Page 104 - Biology - XII

PROJECT - 5
Objective
To study fruit ripening and changes with ripening.

Principle/Theory
1. Fruits after their growth undergo characteristic qualitative changes. These changes are collectively
called/referred to as fruit ripening.
2. Important events in fruit ripening are—
Softening (by cell wall degrading enzymes), hydrolytic changes (leads to formation of sugars),
pigmentation changes (green or various colour), fl avour production, fall in astringent substances, and
respiratory changes.
3. Ripening mechanism is mainly because of respiratory energy, synthesis of new sets of enzymes, and its
action leading to above changes.
4. Ethylene is a ripening hormone. But not for fruits like strawberry and citrus, because these fruits have
no eff ect of ethylene on their ripening.

Materials Required
Seasonal unripe fruits

Procedure
1. Take an unripe fruit from each of the seasonal fruits.
(Such as—banana, apple, citrus fruit—orange, lemon, tomato, chilly (pepper), mango, pear, pod, etc.)

2. Observe the changes and note them.

Results
1. There is a lot of diff erence in the unripe and ripe fruits.
2. These changes in general are—

(a) Softening of fruit fl esh.
(b) Hydrolytic conversion of stored materials in fruit.
(c) Changes in pigments and fl avours.

Obervation Table
Fruit ripening and changes with ripening
S. Name of Appearance Colour Hardness/ Flavour Taste Time taken Inference
No. fruit (pigment) softness astringent for change
1. Banana Green Hard Flavour Sweet three days Unripe banana
Unripe Yellow Soft changes ripe/ripen
Ripe in three days
2. Apple
Unripe
Ripe
3.

4.

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