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.