| Food & Ingredients | | | Educ. Serv. | | | Glossary | | | References | | | Images | FAQ |
|---|
Bananas |
The banana (Musa paradisiaca sapientum L.) belongs to the genus Musa, the family Musaceae, and the order Zingerberales. The Eumusa group of species is the most widespread and includes the major edible varieties. The banana is a berry fruit thought to be of Indian origin (Xzyhrinciw, 1969).
Tha anatomy and development of the banana are discussed by von Loesecke (1949), Simmonds (1959), and Palmer (1971). The edible banana is parthenocarpic and is propagated from a rhizome. The fruit consists of an inedible skin which encircles the edible pulp. The skin is approximately one-fifth the diameter of the pulp. The pulp-to-skin ratio increases throughout development. The skin has a sharply ridged outer margin and its boundary with the pulp is clearly marked by the color contrast with the white, starchy pulp tissue. The peel consists of an epidermis interrupted by stomata, parenchyma cells, and fibrovascular bundles parallel to the long axis. The parenchyma cells of the peel become more and more rounded nearer the center of the fruit and there are more intercellular spaces. A thin layer of protoplasm in which plastids are embedded lines the inner walls of these cells. In outer layers of tissue the plastids have pigments, but in deeper layers the plastids serve as centers for accumulation of starch. A vacuole is found in the center of each cell which accumulates sugars as the starch is hydrolyzed to sugars during ripening.
The pulp develops from the outer edges of the locules. The sterile ovules degenerate to brown flecks embedded in the edible pulp. The three arms of the inner locular walls extend radially from the center. Vascular strands are scattered abundantly in the skin and grouped in three pairs in the center of the pulp. Vascular bundles and associated latex vessels and parenchymatous cells adjoin the vascular strands. The latex system consists of the most conspicuous cells, large and barrel-shaped, joined end to end in a sausage-like fashion. Latex tubes run at right angles to the long axis of the fruit and outline the margin of the individual locules.
Structure of the pulp other than gross observations are not available (Palmer, 1971). The parenchyma cells of green fruit are long and box-like in shape with thin walls. The cells contain a nucleus and cytoplasm. Cells of preclimacteric fruit, i.e., fruit which has nto reached its peak in respiration, are closely packed with little or no intercellular spaces and are obscured by the numerous large starch grains present. During ripening, the cells become progressively depleted of starch and more details of the individual cells are revealed.
Updated: Wednesday, June 20, 2007.
OSU Disclaimer.