The rapid and non-destructive detection of mechanical damage to fruit during postharvest supply chains is important for monitoring fruit deterioration in time and optimizing freshness preservation and packaging strategies. As fruit is usually packed during supply chain operations, it is difficult to detect whether it has suffered mechanical damage by visual observation and spectral imaging technologies. In this study, based on the volatile substances (VOCs) in yellow peaches, the electronic nose (e-nose) technology was applied to non-destructively predict the levels of compression damage in yellow peaches, discriminate the damaged fruit and predict the time after the damage. A comparison of the models, established based on the samples at different times after damage, was also carried out. The results show that, at 24 h after damage, the correct answer rate for identifying the damaged fruit was 93.33%, and the residual predictive deviation in predicting the levels of compression damage and the time after the damage, was 2.139 and 2.114, respectively. The results of e-nose and gas chromatography-mass spectrophotometry (GC–MS) showed that the VOCs changed after being compressed—this was the basis of the e-nose detection. Therefore, the e-nose is a promising candidate for the detection of compression damage in yellow peach.

Hongmeiren is a high-quality orange fruit but susceptible to mechanical damage. This work proposes a new packaging format (Packaging C), which used the plastic partition boards to separate the folding plastic basket to avoid the fruits from crushing each other, and used a PU foam layer and placed it along the inside of the EPE foam layer to meet the different sizes of fruits. The results show that under both 3 and 10 h of simulated transportation, Packaging C achieved a much lower damage and decay rates than Packaging A (plastic bulk containers), and this was further verified by the road transportation. Besides, Packaging C could avoid dents in the peel of some large fruits compared to the gift packaging (Packaging B). Although the use of inner packaging could increase the use of packaging, it can reduce the waste of cultivation and transportation resources caused by not being able to deliver the fruit to the consumer, as well as environmental pollution caused by fruit decay. Moreover, low temperature (10 °C) and high humidity (90% RH) during transportation could further reduce the damage and packages at the rear position obtained a higher damage rate than at the front position, but no obvious difference was found between stack heights.

The preparation of active packaging loaded with antimicrobial, antioxidant, and other functional agents has become a hot topic for food preservation in recent years. In this field, active fiber films based on spinning methods have attracted the interest of researchers owing to their high specific surface area, high porosity, high loading capacity, and good controlled release capacity. In the present work, neatly arranged ethyl cellulose (EC)/polyvinyl-pyrrolidone (PVP) fibrous films loaded with natamycin as an antimicrobial agent were prepared by microfluidic spinning. The encapsulation efficiency of natamycin was more than 90% in each group and the loading increased with increasing natamycin content. According to the characterization results of the natamycin-loaded EC/PVP fibrous films, hydrogen bonding was formed between natamycin and EC and PVP in the fibrous films. Meanwhile, the water contact angle of the fibrous films was increased, suggesting the improved hydrophobicity of the films. In the in vitro bacterial inhibition experiments, the active fiber films loaded with natamycin showed good antimicrobial activity, which could significantly inhibit the growth of gray mold. In conclusion, N-EC/PVP fibrous films with antimicrobial activity prepared by microfluidic spinning showed good potential in the field of active packaging.

In order to improve the prediction accuracy of forced air pre-cooling for small diameter horticultural products, a mathematical model of forced air pre-cooling for blueberries based on the micro-cluster method was established. The results showed that the micro-cluster method effectively solved the challenges of complex configuration, long simulation time and low accuracy compare to the porous medium and equivalent sphere methods. In order to determine the optimal micro-cluster model parameters suitable for forced air pre-cooling of blueberries, three factors controlling the micro-cluster geometry parameters were evaluated by 7/8 pre-cooling time, uniformity and convective heat transfer coefficient. It was found that the optimal values of the number of micro-clusters (n³), the distance between individual units within a micro-cluster (a) and the distance between micro-clusters (c) were 3, 0.75 and 0.2, respectively. Under these optimal values, the temperature error of the micro-cluster method remained below 1 ℃, achieving highly accurate temperature predictions during the blueberry pre-cooling process. Based on the above analysis, it could be concluded that the micro-cluster method provided a theoretical basis for optimizing forced air pre-cooling processes and making informed control decisions.