conserve

fruit preserved by cooking with sugar

keep in safety and protect from harm, decay, loss, or destruction

“children must be taught to conserve our national heritage”

use cautiously and frugally

“conserve your energy for the ascent to the summit”

keep constant through physical or chemical reactions or evolutionary change

“Energy is conserved in this process”

preserve with sugar

“Mom always conserved the strawberries we grew in the backyard”