Epikarp

Epikarp, also spelled epicarp, is the outermost layer of the pericarp, the tissue that forms the fruit wall after fertilization. It develops from the outer wall of the ripened ovary and, in many fruits, constitutes the exocarp—the part that becomes the fruit’s skin or rind. The epicarp’s thickness, texture, and composition vary widely among species, ranging from a thick, waxy rind as seen in citrus to a thin, pigmented skin in grapes and apples, and a delicate covering in some berries.

Functions of the epicarp include protection against mechanical damage, desiccation, and pathogens. It also contributes to a fruit’s appearance, color, aroma, and flavor through pigments, oils, and aromatic compounds embedded in the tissue. The epicarp often forms a barrier that helps regulate water loss, with its cuticle playing a key role in limiting transpiration.

In agriculture and postharvest biology, epicarp properties affect fruit quality, processing characteristics, peelability, and shelf life. Breeding and selection programs may target peel thickness, color development, and waxiness to suit market preferences and handling requirements.

See also: pericarp, exocarp, mesocarp, endocarp, fruit anatomy.