Using xanthan gum and locust bean gum in ice cream is beneficial for several reasons:

1. Texture Improvement: Both gums improve the texture of ice cream. Xanthan gum helps to stabilize and thicken the mixture, while locust bean gum enhances creaminess and reduces ice crystal formation.

2. Stabilization: They act as stabilizers, preventing the separation of ingredients, which is crucial for maintaining a consistent texture.

3. Freeze-Thaw Stability: These gums help ice cream withstand freeze-thaw cycles, reducing the likelihood of ice crystal formation during storage.

4. Enhanced Mouthfeel: They contribute to a smooth and creamy mouthfeel, which is a key quality aspect of good ice cream.

5. Reduced Melting Rate: They can slow down the melting rate of ice cream, which is desirable in warmer conditions.

As for the amount to use, it varies depending on the specific recipe and desired texture:

• Xanthan Gum: Typically used in small amounts, around 0.1% to 0.3% of the total weight of the mixture. For example, for 1 liter of ice cream mix, you might use 1 to 3 grams of xanthan gum.

• Locust Bean Gum: Commonly used in slightly higher amounts than xanthan gum, around 0.2% to 0.5% of the total weight. For 1 liter of ice cream mix, this would be about 2 to 5 grams.

It's important to note that:

• The combination of both gums can be synergistic, meaning they work better together than alone. This can sometimes allow for the use of smaller quantities of each.

• Overuse of these gums can lead to an undesirable gummy or overly thick texture.

• The exact amounts can vary based on other ingredients in your recipe, such as fat content, sugar type, and other stabilizers.

Experimentation and adjustment are key, as different recipes and preferences may require slightly different amounts. Start with the lower end of the recommended range and adjust based on the results.