A review of shelf-life extension studies of Nigerian indigenous fresh fruits and vegetables in the Nigerian Stored Products Research Institute

Abstract

The Nigerian Stored Products Research Institute has been conducting research in technology development suitable for
post-harvest handling of Nigerian indigenous fruits and vegetables for extension of the shelf-life of these commodities,
retention of nutrients and aesthetics of fresh produce in storage, enhancement of the nutritional status and earning
capacity of both the rural and urban poor through proper handling, storage, marketing and consumption of fruits and
vegetables; and production of the best quality fruits/vegetables for local and export markets over three decades. The
research work carried out and the technologies developed for handling of Nigerian indigenous fruits/vegetables postharvest for the farm, market and domestic levels of storage are discussed subsequently. These indigenous fruits and
vegetables are prone to chill injury when kept at low temperatures. However, storage structures developed by the
Nigerian Stored Products Research Institute over the years, such as the evaporative coolers and cooler baskets which
could record some temperature drop from the ambient, have been used in extending the shelf-life of fresh fruits and
vegetables. Packing (wrapping) materials have also showed promise in extending shelf life of Nigerian indigenous
fresh produce. The season and time of harvest also play an important role in storage of fruits and vegetables. Garden
eggs have very short shelf-life of 7 days during the dry harmattan months in Nigeria. Fresh fluted pumpkin Telfairia
occidentalis ‘ugu’ leaves can only be kept for 6 days at 29.1°C and 64.5%rh beyond which physiological breakdown of
tissues lead to deterioration and total loss. Fresh pawpaw (Carica papaya L.) fruits, individually wrapped with waxed
paper (TIXO) kept at ambient conditions in plastic crate, have a shelf-life of 17 days as compared to fresh pawpaw fruits
in evaporative coolers for 7 days. In hot dry weather of the Northern parts of Nigeria, oranges stored in evaporative
cooler (EC) Metal-in-Brick wall have a shelf-life of 10 weeks. Adoption of these technologies will play a very vital role in
post-harvest loss reduction in fresh fruits and vegetables along the food chain, increase income and improve nutrition
for all stakeholders. The interventions to maintain food quality and safety for reduction of postharvest losses in
Nigerian indigenous fruits and vegetables through Research activities in NSPRI for three decades are the focus of this
review paper.