The hardness of the green banana & due to the fact that the cells are
cemented together by an insoluble substance known as protopectin. As
the fruit ripens the protopectin is changed by enzymes into pectin and
finally into various semi-acid and acid bodies. Pectin will swell in water
to form a jelly, provided the concentration of sugar is correct and the
pH is at the optimum point. Neither protopectin nor pectic acid will
form a jelly. As the protopectin is changed into pectin the fruit becomes
soft in texture, because the cell walls are no longer cemented together
by protopectin. During ripening the total pectin (protopectin plus pectin)
remains practically constant, but the pectin increases until the fruit
becomes overripe, at which time a good part of the pectin has been changed
into acid and semi-acid bodies. This is the explanation usually given to
account for the softening of the fruit during maturation. In reality it is