In Jainism, the core principle is ahimsa (non-violence) in thought, word, and deed. This extends to avoiding harm to tiny life forms, which is one reason many Jains avoid root vegetables.

• Root-vegetable rule: Uprooting a plant (like potatoes, onions, garlic, carrots, etc.) can harm and kill small organisms living in the root or soil. Many Jains therefore refrain from eating or even handling these roots.
• Puris and aloo puri example: A common puri recipe often uses potatoes (aloo). For many Jains who follow the root-vegetable restriction, dishes like aloo puri are avoided or modified to omit root ingredients. If puris are made only from wheat flour with no root ingredients, some Jains may still eat them, depending on local tradition.
• Digambar vs. Shwetambar: Differences in practice exist. Some communities are stricter about avoiding certain vegetables and root foods, while others may be more lenient, but the shared aim is minimizing harm to living beings.

So, the hesitation or avoidance of making or eating puris in some Jain households comes from the broader vow of non-violence and the specific root-vegetable restriction observed by many Jains. If you’d like, I can explain how different Jain sects interpret these dietary ideas in more detail.