Producing of Microbubbles in Dried Juice Droplets Treated With Nanosecond Spark Discharges

We studied the influence of plasma nanosecond spark discharges on dried juice droplets. Our samples were juices made of grape, tangerine, lemon, aloe, and beetroot, and also coffee. It is found that all dried droplets treated with discharges form microbubbles. We studied the dynamics of microbubble development and estimated their growth rate in order to determine their shape and internal structure. It was established that bubbles have an almost spherical shape and that they are hollow and thin walled. The walls of microbubbles are elastic, while they are filled with a gas. We think that our microbubbles have a hole at the bottom. The microbubble walls are essentially made of dried juices, which can be obtained from edible fruits. A potential application for such microbubbles can be capsules for small doses of drugs.