Anthocyanins change color with changes in acidity, and eventually turn colorless as acid levels drop. Two things happen during cooking to make Royal Burgundy beans turn from purple to green. A direct effect of the heat is to cause decomposition of anthocyanin. Less anthocyanin means less purple.Click to see full answer. Regarding this, are purple beans edible?Harvesting. Immature, tender pods can be cooked, like green beans. The flavor is much stronger than the common green bean and the purple color disappears with cooking. The leaves and flowers are also edible.Subsequently, question is, why do green beans go black? They’re not ideal. A few brown spots here and there on a bunch of green beans mean they’re getting a little aged, and won’t be the freshest beans you’ll eat. Keep beans fresh longer (for up to a week) by storing them in a sealed zip-top bag in the crisper drawer of the refrigerator. Just so, are there purple green beans? Purple beans are essentially green beans disguised in a violet hued skin. They maintain the same lean cylindric shape, size and stringless seam. Underneath the purple shell is the same crisp translucent succulent green flesh and pale lime green peas.What are purple green beans called?The pods are richly colored and easy to spot among the leaves, and they look beautiful tossed into a green salad. I call them magic beans, and the magic happens when you cook them… The purple in purple beans like the Royal Burgundy (Phaseolus vulgaris) bush variety comes from plant pigments called anthocyanins.