One of the nice things about molecular gastronomy is how many different ways you can create gels. They can be made with many starches, hydrocolloids, and gelatin. For this recipe I made papaya agar agar cubes.
These agar gel cubes are a great way to add a unique visual style to a dish, as well as creating little bursts of papaya. You could use a similar agar recipe to gel many different liquids, depending on the dish you are creating.
The recipe is very easy. You simply take papaya juice, bring it to a simmer, and blend in the agar agar. You can either use fresh papaya juice or make your own by blending a papaya with a little water. The amount of agar agar you use will determine how strong the gel is.
You then pour the agar infused papaya liquid into a mold, I used a parchment paper lined tupperware container, and place it in the refrigerator to set. Once it has fully set you can turn the agar papaya gel out onto a cutting board and cut it into the shapes you want. Here I went for simple 1/2" (12mm) cubes. The cubes will last for several hours if covered.
For more examples of agar agar gels you can read the excellent Alinea cookbook.
If you like this recipe you can get more than 80 other recipes from my book Modernist Cooking Made Easy: Getting Started. The book covers many of the popular modernist techniques such as gelling, spherification, and foams. It also explores modernist ingredients like agar, sodium alginate, tapioca maltodextrin, and xanthan gum. It is all presented in an easy to understand format and I think it's the best way to learn about modernist cooking.
Also, if you are just getting started experimenting with molecular gastronomy and modernist cuisine then I highly recommend one of these molecular gastronomy kits. They have everything you need to do many different dishes.
Bring the papaya juices to a simmer in a pan. Add the agar agar and mix well, preferably with an immersion blender. If using non-strained juice then strain the mixture through a chinois into a container.Pour the liquid into a parchment paper lined, flat-bottomed mold or container that will hold the liquid at a depth that is equal to how tall you want the cubes to be. Place the liquid in the refrigerator for quick setting. You can also leave it on the counter for slightly slower setting as long as it is below 95°F / 35°C.
Once the gel has cooled and become firm turn it out onto a cutting board. Cut the papaya agar gel into the shapes you desire using a knife or other cutting device.
Hold covered in the refrigerator or at room temperature until ready to serve. The cubes will remain a gel as long as they stay below 176°F / 80°C.