The copywriting materials for this food can be written from the following aspects:

1. Ingredients introduction: First, you can introduce the main ingredients of sticky bean buns, such as red beans, glutinous rice flour, etc., and Characteristics and nutritional value of these ingredients.

2. Production process: Describe in detail the making process of sticky bean buns, including preparing ingredients, making fillings, making bean buns, steaming and other steps, so that readers can understand the making process of sticky bean buns.

3. Texture and taste: Describe the texture and taste of sticky bean buns, such as soft and waxy outer shell, sweet fillings, etc., so that readers can imagine the delicious taste when tasting them.

4. Nutritional value: Emphasize the nutritional value of sticky bean buns, such as being rich in protein, fiber, minerals, etc., as well as the benefits to the body, such as enhancing immunity and preventing constipation.

5. Cultural background: Introduce the cultural background and historical origins of sticky bean buns, such as which region it originated from, how it is related to local culture, etc., to increase the depth and breadth of the copywriting.