Lima beans, also known as butter beans, are a delicious and nutritious legume that is popular in many cuisines around the world. They are packed with fiber, protein, vitamins and minerals. But one thing that confuses many home cooks is the color of lima beans – do they start off green and turn white as they mature, or vice versa?
The Stages of Lima Bean Growth
To understand the color progression of lima beans, it helps to look at the different stages of their growth cycle:
- Seed – Lima bean seeds are generally white or pale green in color.
- Sprout – When the seed germinates and begins to sprout, the sprout is green and will continue to photosynthesize.
- Seedling – The seedling that emerges is green as chlorophyll develops in the leaves.
- Young plant – As the plant matures, it remains green.
- Flowering – Small white flowers bloom on the green plants once they reach maturity.
- Podding – After pollination, green seed pods form on the plants.
- Drying – The pods turn yellow and brown as the lima beans inside lose moisture and dry down in the pods.
- Harvest – The dried pods contain the mature dried lima beans, which are white, cream, or pale green in color.
So in summary, lima beans start off white as seeds, turn green as they sprout and grow into plants, then turn back to white/cream/light green as they dry down during maturation. The most common form that consumers purchase lima beans in is the dried mature bean, where they will appear white, cream, or pale green.
Why Do Lima Beans Change Color?
The color changes that lima beans undergo during their growth are related to key processes happening at each stage:
- Seeds – Lima bean seeds contain stored starches and proteins to help feed the embryo, but do not contain chlorophyll since no photosynthesis is occurring. They also contain phenolic compounds that provide pigmentation.
- Sprouting – The sprout produces chlorophyll immediately to harness energy from sunlight. Chlorophyll lends a green color.
- Growth – As more foliage develops, the plant produces abundant chlorophyll to continue photosynthesis. The green color deepens.
- Flowering – The small white flowers rely on insect pollinators and do not produce chlorophyll.
- Podding – The young seed pods are green at first as chlorophyll is still present. As they mature, chlorophyll breaks down.
- Drying – The mature seeds lose moisture, stop photosynthesizing, and degrade their chlorophyll content. Other pigments such as phenolics determine the final white/cream/light green color.
In summary, the green color in lima bean plants comes from chlorophyll produced during photosynthesis. As the plant shifts resources away from foliage growth towards maturing the beans, chlorophyll breaks down and reveals the true color of the seed coats.
What Colors Can Lima Beans Be?
Now that we understand the color progression of lima beans, what colors can we expect them to display? Here is an overview:
- Dry Seeds – White, cream, pale green, tan
- Sprouts – Bright green
- Leaves – Shades of green
- Flowers – White
- Young Pods – Green
- Mature Pods – Yellow, tan, brown
- Freshly Picked – Pale green, greenish-white
- Cooked – Pale green to greenish-tan
There can be variation in specific cultivars – some may have darker green pods, purple flowers, mottled or speckled seeds, etc. But in general, the colors reflect the underlying physiology as chlorophyll levels increase and decrease during growth.
How Green Should Lima Beans Be?
When purchasing fresh or frozen lima beans, here are some guidelines for assessing color:
- Fresh lima beans should be relatively uniform in color. Avoid batches with yellow/brown spots.
- Frozen lima beans may be more pale or grayish, but should not appear brown.
- Canned lima beans will be relatively bright green but may have some gray flecks from canning process.
- Dried lima beans should be creamy white or pale green. Avoid dried beans that are yellowed.
- Sprouted lima beans should have young, bright green sprouts.
Lima beans that are more intensely or uniformly green typically indicate fresher, healthier beans. However, batches with some paler “starchy white” beans mixed in are still perfectly normal and safe to eat. The general rule is to avoid any beans that appear brown, yellow, or faded.
How Color Reflects Freshness
The greenness of lima beans can be a good indicator of freshness and shelf life:
- Brighter green = more freshly picked/frozen
- Pale green or greenish-white = still acceptable but not as fresh
- Dull green/olive = starting to lose freshness
- Greenish-brown = old, degrading chlorophyll
- Yellow/brown = spoiled, rotten
Lima beans will start to lose vibrancy and turn more dull, olive, or brown as they age past their prime. The chlorophyll degrades over time after harvest. This process accelerates if the beans are stored at warm temperatures.
Pale beans may still be safe to eat but will cook down to a more drab and mushy texture versus vibrant green beans. Always inspect your lima beans and compost any that are yellowing or browning.
How Color Changes When Cooked
When lima beans are cooked, some additional color changes occur:
- Chlorophyll starts to break down when heated, causing green beans to become more olive or khaki toned.
- Acids in the cooking liquid can cause the chlorophyll to break down faster.
- Longer cooking times result in more chlorophyll degradation.
- The beans soften and become more translucent, so the inner white color of the bean starts to show through more.
- In canned beans, minerals in the canning liquid can deposit on the surface, dulling the color.
Due to these effects, cooked lima beans will be duller and less vibrantly green than raw beans. This is normal, but try to avoid overcooking them to drab gray or khaki tones.
Canned lima beans tend to be relatively bright green but may look slightly more mineralized from the canning process. Give them a rinse before using in recipes.
Optimizing Color When Cooking
To help preserve the bright green color of lima beans when cooking:
- Start with the freshest beans possible.
- Avoid overcooking the beans into a mush.
- Quickly shock in ice water after cooking to set color.
- Cook in neutral or slightly alkaline liquid – avoid acids.
- Save acidic ingredients like tomato, lemon juice, vinegar for end to minimize exposure.
With careful cooking methods, you can achieve lima beans that are still a nice light green versus drab or yellowed. The flavor will also be best preserved.
How Other Beans Compare
Other types of fresh beans go through similar color changes as lima beans. Here is how their colors compare:
| Bean Type | Fresh Color | Cooked Color |
|---|---|---|
| Lima Beans | Pale green/greenish white | Dull green to khaki |
| Green Beans | Bright green | Olive green |
| Peas | Green | Wilted green |
| Snap Beans | Shiny green | Forest green |
| Soybeans | Pale green/greenish yellow | Yellow tan |
In the raw state, differences come down to chlorophyll content. After cooking, all turn more drab and muted but maintain some of their inherent greenness.
What About Dry Lima Beans?
Unlike fresh lima beans, dried lima beans do not turn green when cooked. This is because:
- Dried beans have degraded most of their chlorophyll during maturation and drying.
- Rehydrating dried beans does not regenerate chlorophyll.
- While new nutrients are uptake during soaking/cooking, chlorophyll is not produced.
- Cooking does not break down carotenoid pigments that give some color.
Therefore, cooked dried beans retain a similar white, cream, or pale tan color that they had when dry:
| Bean Type | Dry Color | Cooked Color |
|---|---|---|
| Lima Beans | Creamy white to pale green | Cream to tan |
| Black Beans | Black/dark purple | Black |
| Pinto Beans | Tan with brown specks | Pinkish tan |
| Kidney Beans | Red | Deep red |
| Navy Beans | White | White |
For dried bean varieties, their natural seed coat color persists after cooking. Only fresh green beans will become greener when cooked.
Conclusion
In summary, the progression of lima bean color through its lifecycle is:
- White seed
- Green sprout
- Green foliage and pods during growth
- White, cream, or pale green mature dried bean
The green color comes from chlorophyll generated during photosynthesis. It starts breaking down as the beans dry and mature. Cooked fresh lima beans will also become more drab green or khaki versus their raw state.
Looking at lima bean color can be a helpful indicator of freshness andproper cooking. Optimal lima beans will have uniform light green color with good vibrancy. With proper storage and cooking methods, you can better retain the color and flavor of delicious lima beans.