Boba poppers are a recent innovation. They are small, edible balls juice, syrup, or purée surrounded in a thin, gelatinous skin.
This creation is the result of the development and exploration of molecular gastronomy. In the late 90's, some chefs began to experiment with a process called spherification.
The fragile, plant-like skin is a natural product created from the instant reaction of sodium alginate (an extract from brown algae, aka 'kelp' or 'seaweed') when dropped into a calcium sulphate bath.
A small amount of one of the chemicals is added to a sauce or fruit compôte - a small enough amount that the flavour is not noticeably affected. A drop of the mixture is dropped into the other chemical (the bath).
When bitten, the ball will 'burst' or 'pop' gently. The skin has no discernible flavour and a quality product will dissolve almost instantly in the mouth after the ball is bitten. The most popular popper is mango and is often used as an optional topping on frozen yogurt. Blueberry caviar is another example of essentially the same product.