A Characterization of Pomegranate (Punica granatum) Aril Morphology and Anatomy

Pomegranate (Punica granatum) is highly valued for its health benefits and is marketed as whole fresh fruit, extracted arils, juice, and as an ingredient in a large array of products.  The fruit is composed of an outer leathery pericarp that contains hundreds of juice-containing arils.  Pomegranate arils have a unique structure and are susceptible to mechanical damage.  Understanding the structural characteristics of arils has important implications during fruit handling and in aril extraction. The morphology and anatomy of arils during late stages of development were investigated using light and scanning electron microscopy.  Arils are made of a single layer of juice cells that radiate outward from a centrally located seed. Juice cells are tightly packed, polygonal in cross section, and have a thick-walled outer cell surface that is covered by a cuticle.  Seed structure and a description of the modified cells that contribute to seed hardness will be described.  Aril anatomy as it relates to shear and compression damage will be discussed.