Answer :
Final answer:
Pectin is a fiber in plant cell walls that gives jams and jellies their texture. It is part of the middle lamella, acting as a gelling agent and is found naturally in many fruits. While pectin aids in the gelling process, cellulose provides structural support in the plant cell wall.
Explanation:
Pectin is the fiber found in plant cell walls that is responsible for giving jams and jellies their solid, spreadable texture. It is a mucilaginous substance occurring naturally in various fruits such as pears, apples, quince, oranges, and other citrus fruits.
Pectin acts as the gelling agent in jams and jellies, transforming the cooked fruit mixture into a set form that is easy to spread. This substance is part of the middle lamella, which contains pectin that cements the cell wall of one cell to the cell wall of an adjacent cell, contributing to plant structure and rigidity.
In the cell wall, pectin is embedded in a matrix that includes fibers of cellulose and hemicellulose. Cellulose is a polysaccharide that makes up the largest portion of the plant cell wall and provides structural support, while hemicellulose serves as a filler between cellulose fibers.
Beyond its role in plant structure, dietary cellulose or 'fiber' found in plants provides health benefits for humans, including promoting a healthy digestive tract and reducing the risk of certain diseases, though it is not digested by humans.
