Final answer:
To refresh wilted celery and carrot sticks, placing them into freshwater is beneficial. This allows the vegetables to reabsorb water through osmosis, which can restore their crispness. Adding salt or sugar would create a hypertonic environment and further dehydrate the vegetables, which is the opposite of the desired effect.
Step-by-step explanation:
If the celery and carrot sticks have become a bit wilted before a party, it would be helpful to put the celery and carrots into freshwater. This process rehydrates the vegetables, restoring their crispness. When vegetables like celery and carrots become wilted, it's often because they have lost moisture. Placing them in freshwater can allow them to reabsorb water through osmosis. Conversely, putting them into saltwater would draw out more moisture due to the high osmotic pressure, exacerbating the wilting by drawing water out of the plant cells.
When salt or sugar is added to food, it affects the food's water activity. The addition of these solutes creates a hypertonic environment outside the microbial cells, drawing water out from the cells to balance the solute concentration. This process is used to preserve foods because it reduces the amount of available water that microorganisms require to grow. However, when it comes to reviving wilted vegetables, a hypertonic solution like saltwater would not be beneficial. Using freshwater provides a hypotonic environment that allows water to flow into the plant cells, restoring the vegetables' turgidity and freshness.