Lunch Box Tip: Keep Apples Appetizing Reader Tina Vanasse Narbonne of Acton, MA, sent in this great idea to prevent sliced apples from turning brown. Use an apple corer to cut the center of the fruit, but leave the bottom half inch uncut. With a paring knife, make slices as shown, again leaving the bottom uncut. Wrap the apple tightly with plastic wrap so that the slices are snug against one another. At lunch your child can break off the slices.