylifera).

Fresh date fruits (cvs. Hillawi and Khadrawi) were harvested at the khalal stage and treated with hot water treatment (HWT) for different time durations (control, HWT-1 min, HWT-3 min, HWT-5 min, and HWT-7 min) to investigate the physicochemical characteristics, phytochemical properties, and sensory attributes. The results revealed that both date cultivars took less time to reach the tamar stage in response to HWT-7 min compared to control. However, Hillawi date fruit showed a higher fruit ripening index (75%) at HWT-3 min, while Khadrawi fruit had a higher ripening index (80%) at HWT-5 min than untreated fruit (10%). Higher weight loss and lower moisture contents were observed in Hillawi (25%) and Khadrawi (20%) date fruit as the immersion period increased in both cultivars. Moreover, soluble solid content was higher in Hillawi (11.77° Brix) in response to HWT-3 min and Khadrawi (10.02° Brix) date fruit immersed in HWT-5 min in contrast with the control group, whereas significantly lower levels of titratable acidity and ascorbic acid content were observed in Hillawi (0.162%, 0.67 mg/100 g) and Khadrawi (0.206%, 0.73 mg/100 g) date fruit in response to HWT (HWT-1 min, HWT-3 min, HWT-5 min, and HWT-7 min) than untreated fruit. Furthermore, noticeably higher levels of reducing sugar (69.83%, 57.01%), total sugar (34.47%, 31.14%), glucose (36.84%, 29.42%), fructose (33.99%, 27.61%), and sucrose (3.16%, 1.33%) were found in hot water-treated Hillawi (immersed for 3-min) and Khadrawi (immersed for 5-min) date fruit, respectively. In addition, total phenolic content, total flavonoids, total antioxidants, and total tannins were substantially superior in date fruits subjected to HWT-3 min (in Hillawi, 128 mg GAE/100 g, 61.78%, 20.18 mg CEQ/100 g) and HWT-5 min (in Khadrawi, 139.43 mg GAE/100 g, 72.84%, and 18.48 mg CEQ/100 g) compared to control. Overall, sensory attributes were recorded to be higher in Hillawi and Khadrawi date fruit after treatment for 3 min and 5 min, respectively. Our findings suggest that HWT is a promising technique that can be adopted commercially to improve fruit ripening and preserved nutritional quality of dates after harvest.

Effects of Hydroxyethyl Cellulose and Sulfated Rice Bran Polysaccharide Coating on Quality Maintenance of Cherry Tomatoes during Cold Storage.

Cherry tomatoes are easily damaged due to their high moisture content. A composite coating was developed to delay deterioration and prolong storage by mixing antibacterial sulfated rice bran polysaccharides (SRBP) and edible hydroxyethyl cellulose (HEC) with film-forming properties. The effects of HEC, HEC-5% SRBP, and HEC-20% SRBP preservative coatings on the maintenance of the quality of cherry tomatoes (LycopersivonesculentumMill., Xiaohuang F2) during cold storage were investigated. The HEC-20% SRBP coating significantly reduced tomato deterioration and weight loss, delayed firmness loss, decreased polyphenol oxidase activity, and increased peroxidase activity. Furthermore, cherry tomatoes treated with HEC-20% SRBP maintained high levels of titratable acid, ascorbic acid, total phenols, and carotenoids. Cherry tomatoes coated with HEC-SRBP also had higher levels of volatile substances and a greater variety of these substances compared to uncoated tomatoes. In conclusion, the HEC-20% SRBP coating effectively delayed deterioration and preserved cherry tomatoes' nutrient and flavor qualities during postharvest cold storage, suggesting it could be a novel food preservation method.

Application of Methyl Jasmonate to Papaya Fruit Stored at Lower Temperature Attenuates Chilling Injury and Enhances the Antioxidant System to Maintain Quality.

Papaya fruit has a limited shelf life due to its sensitivity to decay and chilling damage during cold storage. The application of methyl jasmonate (MeJA) is known to reduce the incidence of disease and chilling injury, and to maintain the overall quality of the papaya fruit when stored at low temperature. Consequently, the effects of postharvest MeJA (1 mM) immersion on papaya fruits during low-temperature storage (10 °C ± 2 °C) for 28 days were studied. The experiment revealed that MeJA treatment significantly decreased the papaya fruit's weight loss, disease incidence, and chilling injury index. Furthermore, the accumulation of malondialdehyde and hydrogen peroxide was markedly lower after the application of MeJA. In addition, MeJA treatment exhibited significantly higher total phenols, ascorbic acid, antioxidant activity, and titratable acidity in contrast to the control. Similarly, MeJA-treated papaya fruits showed higher antioxidant enzymatic activity (superoxide dismutase, catalase, and peroxidase enzymes) with respect to the control fruits. In addition, MeJA reduced the soluble solids content, ripening index, pH, and sugar contents compared to the control fruits. Furthermore, MeJA-treated papaya fruit exhibited higher sensory and organoleptic quality attributes with respect to untreated papaya fruits. These findings suggested that postharvest MeJA application might be a useful approach for attenuating disease incidence and preventing chilling injury by enhancing antioxidant activities along with enhanced overall quality of papaya fruits during low-temperature storage.