are frozen green beans already blanched？

Frozen green beans may or may not be blanched. Some brands of frozen green beans are blanched before freezing to help preserve their color, texture, and nutritional value. Blanching involves briefly boiling the beans and then quickly cooling them. This process inactivates enzymes that cause spoilage and makes the beans easier to store.

However, not all frozen green beans are blanched. Some manufacturers may choose to freeze beans without blanching for a variety of reasons, such as cost considerations or to preserve a different texture.
To determine if frozen green beans are blanched, you can check the package label. Some packages may state whether the beans have been blanched. Additionally, blanched green beans may have a slightly different texture and color than unblanched green beans. Blanched beans are usually brighter in color and may be slightly softer.

In conclusion, whether frozen green beans have been blanched depends on the brand and the manufacturing process. It's best to check the package or do some research on a specific product to find out.