Browsing by Author "Abeywickrama, K.P."

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A study of synergistic effects of some Sri Lankan essential oils against cowpea bruchids
(Callosobruchusmaculatus,Proceedings of eleventh Asian symposium on Medicinal plants, Spices and Other Natural Products, Kunming, China, 2003) Paranagama, P.A.; Adhikari, A.A.C.K.; Abeywickrama, K.P.; Bandara, K.A.N.P.
Aflatoxigenic Aspergillus flavus and aflatoxin formation in selected spices during storage
(2009) Rajasinghe, M.; Abeywickrama, K.P.; Jayasekera, R.
Proliferation of aflatoxigenic fungi and accumulation of aflatoxins take place during storage of spices at various environmental conditions. The objective of this research was to identify the aflatoxigenic fungal species and their aflatoxin forming potential in selected spices during storage in the laboratory and refrigerator. Dilution series of spice samples namely chilli (Capsicum annum) powder, curry powder, turmeric (Curcurma longa) powder and pepper (Piper nigrum) powder (purchased from two producers) were prepared separately and the frequency of occurrence of aflatoxigenic and other fungi were assessed after plating each on Potato Dextrose Agar and incubating at ambient temperature. Aflatoxin formation of A. flavus was confirmed by growing a pure culture on a SMKY medium and identifying toxins on thin layer chromatographic plates. The presence of aflatoxins in spice samples stored at 30 ± 20C and 40C was also confirmed. Long storage of spices leads to aflatoxin production irrespective of storage temperature hence, it is advisable to consume spices such as chilli powerder, tumeric etc. within a relatively short period to avoid build up of aflatoxins.
An integrated strategy to control post-harvest decay of Embul banana by combining essential oils with modified atmosphere packaging
(International Journal of Food science & Technology, 2007) Jayawardena, B.M.; Abeywickrama, K.P.
Mature Embul (Musa, AAB) bananas were treated with emulsions of either cinnamon bark or leaf (Cinnamomum zeylanicum) or clove (Syzygium aromaticum) oils to control post-harvest diseases, packed under modified atmosphere (MA) using low-density polyethylene (0.075 mm, LDPE) bags, and stored in a cold room (14 � 1 �C, 90% RH) or at ambient temperature (28 � 2 �C). The effects of the essential oils on post-harvest diseases; physico-chemical properties and organoleptic properties were determined and compared with controls and bananas treated with benomyl. Treatments with cinnamon bark and leaf oils controlled crown rot, whereas clove oil treatment did not affect crown rot development. Treatment with emulsions of cinnamon oils combined with MA packaging can be recommended as a safe, cost-effective method for extending the storage life of Embul bananas up to 21 days in a cold room and 14 days at 28 � 2 �C without affecting the organoleptic and physico-chemical properties.
Behavioural Studies of Cowpea Seed Bruchid, Callosobruchus maculatus (F.) Against Volatile Leaf Extracts of Lemongrass, Neem and Curry Leaf
(Tropical Agricultural Research, 2002) Adhikari, A.A.C.K.; Paranagama, P.A.; Abeywickrama, K.P.; Bandara, K.A.N.P.
Bioactivity of leaf volatiles of Azadirachta indica A. and Murraya koenigii (spreng) against Sitophilus orysae (L.) (Coleoptera: Curculionidae)
(Tropical Agricultural Research and Extension, 2002) Paranagama, P.A.; Abeysekera, K.H.T.; Nugeliyadde, L.; Abeywickrama, K.P.
Bioactivity of the essential oil of Cymbopogon citratus (Lemongrass) on Sitophllus oryzae(L) (Coleoptera : Curcuolionidae) [Rice Weewil]
(Sri Lanka Association for the Advancement of Science (SLAAS), 2001) Paranagama, P.A.; Jayaratne, K.H.T.; Nugeliyadde, L.; Abeywickrama, K.P.
Bioactivity of the essential oil of lemongrass, (Cymbopogon citratus) against rice weevil-Sitophilus oryzae(L.) and grain moth-Sitorroga cerealella (Olivier)
(Annual Research Symposium, Faculty of Graduate Studies, University of Kelaniya, 2001) Jayaratne, K.H.T.; Paranagama, P.A.; Nugeliyadde, L.; Abeywickrama, K.P.
Bioactivity of volatile constitutents of Sri Lankan plants against cowpea bruchids, Callosobruchus maculatus
(Proceedings of AFASSA Regional Symposium on Natural Products, 2004) Paranagama, P.A.; Abeywickrama, K.P.; Bandara, K.A.N.P.; Adhikari, A.A.C.K.
Cymbopogon citratus (lemongrass) and citral a+ b spray treatments alone or in combination with sodium bicarbonate in controlling crown rot in Embul banana (Musa acuminata AAB)
(2004) Abeywickrama, K.P.; Kularathna, L.; Sarananda, K.; Abeygunawardena, D.
The mounting pressure against synthetic fungicidal dips and sprays, restrict their use in controlling crown rot, a major post-harvest disease in banana. Generally regarded as safe (GRAS) compounds have a great potential to be used as alternatives to fungicides. Identification of chemical constituents of Cymbopogon citratus oil revealed the presence of citral as the main component. Cymbopogon citratus and citral with sodium bicarbonate (SBC) was fungicidal against the 3 banana fungal pathogens at 0.10-0.20 % v/v and 0.07-0.08 % v/v respectively. Embul banana sprayed with C. citratus alone or in combination with SBC after induced ripening, indicated a crown rot severity of 25 - 5 0% whereas, citral treatment resulted in a slightly lower disease severity. The physico-chemical parameters tested were not affected by the treatments. Oil/citral, SBC treated bananas and control were ranked good to excellent with respect to odour, flavour, taste and overall acceptability. The low disease severity of crown rot due to spray treatment of citral and SBC highlights the importance in adapting this simple, alternate treatment strategy for quality maintenance.
Deterrent effects of some Sri Lankan essential oils on oviposition and progeny production of the cowpea bruchid, Callosobruchus maculatus (F.)(Coleoptera; Bruchidae)
(2003) Paranagama, P.; Adhikari, C.; Abeywickrama, K.P.; Bandara, P.
Essential oils extracted from five plant materials were tested on oviposition and progeny production of F1 adult of cowpea bruchid, Callosobruchus maculatus on cowpea seeds. All oils tested showed a significant inhibition of oviposition and F1 adult emergence compared to the control during no-choice tests. Cymbopogon citratus and C. nardus showed higher effect on oviposition and F1 adult emergence than the essential oils of Alpinia calcarata, Cinnamomum zeylanicum and Murraya koinigii. In the choice test, the percentage ovipositions in all oils treated samples (except 10 mg of M. koinigii) were significantly lower than that of the control and ethanol treated samples. The percentage eggs deposited decreased with increasing doses of the oils ranging from 10 to 160 mg. The percentage of eggs laid was zero in samples treated with 40 mg of C. nardus or A. calcarata, 80 mg of C. citratus and 160 mg of C. zeylanicum. The essential oils of M. koinigii showed the lowest effect on oviposition when compared to other four essential oils.
Disease control strategies for extending storage life of papaya (Carica papaya), cultivars ‘Red Lady’ and ‘Rathna’
(2012) Abeywickrama, K.P.; Wijerathna, C.; Rajapaksha, N.; Sarananda, K.; Kannangara, S.
Anthracnose (Colletotrichum gloeosporioides), stem-end rot (Lasiodiplodia theobromae) and Phomopsis rot (Phomopsis caricae-papayae) are major post-harvest diseases in papaya resulting in relatively high postharvest losses, up to 45%, in Sri Lanka. The current consumer preference is for tropical fruits free of synthetic pesticides. The objectives of the present investigation were to identify major post-harvest pathogens in papaya fruits, test in vitro fungitoxic effect of basil oil (Ocimum basillicum) and alum (sodium aluminium sulphate) on major fungal pathogens of papaya fruit and develop a relatively safe, disease control strategy. Alum (1% w/v) and basil oil (0.12– 0.16% v/v) in a liquid bioassay, indicated fungistatic and fungicidal efficacy on C. gloeosporioides, L. theobromae and P. caricae-papayae isolated from „Red Lady‟ and „Rathna‟ cultivars of papaya. In vivo investigation of fruits of both papaya cultivars harvested from fruit plantations in Sri Lanka („Red Lady‟–Yatawarawatta plantation, Kurunegala, „Rathna‟ – CIC plantation, Kekirawa and the Agricultural farm, Polonnaruwa) at 25% maturity level indicated that papaya washed in 1% (w/v) alum and subsequently sprayed with an emulsion solution of 0.16% (v/v) basil oil and enclosed in styrofoam sleeves could be stored for 14 days at 12–14 oC. The visual quality rating (VQR) was high (11–13), shriveling and „green islands‟ were low on fruits with zero disease severity where results were statistically similar to 500 mg/L Bavistin treatment. Physicochemical properties assessed were unaffected by the treatments and were comparable to the controls washed only in water. The organoleptic properties were slightly low in fruits subjected to cold temperature compared to fruits subjected to ambient temperature. No residues of basil oil could be detected on fruit peel by gas chromatography at the end of the experimental period of 14 days. The treatment strategy developed could be adopted for sea shipment or temperature-regulated supermarket storage of papaya fruits where storage life could be lengthened up to 14 days.
Effect of alum in combination with vacuum packaging in extending the shelf life of Embul banana
(Faculty of Graduate Studies, University of Kelaniya, 2015) Siriwardana, H.L.S.; Abeywickrama, K.P.; Kannangara, S.; Jayawardena, B.
Crown rot disease is the major post harvest disease in Embul banana causing severe post harvest loss both in terms of quality and quantity. Due to hazardous effects of fungicides, use of eco-friendly methods of controlling crown rot disease are being investigated throughout the world. In this study, efficacy of alum (sodium aluminium sulphate) in combination with vacuum packaging was investigated in extending the shelf life of Embul banana at cold temperature. Approximately 85-day mature Embul banana hands were washed with 1% alum (w/v) solution and control was washed only in water. Treated and control fruits were packed in Low density polyethylene bags, air inside bags were removed using a vacuum and placed in fibre board cartons and stored in a cold room at 12-14 ºC. Each treatment comprised 8 replicate boxes each with 5 hands. In-package gases were analysed on initial day and every seven days thereafter up to 28 days of storage. Physicochemical and sensory properties and crown rot disease severity (CRS) were determined in ripened fruits after each storage period. Medium (50 kg) and large scale (100 kg) test marketing trials were conducted at fruit outlets in Dambulla and Kiribathgoda, Sri lanka by providing treated Embul banana samples to consumers and staff to obtain feedback on the quality of treated banana. Crown rot disease severity was low (CRS index < 1) in alum treated samples compared to control after 28 days. Physicochemical and sensory properties were unaffected by alum+vacuum packaging treatment. Oxygen within packages was maintained between 3.3 - 4.4 % while CO2 % varied between 3.9 - 4.0 %. In medium and large scale test marketing trials, treatment controlled crown rot disease to a fair extent and obtained higher score values from the customers and staff of fruit outlets for the sensory properties compared to control. Therefore, this eco-friendly treatment method could be adopted for effective control of crown rot disease and to extend shelf life of Embul banana up to one month.
Effect of Chemical Pretreatments on the Quality of Minimally Processed Pineapple Stored in Polystyrene Packages
(2012) Ediriweera, S.; Abeywickrama, K.P.; Latifah, M.
Minimally processed pineapple (Ananas comosus L.) cv. Mauritius stored at cold temperature for seven days were evaluated for physicochemical, sensory and microbiological qualities. Pineapple pieces were treated with 1% sodium chloride, 1% calcium chloride, a combination of 1% sodium chloride and calcium chloride, 1% ascorbic acid, 1% citric acid, 0.1% chitosan and distilled water (control) and packed in polystyrene packages before storage. Pretreatments did not significantly affect the physicochemical properties studied. Many sensory attributes in minimally processed pineapple decreased after seven days of storage. However, sodium chloride (1%) and a combination of 1% sodium chloride and calcium chloride pretreatments resulted in maintaining a better flavour in pineapple after a seven day storage period than the rest of the treatments. Microbial counts for all treatments and the control were within safe-to-consume limits while Salmonella was not detected in any sample.
Effect of coconut (Cocos nucifera) water extract on the development of adventitious roots in Polyscias fillicifolia stem cuttings
(The Journal of Agricultural Sciences - Sri Lanka, 2021) Jayawardena, B.M.; Agampodi, V.A.; Abeywickrama, K.P.
Purpose Vegetative propagation continues to be a popular method to propagate ornamental plant species. Coconut water (CW) can be considered as an abundant source of hormones and other plant growth regulators (PGRs). In this study, vegetative propagation of Polyscias fillicifolia was attempted using PGRs isolated from CW. Research method Stem cuttings were treated with varying concentrations (5, 10, 25, 50,100 μg mL-1) of PGR isolated from CW. The results were compared with a control set (treated with distilled water) and with those treated with solutions of pure synthetic indole acetic acid (IAA). Findings P. fillicifolia canes treated with a 25 μg mL-1 concentration of IAA, isolated from CW, showed the highest levels of root induction and development. Root development was more rapid (5 weeks) in the samples treated with PGRs isolated from CW compared to the canes propagated in the field by placing the canes on coir beds in plant nurseries. (6 weeks). Originality This is the first study to use PGRs isolated from CW extracts to improve lateral root proliferation, induce shoot development and leaf emergence in P. fillicifolia.
Effect of pretreatments on quality of minimally processed cooking banana variety Alukesel (Musa acuminata * Musa balbisiana, ABB Group)
(Sabaragamuwa University of Sri Lanka, 2015) Siriwardana, H.; Abeywickrama, K.P.; Kannangara, S.
Cooking banana is a vegetable which can be stored for longer periods in intact form but undergoes browning soon after slicing. A study was undertaken to evaluate the effect of selected pretreatments in maintaining quality of minimally processed cooking banana variety Alukesel. Minimally processed Alukesel was subjected to pretreatments of ascorbic acid (3%), citric acid (3%), ascorbic acid (2%), citric acid (2%), citric acid + ascorbic acid (1.5% each), sodium metabisulphite (2%) and distilled water (control), packed in polystyrene packages and stored at 5-70 C for a week. The effects of pretreatments on sensory and physicochemical properties (percentage weight loss, changes in firmness, pH, Total Soluble Solids (TSS) and Titratable Acidity (TA)) were evaluated on day 0 and day 7, while browning was assessed using a spectrophotometric method. Pretreatments had a significant effect on physicochemical and sensory attributes of minimally processed cooking banana compared to control. Ascorbic acid (3%), citric acid (3%) and citric acid + ascorbic acid (1.5% each) pretreated cooking banana obtained higher ranking values for sensory properties (appearance, colour, odour, flavour, taste and overall acceptability) while the same three pretreatments and sodium metabisulphite (2%) pretreatment effectively controlled enzymatic browning. This research revealed that pretreatments of ascorbic acid (3%), citric acid (3%) and citric acid + ascorbic acid (1.5% each) were more successful in retaining quality of minimally processed cooking banana for one week in cold storage. It could be concluded that Alukesel treated as above can be considered as a potential value added sale item at local supermarkets where cold storage facility is available.
Effect of pretreatments on the quality of minimally processed green bell pepper (Capsicum annuum L.) strips in polyvinyl chloride packages
(Institute of Biology, Sri Lanka, 2011) Ediriweera, S.; Abeywickrama, K.P.
Effect of the essential oil of Cymbopogon nardus on Aspergillus flavus Link isolated from Sri Lankan paddy and rice
(University of Kelaniya, 2002) Paranagama, P.A.; Abeysekera, K.H.T.; Nugeliyadde, L.; Abeywickrama, K.P.
Effect of the essential oils of Cymbopogon citratus, C. nardus and Cinnamomum zeylanicum on pest incidence and grain quality of rough rice (paddy) stored in an enclosed seed box
(WFL Publisher, 2003) Paranagama, P.A.; Abeysekera, T.; Nugaliyadde, L.; Abeywickrama, K.P.
The protective effect of the essential oils of Cymbopogon citratus, C. nardus and Cinnamomum zeylanicum leaf on paddy stored in wooden boxes lined with aluminium foil were evaluated. After 168 days of storage in oil treated boxes Sitotroga cerealella population was significantly lower in oil treated paddy than the control. The 1000 grain weight was higher in all three treatments (21.1 - 22.9 g) compared to the control (19.8 g). Percentage grain damage was lower in C. citratus and C. nardus treated paddy than the control. The percentage seed germination was not significantly different from that of the control in oil treated paddy though, in C. citratus treatment the seed germination was reduced. The milling quality of paddy was not affected by the essential oil treatment however; the flavour and stickiness of cooked rice was enhanced when treated with C. zeylanicum and C. citratus oils.
Effect of volatile constituents of Curry leaf, Murraya koenigii on cowpea seed bruchid, Callosobruchu smaculatus (F.) in stored cowpea
(University of Kelaniya, 2001) Adhikari, A.A.C.K.; Paranagama, P.A.; Bandara, K.A.N.P.; Abeywickrama, K.P.
The efficacy of methanol extracts of leaves of lemongrass- Cymbopogon citratus (DC) Stapf and Curry leaf – Murraya koinigii Spreng on Callosobruchus maculatus
(Proceedings of Sri Lanka Association of Advancement of Science, 2002) Paranagama, P.A.; Adhikari, A.A.C.K.; Abeywickrama, K.P.; Bandara, K.A.N.P.