Browsing by Author "Jayakody, R."

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In vitro antifungal effi cacy of selected essential oils in controlling fungi associated with the stem-end rot disease of mango (cv. Karutha Colomban) fruits and characterisation of antifungal components
(Journal of the National Science Foundation of Sri Lanka,, 2020) Kodituwakku, T.; Ekanayake, G.; Abeywickrama, K; Jayakody, R.
Karutha Colomban is one of the most delightful mango varieties popular among Sri Lankan consumers. A signifi cant postharvest loss of mango takes place every season due to diseases including stem-end rot (SER), which is caused by a group of endophytic fungal pathogens. In this research, in vitro antifungal effi cacy of diff erent concentrations of essential oils of basil, clove, and cinnamon were evaluated for their ability to control SER causing fungal pathogens of mango (cv. Karutha Colomban) as bio-safe alternatives to conventional fungicides, by conducting liquid and disc volatilisation bioassays. Major bioactive compounds of the selected essential oils were identifi ed by gas chromatography-mass spectroscopy (GC-MS). Basil and cinnamon bark oils (0.20 – 0.30 μL/mL) in liquid bioassay showed high effi cacy against Lasiodiplodia theobromae, while basil and cinnamon leaf oils (0.40 – 0.60 μL/mL) successfully inhibited Pestalotiopsis sp. Cinnamon bark oil (0.60 μL/mL) was identifi ed as the most eff ective oil against Phomopsis sp. According to disc volatilisation bioassay, vapour of cinnamon oils (0.20 – 0.40 μL/mL) was the most eff ective in controlling L. theobromae. Pestalotiopsis sp. was effi ciently controlled by clove and cinnamon bark oil (0.20 – 0.60 μL/mL) vapour. In vapour phase, clove and cinnamon oils (0.40 μL/mL) were the most eff ective against Phomopsis sp. According to GC-MS characterisation, methyl chavicol was the most abundant antifungal component in basil oil while it was (E)-cinnamaldehyde in cinnamon bark oil. Moreover, eugenol displayed the highest abundance in clove and cinnamon leaf oils. Based on in vitro studies, it could be concluded that cinnamon bark oil in liquid and vapour phases demonstrated a higher antifungal effi cacy among the tested essential oils in controlling fungal pathogens causing SER of mango.
Quality assessment minimally processed immature jackfruit (Artocarpus heterophyllus, Lam.) as affected by pretreatments
(Association of Food Scientists & Technologists, India, 2015) Ekanayaka, H.; Abeywickrama, K.P.; Jayakody, R.; Herath, I.
Abstract Degree of browning, firmness, sensory properties and microbiological quality of minimally processed immature jakfruit were investigated on initial and seventh day after stor- age at 5–7 °C. Samples were pretreated with 0.5 % and 1 % sodium metabisulphite, 1.5 % citric acid+1.5 % ascorbic acid, 3 % citric acid, 3 % ascorbic acid and packed in polystyrene packages and over wrapped with polyvinylchloride (PVC) stretch film before storage. When degree of browning in rela- tion to absorbance was assessed, immature jakfruit pretreated with 1.5 % citric acid+1.5 % ascorbic acid showed the lowest absorbance at 420 nm among all pretreated samples indicating low browning in samples. At 450 nm, minimally processed immature jackfruit samples pretreated with 1.5 % citric acid+ 1.5 % ascorbic acid showed the highest reflectance (indicating lowest absorbance) compared to other treatments. Variations in firmness were observed after treatment. Microbial counts were within safe-to-consume limits while coliforms were not detected in any of the samples. Erwinia aphidicola and Bacillus subtilis were identified from minimally processed immature jakfruit samples using molecular tools. 1.5 % citric acid+1.5 % ascorbic acid, 1 % sodium metabisulphite and 3 % citric acid were relatively more successful in retaining acceptable sensory quality of jakfruit even after 7 days of storage. Above pretreatments could be recommended during minimal processing of immature jakfruit meant for local sale in supermarkets where cold storage is available.