Scientists have developed a hydrogel that can actually extend the shelf life of bananas.

Ripening of a fruit depends upon its rate of respiration. Bananas respire through their skin, and since the respiration rate is quite rapid after they are picked, they ripen faster than other fruits.
The coating is a type of hydrogel which works by reducing the rate of respiration and also destroys the bacteria which makes the fruit rot.
During the research, the team led by Dr. Xihong Li sprayed hydrogel onto green bananas, and they remained fresh for up to 12 days.
Source-Medindia