Effects of smoke, hexanal, and calcium chloride on post-harvest quality of oranges [Citrus x sinensis (L.) Osbeck] cvs Msasa and Jaffa under different storage durations and conditions in Tanzania
Keywords:Post-harvest treatments, post-harvest loss, shelf life, physiological weight loss, fruit firmness, total soluble solids (TSS), titratable acidity (TA), TSS/TA ratio
AbstractExperiments were conducted to assess the effects of hexanal, calcium chloride, and smoke on the post-harvest quality of oranges under ambient (room) temperature (28±2?C) and reduced temperature storage (18±2?C) conditions on two varieties of sweet orange (Citrus x sinensis (L.) Osbeck) cvs ‘Msasa’ and ‘Jaffa’. Fruit were dipped in enhanced freshness formulation (EFF) containing hexanal as the key ingredient at 0.01%, 0.02%, and 0.04% (volume/volume), or calcium chloride solution at 1%, 2%, and 4% (weight /volume) for five minutes each, or subjected to a smoking regime, simulating a popular traditional practice, by burning 0.5 kg, 1.0 kg, and 1.5 kg of dried banana leaves, or left untreated (control). Various parameters including physiological weight loss, fruit firmness, total soluble solids (TSS), titratable acidity (TA), and the TSS/TA ratio were assessed to determine effects on post-harvest quality of fruit. Results indicate that hexanal and calcium chloride treatments significantly (p < 0.001) reduced physiological weight loss, maintained fruit firmness and significantly higher TSS in both varieties compared to smoke treatment and untreated controls. Reduced temperature storage also significantly (p < 0.001) lowered physiological weight loss of hexanal- and calcium chloride-treated oranges. Based on the results of this study, post-harvest dip treatments with hexanal solution at 0.02% or calcium chloride solution at 2% coupled with reduced temperature storage at 18°C are recommended to maintain the quality of fresh oranges in Tanzania. On the contrary, the application of smoke is highly discouraged as it reduces the quality of oranges.