Polyvinyl alcohol films incorporated with clove essential oil emulsions stabilized by soy protein isolate-derived amyloid fibrils: Fabrication, characterization, and its application for active packaging.

This study aimed to prepare a novel emulsion film with high stability, using soy protein-derived amyloid fibrils (SAFs) as an emulsifier incorporating clove essential oil (CEO) as the active component, and the polyvinyl alcohol (PVA) matrix to stabilize the system. The results demonstrated that SAFs can successfully stabilize CEO. Emulsion prepared by SAFS and CEO (SAC) exhibited a small droplet size and better dispersibility compared with SPI and CEO (SC) emulsion. According to FT-IR results, PVA addition increased the hydrogen bond interactions among emulsion film components, thus further reinforcing the protein matrix, increasing the tensile strength (TS) (41.18 MPa) and elongation at break (E) (121.62 %) of the films. The uniform appearance of SAC-PVA (SACP) emulsion films was confirmed by SEM images. Furthermore, SACP emulsion films show distinctive barrier properties, optical properties, and outstanding antioxidant properties. Finally, emulsion films exhibited excellent preservation of strawberries, resulting in an effective decline of the decay rate.

Finding Traceability Granularity Influencing Factors Using Rough Set Method: An Empirical Analysis of Vegetable Companies in Tianjin City, China.

The effectiveness evaluation of the traceability system (TS) is a tool for enterprises to achieve the required traceability level. It plays an important role not only for planning system implementation before development but also for analyzing system performance once the system is in use. In the present work, we evaluate traceability granularity using a comprehensive and quantifiable model and try to find its influencing factors via an empirical analysis with 80 vegetable companies in Tianjin, China. We collect granularity indicators mostly through the TS platform to ensure the objectivity of the data and use the TS granularity model to evaluate the granularity score. The results show that there is an obvious imbalance in the distribution of companies as a function of score. The number of companies (21) scoring in the range (50,60) exceeded the number in the other score ranges. Furthermore, the influencing factors on traceability granularity were analyzed using a rough set method based on nine factors pre-selected using a published method. The results show that the factor "number of TS operation staff" is deleted because it is unimportant. The remaining factors rank according to importance as follows: Expected revenue > Supply chain (SC) integration degree > Cognition of TS > Certification system > Company sales > Informationization management level > System maintenance investment > Manager education level. Based on these results, the corresponding implications are given with the goal of (i) establishing the market mechanism of high price with high quality, (ii) increasing government investment for constructing the TS, and (iii) enhancing the organization of SC companies.

Potential role of exogenous melatonin involved in postharvest quality maintenance of Vitis labrusca × vinifera 'Kyoho'.

BACKGROUND: Melatonin is an endogenous free radical scavenger with antioxidant activity that preserves the commercial value of postharvest fruits and delays fruit senescence. To explore the effect of exogenous melatonin on antioxidants and aroma volatile compounds of grapes (Vitis labrusca × vinifera 'Kyoho'), the grapes were treated with distilled water (control), 50 µmol L-1 of melatonin (M50), and 100 µmol L-1 of melatonin (M100) for 30 min and were then stored at 4 °C for 25 days. RESULTS: Exogenous melatonin decreased the rachis browning index, the decay development, the weight loss rate, the berry abscission rate, and the respiration rate, promoted the accumulation of total phenolics and total flavonoids, and delayed the reduction of anthocyanins and total soluble solids. In volatile compounds, the accumulation of esters, aldehydes, and alcohols in grapes was promoted, and the terpenes content was reduced by exogenous melatonin. CONCLUSION: Exogenous melatonin had potentially positive effects on the postharvest life and quality maintenance of grapes. These findings provide theoretical support for the application of melatonin in grape storage and preservation. © 2023 Society of Chemical Industry.

Application of proteomics to determine the mechanism of ozone on sweet cherries (Prunus avium L.) by time-series analysis.

This research investigated the mechanism of ozone treatment on sweet cherry (Prunus avium L.) by Lable-free quantification proteomics and physiological traits. The results showed that 4557 master proteins were identified in all the samples, and 3149 proteins were common to all groups. Mfuzz analyses revealed 3149 candidate proteins. KEGG annotation and enrichment analysis showed proteins related to carbohydrate and energy metabolism, protein, amino acids, and nucleotide sugar biosynthesis and degradation, and fruit parameters were characterized and quantified. The conclusions were supported by the fact that the qRT-PCR results agreed with the proteomics results. For the first time, this study reveals the mechanism of cherry in response to ozone treatment at a proteome level.

Partial compression increases acidity, but decreases phenolics in jujube fruit: Evidence from targeted metabolomics.

Jujube fruit (Ziziphus jujuba Mill.) is extremely susceptible to mechanical injury by extrusion and collision during storage, transportation and processing. In this study, we examined the morphology and endogenous metabolism of jujubes at three developmental stages after applying partial compression (PC) to mimic mechanical injury. Generally, PC did not affect the total soluble solids content, but increased the acidity and decreased the amount of phenolics in the jujube fruit. Targeted metabolomics analysis further confirmed that acid and phenolics content were differentially altered in response to PC. To our knowledge, this is the first study to characterize metabolic variations in ready-to-eat fruit that occur in response to physical damage. The results will provide insight into the understanding the consequences of mechanical injury on fruit nutrition and health benefits.

Glycine betaine inhibits postharvest softening and quality decline of winter jujube fruit by regulating energy and antioxidant metabolism.

Winter jujube fruit easily softens after harvest. To investigate the effects of glycine betaine (N,N,N-trimethylglycine; GB) treatment on the quality of postharvest jujubes, fresh winter jujubes (Zizyphus jujuba Mill. cv. Dongzao) were immersed in 20 mmol·L-1 GB for 20 min. The results showed that GB application can effectively maintain cell wall component content by restraining gene expression and enzyme activities, including PG, CX, PME and ß-Glu. Meanwhile, the activities of antioxidant enzymes (APX, CAT, SOD, POD) and the contents of nonenzymatic antioxidants (MDA, H2O2, ASA, GSH) were enhanced in treated jujubes, thereby reducing the content of ROS. In addition, energy metabolism enzyme activities (H+-ATPase, Ca2+-ATPase, SDH and CCO) and gene expression were also significantly increased, thus maintaining higher energy levels (ATP, ADP, AMP and EC). In summary, GB enhances ATP biosynthesis by increasing energy metabolism. It offers essential energy for the antioxidant metabolism, thus retarding the softening of postharvest jujubes.

Effects of Atmospheric Cold Plasma Treatment on the Storage Quality and Chlorophyll Metabolism of Postharvest Tomato.

Atmospheric cold plasma (ACP) is a potential green preservation technology, but its preservation mechanism is still unclear, and the effects of different plasma intensities on postharvest tomatoes are little studied. In this study, the effects of different ACP treatments (0 kV, 40 kV, 60 kV, and 80 kV) on the sensory quality, physiological indexes, key enzyme activities, and gene expression related to the chlorophyll metabolism of postharvest tomatoes were investigated during the storage time. The results showed that compared with the control group, the tomatoes in the plasma treatment group had a higher hardness and total soluble solid (TSS) and titratable acid (TA) contents, a lower respiratory intensity and weight loss rate, a higher brightness, and a lower red transformation rate, especially in the 60 kV treatment group. In addition, chlorophyll degradation, carotenoid accumulation, and chlorophyllase and pheophorbide a mono-oxygenase (PAO) enzyme activities in the postharvest tomatoes were inhibited in the 60 kV treatment group, and the expressions of three key genes related to chlorophyll metabolism, chlorophyll (CLH1), pheophytinase (PPH), and red chlorophyll catabolic reductase (RCCR) were down-regulated. The results of the correlation analysis also confirmed that the enzyme activity and gene expression of the chlorophyll metabolism were regulated by the ACP treatment, aiming to maintain the greenness of postharvest tomatoes.

Propyl Gallate Treatment Improves the Postharvest Quality of Winter Jujube (Zizyphus jujuba Mill. cv. Dongzao) by Regulating Antioxidant Metabolism and Maintaining the Structure of Peel.

The quality and color of winter jujube fruits are easy to change after harvest. We studied the regulation mechanism of propyl gallate (PG) on post-harvest physiological quality of winter jujube, from the perspective of antioxidant metabolism and peel structure. In our research, winter jujube fruits were treated with 0.001 mol L-1 PG solution for 20 min. Our results showed that PG delayed the development of peel color, and improved the firmness, total soluble solids (TSS), and titratable acid (TA) of winter jujube. Meanwhile, the PG treatment had higher content of total phenols, total flavonoids, ascorbic acid (AsA), and reduced glutathione (GSH), and kept the enzyme activity including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD) at a higher level. PG treatment reduced membrane oxidative damage and maintained the integrity of pericarp structure by reducing electrolyte leakage (EL), lipoxygenase activity (LOX), hydrogen peroxide (H2O2), and malondialdehyde (MDA) content in the peel. Accordingly, PG improved the postharvest quality of jujube fruits by regulating antioxidant metabolism and maintaining the structure of peel. The appropriate concentration of PG has good application potential in the storage and preservation of fresh fruits such as winter jujube.

Comparative transcriptomic analysis of cantaloupe melon under cold storage with ozone treatment.

Ozone treatment was found to delay the postharvest cantaloupe melon decay and improve its intrinsic quality during the cold storage. The transcriptomes of cantaloupe peel and pulp in response to ozone treatment were investigated to reveal the mechanisms using a high-throughput RNA sequencing approach. Results showed that 570 and 313 differentially expressed genes were identified in peel and pulp, respectively. According to these identified genes, the gene ontology and pathway enrichment analysis indicated that the ozone treatment could maintain the firmness of the cantaloupe by changing pectin metabolites and reduction of the ethylene production by regulating relevant genes especially in the peel. The total flavonoid content changes in peel and pulp related to the regulation of phenylalanine ammonia lyase, 4-coumarate-CoA ligase and P450 family genes which further leading to the inhibition of phenylalanine metabolic pathway in peel but promotion of secondary metabolism in pulp. The qRT-PCR results were in accordance with our RNA sequencing results which validated the conclusions. The present study for the first time reveals the mechanism of cantaloupe in response to ozone treatment at a transcriptome level which is of importance for cantaloupe storage.

Effects of ozone concentration on the postharvest quality and microbial diversity of Muscat Hamburg grapes.

Grapevines are widely planted around the world. Although grapes have high nutritional value, they are highly perishable. To explore the effect of ozone concentration on the postharvest quality of Muscat Hamburg grapes, the ethylene production rate, respiratory intensity, soluble solids, titratable acidity, firmness, threshing rate, total yeast and mold counts, and the activities of superoxide dismutase, peroxidase, catalase, polyphenol oxidase and phenylalanine ammonia lyase were determined, and the fungal metagenome on the grape surface was analyzed. Among the ozone treatment groups, 14.98 mg m-3 ozone showed a positive effect on grape preservation. After 80 days of storage, the contents of soluble solids and titratable acidity increased by 3.1% and 0.03%, respectively, compared with the control group. Over the same period, firmness increased by 4.22 N and the threshing rate decreased by 0.5%. During storage, the activity of polyphenol oxidase was inhibited and the activities of superoxide dismutase, peroxidase, catalase, and phenylalanine ammonia lyase were maintained, which delayed the senescence of grapes and maintained freshness. Ozone can reduce the number of fungi on the grape surface, change the colony structure, and reduce the occurrence of diseases. An ozone concentration of 14.98 mg m-3 can delay the senescence of Muscat Hamburg grapes and improve storage quality.

Effects of ozone treatment on SOD activity and genes in postharvest cantaloupe.

Ozone has been shown to play a positive role in the storage and preservation of agricultural products. However, there is little research on the cantaloupe preservation mechanism of ozone treatment (OT), especially the effect on superoxide dismutase (SOD) and the mechanism of scavenging superoxide anion In this study, xizhoumi 25 was used as a typical cantaloupe material to detect content, hydrogen peroxide (H2O2) and SOD enzyme activity in the pericarp and pulp, respectively, and transcriptomics and qRT-RCR were used for cantaloupe SOD family gene expression. The results showed that the rate of and H2O2 content were inhibited and SOD activity was higher in the treatment group compared with the control (CK) group in the pericarp and pulp; SOD was more active in the pericarp and was higher than that in the pulp. The transcription level of Cu/Zn-SOD, identified as the most abundant component of the cantaloupe SOD gene family, was promoted in the OT group, especially the key gene Cu/Zn-SOD-1. The expression level of the Fe-SOD gene was promoted in the pericarp but regulated in the pulp, while the expression of the Mn-SOD gene was down-regulated in the OT group in both pericarp and pulp. In addition, the results of qRT-PCR were consistent with the transcriptome results. Correlation analysis showed that OT not only enhanced the positive correlation between and H2O2 in the whole cantaloupe and the negative correlation between and SOD activity in the pericarp but also altered the correlation between SOD genes and The mechanism of regulation in postharvest cantaloupe treated with ozone may be through stimulating the SOD activity and altering the expression of related genes in the pericarp and pulp.

Effects of ozone treatment on the antioxidant capacity of postharvest strawberry.

Strawberries are highly popular around the world because of their juicy flesh and unique taste. However, they are delicate and extremely susceptible to peroxidation of their membrane lipids during storage, which induces water loss and rotting of the fruit. This study investigated the effects of ozone treatment on the physiological traits, active oxygen metabolism, and the antioxidant properties of postharvest strawberry. The results revealed that the weight loss (WL) and respiration rate (RR) of strawberry were inhibited by ozone treatment (OT), while the decline of firmness (FIR) and total soluble solids (TSS) were delayed. Ozone also reduced the generation rate of superoxide radical anions , and the content of hydrogen peroxide (H2O2) enhanced the activity of superoxidase (SOD), catalase (CAT), ascorbate peroxidase (APX), and monodehydroascorbate reductase (MDHAR), as well as promoted the accumulation of ascorbic acid (ASA), glutathione (GSH), and ferric reducing/antioxidant power (FRAP). In addition, a total of 29 antioxidant-related proteins were changed between the OT group and control (CK) group as detected by label-free proteomics during the storage time, and the abundance associated with ASA-GSH cycle was higher in the OT group at the later stage of storage, and the qRT-PCR results were consistent with those of proteomics. The improvement of the antioxidant capacity of postharvest strawberry treated with ozone may be achieved by enhancing the activity of the antioxidant enzymes and increasing the expression of the antioxidant proteins related to the ascorbic acid-glutathione (ASA-GSH) cycle.

Impact of elevated O2 and CO2 atmospheres on chemical attributes and quality of strawberry (Fragaria × ananassa Duch.) during storage.

Modified atmosphere has widely been evident to contribute to fruit quality maintenance, however the correlation among these quality traits was less known. To explore main factors of elevated atmosphere and reduce the detection indexes, we exposed strawberry to either high O2 (80% O2 + 20% N2) or CO2 (20% CO2 + 20% O2 + 60% N2) atmosphere and compared quality characteristics. It was demonstrated that both atmospheres well maintained the fruit firmness, alleviated weight loss and decay rate. Elevated O2 maintained the polyphenolic contents and cell integrity by significantly decreasing superoxide and hydrogen peroxide levels. PCA analysis implied that HO treatment mainly affected oxygen metabolism while HCO affected carbon metabolism more. Significantly positive correlation was observed between weight loss, anthocyanin content and decay rate in elevated O2 and control groups. This study provided new insights into correlation and difference between impact of elevated O2 and CO2 to postharvest preservation.

Exogenous Melatonin and Abscisic Acid Expedite the Flavonoids Biosynthesis in Grape Berry of Vitis vinifera cv. Kyoho.

Grape polyphenols contributing to more than half of the global polyphenol market were well studied; however, how melatonin (MLT), a potential plant hormone, and abscisic acid (ABA) affects polyphenols profile is still poorly understood. To explore whether these hormones are involved in polyphenolic biosynthesis, grape (Vitis vinifera cv. Kyoho) was exposed to MLT, ABA, and NDGA (nordihydroguaiaretic acid, an ABA biosynthesis inhibitor) treatments, and 16 polyphenols were identified from grape extracts by high performance liquid chromatography quadrupole time of flight mass spectrometry (HPLC-Q-TOF-MS). Both exogenous MLT and ABA significantly enhanced the biosynthesis of each flavonol and flavanol component, especially catechin, which was almost increased double by 200 µM of MLT treatment. Furthermore, the expression of genes involved in flavonoid biosynthesis, including 4-coumaroyl-CoA synthase, chalcone synthase, flavonoid 3'-hydroxylase, anthocyanin 3'-methyltransferase, flavonol synthase, flavonoid-3-O-glucosyltransferase, and flavonoid 3',5'-methyltransferase were highly up-regulated as well but were down-regulated by NDGA. The present study provided new insights for improving flavonoids accumulation in agricultural production and its underlying mechanism.

Effects of Controlled Atmosphere on the Storage Quality and Aroma Compounds of Lemon Fruits Using the Designed Automatic Control Apparatus.

'Eureka' lemon fruits were stored under four controlled atmosphere- (CA-) combinations at 8°C for 20 days to investigate the effects on weight loss (WL), total soluble solids (TSS), titratable acidity (TA), vitamin C (VC), total phenolic content (TPC), sodium carbonate-soluble pectin (SSP), malondialdehyde (MDA), and volatile compounds. Results showed that the contents of TSS, TA, VC, and SSP in the stored fruits reduced during the storage period, while the WL and MDA increased. Fruit stored under CA2-combination (6 % O2+8 % CO2) showed the lower contents of WL and MDA and the higher content of TSS, TA, TPC, and VC than that of other treated fruits. The main volatile compounds present in the lemons were terpenoids, aldehydes, alcohols, and esters. In addition, both the terpenoid and aldehyde content are substantially higher in lemons exposed to CA2 conditions. In contrast, the alcohols and esters displayed elevated levels in the regular air (RA) stored fruit. In conclusion, CA with the suitable conditions proves to be better than RA as a storage regimen to keep the quality of lemons. These results indicated that the application of 6% O2+8% CO2 CA conditions could maintain the quality of 'Eureka' lemon fruit during the storage time of 20 days and should be the optimal storage environment for postharvest Eureka lemons.

Label-free quantitative proteomics to investigate the response of strawberry fruit after controlled ozone treatment.

To elucidate postharvest senescence in strawberry (Fragaria ananassa Duch. var. 'JingTaoXiang') fruit in response to ozone treatment at different concentrations (0, 2.144, 6.432, and 10.72 mg m-3), a label-free quantitative proteomic investigation was performed. Postharvest physiological quality traits including respiration rate, firmness, titratable acid, and anthocyanin content were characterized. The observed protein expression profile after storage was related to delayed senescence in strawberries. A total of 2413 proteins were identified in differentially treated strawberry fruits, and 382 proteins were differentially expressed between the four treatments on day 7 and the initial value (blank 0). Proteins related to carbohydrate and energy metabolism and anthocyanin biosynthesis, cell stress response, and fruit firmness were characterized and quantified. Ozone treatment at the concentration of 10.72 mg m-3 effectively delayed the senescence of the strawberry. The proteomic profiles were linked to physiological traits of strawberry fruit senescence to provide new insights into possible molecular mechanisms.

Effect of ozone treatment on the phenylpropanoid biosynthesis of postharvest strawberries.

Ozone treatment at a suitable concentration can improve the antioxidant capacity of postharvest fruits. However, few studies have examined the antioxidant bioactive compounds in ozone-treated postharvest strawberries, especially in relation to proteomics. In this study, the total phenol content (TPC), total flavonoid content (TFC), and total anthocyanin content (TAC) were used as the main antioxidant compound indicators and unlabeled proteomics was used to study the metabolism of phenylpropanoids in postharvest strawberries (Jingtaoxiang) treated with different concentrations of ozone (0, 1, 3, and 5 ppm) throughout the duration of storage. The results showed that the postharvest strawberries treated with 5 ppm ozone concentration exhibited improved accumulation of total phenols, flavonoids and anthocyanins in the antioxidant bioactive compounds, which was beneficial to the expression of phenylpropanoid metabolism-related proteins over the whole storage period compared with the other three groups. The results of proteomics were consistent with the changes in the key metabolites of phenylpropanoids, which indicated that ozone treatment at a suitable concentration aids the accumulation of TPC, TAC and TFC by promoting the key proteins associated with phenylpropanoid metabolism.

Preservation Mechanism of Chitosan-Based Coating with Cinnamon Oil for Fruits Storage Based on Sensor Data.

The chitosan-based coating with antimicrobial agent has been developed recently to control the decay of fruits. However, its fresh keeping and antimicrobial mechanism is still not very clear. The preservation mechanism of chitosan coating with cinnamon oil for fruits storage is investigated in this paper. Results in the atomic force microscopy sensor images show that many micropores exist in the chitosan coating film. The roughness of coating film is affected by the concentration of chitosan. The antifungal activity of cinnamon oil should be mainly due to its main consistent trans-cinnamaldehyde, which is proportional to the trans-cinnamaldehyde concentration and improves with increasing the attachment time of oil. The exosmosis ratios of Penicillium citrinum and Aspergillus flavus could be enhanced by increasing the concentration of cinnamon oil. Morphological observation indicates that, compared to the normal cell, the wizened mycelium of A. flavus is observed around the inhibition zone, and the growth of spores is also inhibited. Moreover, the analysis of gas sensors indicate that the chitosan-oil coating could decrease the level of O2 and increase the level of CO2 in the package of cherry fruits, which also control the fruit decay. These results indicate that its preservation mechanism might be partly due to the micropores structure of coating film as a barrier for gas and a carrier for oil, and partly due to the activity of cinnamon oil on the cell disruption.