The Effects of Ultrasound Treatment and Nano-zinc Oxide Coating on the Physiological Activities of Fresh-Cut Kiwifruit

Abstract

This study evaluated the efficacy of ultrasound treatment and nano-zinc oxide (ZnO) coating individually and in combination in preserving the quality of fresh-cut kiwifruit. The nano-ZnO coating solution was prepared by mixing the ZnO nanoparticles in premixed chitosan-acetic acid solution. The fresh-cut kiwifruit were dipped in NaClO solution (50 μLL −1 sodium, control), subjected to ultra- sound treatment (40 KHz, 350 W, 10 min), or coated with nano-ZnO solution. The fresh-cut kiwifruit samples were also subjected to combined ultrasound treatment and nano- ZnO coating. All of these test samples were stored at 4 °C for 10 days. The effects of these treatments on the quality parameters such as the production of carbon dioxide and ethylene, mass loss, and flesh firmness were investigated. At the end of storage, the combination treatments with ultra- sound treatment at 40 KHz with 1.2 gL −1 nano-ZnO coating showed lower production of ethylene (1.86 μLkg −1 h −1 ) and carbon dioxide (10.01 mgkg −1 h −1 ), water loss (0.46 %), and texture (7.87 N). Hence, it was concluded that the combi- nation of ultrasound treatment with nano-ZnO coating is a promising approach to extend the shelf-life of fresh-cut kiwifruit.