Short answer: Avoid fresh corn during Paryushan. Dry, mature corn (maize kernels/corn flour) may be taken only if it fits the pachchakkhān (vows) you have accepted from your Guru/tradition.

Details:

• Shwetāmbars in Paryushan generally renounce “harit‑śākh” (green/fresh produce). Fresh corn on the cob, sweet corn, baby corn are treated as green produce and are avoided.
• Digambars in Das‑lakshan also tighten food discipline and avoid green/fresh items; many take very simple or boiled food. Fresh corn is thus avoided.
• Dry, fully matured corn (makai dāna, makki ka aata) is counted as a grain (ānaj). If your Paryushan vows allow grains, you may take it in simple, same‑day prepared food before sunset, without fermentation, sprouting, or leftovers.
• If you have stricter vows (e.g., boiled‑food only, one‑grain rule, or additional renunciations), treat corn as that one grain, or omit it accordingly.

Always follow the pachchakkhān given by your Āchārya/Guru and your sect’s maryādā. The aim is to minimize hiṃsā and observe utmost simplicity in food during these days.