Ultrasonic fog application of organic acids delays postharvest decay in red bayberry

Red bayberry (Morella rubra Lour.) has attractive fruit with appealing flavour and global market potential. However, its fresh fruit are highly susceptible to mechanical damage and postharvest fungal decay. The objective of the current study was to assess the efficacy of weak organic acids in delaying decay when applied to the fruit as an ultrasonic fog. Preliminary screening identified genotypes with acceptable postharvest longevity for use in the experiments. Fruit of genotype N1MR06 that received a 1 h ultrasonic fog treatment with acetic acid exhibited a significantly (P < 0.05) lower decay incidence of 18% after 10 d at 5 °C as compared with 70% for untreated control fruit. However, the decay incidence in fruit treated with citric acid (55%) did not significantly (P > 0.05) differ from the control. Subsequent experiments using fruit of genotypes N1MR06 and N1MR09 confirmed that ultrasonic fogging with acetic acid was an effective measure for delaying postharvest decay in red bayberry. Sensory evaluation along with total soluble solids and titratable acidity measurements showed that the acetic acid treatment had no adverse effect on the organoleptic quality of red bayberry. Overall, the study determined that genotype selection has an impact on red bayberry shelf life and that further shelf life gains can be achieved through ultrasonic fogging of safe, natural and inexpensive acetic acid.