Short answer: No. During Paryushan, both Shwetambar and Digambar traditions avoid fermented and factory‑made foods. White bread is usually made with yeast (fermentation) and additives, so it is not taken.

Better choices

• Fresh, home‑made unleavened rotli/chapati or khakhra
• Simple rice, plain dal/moong, laapsi, and other non‑fermented, non‑root, non‑leafy items
• Eat only in daylight and use boiled/filtered water, as per your vrata

Notes by tradition

• Shwetambar (8 days Paryushan): Along with no fermentation, people generally avoid green leafy vegetables and all roots for the festival days.
• Digambar (Das‑Lakshan overlapping days): Same spirit of austerity; fermented/outside foods avoided and meals are kept even simpler per one’s vows.

Even “yeast‑free” or “baking‑soda” breads are best avoided in Paryushan because they are typically commercial, processed, and not in the spirit of simplicity.

For an easy list of what’s allowed and avoided during Paryushan: