The stems and fruits of pineapple plants contain a group of protein-digesting enzymes collectively called bromelain and often used as an antibrowning agent for fruits and vegetables. Fruits and
vegetables brown when they are bruised during transport or sliced and exposed to air. This browning is
controlled by enzymatic pathways that produce brown pigments. The browning of fruits and vegetables
reduces the nutritional value of the food, so antibrowning agents such as bromelain are used.