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Why Is Asparagus Stringy?

Asparagus is most preferred fresh.

When selecting asparagus spears, you want to make sure they are fresh so that when you snap off the hard inedible base, you still have a lot of soft asparagus to use for your recipes.

The longer the asparagus sits after harvesting; the more portions of the asparagus spear changes in texture and becomes difficult to use.

Storing asparagus is quite a challenge as this unpleasant change in texture progresses the longer it is stored. 

This could leave you with a smaller portion of the asparagus to use, as the stringy part does not get soft even with cooking.

But why do asparagus become stringy after harvesting them? The answer is due to a  complex process known as lignification.

In this post, we are going to explain the process that causes asparagus to acquire a woody texture.

Why do asparagus spears become stringy?

Both fruit and vegetables undergo several changes during storage including in their taste and texture.

Some fruits may undergo degradation when stored becoming softer in texture. Some vegetables continue to grow and their cell wall enlarges after harvesting them.

For some plants such as asparagus, their stems continue to mature and differentiate even after harvesting them.

Together with a loss of water from their stems, post-harvest lignin deposition in the cells of asparagus is responsible for the textural change that occur after asparagus spears have been harvested.

Lignification begins at the base of asparagus spears and process extends from there upwards.

The spear also lose their sugars as they continue to toughen.

Lignin cannot be softened by heat, and therefore, you might have to snap off the hardened portion of the asparagus.

What is lignin?

Lignin is a polymer that gives plants rigidity.

Trees and other plants undergo lignification, a process by which lignin is deposited in their cell wall.

This process helps to make their stems strong and to be able to withstand mechanical stress and the load on them

Asparagus spears are harvested while the plant is still very young and when this lignification process has not fully occurred.

The basal portions of the asparagus are more mature than the apical portions, and therefore hardening starts there.

However, Lignin formation and deposition in asparagus spears continues even after the spears are harvested, and this leads to strengthening of their cell wall thereby causing an undesirable change in texture.

Selecting and storing asparagus

When selecting asparagus spears, look out for their texture, color and the tips to ensure that they are fresh.

The longer the asparagus spears are stored, they acquire an unpleasant texture and lose some of their flavor.

Refrigeration may decrease this process for a while. A method often used to store asparagus involves putting them in a fridge while standing them upright in a jar of water.

Asparagus nutrition

Asparagus is low in calories but rich in many nutrients.

They are rich in vitamin K, vitamin C, vitamin A, Vitamin E, potassium, phosphorus and fiber.

Asparagus also contains zinc, iron, and it has several important health benefits

In conclusion

Asparagus begins to change in texture after harvesting them.

This is due to a biochemical process known as lignification.

They may become stringy postharvest, and this often leaves a smaller portion of the asparagus spear to cook while the woody parts are often wasted.

Therefore, it is important to always look out for the ones that are still fresh when selecting asparagus.