Postharvest and Processing Research and Development Office
Postharvest and Processing Research and Development Office
Khapanya W.,Kasetsart University |
Hongprayoon R.,Kasetsart University |
Hongprayoon R.,Center for Agricultural Biotechnology PERDO CHE |
Chinaphuti A.,Postharvest and Processing Research and Development Office
Journal of the International Society for Southeast Asian Agricultural Sciences | Year: 2017
Aflatoxins are cancer-causing chemicals produced primarily by Aspergillus flavus and A. parasiticus. Aflatoxin B1 (AFB1) is the most commonly found aflatoxin in improperly stored staple commodities such grain and feed. Its presence in the food supply, can be carried over to animal products such as meat, liver, kidney, pig blood and milk. A specific and sensitive detection method is required for preliminary screening of these samples. This research sought to develop a detection kit for total aflatoxin by immunochromatographic technique using monoclonal antibody (MAb) from the hybridoma cell line 4G6. The experiments were conducted at the Serology and Diagnostic Laboratory, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom province during 2014-2016. The MAb is composed of IgG2b isotype and lambda light chain. Its specificity recognized four aflatoxins including AFB1, AFB2, AFG1 and AFG2 with cross reactivity at 100%, 89.2%, 82.6%, and 72.7%, respectively by direct competitive enzyme-linked immunosorbent assay (dcELISA). In vitro propagation of the hybridoma was carried out using an Integra CELLine Culture System and the antibody was purified by affinity column chromatography. The conjugate probe was prepared by comparing two sizes of colloidal gold particles at 20 and 40 nm in diameter for the conjugation with the MAb. The MAb conjugate with 40 nm colloidal gold was selected and sprayed onto the conjugate release pad (CRP). The target cut-off value for the developed immunochromatographic strip (ICS) was 20 ng/mL according to a regulation limit in Thailand. The study on the appropriate conditions for this strip showed that aflatoxin B1 conjugated to bovine serum albumin (AFB1-BSA) and goat anti-mouse immunoglobulin (GAM) should be immobilized at the test line and control line at the same concentrations of 0.25 mg/mL. The testing sample was extracted with 70% methanol and further diluted 1:4 with Tris buffer saline with 0.05% Tween-20 (TBST) before application on the sample application pad (SAP) and the reaction could be visualized within 15 min. The analysis of 5 naturally contaminated corn samples (n=7) indicated that 2 samples contained ≥ 20 µg/kg and 3 samples contained < 20 µg/kg. Five samples, analyzed by dcELISA, showed contamination levels at <4, 9.6, 19.9, 10.5 and 39.7 µg/kg which delivered a good correlation to the results from ICS analysis. © 2017, International Society for Southeast Asian Agricultural Sciences. All rights reserved.
Aukkasarakul S.,Kasetsart University |
Chamswarng C.,Postharvest and Processing Research and Development Office |
Piasai O.,Kasetsart University |
Chinaphuti A.,Kasetsart University |
Manoch L.,Kasetsart University
Thai Journal of Agricultural Science | Year: 2014
Isolates of non-toxigenic Aspergillus niger (KUFC 7124 and 7170) and A. tubingensis (KUFC 7112 and 7123) were selected to assess in vitro antagonist activity against ochratoxin A and fumonisin producing A. niger (KUFC 7180, 7204, 7206, 7215 and 7216) and five plant pathogenic fungi viz. Fusarium oxysporum, Phytophthora palmivora, Pythium aphanidermatum, Rhizoctonia solani and Sclerotium rolfsii. Two isolates each of non-toxigenic A. niger and A. tubingensis were cultivated in dual culture with five isolates of toxigenic A. niger and plant pathogenic fungi. Non-toxigenic A. niger (KUFC 7124) suppressed toxigenic A. niger (KUFC 7180, 7125 and 7126) at levels of 62.1, 52.7 and 51.1% respectively. Non-toxigenic A. niger (KUFC 7124) reduced the growth of Phytophthora palmivora and Fusarium oxysporum with 70.6% and 68.6%, respectively. Non-toxigenic A. niger (KUFC 7170) inhibited toxigenic A. niger (KUFC 7180, 7206, 7215 and 7216) approximately 50%, whilst inhibited mycelium growth Phy. palmivora and F. oxysporum 77.8% and 58.2%, respectively. However all non-toxigenic isolates failed to inhibit the mycelial growth of S. rolfsii. Non-toxigenic A. tubingensis (KUFC 7112) effectively inhibited mycelium growth of F. oxysporum by 62.3%, but only inhibited mycelium growth of Phy. palmivora, R. solani and P. aphanidermatum by approximately 40%.
Ratanachinakorn B.,Postharvest and Processing Research and Development Office |
Srithanyarat S.,Postharvest and Processing Research and Development Office |
Kotepong P.,Postharvest and Processing Research and Development Office
Acta Horticulturae | Year: 2010
Storage life of consumer packed longan (Dimocarpus longan Lour.) fruit was conducted by packing the fruit in polyvinyl chloride (PVC) tray with or without ventilation holes or packed in PVC tray and over-wrapped with PVC stretch film prior to being stored at 2°C. Control fruit were placed on PVC tray without lid. Samples of fruit were evaluated for weight loss, skin color, firmness, soluble solids, acidity and sensory quality once a week for up to 2 weeks. During 2 weeks of storage, the control had slight brown skin color and higher weight losses and tougher skin than the others. The fruit of all treatments had no differences in soluble solids and titratable acidity. The control and others had good sensory quality for 3 and 4 weeks, respectively. The fruit transferred to further storage at 20°C decay within a few days.
Limphapayom W.,Postharvest and Processing Research and Development Office |
Wattanawichit W.,Postharvest and Processing Research and Development Office |
Satayavut K.,Postharvest and Processing Research and Development Office
Acta Horticulturae | Year: 2014
Extracts of Thai garlic from Si Sa Ket and Chiang Mai provinces were compared to Chinese garlic and were investigated for garlic oil and chemical compositions. Oil contents in Si Sa Ket, Chiang Mai and Chinese garlic were 1.25±0.7, 1.30±0.5, and 0.88±0.35%, respectively. Protein contents in Si Sa Ket, Chiang Mai and Chinese garlic were 10.93±0.12, 14.32±0.10 and 13.83±0.10%, respectively. Ethanol extraction indicated that garlic oil of Si Sa Ket, Chiang Mai and Chinese garlic contained 1.20±0.49, 1.45±0.78 and 1.30±0.18%, respectively. Chemical composition of fresh garlic extracted by using Head space SPME with fiber 100 μm PDMS include allyl mercaptan, diallyl monosulfide, dially disulfide, methyl allyl trisulfide, 3-vinyl-1,2-dithiocyclohex-4-ene, diallyl trisulfide and 3-vinyl- 1,2-dithiocyclohex-5-ene. Chemical compositions were not significantly different among the three kinds of Thai and Chinese garlics. © ISHS.