Khurnpoon, Lampan

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Changes of cut orchid quality after fumigation with clove and cinnamon essential oils
(2015-03-25)
Pumnuan, J.
;
Khurnpoon, L.
;
Insung, A.
Clove and cinnamon essential oils have been recently considered as effective alternative fumigants against thrips and mealybug, which are the major pests infecting exported orchid cut flowers in many countries. Therefore, this study aimed to investigate effects of clove and cinnamon essential oils in non-targeted fumigation on Dendrobium orchid cut flower. Changes in L∗, a∗ and b∗ values, weight loss, polyphenoloxidase (PPO) activity, total phenolics and anthocyanin content were determined. All fumigations in this study were conducted using the essential oils at the concentrations of 0.0, 3.0 and 6.0 ml/m3 for 1 h with 15-min air circulation in 1-m3 glass chambers. The effects of eugenol under the same conditions were examined. The samples were evaluated prior to the treatments, immediately after the treatments, and 3 d after the treatments at 25±1°C. The results showed a decrease of L∗ and a∗ values, and anthocyanin content in all groups, while b∗ value, percentage of weight loss and total phenolic content increased. PPO activity did not change throughout the sampling period. Remarkably, the orchids fumigated with clove and cinnamon essential oils, and eugenol at 3.0 ml/m3 did not differ from the control. However, fumigations at 6.0 ml/m3 reduced flower quality, leading to increased weight loss and petal discoloration.
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The correlation between total phenol and antioxidant capacity of sweet potato (Ipomoea batatas L.) with varying flesh color
(2012-04-01)
Khurnpoon, L.
;
Rungnoi, O.
The study established baseline data on the total phenol content and antioxidant activities of 36 sweet potato (Ipomoea batatas) cultivars with distinctive flesh color (white, yellow, orange and purple) grown in Pijit Province in the northern part of Thailand. Total phenol were measured using the Folin-Ciocalteau method while antioxidant capacity in sweet potato flesh was measured by 2,2- diphenyl-1-picrylhydrazyl (DPPH). Total phenol content ranged from 75.47- 1,283.37 ?g gallic acid equivalent (GAE) g-1 dry weight. The highest phenolic content was found in cultivar 'PJ25' (purple fleshed) and lowest in cultivar 'PJ18' (orange fleshed). Antioxidant capacity in different flesh color ranged from 72.1-84.56% of DPPH inhibition. The highest total phenol was concomitant with the highest antioxidant activity which was 84.56% for DPPH radical scavenging activity on a dry weight in cultivar 'PJ25'. Significant (*P<0.05) positive correlation was observed between total phenol content and antioxidant capacity (%inhibition) for DPPH radical scavenging activity in white (R2=0.652), yellow (R2=0.5386), orange (R2=0.6518) and purple (R2=0.899) fleshed sweet potatoes.
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Quality change on holy basil after fumigation with insecticidal essential oil formula from clove and cinnamon
(2018-04-04)
Pumnuan, J.
;
Khurnpoon, L.
;
Insung, A.
The essential oil formula from clove (Syzygium aromaticum) and cinnamon (Cinnamomum bejolghota) at the ratio of 1:3 (Cl1Ci3) has been recently considered as an effective alternative fumigant against thrips (Thrips palmi) and aphid (Aphis gossypii), which are the major pests attacking exported holy basil (Ocimum sanctum) in Thailand. This study aimed to investigate the effects of the C1Ci3 formula used as fumigant on physical quality of holy basil compared to methyl bromide application. The percentage of insect mortality and change in L*, a* and b* values, as well as weight loss of holy basil, were determined. All fumigations in this study were conducted using the formula Cl1Ci3 at the concentrations of 0.0, 2.0 and 3.0 mL m-3 for 2 h with 15-min air circulation in 1 m3 fumigation chamber and compared to methyl bromide at 20 g m-3 (recommended concentration). The observations of insect mortality were conducted at 24 h after treatment. The holy basil samples were evaluated prior to the treatments, immediately after the treatments, and after 3 and 6 days at 25±1°C. The methyl bromide fumigation showed 100% mortality of all insects and its efficacy was significantly higher than that of the Cl1Ci3 formula (73.9-96.0%). Leaf burning was observed immediately after methyl bromide fumigations. On the other hand, no significant physiological changes were observed on plants fumigated with the Cl1Ci3 formula, as compared to the control.
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Change in fruit quality and cell wall polysaccharides in bruised papaya cultivars 'Khak dum' and 'Holland'
(2012-04-01)
Khurnpoon, L.
;
Siriphanich, J.
Papaya bruising is a major postharvest problem that substantially reduces fruit quality. During the process of ripening, Thai papaya 'Khak dum' is softer than imported cultivar 'Holland' (Pak Mai Lai). 'Khak dum' is more susceptible to bruising than 'Holland'. Due to lack of detailed knowledge about bruising mechanisms, effective bruise prevention is difficult. Pulp firmness at bruised site were approximately 60 and 30 N before impact then rapidly dropped to about 30 and 20 N after 2 days following impact, while it dropped to about 45 and 28 N in control for 'Khak dum' and 'Holland', respectively. The bruised tissues expanded, became darker in color to larger bruise areas of 20.42 and 24.09 cm2, respectively and decayed 2 and 4 days following impact. Respiration rate also increased by 1.5-times in 24 h following impact then declined. Soluble solids content was not significantly different between bruised and control fruit, but slightly increased by the end of storage. Pulp softening at the bruise area was associated with the increase in water soluble pectin fraction approximately 3 and 1.5 times as compared to the control in 'Khak dum' and 'Holland', respectively, while CDTA and 4 M KOH soluble fractions slightly decreased by the end of storage. Na2CO3 slightly increased in 'Khak dum' while it decreased in 'Holland'.

Khurnpoon, Lampan

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