With the deepening of agricultural supply-side structural reform and the improvement of people’s living standards, the consumer demand and the production-marketing model of fruits and vegetables in China are undergoing tremendous changes. Accordingly, the postharvest supporting system is playing a more and more important role in the fruits and vegetables industry. After years of development, we had made great progress on the theories and technologies of postharvest fruits and vegetables. However, the local processing of fruits and vegetables were still the short board, which had become a bottleneck problem for the improvement of postharvest supporting system. Thus, the present study reviewed the development status of the technologies for local commoditization of fruits and vegetables in China, in order to provide some inspiration for the future development of this area.

The postharvest commercial treatment of fruits and vegetables involves a variety of physiological and biochemical reactions such as ripening and senescence processes. The qualitative and quantitative analysis of proteins by using high-throughput proteomics can identify important proteins and their functions in the ripening and senescence process of fruits and vegetables, so that in-depth studies can be conducted on the regulation mechanism of fruit ripening and senescence, stress resistance, allergy and the response to exogenous treatment. This paper reviewed the physiological and biochemical changes of fruits and vegetables and the molecular mechanism of regulation after harvest by quantitative proteomics, which provides the guiding significance for the preservation study of fruits and vegetables during postharvest commercial treatment.

China ranks the first in both yield and cultivation areas for fresh fruits and vegetables in the world, but quality deterioration and post-harvest decay of fresh fruits and vegetables still lead to tremendous economic loss nowadays. Bamboo is one of the major forest resources widely used worldwide. However, plenty of bamboo resources are wasted due to various reasons. Bamboo is abundant in secondary metabolites, including flavonoids, phenolic substances, bioactive polysaccharides, amino acids and other functional substances, and thus it is crucial for reducing the waste of bamboo resources to utilize fully secondary metabolites from bamboo and improve the utilization values of bamboo remains. Currently, accumulating results have shown that many secondary metabolites in fresh bamboo can be used as effective biological freshness-keeping resources for fruits and vegetables to improve antimicrobial and antioxidative activities. In the present study, we perform a review on current utilization status of bamboo resources and categories for secondary metabolites in bamboo, and place additional emphasis on the application of secondary metabolites in disease control and freshness-keeping of fruits and vegetables at post-harvest stage.

The quality of fruit and vegetable products is one of the important factors affecting market prices and customer satisfaction. Nondestructive testing techniques provide a rapid way to perform quality evaluation at a relatively low cost. Considering the rapid development of nondestructive testing techniques, some relevant literatures are reviewed in this paper. The principles, applications, characteristics and problems of near infrared spectroscopy technology, machine vision, hyperspectral imaging analysis, acoustic detection, electronic nose, dielectric properties analysis and nuclear magnetic resonance technology are briefly highlighted and summarized. Based on above the review, this paper discusses the solutions further and explores future opportunities and prospects to form the latest reference for researchers.

Harvested banana fruit was treated by a mixed solution of morin and luteolin (in a mass ratio of 1∶2), and the combined effect on quality maintenance and shelf life of banana was investigated. The results showed that the combined treatment significantly delayed the ripening process, effectively reduced crown rot, maintained the appearance including color and firmness, reduced the respiratory rate and delayed the emergence of ethylene release and respiratory peak. The data from nuclear magnetic resonance (NMR) spectroscopy of the peel revealed the composition and level of metabolites during the banana ripening and senescence. Principal component analysis reflected that the first principal components were carbohydrates, free amino acids and other organic components such as ethanol. In a word, the combined treatment of morin and luteolin effectively delays the changes of metabolite profiles, thus maintains the fruit quality and delays senescence. As flavonoids are natural plant metabolites, which are safe, non-toxic and cost-effective, so they have the potential to be developed into broad-spectrum fruit preservatives.

In order to overcome the disadvantages of the large pressure loss, temperature unevenness and slow cooling rate, a packaging system which was suitable for the small diameter fruit of pre-cooling was discussed by using computational fluid dynamics (CFD) software. The mathematical models of four types of packaging systems were established, taking the current harvesting, pre-cooling and storage boxes of blueberry as the research objects to investigate the influence of height of trapezoidal hole on the pre-cooling effect of blueberry when the opening rate was constant. The results indicated that the change trend of pre-cooling time of the four types of packaging systems was box 1 ＞ box 2 ＞ box 4 ＞ box 3, and the pre-cooling time and the height of the trapezoidal hole showed the positive correlation; the change trend of pressure loss, unevenness and plot ratio were the same, all of which were box 4 ＞ box 3 ＞ box 2 ＞ box 1, and there was negative correlation between the pressure loss, unevenness, plot ratio and the height of the trapezoidal hole. The change rate of pre-cooling time, pressure loss, unevenness and plot ratio were 6.98%, 24.10%, 28.10% and 23.30%, respectively, when the trapezoidal height increased from 20 mm to 34 mm. In general, pre-cooling time, pressure loss, unevenness and plot ratio should be comprehensive considered when the packaging systems of blueberry are chosen. Box 3 or 4 should be opted, if highly cooling rate and plot ratio are carried out. Contrarily，box 1 or 2 are a better choice，if the operators want to decrease energy consumption and increase uniformity of blueberry on pre-cooling.

To study the effect of different polyethylene packaging bags on the preservation of water bamboo, the water bamboo (Zizania latifolia cv. Longjiao No. 2) from Tongxiang of Zhejiang Province were packaged in polyethylene (PE) bags with different thicknesses (0.02, 0.04, 0.06, 0.08 mm), and then stored at (2±1) ℃ with the relative humidity (RH) of 80%-85%. The gas content in the packaging bags, the color, firmness, pectin content, soluble pectin content, and the activities of polygalacturonase (PG) and Cx cellulose of water bamboo were analyzed to reveal the effects of PE bags with different thicknesses on the quality and lignification of water bamboo during storage. The results showed that, with the increase of PE packaging bag thickness, the O₂ concentration decreased and the CO₂ concentration increased. The PE packaging bags with 0.06 mm could maintain better color, higher firmness than the other three packaging bags. The change analysis on cell wall components of water bamboo showed that the packaging of the PE bags with 0.06 mm could delay the increase of lignin and cellulose contents. It also could delay the decline of pectin content and the increase of soluble pectin. In addition, the packaging of the PE bags with 0.06 mm could maintain the activities of PG and Cx cellulose; thus, it delayed the lignification process of water bamboo during storage. In brief, the modified atmosphere packaging with 0.06 mm PE bags shows the best effect on quality preservation and delaying lignification.

The effects of high voltage electrostatic field (HVEF) treatment on the storability of postharvest ponkan (Citrus reticulata Blanco cv. Ponkan) fruit were studied. The results showed that, the HVEF treatment reduced the decay rate of ponkan fruit, with the single treatment at 200 kV/m for 2 h as the optimum measure. Correspondingly, the number of surface microorganisms was reduced by the HVEF treatment. The fruits treated by the HVEF had the lower weight loss rate, the respiration rate and the accumulation of ethanol, but had the higher sucrose, glucose and fructose contents than those of the control. The indole-3-acetic acid (IAA) level of fruits by the HVEF treatment was significantly elevated throughout the storage process; in addition, the abscisic acid (ABA) level was significantly elevated at the early stage of storage (30 d). The results of transmission electron microscope observation showed the structural changes in the cell of the fruit peel. In conclusion, the HVEF treatment is effective in reducing the postharvest loss and maintaining the quality of ponkan fruit through sterilization and fruit physiological regulation.

Using fresh-cut broccoli as the experimental material, we analyzed the effects of water/oil/water （W/O/W） double-preservation emulsion on the main quality indexes [lightness (L^*) value, yellow-blue (b^*) value, relative electronic conductivity, malondialdehyde, chlorophyll, chlorophyllase, Mg-dechelatase (MDCase), total phenols, total flavonoids, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, total number of colonies, vitamin C, glucosinolate] of broccoli under 25 ℃ storage conditions. The experimental results showed that W/O/W double-preservation emulsion could inhibit the increase of b^* value, relative electronic conductivity and malondialdehyde content, and delay the reduce of the contents of the chlorophyll, total phenols, total flavonoids and vitamin C, and the activities of chlorophyllase, MDCase, and the DPPH free radical scavenging rate in the broccoli. These results suggest that W/O/W double-preservation emulsion could effectively maintain the quality of broccoli and extend the shelf life.

In order to study the effects of 1-methylcyclopropene (1-MCP) treatment on the physiological quality and physical changes of fruit during storage time, red Fuji apples were used as research objects. The apple fruit was fumigated with 1.0 μL/L 1-MCP, and then the firmness, soluble solid content, titratable acid content, ethylene release amount, respiratory intensity, anthocyanin content, total phenolic content, and flavonoid content were determined by timing. The results showed that 1-MCP could significantly delay the decrease of firmness and titratable acid content of red Fuji apples. At 24 d, the firmness of red Fuji apples in the treatment group (1.0 μL/L 1-MCP) was 13.54% higher than that in the control group (0 μL/L 1-MCP), and the titratable acid content was 31.78% higher. 1-MCP could delay the increase of soluble solid content, which of the red Fuji apple pulp in the control group was 7.74% higher than that in the treatment group at 24 d of storage. Moreover, the ethylene release amount and respiratory intensity were inhibited (P＜0.001). The decrease of the total phenolic content in the peel and pulp and the anthocyanin content in the peel was postponed during the later storage period, as well as the increase of flavonoid content in the peel. In summary, 1-MCP treatment can effectively maintain the storage quality of red Fuji apples after harvesting, which is conducive to short-term storage at the room temperature after harvesting and enhances the economic value of fruits.

The fresh Chinese cabbage was packaged in three different material bags, including polyethylene (PE) bags, polylactide/poly(butylenes adipate-co-terephthalate) (PLA/PBAT) bags, and nano-SiO₂ bags, and then stored at 20 ℃ for 8 d. The Chinese cabbage packaged in PE bags was taken as a control, and the effects of different bags on the quality of Chinese cabbage during shelf life were compared. The results showed that nano-SiO₂ bags had the best fresh-keeping effects on Chinese cabbage during shelf life, and followed by PLA/PBAT bags. Compared with the control, after packaged in two novel material bags, the respiration rate and ethylene release rate were significantly reduced, and the accumulation of malondialdehyde (MDA) and nitrite was inhibited. Besides, the degradation of chlorophyll and ascorbic acid was also delayed and the higher activities of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) were maintained. In general, both PLA/PBAT and nano-SiO₂ bags can maintain the quality of Chinese cabbage during shelf life to a certain degree, but the shelf life of Chinese cabbage packaged in PLA/PBAT bags is 2 d, while nano-SiO₂ bags can extend the shelf life to 4 d.

Enzymatic browning is one of the main factors affecting the quality and shelf life of fresh-cut lotus root. The present study aimed to investigate the mechanism of inhibition of elevated carbon dioxide (CO₂) on enzymatic browning by applying 20% CO₂ to fresh-cut lotus roots. The results showed that 20% CO₂ treatment significantly inhibited the increase of yellow-blue (b^*) value, browning index, and the decrease of lightness (L^*) value, thus delaying browning of fresh-cut lotus root. During the storage, the lotus root in 20% CO₂ treatment group showed lower malondialdehyde (MDA) content and relative electrolyte leakage compared with those of the control group, indicating that 20% CO₂ treatment effectively maintained membrane integrity and good locular distribution of enzymes and substrates. Enzymatic activity analysis showed that 20% CO₂ treatment decreased the activities of phenylalnine ammonialyase, polyphenol oxidase and peroxidase, resulting in inhibiting the rate of enzymatic reactions. In addition, 20% CO₂ treatment also decreased nicotinamide adenine dinucleotide reduced form (NADH) content and increased nicotinamide adenine dinucleotide phosphate reduced form (NADPH) content by activating nicotinamide adenine dinucleotide kinase (NADK) activity, which led to the decrease of energy charge and the enhancement of antioxidant levels, and caused delay in senescence and enzymatic browning during the storage. The above results suggest that elevated CO₂ might be an effective strategy to inhibit postharvest enzymatic browning.

An apple hardness tester was designed based on acoustic pulse method. The detection equipment was mainly composed of signal excitation device and signal acquisition system. Most apples could be knocked in this signal excitation system, because of proper designs of the swing angle, the bending angle and the adjustable height of the striking steel plate. Apple could be knocked freely to meet the requirements of automatic detection on assembly line by controlling the work of electromagnet and solenoid valve. In the signal acquisition system, the EAROBE SuperLav microphone and MPU6050 vibration sensor were used to collect acoustic vibration signals, and the collected data were analyzed using MATLAB software. The results showed that, using the designed detection equipment, most of the apples could be hit non-destructively, and the acoustics and vibration signal patterns of apples with different hardnesses were obviously different. It is indicated that the non-destructive testing and grading of apple can be realized on assembly line by acoustic pulse method.

A self-developed portable non-destructive quality detector was used to collect spectral data of ‘Baiyu’ loquat fruit harvested in 2018 and 2019, respectively, and then chemometric analysis methods were used to build detection model for total soluble solids (TSS) of loquat fruit. Finally, annual verification of independent samples was conducted. The results showed that correlation coefficient of prediction (R_p) and root mean square error of prediction (RMSEP) of the established competitive adaptive reweighted sampling-least squares support vector machines (CARS-LS-SVM) model were 0.818 and 1.453, respectively, which indicated that the self-developed non-destructive detector could achieve rapid non-destructive measurement on TSS of ‘Baiyu’ loquat. Moreover, the grading and screening model improved the first-class fruit rate and the second-class fruit rate from 50.00% to 86.67%, 73.33% to 85.71%, respectively. In conclusion, this study establishes a more practical loquat fruit grading model, which achieves rapid non-destructive measurement of postharvest ‘Baiyu’ loquat fruit in Suzhou area of Jiangsu Province and provides technological support for further improving economic value of loquat fruit and market regulation in Suzhou.

Six pathogens were isolated from postharvest sweet cherries during the transportation and low-temperature storage. They were Alternaria alternata NCPS1 andNCPS2, Alternaria sp. NCPS3, Penicillium expansum NCPS4, Cladosporium herbarum NCPS5 and Sarocladium terricola NCPS6. Then, the biological characteristics of the six pathogens were studied in three aspects of growth rate, growth temperature and growth pH value. The results showed that the optimum growth temperature of NCPS1, NCPS2, NCPS3, NCPS5 and NCPS6 was 25 ℃, and the optimum pH value was 8. The optimum temperature of NCPS4 was 30 ℃, and it could grow at pH 2-10. Only NCPS1 and NCPS2 could grow at the low temperature of 0 ℃. The results of pathogenicity study showed that the six strains could be divided into strong pathogenic strains of NCPS1, NCPS2, NCPS3, moderate pathogenic strains of NCPS4 and NCPS5, weak pathogenic strains of NCPS6. In a word, it provides a scientific theory basis for the development of low-temperature storage and fresh-keeping technology of the postharvest sweet cherries.