Techniques for extending shelf life of guava fruits: a review

Guava (Psidium guajava L.) is an exquisite, nutritionally and economically valuable fruit crop of tropical and sub-tropical regions of the world. Guava fruits are relished world over for fresh consumption, as well as processed into other delicacies like juice, jam and jelly to extend availability throughout the year. Guava outshines other tropical fruits in productivity, hardiness, adaptability, nutritional value, and ensures higher economic returns to growers with minimal inputs. Guava is highly nutritious and a good source of calcium, iron and phosphorus. Vitamin C content of guava fruit is 2-5 times that of citrus fruit. Despite its wide adaptability and high nutritive value, world trade of guava fruit is limited due to its delicate nature, short postharvest life and susceptibility to chilling injury and diseases. Guava, being a highly perishable fruit, undergoes rapid postharvest ripening in a few days under ambient conditions and becomes overripe and mealy within a week. In cold storage, the fruit can maintain quality for up to 15 days at 8-10°C and 85-90% RH. Controlled/modified atmosphere storage methods can extend the shelf life, but, an inappropriate storage atmosphere may result in accumulation of fermentative metabolites resulting in development of severe off-flavors. The use of anti-transpirants, wax coatings, growth retardants, irradiation and different types of storage facilities have been tried to increase the shelf life of harvested fruits with limited success. Recent technologies such as the phospholipase D inhibition technology using hexanal compositions have been observed to enhance shelf life for a month through its multifold actions involving the modulation of ethylene signal transduction pathway and gene expression.