Anatomical characterization of Passiflora cincinnata Mast. fruit subjected to refrigeration

Abstract

Passiflora cincinnata is a species of wild passion fruit whose fruit has potential for use by the food industry. In this context, an anatomical study of the pericarp may help in understanding the changes which occur during the postharvest period. The objective of this work was to anatomically characterize the P. cincinnata pericarp, focusing on the structural changes which occur during refrigerated storage. The selected fruits were kept in net-like packaging at 5°C and evaluated every 15 days for a period of 90 days. Pericarp samples were hand cut on these dates for structural description and to detect starch, phenolic compounds, alkaloids, polysaccharides, proteins, lipids and lignin through histochemical tests. Other samples were analyzed by scanning electron microscope. The fruit is composed of three anatomically distinct regions: exocarp, mesocarp and endocarp. The mesocarp stands out for the presence of sclerified cells and the lax parenchyma, which increased its number of layers during the evaluated period. Idioblasts with prismatic crystals, drusen, silica crystals and raphides were identified, but the amounts reduced over time. This reduction and enlargement of the lax parenchyma were the main changes observed in the postharvest period of P. cincinnata pericarps.