2018 ASHS Annual Conference

‘Nova’ mandarin were coated with commercial carnauba and shellac microemulsions and an experimental carnauba nanoemulsion coating compared to an uncoated control. Fruit quality evaluation included weight loss, gloss, soluble solids (SS), titratable acidity (TA), pH, SS/TA ratio, internal CO₂ and O_2, internal ethanol, and a sensory shine rank test after storage at 20 °C for 7 days. Conventional and nanoemulsion carnauba wax resulted in the least weight loss compared to control and shellac. There were no differences for gloss measurements, but gloss decreased with time and shellac-coated fruit ranked highest for shine in the sensory test. There were no differences for SS, TA, pH and ratio among treatments, CO₂ and ethanol generally increased and O₂ decreased during storage while the highest levels of CO₂ and ethanol were found for the shellac treatment along with the lowest O_2, with no differences among the other treatments. Meanwhile, antimicrobial activity of ginger oil extracts (GOE) was evaluated using the poisoned food (PF) and inverted Petri-dishes test (IPD), minimum inhibitory concentration (MIC), minimum fungicide concentration (MFC) and percentage of spore germination for the citrus fruit pathogen, Penicilium digitatium. GOE significantly reduced mycelium growth of P. digitatium while spore germination was inhibited at 1% GOE, compared to 37.4% for controls after 24 h of incubation. GOE exhibited at a MIC between 0.4% and 0.8% (v/v). Now we will test the effect of 0.8% GOE in a nanoemulsion coating with P. digitatum-inoculated ‘Unique’ tangerines stored at 10 °C followed by a simulated marketing period for which results will be discussed.