Black beans are a popular type of bean with a distinctive black color. They are used in many cuisines around the world and provide a range of nutritional benefits. In this article, we will explore the key questions around the color of black beans:
What makes black beans black?
The black color of black beans is due to the presence of certain pigments. The main pigments that give black beans their color are:
– Anthocyanins: These are water-soluble pigments that range in color from red to blue to purple. In black beans, the anthocyanins appear black.
– Tannins: These are polyphenolic compounds that tend to have a brownish-black color.
– Phytomelanins: These are dark pigments formed from the oxidation of polyphenols. They help contribute to the black shade of black beans.
The levels and types of these pigments can vary depending on the specific cultivar or variety of black bean. But overall, the combination of anthocyanins, tannins, and phytomelanins results in the deep black color.
What is the pigment composition?
Researchers have analyzed the specific pigment composition of black beans to better understand what contributes to their characteristic color.
One study found that tannins accounted for around 37% of total phenolic content in black beans. Anthocyanins accounted for around 16% of total phenolics. Specific anthocyanins identified include delphinidin, petunidin, and malvidin. Trace amounts of other flavonoids were also present.
Another analysis found that the anthocyanin content of black beans consisted primarily of cyanidin, delphinidin, and petunidin glycosides. Delphinidin 3-glucoside was the most abundant anthocyanin. Overall, the total anthocyanin content can range from around 89 to 150 mg per 100 grams of black beans.
So in summary, tannins appear to be the predominant pigment, followed by specific anthocyanins like delphinidin, petunidin, cyanidin, and malvidin. Understanding the pigment profile helps explain why black beans appear such a deep, dark color compared to other bean varieties.
How does the color change when cooking?
When black beans are cooked, the heat can cause chemical changes that shift the color slightly. Specifically, the heat breaks down anthocyanins and alters their structure. This tends to shift the color from a very dark black to a blackish-brown or very dark brown.
Longer cooking times and higher heats will cause more of the anthocyanins to degrade, resulting in a lighter brown/black color. Using an acidic cooking liquid, like tomato sauce, can also cause more anthocyanin degradation.
While the color may lighten slightly, black beans maintain a predominantly dark color even after cooking due to the remaining anthocyanins and the presence of tannins and phytomelanins. But the hue may become more brown than black.
| Cooking Method | Effect on Color |
|---|---|
| Boiling/Simmering | Slight shift to dark brown/black color |
| Pressure Cooking | More retained black color due to shorter cook time |
| Baking | Deeper brown or black as sugars caramelize |
| Frying | May become blackish-brown from oil |
As shown in the table, different cooking methods can impact the final black bean color, but it remains predominantly dark across methods.
Do different varieties have different colors?
There are many cultivars of black beans grown around the world. While they all have a black or very dark coloration, some subtle color differences can exist between varieties.
For example, some popular black bean varieties include:
– Black Turtle Bean: Deep black and shiny exterior. Maintains dark black color when cooked.
– Chinese Black Bean: Smaller bean with black matte exterior that can look greyish. Turns brownish-black when cooked.
– Black Valentine: Medium-sized bean with deeper black color and sheen. Holds black color well during cooking.
– Jamapa Bean: Smaller flat bean with a matte black color that can fade to dark brown with extended cooking.
– Brazilian Black Bean: Larger beans with a shiny black exterior. Becomes brownish-black when cooked.
So while the color differences are subtle, factors like the surface sheen, underlying tone, and ability to hold the black color during cooking can vary across black bean varieties. But they remain among the darkest bean types.
Conclusion
In summary, the deep black color of black beans is due to the presence of anthocyanin, tannin, and phytomelanin pigments. Cooking can cause subtle shifts to a very dark brown but black beans maintain a predominantly dark hue. Color may vary slightly between cultivars but remains quite dark. So while not literally black, black beans come about as close as any food does to having a true black color. Their distinctive dark shade adds visual appeal and indicates the presence of certain health-promoting pigments.
