The fiber structures of vegetables (including cellulose and pectins) give them shape and firmness. Cooking softens some of these components.
The amount of fiber varies:
- In different vegetables. Spinach and tomatoes have less fiber than carrots and turnips, for example.
- In different examples of the same vegetables. Old, tough carrots have more fiber than young, fresh carrots.
- In the same vegetable. The tender tips of asparagus and broccoli have less fiber than their tougher stalks.
Fiber is made firmer by acids or sugars: