Effect of Chitosan Composite Coatings with Salicylic Acid and Titanium Dioxide Nanoparticles on the Storage Quality of Blackcurrant Berries

The use of chitosan and chitosan composite coatings for the preservation of fruits and vegetables during storage is attracting increasing attention. In this study, a chitosan-based edible coating, as well as a second chitosan-based edible coating containing salicylic acid (CTS + SA), a third containing nanosized titanium dioxide particles (CTS + TiO2), and a fourth containing a combination of these two (CTS + SA + TiO2) were evaluated in terms of their effects on the postharvest quality of blackcurrant fruit during storage at 4 °C. The results showed that compared with the other three treatment groups, the blackcurrants treated with CTS + SA + TiO2 underwent the smallest changes in weight loss, total soluble solids, titratable acidity, vitamin C, and total anthocyanin content, and retained the highest total flavonoid content. This combined treatment significantly inhibited polyphenol oxidase activity during storage, and the CTS + SA + TiO2 samples also displayed the lowest malondialdehyde content. These results, thus, indicate that the CTS + SA + TiO2 composite coating could maintain the nutrient composition of blackcurrants, thereby playing a significant role in preserving the quality of this fruit at 4 °C

Antimicrobial Nanoparticles Incorporated in Edible Coatings and Films for the Preservation of Fruits and Vegetables

Edible coatings and films (ECF) are employed as matrixes for incorporating antimicrobial nanoparticles (NPs), and then they are applied on the fruits and vegetables to prolong shelf life and enhance storage quality. This paper provides a comprehensive review on the preparation, antimicrobial properties and mechanisms, surface and physical qualities of ECF containing antimicrobial NPs, and its efficient application to vegetables and fruits as well. Following an introduction on the properties of the main edible coating materials, the preparation technologies of ECF with NPs are summarized. The antimicrobial activity of ECF with NPs against the tested microorganism was observed by many researchers. This might be mainly due to the electrostatic interaction between the cationic polymer or free metal ions and the charged cell membrane, the photocatalytic reaction of NPs, the detachment of free metal ion, and partly due to the antimicrobial activity of edible materials. Moreover, their physical, mechanical and releasing properties are discussed in detail, which might be influenced by the concentration of NPs. The preservation potential on the quality of fruits and vegetables indicates that various ECF with NPs might be used as the ideal materials for food application. Following the introduction on these characteristics, an attempt is made to predict future trends in this field