Respiration

 It is the major biological process of decay of harvested fruits and vegetables by the oxidative breakdown of complex materials (CHO or carbohydrates/acids) into simpler molecules (CO₂, H₂O) with the production of energy. Since the products are still alive after harvested, their living cells respire for secure energy. The equation for respiration is as follows.

The rate of respiration during storage is affected by many factors. These factors are divided into two groups. (A) Plant factors (B) Environmental factors.

A) Plant Factors:

1) Soluble Sugars:

Soluble glucose is the major sugars used especially in respiration. Therefore, the higher the concentration of soluble sugars within living tissues, the higher the rate of respiration.

2) Ratio of living cells:

Living cells have a constant need for energy. Respiration releases the necessary energy. So, the rate of respiration will be directly proportional to the number of living cells.

3) Water content of the product:

The rate of respiration varies directly with the water content of the product. Succulent products generally respire more rapidly than non-succulent products. Thus, lettuce heads breathe more rapidly than potatoes or sweet potatoes or even peppers.

B) Environmental factors:

1. Concentrations of O₂ and CO₂: The higher the concentration of O₂ the higher the respiration rate and conversely the higher the CO₂ concentration, the lower the respiration rate.
2. Temperature: Higher the temperature, the higher will be the respiratory rate.