Answer

Yes, mustard seeds and mustard oil are generally acceptable in a Jain vegan diet, including during Das Lakshan, if your family/sampraday tradition permits it.

However, during Das Lakshan many Jains follow stricter discipline, so some may avoid mustard because it is considered strong, pungent, and stimulating.

Explanation

In Jain food practice:

• Mustard is not a root vegetable, so it is not prohibited for that reason.
• Mustard seeds are plant seeds, and mustard oil is extracted from them.
• It is also vegan, as it does not come from animals.

But during Das Lakshan, many people simplify food and avoid items that increase taste, attachment, or stimulation. So the question is less about “vegan” and more about the level of Jain discipline you are observing.

Spiritual Understanding

Das Lakshan is a time for reducing attachment to taste and practicing restraint. If mustard is used mildly in simple food and your tradition allows it, it is generally fine. If you are observing a stricter tapasya or very plain diet, avoiding it may be more spiritually aligned.

Takeaway

Mustard is usually Jain and vegan, but during Das Lakshan follow your guru, family, or sangh’s niyam. If in doubt, avoid it for the festival period.