Papers by Thamarath Pranamornkith
Acta horticulturae, Mar 1, 2022
Papaya (Carica papaya L.) is a tropical fruit grown widely in Thailand. However, the export volum... more Papaya (Carica papaya L.) is a tropical fruit grown widely in Thailand. However, the export volume is low which could be due to temperature mismanagement during storage and transportation that lead to low quality fruit. This research investigated the effects of intermittent warming (IW) on ‘Holland’ papaya during storage. Papayas with 25% peel yellowing were submitted to four conditions: untreated fruit stored at 5°C (control), 15°C, IW1 condition (5°C for 4 days then subjected to 15°C for 1 day, 1 cycle) and IW2 condition (5°C for 4 days and moved to 15°C for 1 day, 2 cycles) then stored at 5°C, 90% RH until the end of storage. The quality of papayas was evaluated periodically at 0, 5, 10, 15 and 20 days of storage. The results showed that weight loss of fruit in all treatments was lower than 1.2% throughout the storage period. Fruit stored at 15°C, 80% RH had significantly (p 2) was observed since 10 days of storage. The more severity of CI symptoms for the control fruit developed...
New Zealand Plant Protection, 2015
High sorption by Pinus radiata (D Don) logs may limit insecticidal efficacy of a fumigant by rapi... more High sorption by Pinus radiata (D Don) logs may limit insecticidal efficacy of a fumigant by rapidly removing it from the treated headspace The sorption characteristics of a new fumigant ethanedinitrile (EDN) were quantified for recently harvested pine logs and the robustness of a proposed EDN sorption model developed for sawn timber was tested Over a 10h period average concentrations were 173 plusmn;1048724; 07 of the initial dose for logs with sealed ends and 94 1048724;plusmn; 04 for unsealed ends This is a high rate of sorption compared with other fumigants such as methyl bromide A proportional drop in headspace concentration over time was consistent for the two doses (20 and 50 g/m3) evaluated confirming that EDN sorption is influenced by the dose applied Bark cover did not significantly influence EDN sorption A revised sorption model for EDN is proposed here
New Zealand Plant Protection, 2014
The efficacy of ethanedinitrile (EDN syn cyanogen EDN Fumigas) for the control of burnt pine long... more The efficacy of ethanedinitrile (EDN syn cyanogen EDN Fumigas) for the control of burnt pine longhorn beetle (Arhopalus ferus (Mulsant)) adults was tested using a 126 g/m3 The results demonstrate that ethanedinitrile is a potential phytosanitary alternative to methyl bromide for disinfesting burnt pine longhorn adults from sawn timber exported from New Zealand
Journal of Stored Products Research, 2018
Acta Horticulturae, 2010
The high quality cold storage life of lime (Citrus latifolia Tanaka) fruit can be restricted by a... more The high quality cold storage life of lime (Citrus latifolia Tanaka) fruit can be restricted by a number of factors including chilling injury, degreening and rots. The objective of this study was to investigate the effects of various postharvest treatments on quality changes in main-and late-season New Zealand lime fruit. Controlled atmosphere storage (CA; 10% O 2 with 0 or 3% CO 2) was compared to regular air storage (RA) and intermittent warming (IW; varying durations) treatments across a range of temperatures. Chilling injury limited storage of fruit under all conditions at constant low temperatures. CA storage at 3% CO 2 delayed yellowing and gave better fruit quality than the 0% CO 2 treatment. Three % CO 2 CA treatments at 5 or 7°C decreased the rate of colour change compared to other constant temperature treatments but did not protect against chilling injury. IW benefited fruit quality and provided the highest overall fruit quality of all postharvest treatments tested.
Acta Horticulturae, 2017
A significant proportion of New Zealand's kiwifruit production is held as stock in local cool-sto... more A significant proportion of New Zealand's kiwifruit production is held as stock in local cool-stores for extended periods of time before being exported to global markets. The variability in fruit quality at harvest contributes to a wide range in fruit storage potential. The development of soft fruit (flesh firmness <9.81 N) during storage and the difficulty in identifying and segregating them prior to distribution cause the industry financial loss. This study aimed to evaluate the feasibility of applying visiblenear infrared (Vis-NIR) spectroscopy after cool storage, to segregate kiwifruit on their flesh firmness values so as to reduce the proportion of soft fruit for subsequent distribution in the supply chain. 'Hayward' kiwifruit (Actinidia deliciosa) from 51 growers were sourced from commercial orchards in New Zealand and stored in trays at 0°C. At the end of storage (after 75, 100 or 125 days), fruit were scanned nondestructively using an NIR spectroradiometer in the reflectance mode before flesh firmness assessment. A global calibration model for all storage times was developed based on the spectral data using a support vector machine to categorise the fruit into two groups; 'Soft' (<9.81 N) or 'Good' (≥9.81 N). The validation model was able to accurately classify approximately 48% of soft fruit and 80% of good fruit irrespective of storage time. Applying the developed model for segregation before distribution would reduce the proportion of soft fruit from 25.4% in the original population to 17.9% in the remaining population after removal of 27% of the population (predicted as soft fruit). Sorting fruit by NIR after storage may enable reduction of the effort and cost to segregate poor fruit from good fruit throughout the supply chain.
Journal of Food Engineering, 2017
Packaging Technology and Science, 2015
ABSTRACT Ethylene plays a major role in regulating fruit ripening and fresh produce senescence du... more ABSTRACT Ethylene plays a major role in regulating fruit ripening and fresh produce senescence during the postharvest period. Accumulated ethylene inside a fresh produce package has the potential to stimulate physiological activity and consequently accelerate deterioration, limiting storage life and leading to product losses. Current scientific effort focuses on the minimization of ethylene effects through ethylene removal or suppression of ethylene response. Other researchers are focussing on the development of sensors for measuring ethylene exposure within supply chain systems in order to be able to use this information to indicate produce quality and predict remaining shelf life. Full and optimal utilization of either ethylene removal or sensing technologies requires knowledge of the rates in which ethylene can flow to or from the package that the product is contained in. This study discusses the need for ethylene permeability data for polymer films and reviews the data available. Ethylene permeability of commercial films was found to range from 57 to 2.7 × 10−16 mol.m/m2.s.Pa at ambient temperatures, with activation energies being in the range of 37 000-48 000 J/mol. Amongst novel films, some containing zeolites could be 10 times more permeable, while permeability of wheat gluten films was highly influenced by relative humidity. However, generally, to date, it would seem that there is a scarcity of information on the transmission of ethylene through commonly used materials, especially at industrially relevant conditions of low temperature and high relative humidity, making prediction of ethylene conditions within a commercial package difficult. Collection of ethylene transmission data for the wide range of available films at industrially relevant conditions is required in order to maximize the utilization of newly developed ethylene removal or sensing technologies and subsequently contribute to the reduction in fresh produce losses within the supply chain.
Postharvest Biology and Technology, 2012
New Zealand Plant Protection, 2014
Ethanedinitrile (EDN syn cyanogen EDN Fumigas) is a relatively new fumigant with the potential to... more Ethanedinitrile (EDN syn cyanogen EDN Fumigas) is a relatively new fumigant with the potential to disinfest quarantine pests from radiata pine (Pinus radiata D Don) logs and sawn timber for export This research evaluated the effects of dose (20 g/m3 or 50 g/m3) timber moisture content (green or kiln dried sawn timber) endgrain sealing (sealed or unsealed timber endgrain) and load factor (11 or 44) on sorption of EDN fumigation chambers Chamber loading significantly influenced sorption with higher loading resulting in greater sorption Changes in the dose of EDN did not affect the sorption pattern Increased moisture content and endgrain sealing both reduced sorption but these effects were relatively small and the differences in sorption patterns caused by moisture content or endgrain sealing decreased over time
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Papers by Thamarath Pranamornkith