Effectiveness of Selected Postharvest Handling Practices and Technologies to Preserve the Postharvest Quality of Mango Fruit

Abstract

Mango (Mangifera Indica L.) is one of the major fruits produced in Kenya mainly for the domestic market. Production of mango is dominated by the smallholder farmers, majority of whom depend on it for their livelihoods. Mango fruit is a highly perishable climacteric fruit whose shelf life is limited after maturity, resulting in high post-harvest losses. Postharvest deterioration and subsequent losses are as a result of various metabolic processes including respiration and transpiration whose rate depends on temperature management. Cold chain management which entails handling perishable produce at cool (safe) temperature from harvest until the produce reaches the end-user is critical for the preservation of quality. The aim of this study was to evaluate the effectiveness of selected postharvest handling practices and simple technologies to achieve cold chain, extend shelf life and preserve quality of mango fruit. This was achieved through two related on-farm and laboratory experiments. In the first experiment, four mango varieties namely ‘Apple’, ‘Ngowe’, ‘Kent’ and ‘Tommy Atkins’ harvested at the mature green stage from the farmers’ orchards were used in an on-farm study. To demonstrate proper cold chain management, fruits were harvested early in the morning (before 8 am) and transported in crates which were lined with dampened newspapers to cool the fruits during transit. Upon arrival at the experimental site (Karurumo Aggregation Center), the fruits were precooled using evaporative coolers to remove field heat then stored in the Coolbot™ cold room (10±2oC). The described proper cold chain practices were compared with the common practices among farmers (poor cold chain practices). In this case, the fruits were harvested at midday (noon), transported to the aggregation centre in open crates and then stored at ambient room conditions (Temperatures of 25±7oC, Relative Humidity of 55±15%). The air and fruit pulp temperatures from harvest and subsequent handling and storage at the various conditions were monitored regularly using HUATO® data loggers. During storage, a random sample of 3 fruits (per variety) was taken from each of the storage options after every 3 days to evaluate ripening-related changes including physiological weight loss, colour, firmness and total soluble solids. In the second experiment, a homogenous sample of mature green ‘Apple’ and ‘Kent’ mango fruits were divided into 10 batches of 60 fruits each to evaluate the effectiveness of four different low-cost storage technologies to preserve quality and extend the shelf life of mango fruits. The technologies evaluated include Coolbot™ cold room (10±2oC, 75±20%RH), Evaporative charcoal cooler (20±5oC, 95±5%RH), Zero energy brick cooler (20±5oC,..........................................................