Burapha Science Journal

Variations of Sediment Organic Matter and Nutrients in Nam Oun Dam Reservoir, Sakon Nakhon Province

Kritsana Akkharaphat — 2026-01-07

Background and Objectives : Nam Oun Dam is a large reservoir, serves water storage, irrigation, flood control and drainage. Nam Oun Dam Reservoir covers the areas of many districts in Sakon Nakhon province. Land use in the areas surrounding the reservoir, such as residential communities, tourist sites, fisheries, agriculture (crop cultivation and livestock farming), fisheries conservation zones, and water inflow and outflow areas. These areas are important for the generation of sediments and nutrients within the reservoir. This reservoir is currently facing the problem of Giant Salvinia infestation (Salvinia molesta D.S. Mitchell), which creates a risk to accelerate the accumulation of sediments and may affect the water quality in the long-term of the reservoir. This study aimed to investigate the spatial and seasonal variations of organic matter and nutrient contents in the sediments of Nam Oun Dam Reservoir, including sediment water content and particle size.

Methodology : Study sites in Nam Oun Dam Reservoir were 10 stations (S1-S10) such as S1 (water outlet-left gate), S2 (water outlet-right gate), S3 (tourist attraction and community), S4 (raft-ecotourist attraction and fisheries conservation zone), S5 (pumping station for tap water production and agriculture areas), S6 (Huai Lek Fai inlet and community areas), S7 (fisheries conservation zone), S8-S9 (fisheries and agriculture area) and S10 (Nam Oun River inlet area). Surface sediment samples were collected using an Ekman Grab sampler (15x15 cm) from 10 stations (S1-S10) located in areas with different land uses surrounding the reservoir. Sampling was conducted seasonally within a year, three sampling periods were summer (late March 2023), rainy (mid- August 2023) and winter (early January 2024). The sediment samples were analyzed to determine the contents of organic carbon (OC), organic matter (OM), ammonium-nitrogen (NH₄⁺-N), nitrate-nitrogen (NO₃^--N), phosphate-phosphorous (PO₄^3--P), sediment water content (WC) and percentage (%) of sediment particles (clay, silt and sand). The data were statically analyzed using One-Way Analysis of Variance (ANOVA), the averages were compared by Duncan’s Multiple Range Test, and the relationships between parameters were analyzed by Pearson’s Correlation.

Main Results :The contents of OC and OM ranged from 0.85-4.93% and 1.46-8.50%, with the averages of 2.22±0.97% and 3.83±1.66%, respectively. There were not significant seasonal differences (p>0.05), whereas significant spatial differences were found among the study sites (p<0.05). Site S7 was the highest OC and OM contents, while the lowest contents were found at S1, S2, S3, S6, S9 and S10. The averages of OM content in most areas of the reservoir indicated a low level of organic matter in the sediments. The averages of NH₄⁺-N, NO₃^--N and PO₄^3--P contents ranged from 3.68-58.69 mg/kg, 10.94-160.23 mg/kg and 0.07-0.72 mg/kg, with the averages of 17.55±12.99 mg/kg, 50.17±40.73 mg/kg and 0.36±0.20 mg/kg, respectively. There were not significant spatial differences for nutrients (p>0.05). However, significant seasonal differences were observed for NO₃^--N and PO₄^3--P (p<0.05), with the highest averages recorded in winter and rainy seasons, respectively. In contrast, NH₄⁺-N was not significant seasonal difference (p>0.05). The NH₄⁺-N content was significantly correlated with OM content (p<0.05, r=0.41) and highly significantly correlated with NO₃^--N content (p<0.001, r=0.68). Furthermore, PO₄^3--P content was also found to be very significantly correlated with OM content (p<0.01, r=0.49). These indicated that the organic matter content in the sediments had positive effect on the nutrient contents. WC ranged from 41.47-77.11%, with the averages of 58.45±9.03%. WC was not significant differences between seasons (p>0.05), but significant difference was found among study sites (p<0.05). The highest contents were found at S7 and S8, with the lowest content was found at S3. WC showed highly significant positive correlation with the contents of OM (p<0.001, r=0.83), very significant positive correlation with NH₄⁺-N (p<0.01, r=0.48), and PO₄^3--P (p<0.01, r=0.55) and significant positive correlation with NO₃^--N (p<0.05, r=0.39). Therefore, WC could be the important parameter for preliminary indicator of the organic matter and nutrient conditions in the sediments. The results of the sediment particle size were found that clay, silt and sand ranged from 19.96-54.27%, 14.72-44.57% and 22.63-62.09%, with the averages of 29.06±8.50%, 26.83±8.28% and 44.17±11.60%, respectively. Particle size was not statically significant seasonal difference (p>0.05), but it was statically significant spatial difference (p<0.05). The results of sediment texture analysis showed that sandy clay loam was mostly found in the study areas of the reservoir (S2, S4, S7 and S8), followed by loam (S1, S3 and S5), clay loam (S6 and S9) and clay (S10), respectively. This research did not detect a correlation in the particle size and the contents of organic matter and nutrients.

Conclusions : The land use areas surrounding the Nam Oun Dam Reservoir had a significant effect (p<0.05) on the variations in sediment organic matter contents (OC and OM), water content (WC) and Particle size (clay, silt and sand) within the reservoir, but had no significant effect (p>0.05) on the sediment nutrient contents. In contrast, the season had a significant effect (p<0.05) on the variations of OC, OM and particle size, but had no significant effect (p>0.05) on the variations of most sediment nutrients. Further study on water current velocity could provide more explanation of sediment transport direction. The data from this research can be used as baseline for sustainable management of Nam Oun Dam Reservoir.

Prediction of above Ground Carbon Sequestration from Landuse/Landcover Changes in the Upper Northern Thailand Using CASA-Biosphere Model

Jirapon Samsen — 2026-01-07

Background and Objectives : Aboveground carbon sequestration, or Net Primary Productivity (NPP), is an important ecological indicator that reflects the potential growth of vegetation in absorbing and storing carbon dioxide from the atmosphere through photosynthesis. This process plays a critical role in offsetting carbon emissions resulting from human activities. Therefore, assessing aboveground carbon sequestration in a specific region is essential for understanding carbon balance within ecosystems and promoting ecological restoration. This study selected the Upper Northern Region of Thailand as the study area due to several unique characteristics, including high ecological diversity, the presence of various forest and agricultural landscapes, topographical variation ranging from highlands to watershed areas, and seasonal climatic fluctuations. Land use/land cover (LULC) in this region directly affects the carbon sequestration potential of each land type. However, systematic studies on the relationship between LULC types and carbon sequestration in the Upper Northern Region of Thailand remain limited, especially those employing remote sensing technology for detailed spatial analysis. This study aims to (1) Analyze the relationship between carbon sequestration and changes in land use/land cover, and (2) Predict future carbon sequestration and land use/land cover changes.

Methodology : The study begins with an analysis of the relationship between land use/land cover and aboveground carbon sequestration by classifying land use types for three time periods 2016, 2019, and 2024 using the Random Forest model. The CASA-Biosphere Model is then applied to estimate carbon sequestration, and the estimated results are validated using field data through Pearson’s correlation coefficient. Subsequently, future aboveground carbon sequestration is predicted using the hybrid Markov-CA model to simulate future LULC changes. Regression equations are then developed to predict the Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST). These predicted datasets, together with projected LULC data, are incorporated into the CASA-Biosphere Model to estimate future NPP. Finally, the accuracy of NPP prediction is assessed using Pearson’s correlation coefficient, Correlation Coefficient, Root Mean Square Error (RMSE), and Mean Absolute Error (MAPE).

Main Results : The analysis using the CASA-Biosphere Model revealed distinct variations in aboveground carbon sequestration across different land use and land cover (LULC) types, with forest areas exhibiting the highest sequestration potential (0.249–1.256 gC/m²) due to dense vegetation, complex canopy structures, and robust root systems, followed by perennial crops (0.245–0.836 gC/m²), while rice paddies and field crops showed moderate values (up to 0.596 gC/m² and 0.637 gC/m², respectively), reflecting differences in species composition, management practices, and growing seasons. In contrast, urban and industrial areas showed very low or negative sequestration (0.057 to –0.287 gC/m²), indicating their role as net carbon sources as a result of limited vegetation cover and high anthropogenic emissions. Model validation using three sets of field data produced Pearson’s R² values of 0.663, 0.710, and 0.994, confirming strong agreement between modeled and observed NPP. Future projections for 2033 indicate increasing carbon sequestration across most LULC categories, with forests remaining the highest (up to 1.326 gC/m²), alongside rising values for rice paddies (0.569 gC/m²) and perennial crops (0.778 gC/m²), a trend potentially influenced by climatic conditions that enhance vegetation productivity. The accuracy of NPP predictions, validated using historical data, achieved a high correlation coefficient (R² = 0.924), demonstrating the model’s strong capability to capture spatial–temporal patterns and its suitability for long-term carbon sequestration forecasting and environmental planning

Conclusions : The assessment of aboveground carbon sequestration under land use/land cover changes using the CASA-Biosphere Model reveals that forest areas possess the highest carbon sequestration potential, followed by perennial crops. Agricultural areas show moderate potential, with field crops performing similarly to rice paddies. Urban and industrial areas exhibit very low or negative sequestration, acting instead as carbon sources. The CASA-Biosphere Model demonstrates high accuracy when validated with field data. Forecasts for the year 2033 indicate increasing carbon sequestration for all LULC categories, with forests remaining the strongest contributors, followed by perennial crops and agricultural areas. The high predictive accuracy confirms the suitability of this approach for assessing carbon sequestration trends within the study region. The findings support forest conservation and sustainable agricultural practices to enhance carbon sequestration and mitigate climate change impacts. The results can guide policy-making on forest resource conservation by identifying priority areas for preservation and restoration, as well as informing national greenhouse gas reduction targets under the Paris Agreement. Moreover, the projected carbon sequestration trends can serve as a foundation for sustainable land management, low-carbon agriculture, and the development of agricultural carbon credit mechanisms to enhance regional and national carbon sequestration efficiency.

Investigation of Land Use and Land Cover Change and Urban Heat Island Phenomenon in Nakhon Ratchasima Province

Anake Srisuwan — 2026-01-07

Background and Objectives: Urbanization constitutes a significant physical and sociodemographic transformation of the 21st century, exerting considerable influence on global ecosystems and local microclimates. Human-induced alterations in the previously vegetated and permeable soil structure of natural landscapes, along with their transformation into concrete, asphalt, and decorative architectural developments, significantly affect the Surface Energy Budget (SEB). These alterations generate an artificial environment that disrupts the natural equilibrium of the Latent Heat Flux. Latent Heat Flux decreases exponentially because of insufficient evapotranspiration, concurrently leading to an increase in the storage and re-release of Sensible Heat Flux. The Urban Heat Island (UHI) Effect refers to the phenomenon where urban areas experience higher temperatures than their rural surroundings due to human activities and alterations in land cover. The Urban Heat Island (UHI) Effect refers to a temperature phenomenon where urbanized areas exhibit markedly elevated atmospheric and surface temperatures compared to nearby rural regions. The Urban Heat Island (UHI) Effect refers to a temperature phenomenon in which urbanized areas exhibit markedly elevated atmospheric and surface temperatures compared to nearby rural regions. The UHI Effect has significant implications, including increased energy demands for air conditioning, deterioration of air quality due to heightened ground-level ozone production, and substantial risks to human health and urban living conditions. Nakhon Ratchasima Province is strategically located as the Gateway of Isan, serving as the biggest economic, industrial, and transportation center of Northeastern Thailand. The province has undergone significant structural urbanization in the last two decades. The expansion has been driven by major infrastructure assets and an increase of industrial areas. The city is experiencing thermal challenges due to its expansion. The previous study on the UHI phenomenon in this domain has been mainly descriptive. Literature often exhibits insufficient statistical validation to quantify temperature variations among various Land Use and Land Cover (LULC) types and is frequently hindered by methodological limitations concerning satellite image data calibration. Addressing these significant studies problems. This study aims to: (1) analyze the spatiotemporal changes in land use and land cover (LULC) from 2006 to 2021 and (2) assess the impact on structural changes in urban heat island (UHI) intensity and dynamics, by using high-quality radiometric data and robust statistical methods to verify the accuracy and reliability of the results.

Methodology: This study employed a Hybrid Classification method for the analysis of Land Use and Land Cover (LULC) for optimal accuracy of data and consistency. The 2006 LULC database published by the Land Development Department (LDD) was used as the baseline for this study. In 2021, LULC classification occurred by using multispectral imagery from the Landsat 8 Operational Land Imager (OLI) sensor that was acquired during the dry season in February to avoid cloud influence and variations in the season. The classification process used the Maximum Likelihood Classification (MLC) algorithm, that is a parametric supervised learning method based on the assumption of a normal distribution of image pixels within each training class. The classification accuracy was assessed through Stratified Random Sampling involving 205 reference points, results in an Overall Accuracy of 95% and a Kappa Coefficient of 0.90, which refers to an excellent level of agreement between the LULC classified map and in-situ data. The temperature evaluation focused on capturing Land Surface Temperature (LST) and identified data quality through the selection of USGS Collection 2 Level-2 Science Products (L2SP). The measurements of temperatures have been acquired from Landsat 5 Thematic Mapper (TM) for February 2007 and from Landsat 8 Thermal Infrared Sensor (TIRS) for February 2021. A selection was taken to apply data from the same temporal season (dry/cool season), and the selection of 2007 LST as a baseline estimate effectively reduced discrepancies associated with seasonal variability and atmospheric absorption. This study uses advanced statistical methods to evaluate the relationship between LST and various LULC types, expanding higher than simple descriptive statistics. Welch’s One-way ANOVA was used to improve its resistance against violations of homogeneity of variance assumptions, which are often present in environmental datasets. Post-hoc pairwise comparisons were performed utilizing the Games-Howell method. The spatial impact of heat island variation has been evaluated by using the Urban Heat Island Ratio Index (URI) and the Temperature Grade Change Index (TGCI) to show and quantify heat island expansion.

Main Results: The Transition Matrix analysis showed that the city's urban morphology changed a lot in terms of structure throughout the 15 years of research. Urban and built-up areas grew by a net of 73.66 square kilometers, which is a huge growth rate of 34.46% compared to the baseline. This urban and built-up area expansion primarily occurred on agricultural land (55.32 sq. km.) while other of LULC (23.35 sq. km.). Additionally, the analysis found that forest land decreased by 49.83%, which shows how significantly people are placing stress on natural resources and their buffers. Statistical analysis of the 2021 LST data found important proof of the UHI effect. The average surface temperature in urban and built-up areas was 28.4°C, which was significantly greater than the average surface temperature in forests land (25.40°C), with a statistical significance of p < .001. The average temperature difference of about 2.99°C shows how urbanization impacts the temperature. The result is distinct from the baseline LULC data from 2007, that showed a lack of statistical significance between urban and built-up areas and forest area temperatures. This indicates that the city has changed from a temperature balanced condition to a distinct island. In 2021, the mean temperature in the area decreased into slightly because of the La Niña phenomenon, which decreases the region. However, the location inside thermal structure became more severe. The URI analysis showed that the number of regions classified as "High Temperature Grade" increased from 7.30% to 7.39% of the whole area studied. This indicates that the increase due to urbanization is strong enough to cause local cooling patterns in the surrounding environment. The Linear Regression study also showed a strong positive relation between the Normalized Difference Built-up Index (NDBI) and LST. The coefficient of slope increasing higher in 2021 shows that the current urban surface elements in Nakhon Ratchasima are becoming increasingly prone to heat accumulation and retention.

Conclusions : This study shows that the fast urbanization of Nakhon Ratchasima during the past fifteen years has greatly exacerbated the UHI phenomena. The city has transitioned from thermal equilibrium to a fully developed heat island, mostly due to alterations in urban morphology rather than regional climatic influences. The results have serious effects on urban planning and policy. Statistical evidence indicates that there is a major negative relationship between LST and NDVI and MNDWI. Therefore, city planners require that they quickly add "Blue-Green Infrastructure" to the city's overall strategy. Several actions that should be implemented are to protect the original forest areas, build green spaces in cities, and restore water bodies. These actions have been shown to be the most effective approaches to decrease UHI intensity, increase Nakhon Ratchasima more comfortable in hot weather, as well as making it more resilient to climate change as the future urban expansion.

Synergistic Antibacterial and Antibiofilm Activity of Glochidonol Isolated from Glochidion acuminatum with Antibiotics against Opportunistic Bacteria

Wisatre Kongcharoensuntorn — 2026-01-08

Background and Objectives: Glochidonol, a bioactive compound isolated from Glochidion acuminatum, has been traditionally recognized for its analgesic, antipyretic, and diuretic properties. In recent years, scientific investigations have revealed that Glochidonol also possesses a broad spectrum of biological activities, including anti-inflammatory, antibacterial, antioxidant, and anticancer effects. These properties make it a promising candidate in the search for novel agents to combat emerging threats from drug-resistant microorganisms. Opportunistic bacterial pathogens such as Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus are increasingly responsible for healthcare-associated infections, especially among immunocompromised individuals. Infections caused by this group of bacteria are often severe and tend to develop into bloodstream infections (septicemia), which may lead to serious complications or death. This condition reduces the effectiveness of antibiotics in the tetracycline group (such as Oxytetracycline) and the penicillin group (such as Ampicillin), rendering them less effective or ineffective.Opportunistic bacteria have developed various mechanisms of antibiotic resistance, such as producing drug-degrading enzymes, reducing membrane permeability, and most importantly, forming biofilms, complex structures composed of extracellular polymeric substances (EPS) secreted by the bacteria to encapsulate themselves and neighboring cells within the community. This protective matrix enables the bacteria to survive under unfavorable environmental conditions and adhere firmly to surfaces such as wounds or medical devices, making biofilm formation a key factor that accelerates the high incidence of antibiotic resistance among opportunistic bacteria. As conventional antibiotics such as Oxytetracycline) and Ampicillin) become less effective due to these resistance mechanisms, the development of new therapeutic strategies is urgently needed. One promising approach is the combination of natural bioactive compounds with existing antibiotics to restore or enhance antibacterial efficacy. Natural products like Glochidonol are of particular interest because they may disrupt biofilm formation, increase bacterial membrane permeability, or inhibit resistance-related enzymes, thereby potentiating the activity of conventional antibiotics. Therefore, the use of Glochidonol in combination with antibiotics may represent a new therapeutic alternative and constitutes the first study of this compound. Given this context, this study aims to evaluate the potential synergistic effects of Glochidonol, in combination with standard antibiotics, against opportunistic bacterial pathogens, with a particular focus on its ability to inhibit bacterial growth and biofilm formation. By investigating these combined effects, the research seeks to provide a scientific basis for utilizing Glochidonol as a complementary agent in antimicrobial therapy, offering a novel and sustainable strategy to combat drug-resistant infections and reduce the environmental impact of antibiotic-resistant bacteria.

Methodology : This study investigates the efficacy of Glochidonol in inhibiting the growth of opportunistic bacteria by determining the Minimal Inhibitory Concentration (MIC) using the broth microdilution assay. Glochidonol was prepared in various concentrations in Mueller Hinton Broth (MHB) and mixed with bacterial suspensions adjusted to 1 × 10⁸ CFU/mL. The samples were incubated at 37°C for 18–24 hours, and bacterial growth was conducted by measuring optical density at 600 nm (OD_₆₀₀) to determine the MIC. To evaluate the synergistic antibacterial activity, the Fractional Inhibitory Concentration Index (FICI) was calculated using the checkerboard microdilution assay. Glochidonol was combined with antibiotics, and the mixtures were tested against bacterial suspensions at 1 × 10⁸ CFU/mL, following the same incubation protocol as the MIC assay. The FICI was calculated to determine potential synergistic effect between Glochidonol and antibiotics. The anti-biofilm activity of Glochidonol was determined using the Crystal Violet Assay. Bacterial cultures were incubated with Glochidonol or antibiotics for 24 hours, after which non-adherent cells were removed by washing with Phosphate Buffered Saline (PBS). Bacterial biofilms were stained with 0.1% crystal violet, fixed with 100%methanol, and the bacterial bound dye was solubilized using 33% glacial acetic acid. Biofilm biomass was quantified by measuring optical density at 600 nm.

Main results : The purified compound Glochidonol (GE-12) was found to inhibit the growth of opportunistic bacteria, including both Gram-positive and Gram-negative bacteria. GE-12 exhibited its strongest antibacterial activity against Gram-negative bacteria, particularly against A. baumannii and K. pneumoniae, with a MIC of 128 µM. When compared with conventional antibiotics, GE-12 demonstrated comparable efficacy to Ampicillin and Oxytetracycline. Moreover, GE-12 showed the best synergistic effect with Oxytetracycline against Escherichia coli, with a FICI value of 0.56. In contrast, it showed antagonistic effect against Pseudomonas aeruginosa (FICI = 32) and had no synergistic effect against A. baumannii. The time-kill assay revealed that GE-12 most effectively inhibited E. coli growth at 8 hours when used at 16 µM (1/64 MIC) in combination with Oxytetracycline at 256 µM (1/8 MIC). For P. aeruginosa, the best inhibitory effect was observed when GE-12 at 16 µM (1/32 MIC) was combined with Oxytetracycline at 2048 µM (1× MIC). Additionally, GE-12 at a concentration of 2048 µM was most effective in inhibiting biofilm formation of A. baumannii, E. coli, and P. aeruginosa over a 2–24hour period, with inhibition rates ranging from 25% to 68%.

Conclusions : Glochidonol isolated from G. acuminatum demonstrated stronger inhibitory activity against Gram-negative bacteria compared to Gram-positive bacteria. It also exhibited synergistic effects in inhibiting bacterial growth and biofilm formation in both drug-resistant and non-resistant strains, particularly E. coli and P. aeruginosa.

Effect of Supplementation Amino Acids in Common Lowland Frog; Rana rugulosa (Wiegmann, 1935) Diets on Growth Performance and Survival Rate

วิจิตรตา อรรถสาร — 2026-01-20

Background and Objectives: This study aimed to investigate the optimal dietary amino acid supplementation level on weight gain and survival rate of the common lowland frog (Raguna rugulosa). The common lowland frog is an economically important aquatic species that is widely favored by consumers and has a continuous market demand throughout the year. Moreover, it has considerable potential for international trade in both live and frozen forms, resulting in increasing interest in common lowland frog culture among farmers. However, frog farming often encounters limitations related to feed efficiency, leading to relatively high feed conversion ratios and increased production costs. Therefore, the development of appropriate nutritional strategies to enhance growth performance is of particular importance. Dietary amino acid supplementation represents a potential approach, as amino acids are the basic components of proteins and can be absorbed and utilized by the organism more efficiently than intact proteins. Under normal conditions, dietary proteins must be digested into amino acids before absorption into the bloodstream, whereas direct amino acid supplementation allows for more rapid utilization by the body. This may promote improved growth performance and enable frogs to reach marketable size within a shorter rearing period compared with conventional feeding practices.

Methodology : The experiment was conducted using a Completely Randomized Design (CRD) with six dietary treatments, each with three replicates. The treatments consisted of different levels of concentrated amino acid supplementation in a commercial pelleted diet at 0 (control), 0.125, 0.25, 0.50, 0.75, and 1.00 mL per Kg of feed. The amino acid concentrate comprised 19 amino acids: arginine, isoleucine, leucine, histidine, threonine, methionine, tryptophan, phenylalanine, valine, lysine, glutamine, aspartate, glycine, cysteine, tyrosine, proline, alanine, serine, and hydroxyproline. Common lowland frog juveniles 45 days old with an initial body weight of approximately 2–3 g, were used in the study. The frogs were randomly stocked into land-based net cages measuring 1 × 1 × 0.8 m at a density of 20 individuals per cage, resulting in a total of 240 frogs. Initial body weight was recorded for all individuals (100%) in each experimental unit and replicate. The feeding trial lasted for 90 days and was divided into 3 phases. During days 1–20, frogs were fed a high-grade commercial diet containing 42% crude protein. From days 21–40, a small pellet diet containing 35% crude protein was provided, and from days 41–90, a medium pellet diet containing 30% crude protein was used. The diets were supplemented with liquid concentrated amino acids according to the respective treatments. Frogs were fed at a rate of 10% of body weight per day during the first 20 days and 5% of body weight per day thereafter. Feeding was conducted twice daily, in the morning and evening. Growth performance and survival rate were evaluated by randomly sampling and weighing 10 frogs (50%) from each experimental unit and replicate at 10 day intervals throughout the 90 day experimental period.

Main Results : At the beginning of the experiment, common lowland frogs had an average initial body weight of 2.46 ± 0.06 g. Throughout the experimental period, frogs fed diets supplemented with amino acids exhibited a continuous increase in body weight. At the end of the experiment, the data were subjected to statistical analysis using analysis of variance (ANOVA). The results indicated no significant differences (P > 0.05) in weight growth performance or survival rate among frogs fed diets supplemented with different levels of amino acids. However, frogs receiving amino acid supplementation at levels of 0.125, 0.25, 0.50, 0.75, and 1.00 mL per kg of feed tended to show higher growth performance and survival rates compared with frogs fed the control diet without amino acid supplementation. Notably, frogs fed diets supplemented with amino acids at 0.25 mL per kg of feed exhibited the best performance in terms of final body weight, average weight gain, average daily weight gain, and survival rate, with values of 101.27 ± 3.03 g, 1.13 ± 0.03 g per day and 98.33 ± 2.89 %, respectively. This was followed by supplementation levels of 0.50, 0.75, 1.00, 0.125, and 0 mL per kg of feed (control).

Conclusions : The results of this study indicated that amino acid supplementation in the diets of common lowland frogs had no significant effects on growth performance, feed conversion ratio (FCR), or survival rate. However, frogs fed amino acid supplemented diets tended to exhibit better growth performance and survival compared with those fed the unsupplemented control diet. In particular, the supplementation level of 0.25 mL per kg of feed showed superior performance compared with all other treatments. In contrast, higher levels of amino acid supplementation (0.75 and 1.00 mL per kg of feed) tended to result in reduced growth performance and survival rates. Therefore, amino acid supplementation in aquaculture feeds should be carefully evaluated to determine appropriate and optimal inclusion levels that meet the nutritional requirements of the cultured species without adverse effects.

Long-Term Cryopreservation of 2-Cell Stage Embryos in ICR/Mlac-Hydro and ICR/Mlac-Free Hydro Mice at the National Laboratory Animal Center, Mahidol University

Theerapong ฺBuaban — 2026-01-21

Background and Objectives : The National Laboratory Animal Center, Mahidol University, is a source of laboratory animal production for research in Thailand. ICR/Mlac-hydro and ICR/Mlac-free hydro mice were developed as an animal model for hydronephrosis in humans. Additionally, these mouse strains have been preserved in the embryo bank since 2014. To prevent the loss of mouse strains, ensure the stability of laboratory animals, increase the diversity of mouse strains, develop the science of laboratory animal, reduce the import of expensive laboratory animals, and reduce the costs of laboratory animal breeding. However, the production of these mouse strains has been discontinued as research using these animals has been completed. To ensure that the new colony of ICR/Mlac-hydro and ICR/Mlac-free hydro mice can be established in the future. Therefore, 11-year frozen 2-cell stage embryos of ICR/Mlac-hydro and ICR/Mlac-free hydro mice will be tested by the thawing to determine the percentage of survival 2-cell stage embryos (% survival). The survival 2-cell stage embryos of ICR/Mlac-hydro and ICR/Mlac-free hydro mice were used for embryo transfer in recipients to determine the percentage of newborns (% newborn). After that, a pair of newborns in each mouse strain was tested for fertility with natural mating.

Methodology : This study was approved by the National Laboratory Animal Center-Animal Care and Use Committee (NLAC-ACUC, protocol no. AP2024-02). All animal procedures were conducted at the Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC) International. All mice were maintained under routine husbandry procedures in the animal room with strict hygienic conventional, controlled temperature at 22±3ºC, 30-70% humidity, 14 hours light conditions (lights on from 6:00 AM to 8:00 PM), 5-7 ppm choline reverse osmosis water, and a standard mouse diet. Mice had access to diet and water at all times (ad libitum). Mice are kept in plastic cages and stainless-steel lids. The sterile bedding used consisted of corn cobs and dried water hyacinth. Before thawing, the culture plate was prepared with M16 medium on a 35 mm sterile plastic dish consisting of a 3 drop of wash drop (50 µl), and a culture drop (150 µl) covered with mineral oil in a CO₂ incubator, overnight. The next morning, the 0.25 ml straw tube was removed from the liquid nitrogen tank, warmed at room temperature for 20 seconds, then warmed in a 37ºC water bath for 20 seconds. The 0.25 ml straw tube was cut with sterilized scissors, and the 2-cell stage embryos, along with 35EG and 0.3 M Trehalose, were released into a 35 mm sterile plastic dish. 30 seconds later, the embryos were found under a stereomicroscope and thawed using a 50 µl of 37°C 0.3 M Trehalose for 3 minutes, a 50 µl of 37°C 0.15 M Trehalose for 3 minutes, a 50 µl of 37°C 0.075 M Trehalose for 3 minutes, and a 50 µl of 37°C Holding medium for 5 minutes. Embryos were washed in 50 µl of M2 medium 3 times and washed in a wash drop 3 times. The survival 2-cell stage embryos were cultured in a 150 µl culture drop in a CO₂ incubator, waiting for embryo transfer. The survival 2-cell stage embryos were used for transfer to the oviducts of recipients. The recipients were natural-born on days 19-20 after embryo transfer. The newborns were set to mate at 7 weeks of age.

Main Results : The thawing of 157 embryos in ICR/Mlac-hydro mice. The results show that 142 embryos were recovered under a stereomicroscope, and then 48 embryos were found dead. Ninety-four of the 2-cell stage embryos were alive, with the percentage of survival 2-cell stage embryos was 59.9 (94/157). In ICR/Mlac-free hydro mice, 208 embryos were thawed, and 196 embryos were discovered. After that, 88 embryos were determined to be dead. 108 of the 2-cell stage embryos were alive, with the percentage of survival 2-cell stage embryos being 51.9 (108/208). The percentage of survival 2-cell stage embryos did not differ significantly between the two mouse strains (Fisher’s Exact Test, P>0.05). The embryo transfer of survival 2-cell stage embryos. In ICR/Mlac-hydro mice, the 94 survival embryos were transferred to 8 recipients. 19-20 days later, the number of newborns was 7, 8, 6, and 8 in recipients no. 3, 4, 6, and 8, respectively. The percentage of newborns was 30.9 (29/94), consisting of 19 males and 10 females. For ICR/Mlac-free hydro mice, 108 of the survival 2-cell stage embryos were transferred to 7 recipients. The number of newborns was 7 and 4 in recipients no. 10 and 13, respectively. The percentage of newborns was 10.2 (11/108), including 7 males and 4 females. However, the percentage of newborns differed significantly between the two mouse strains (Fisher’s Exact Test, P<0.05). After natural mating of each mouse strain, ICR/Mlac-hydro mice gave birth to 6 offspring, including 3 males and 3 females. In ICR/Mlac-free hydro mice, 7 offspring were born, consisting of 3 males and 4 females.

Conclusions : The embryo bank can preserve the strains of ICR/Mlac-hydro and ICR/Mlac-free hydro mice. The 11-year-frozen 2-cell stage embryos survive after thawing and will be born after embryo transfer. Mice can give birth naturally and are sufficient for establishing the new colony.

Leaf Epidermal Anatomy of Medicinal Plants in Lamtakhong Research Station, Nakhon Ratchasima Province

Phutsadee Phromprasit — 2026-02-09

Background and Objectives : Nowadays, medicinal plants are being utilized in a wide range of applications, leading to the compilation of traditional knowledge and local wisdom from various sources within Nakhon Ratchasima Province. However, accurate species identification prior to use is crucial, as some plants may exhibit similar external morphological features while possessing distinct anatomical structures that influence phytochemical accumulation and medicinal properties. Leaf epidermal anatomy of medicinal plants serves as an important diagnostic tool because these characters are genetically inherited, can be examined throughout all seasons, and allow species identification even when plant materials are incomplete, highly fragmented, or ground into herbal powders, conditions that increase the likelihood of adulteration with parts from different plant species. The aim of this study was therefore to establish a reference database of leaf epidermal anatomical characteristics for selected medicinal plant species found in the herbal garden of the Lamtakhong Research Station, Nong Sarai Subdistrict, Pak Chong District, Nakhon Ratchasima Province. This research station is a significant learning resource in Thailand, housing a diverse collection of medicinal plants used in both pharmaceutical applications and pest control. Nevertheless, anatomical information on the leaf epidermis of many species cultivated in this garden remains lacking. The findings from this study help fill this knowledge gap and provide foundational data that can be applied to future work in plant taxonomy and pharmacobotany.

Methodology : Medicinal plants were gathered from the herbal garden at Lamtakhong Research Station, Nakhon Ratchasima Province, and fixed in 70% ethyl alcohol for preservation. Anatomical characteristics of the leaf epidermis were examined for 86 medicinal plant species, representing 75 genera and 42 families. The characters investigated included cuticular ornamentation, stomatal types and position, stomatal density, epidermal cell shape and density, trichome types and distribution patterns, and the presence of crystals and other inclusions. The specimens were prepared by the clearing technique using a 5 percent sodium hydroxide (NaOH) solution. The mature leaf blades (margin, blade, and midrib) were cut into sections of approximately 5×5 mm. The samples were immersed in a 5% Clorox solution for 15-30 minutes (until the sample is colorless). Afterward, rinse with clean water 4–5 times. Dehydration was performed using a graded ethanol series (30%, 50%, and 70%) for 15 minutes each, respectively. The samples were stained with 1% Safranin-O in 70% in ethyl alcohol solution for 3–12 hours, then washed off the excess stain with 95% ethanol 2–3 times. Dehydrated with a series of increasing 95% ethanol, 100% ethanol, then a 1:1 mixture of ethanol and xylene, and finally in pure xylene, for 30 minutes at each step. The slides were mounted using DePeX. The abaxial and adaxial surfaces of leaf epidermis were described under the light microscope (LM). Photographs were taken using a Leica ICC50W digital camera connected to the light microscope. The voucher specimens were deposited in the Herbarium of Nakhon Ratchasima Rajabhat University.

Main Results : The generalized qualitative anatomical characteristics of the eighty six medicinal plants studied were as follows: 1) the cuticular ornamentation is smooth or striated 2) the shapes of epidermal cells are polygonal, jigsaw-like and irregular, 3) the stomata are present in both abaxial and adaxial epidermis (amphistomatic leaf) or present in only abaxial epidermis (hypostomatic leaf), the stomatal types are anomocytic, paracytic, actinocytic, cyclocytic, tetracytic, anisocytic and diacytic, 4) the trichome are present in both sides, only abaxial or absent, the trichome types are unicellular trichome, bicellular trichome, multicellular trichome and glandular trichome, and 5) the types of inclusions are prismatic crystal, druse crystal, raphide crystal, sand crystal cystolith crystal and inclusion not present. These characteristics can be used to identify some closely related species. The quantitative data of leaf epidermal anatomical characteristics in adaxial surface: Trevesia palmata had the highest average epidermal cell density (236.55±11.0 cell/mm²) while Dracaena angustifolia had the lowest average epidermal cell density 33.44±4.19 cell/mm²). Murraya paniculata had the highest average stomatal density (60.33±7.12 stomata/mm²) while Platostoma palustre had the lowest average stomatal density (1.11±0.31 stomata/mm²). The quantitative of leaf epidermal anatomical data in abaxial surface: Buddleja paniculata had the highest average epidermal cell density (185.00±6.63 cell/mm²) while Strobilanthes cusia had the lowest average epidermal cell density (7.44 ±11.28 cell/mm²). Murraya paniculata had the highest average stomatal density (63.44±9.87 stomata/mm²) while Platostoma palustre had the lowest average stomatal density (2.33±1.33 stomata/mm²).

Conclusions : The leaf epidermal anatomical study of medicinal plant species at Lamtakhong Research Station revealed several qualitative anatomy features that can be used to authenticate certain species present in the area. These include variation in cuticular ornamentation patterns, shape of epidermal cells, stomatal cells position, type of stomata, type of trichomes, and crystal type and deposit. Quantitative anatomical data are variable and cannot be used to identify all medicinal plants; however, they can be used to distinguish between certain species that share similar qualitative characteristics. Such information provides a fundamental reference framework that can support future applications in the pharmacognostic and pharmaceutical evaluation of medicinal plants.

Trematode Infections of Gastropods in Saraburi Province

Wivitchuta Dechruksa — 2026-02-10

Background and Objectives : Gastropods are economically important and also play a significant role in medical malacology as intermediate hosts of various trematode parasites. Trematode infections of humans and animals are generally classified into four major groups: liver flukes, lung flukes, intestinal flukes, and blood flukes. Each trematode group is transmitted from the definitive host to freshwater snails that serve as the first intermediate host, where the larval stages multiply asexually to increase the number of trematode larvae within the snail. The cercarial stage released from snails then infect the second intermediate hosts and develop into metacercariae, the infective stage found in second intermediate hosts in aquatic animals such as shrimp, snails, crabs, and fish. These metacercarial stage develop into adult flukes in the definitive host following the consumption of raw or undercooked food, except for blood flukes, whose cercarial stage is infective and can directly penetrate the skin of humans and animals, causing schistosomiasis. Trematode infections are found in many areas of Thailand. Knowledge of the distribution of snails that can serve as intermediate hosts in aquatic habitats can provide important information for assessing the risk and epidemiology of trematode infections. Therefore, this study aimed to investigate trematode infections in gastropods and to identify the species of trematodes infecting gastropods in Saraburi Province, which is one of the provinces where outbreaks of paragonimiasis have previously been reported in Thailand.

Methodology : Snail samples were randomly collected from natural water sources at 13 sampling sites in 5 districts (Wang Muang, Muak Lek, Kaeng Khoi, Mueang Saraburi, and Sao Hai) in Saraburi Province, Thailand, in June 2023. Snails were collected by hand picking and scooping method using the counts per unit of time method, with five collectors sampled for 10 minutes at each site. Parasitic infections were examined using the shedding and crushing methods. For the shedding method, snails were placed individually in plastic cups containing dechlorinated water and maintained overnight, after which cercarial emergence was examined under a stereomicroscope. The emerging cercariae were described as the morphology based on living cercariae which unstained or vitally stained with 0.5% neutral red. Measurements in micrometers were taken from 10 specimens fixed with 10% formalin. For the crushing method, snail shells were cracked, and the digestive glands were then examined for larval trematodes under a light microscope to estimate trematode infection rates in the gastropods. Snail species and trematode larvae were identified based on morphological characteristics.

Main Results : A total of 970 snails were collected and identified morphologically into 15 species. The species identified were Radix rubiginosa (5), Bithynia siamensis siamensis (187), Rivomarginella morrisoni (1), Mieniplotia scabra (118), Melanoides tuberculata (8), Tarebia granifera (362), Anentome helena (183), Mekongia swainsoni braueri (8), M. s. swainsoni (2), Filopaludina filosa (1), F. sumatrensis polygramma (23), F. martensi martensi (63), Indoplanorbis exustus (6), Gyraulus convexiusculus (1) and Pomacea canaliculata (2). The prevalence of cercarial infection in snails was investigated using the shedding and crushing methods. Fourteen snails were found to be infected with cercarial larvae. A total infection rate of 1.44% (14/970). Infected snails were found in five snail species, with M. scabra exhibiting the highest infection prevalence. Cercariae were morphologically classified into three types and four species: type 1, Xiphidiocercariae (Maritreminoides obstipus and Loxogenoides bicolor); type 2, Cotylomicrocercous cercariae (Coitocaecum anaspidis); and type 3, Parapleurolophocercous cercariae (Acanthotrema tridactyla). However, this study identified several snail species in Saraburi Province that serve as the first intermediate hosts for various trematodes. The data showed that five snail species in the families Thiaridae (M. scabra, T. granifera), Viviparidae (F. s. polygramma, F. m. martensi), and Nassariidae (A. helena) can act as the first intermediate hosts for intestinal flukes, which develop into adult worms in fish, frogs, birds, and humans. Although the overall prevalence of trematode infections is low, the detection of medically important cercarial larvae is useful for assessing the potential risk of trematode infection.

Conclusions : These studies were found snails variation species from Saraburi province, Thailand. The snails were identified by shell morphology into 15 species consist of R. rubiginosa, B. s. siamensis, R. morrisoni, M. scabra, M. tuberculata, T. granifera, A. helena, M. s. braueri, M. s. swainsoni, F. filosa, F. s. polygramma, F. m. martensi, I. exustus, G. convexiusculus and P. canaliculata. Trematode infections in freshwater gastropods in Saraburi Province revealed five snail species acting as the first intermediate hosts: A. helena, M. scabra, T. granifera, F. m. martensi, and F. s. polygramma. Four species of intestinal trematode cercariae were identified: M. obstipus, L. bicolor, C. anaspidis, and A. tridactyla. In addition, A. tridactyla infected the highest number of gastropod species. Therefore, identifying cercarial species helps to assess the risk of trematode disease occurrence and to understand their adaptation in intermediate hosts. This information provides guidance for enhancing the effectiveness of trematode disease prevention and control in the country.

Differential Pulse Voltammetric Determination of Sulfite in Fruit Juice Samples Using an Unmodified Screen-Printed Graphene Electrode

Kanokphon Phuangkum — 2026-02-12

Background and Objectives : In recent years, consumers have become increasingly health-conscious and tend to consume fruit juices more frequently due to their valuable content of essential vitamins and minerals. However, commercially packaged fruit juices often contain food additives such as sulfites, which serve as preservatives to extend shelf life and maintain product quality. However, excessive intake of sulfites can pose potential health risks. Therefore, the development of analytical methods that are rapid, accurate and cost-effective for sulfite determination is essential. Electrochemical techniques, particularly Differential Pulse Voltammetry (DPV) combined with Screen-Printed Electrodes (SPEs) have gained considerable attention due to their high analytical sensitivity, low cost, minimal sample preparation requirements and suitable on-site analysis. In this study, an unmodified Screen-Printed Graphene Electrode (SPGE) was employed owing to its outstanding electrical conductivity, chemical stability and mechanical strength including robust structural properties. The objective of this research was to develop and apply the unmodified SPGE coupled with DPV for the determination of sulfite in commercially available fruit juice samples, as well as to evaluate the analytical performance in terms of sensitivity, accuracy and precision including feasibility of this method for practical field applications in the future.

Methodology : The sulfite analysis was carried out using DPV under optimized conditions. Standard sulfite solutions with concentrations ranging from 25 to 500 µM were prepared, and 80 µL of each solution was used for measurement. The applied potential was set between 0.00 and 1.50 V with a step potential of 20 mV, modulation amplitude of 80 mV, modulation time of 50 ms and interval time of 200 ms. The electrochemical behavior of the electrode was examined by Cyclic voltammetry (CV), while the optimal analytical conditions were determined by studying the effects of buffer pH and various DPV parameters, including step potential, modulation amplitude, modulation time and interval time considering the current response and peak characteristics. Analytical performance was evaluated in terms of linearity, limit of detection (LOD) and limit of quantitation (LOQ). Additionally, the precision of the method was assessed through repeatability and reproducibility tests in terms of relative standard deviation (%RSD). The study of interferences was investigated using compounds commonly present in fruit juices for instant ascorbic acid, citric acid, potassium sorbate and sucrose. For real sample analysis, nine (9) types of fruit juice such as coconut, apple, mixed fruit and vegetable, orange, lychee, longan, guava, strawberry and pandan were purchased from a local supermarket. All samples were analyzed using the unmodified screen-printed graphene electrode under the optimized DPV conditions.

Main Results : The screen-printed graphene electrode (SPGE) exhibited a significantly higher current response compared to the screen-printed carbon electrode (SPCE) indicating superior electrical conductivity as previously reported for graphene-based materials. This observation was consistent with the electrochemical impedance spectroscopy (EIS) results, which showed that the SPGE possessed a lower charge transfer resistance. The effect of pH on the voltametric response behavior of sulfite was also examined. The results revealed that the current increased within the pH range of 2.0 – 3.5 and decreased at pH values above 5.5. Therefore, pH 3.5 was selected as the optimal condition for subsequent measurements. For differential pulse voltametric parameters, the sharpest and most stable peak was obtained under the following conditions of step potential of 20 mV, a modulation amplitude of 80 mV, a modulation time of 50 ms and an interval time of 200 ms. These parameters provided a well-defined peak with minimal background noise, ensuring reliable quantitative analysis. Under the optimized conditions, the developed method demonstrated a linear response for sulfite determination within the concentration range of 25 – 500 µM with a correlation coefficient (r²) of 0.9945, indicating excellent linearity. The limits of detection (LOD) and quantification (LOQ) were found to be 12.27 µM and 40.92 µM, respectively. Interference studies revealed that sucrose caused the least interference, whereas ascorbic acid produced the most noticeable interference due to its electroactive nature. Nevertheless, the magnitude of this interference remained within an acceptable range and did not compromise the overall analytical performance. Application of the method to nine commercially available fruit juice samples yielded recovery values ranging from 80 – 120%, which fall within the acceptable limits for standard analytical procedures (AOAC standard). These results confirm that the proposed method provides satisfactory accuracy and precision. Overall, the findings indicate that the developed method is suitable for sulfite determination in fruit juice beverages and gives potential for practical implementation in quality control laboratories.

Conclusions : This study successfully developed a method for the rapid and efficient determination of sulfite in fruit juice using DPV coupled with an unmodified screen-printed graphene electrode (SPGE), achieving optimal results at an electrolyte pH of 3.5. The method demonstrated high analytical performance, exhibiting a wide linear range of 25 – 500 µM (r² = 0.9945), low limits of detection and quantification of 12.27 µM and 40.92 µM, respectively and excellent precision with repeatability and reproducibility values of 6.04% and 5.68%, respectively. Furthermore, the method proved highly reliable when tested with real fruit juice samples, %recovery in the range of 80 – 120%, thereby confirming its accuracy, precision and stability for practical quality control applications.

An Improvement Technique in in vitro Propagation of Vanda curvifolia, a Rare Orchid Species

Wuttichai Ritti — 2026-02-19

Background and Objectives: Thailand is widely recognized as a globally significant epicenter of biological resources and a biodiversity hotspot. This ecological prominence is attributed to its strategic geographical location at the confluence of three major phytogeographical regions: the Indo-Chinese, Indo-Malayan, and Indo-Burmese regions. Such a unique positioning facilitates a remarkable richness in natural resources, with the Orchidaceae family representing one of the most ecologically and economically significant groups. Among these, Vanda curvifolia (Lindl.) L.M. Gardiner, an epiphytic orchid known for its striking floral characteristics, is currently facing a precarious survival status. It is classified as a rare species in Thailand, with scientific reports indicating a rapid and alarming decline in wild populations. The primary drivers of this decline include the intensifying effects of climate change, extensive habitat encroachment due to land development, and the persistent pressure of illegal poaching for the horticultural trade. Given the slow natural regeneration rate of this species, establishing a method for mass propagation within a short timeframe is imperative for its survival. This study was therefore designed to systematically evaluate several critical factors affecting the in vitro propagation of V. curvifolia seedlings. The research objectives focused on: 1) evaluating the efficiency of different basal media formulations; 2) investigating the physiological effects of plant growth regulators within the auxin and cytokinin groups; and 3) examining the growth-stimulating potential of chitosan on seedling proliferation. As there is currently a total absence of prior comprehensive reports regarding these specific developmental factors for V. curvifolia, this research provides a critical scientific foundation for the genetic conservation and sustainable management of this rare orchid species.

Methodology: The experimental plant materials consisted of V. curvifolia seedlings previously obtained through asymbiotic seed germination under sterile in vitro conditions. The research was divided into four distinct experimental phases to ensure a comprehensive analysis of growth factors. Experiment 1 focused on the influence of basal media; four distinct formulations VW, ½VW, MS, and ½MS were compared to identify the optimal nutrient base for vegetative growth. Experiment 2utilized the superior basal medium identified in the first phase, supplementing it with various auxins, namely NAA, IAA, and IBA. These were tested at concentrations of 0, 0.1, 0.5, 1.0, and 2.0 mg/L to determine their efficacy in inducing organogenesis. Experiment 3 followed a similar concentration gradient (0–2.0 mg/L) but focused on the cytokinin group, including BA, Kinetin, and TDZ, to evaluate shoot multiplication. Finally, Experiment 4 investigated the biostimulatory effects of chitosan. Chitosan was added to the optimal basal medium at concentrations ranging from 0 to 100 mg/L (at 10 mg/L intervals) to pinpoint the most effective concentration for enhancing seedling quality and quantity. All experiments were conducted under controlled environmental conditions with regular monitoring of growth parameters.

Main Results: Following a rigorous 12-week culture period, the data revealed significant variations across treatments. In the initial assessment of basal media, the VW medium emerged as the most effective formulation. It induced the highest shoot formation rate at 13.33%, with an average of 1.23 shoots per explant. This result was statistically significant (p≤0.05) when compared to the MS and ½MS formulations, which showed lower performance. Furthermore, seedlings cultured on VW medium exhibited superior vegetative development, characterized by the highest average number of leaves (4.46 leaves per explant) and the greatest average seedling height (0.94 cm). Regarding the application of exogenous hormones, the results from Experiment 2 indicated that auxin supplementation significantly influenced developmental pathways. Specifically, VW medium supplemented with 0.5 mg/L IAA yielded the most favorable outcomes, inducing a 40% shoot formation rate and an average of 1.70 shoots per explant. This treatment also stimulated the highest callus formation rate (20%) and the highest protocorm-like body (PLB) formation (25%), with an average of 2.45 protocorms per explant, showing clear statistical superiority over NAA and IBA treatments. In the cytokinin trials (Experiment 3), BA proved to be the most effective cytokinin; the addition of 0.5 mg/L BA resulted in a 35% shoot formation rate and a maximum average of 5.35 leaves per explant. One of the most notable findings of this study was the impact of chitosan (Experiment 4). The addition of 100 mg/L chitosan to the VW medium significantly outperformed other concentrations, resulting in a 35% shoot formation rate. More importantly, it produced the highest average number of shoots at 3.50 per explant and the most robust root system, with an average of 4.95 roots per explant. It also maintained a high rate of protocorm proliferation (2.10 per explant). These results suggest that chitosan acts as a powerful growth enhancer for V. curvifolia, providing a viable alternative or supplement to traditional plant growth regulators.

Conclusions: This research successfully established a highly efficient propagation protocol for V. curvifolia using VW medium supplemented with 100 mg/L chitosan. This method enables the rapid production of high-quality seedlings in large quantities. This protocol serves as a vital tool for ex-situ conservation, facilitating plant production for forest restoration or sustainable commercial trade, which can ultimately reduce the illegal poaching of V. curvifolia from the wild and promote the sustainable conservation of orchid biodiversity.

Effect of Osmotic Dehydration on Characteristics and Physicochemical Properties of Plant-Based Crisps with Vacuum Fryer

Tunyaporn Sirilert — 2026-02-26

Background and Objectives : Almost fried products contain high amount of oil since there was an exchange between water in food and oil during frying. Dehydration is one of the methods can reduce moisture content in food products leading to a reduction of oil uptake in fried products. Moreover, vacuum frying can also reduce the amount of oil content in fried food compared to atmospheric frying. Due to the fact that water evaporation under the vacuum condition, there was low excessive retention of oil inside the product. In addition, temperature also affects to product characteristics. Around the glass transition, molecular mobility of food molecules increases resulting in softer product and enhancement of water molecular movement. Objective of the research was; therefore, to study the effect of a pre-treatment method on characteristics of plant-based crisps using osmosis dehydration (OD) prior to vacuum frying and to study thermal properties (glass transition temperature and α-relaxation) of plant-based crisps using a Differential Scanning Calorimeter (DSC) and a Dynamic Mechanical Analyzer (DMA), respectively. All data were used to evaluate the correlation of product characteristics, texture and physicochemical properties of plant-based crisps as well as to provide a guideline for application in other fried food industries.

Methodology : In the present study, there were 2 treatments consisting of the plant-based products without pre-treatment before frying (Control) and the products with pre-treatment with osmosis dehydration (OD) using 0.5% (w/w) salt solution (NaCl) prior to frying. The 200 g of pre-treatment products prior to frying were poured in the bowl containing 0.5% (w/w) NaCl solution in the ratio of samples to salt solution at 1:10 and soaked at 30°C for 1 hour. Then, the salt solution was drained and the excess water on the products was wiped off by tissue papers. The samples from both treatments were vacuum fried at 13.33 kPa for 3 hours. All vacuum fried products were analyzed as the physicochemical properties including shrinkage ratio, weight loss, hardness using texture analyzer, T_g using Differential Scanning Calorimetry (DSC), and storage modulus (E’) using Dynamic Mechanical Analyzer (DMA).

Main Results : Pre-treatment frying method significantly affected characteristics and physicochemical properties of fried products (p≤0.05). Shrinkage ratio, %moisture content, %fat content and texture of the fried product (control) were 2.53±0.15, 6.90±0.49, 4.36±0.18 and 214.96±1.17 N, respectively, which were higher than those of the fried product with OD method. The shrinkage ratio, %moisture content, %fat content and texture of the fried product with OD method were 1.29±0.08, 3.22±0.54, 3.42±0.26 and 115.20±1.20 N, respectively. On the other hand, %weight loss of the fried product (control) was 88.6±0.82, which was lower than that of the fried product with OD method having 93.4±0.51. Moreover, glass transition temperature (T_g) of the fried product with OD method were 41.17±0.58, which were significantly higher than those of the control fried product having 31.14±0.82 (p≤0.05) as a result of water plasticization behavior. Around the glass transition, storage modulus of the fried product (control) decreased dramatically, whereas a slight decrease in the storage modulus was found in the fried product with OD method. With consideration of a change in mechanical properties (storage modulus, ∆E’), we found that the ∆E’ of the fried product with OD method were lower than that of the control fried product. The ∆E’ of the fried product with OD method was 1.51x10⁹, while the ∆E’ of the control fried product was 5.02x10⁹. This was also consistent with a-relaxation as observed from a change in storage modulus around the glass transition. The a-relaxation temperature (T_a) of the fried product with OD method was 60.93±0.88 ºC, which was significantly higher than that of the control (p≤0.05). The T_a of the fried product (control) was 41.13±0.83 ºC. Texture of the fried products with and without OD method was measured as force value. The results indicated that the storage temperature affected a product texture. Force values of the fried products with OD method stored at 35 ºC were around 115 N, whereas force values of the control were approximately 215 N during storage. However, it seems that the force values of the fried products increased with increasing storage temperature. The force values of the fried products ranged from 215 to 250 N at storage temperature of 45 ºC. The results indicated that the ∆E’ had the correlation with changes in texture of the fried product, which were measured by the texture analyzer.

Conclusions : The pre-treatment process prior to frying could reduce shrinkage ratio, but increase weight loss of the fried products. Osmosis dehydration method could decrease moisture and fat content in the fried product, and also reduce changes in physicochemical properties during storage. In addition, DSC and DMA that were used to analyze thermal and mechanical properties of the products can be used to evaluate physical properties, such as fragility and crispness of the fried products during storage. The information could be a guideline to determine changes in fried products during process and storage including shelf-life extension.