Vietnam Academy of Science and Technology: Journals Online
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Detection of a Sudan dye at low concentrations by surface-enhanced Raman spectroscopy using silver nanoparticles
Get PDFSudan dyes are red colorants banned from use for food due to their toxic properties. However, because of the cheapness, they are sometimes adulterated into food illegally. Currently surface-enhanced Raman spectroscopy (SERS) is emerging as a good method to detect residues (including trace amounts) of Sudan dyes in food. In this report we present the SERS detection of Sudan I (a type of Sudan dyes) to concentrations as low as 1 ppb, using a very simple SERS substrate, which is made from silver nanoparticles chemically deposited on silicon surface
Allelic polymorphism of crtRB1 and LcyE genes related to the β-carotene content in Vietnamese traditional maize accessions,
Get PDFMaize is the third most important food crop after wheat and rice. Maize is used as food for more than a billion people around the world and is used as animal feed, especially, poultry. The concentration of carotenoids, especially, β-carotene in maize grains, is very low. Therefore, the study of increasing the amount of provitamin A carotenoids including β-carotene is important. In maize, different alleles of crtRB1 and LcyE genes have a significant effect on β-carotene content. In this paper, we present the results of the study of allele polymorphism of these two genes related to the provitamin A carotenoid content in some traditional maize accessions collected from several regions in North and Central Highlands of Vietnam. The results showed that there were polymorphisms at the 3’ and 5’ ends of the crtRB1 and LcyE genes. Among 22 maize accessions, the proportion of favorable alleles at the 3’ end of crtRB1 gene was relatively high (5/22 = 22.73%). Similar results were obtained for alleles at 3’ end of the LcyE gene. Especially, there is an accession (Northern white gold maize) that carries favorable alleles at the 3’ ends of both crtRB1 and LcyE genes. While all investigated maize accessions did not carry favorable alleles at the 5’ end of both crtRB1 and LcyE genes. The identification of traditional maize accessions that carry favorable alleles for increasing b-carotene content opens up potential to exploit indigenous genetic resources for genetic research as well as to develop maize varieties with high β- carotene content.
OPTIMIZATIONOFENZYMATIC HYDROLYSIS PROCESS FROM SHRIMP BY-PRODUCT FOR SHRIMP SAUCE PRODUCTION
Get PDFShrimp by-product from shrimp processing industry adapted to food safety was hydrolyzed by alcalase and flavourzyme and optimized by response surface methodology. Shrimp by- product was grounded and treated with fixed alcalase 0.2% (4.8AU/kg protein) andflavourzyme loadings (0.1-0.4%), pH (6.0-9.0), temperature (45-650C) and hydrolysis time (5-13h) in order to improve hydrolysis process in shrimp sauce production. At optimal conditions of pH of 7.5, temperature of 590C,flavourzymeloadings of 0.4% (100LAPU/g protein), alcalaseof 0.2%, and hydrolysis time of 8.2h, hydrolysis degree was 36.76% compared to control sample (hydrolysis by HCl 6N at 1000C for 24h). Shrimp hydrolysis solution was mixed with 25% of NaCl before fermentation. After 10 days of fermentation, shrimp sauce had total nitrogen of 13.2g/l, amino nitrogen of 9.625 g/l, NH3 of 2.13g/l. These properties and sensory quality were equivalent to control sample(2.5 months of fermentation by traditional process).
EFFECT OF FISH SCALE COLLAGEN ON SOME CHARACTERISTICS AND DRUG RELEASE OF CARRAGEENAN/COLLAGEN/ALLOPURINOL FILM
Get PDFABSTRACT - QMFS2019Collagen from fish is attracting a lot of attention thanks to its high absorbance ability, biocompatibility as well as non-religious obstruction and cheap sources. It could be applied in many fields, for example: food, cosmetic, or biomedicine. Using of collagen also helps to reduce the environment pollution from fish scale waste in fish processing. In this study, collagen extracted from Vietnamese fresh-water tilapia fish scales was used in combination with carrageenan for the improvement of drug release control. The influence of fish scale collagen content on morphology, thermal behavior and drug release from carrageenan/collagen/allopurinol composite film was evaluated by methods such as field emission scanning electron microscopy (FESEM), differential scanning calorimetric (DSC) and ultraviolet-visible spectroscopy (UV-Vis). From the DSC data, FESEM analysis and drug release of carrageenan/collagen/allopurinol composite films, the most suitable collagen in composite film is 5 wt.%
Quaternary benthic Foraminifera in the Tu Chinh - Vung May marine areas (continental shelf of Vietnam) and island, coral reef regions of the Truong Sa archipelago, Vietnam and their significance
Get PDFThe results of identifying and studying micropaleontological samples from the Quaternary sediments in the Tu Chinh - Vung May marine areas (1) and some coral reef islands of Truong Sa archipelago (2) have found more than 300 species of Benthic foraminifera, in which 291 species have been studied and described in detail, belonging to 112 genera, 43 families, 5 orders and 3 classes of the phylum Foraminifera. Among them, there are 19 new species, 3 new subspecies and 3 new genera. In the first region there are 195 species and the second one - 121 species (including 25 common species for both regions). They have important significations in the stratigraphic-biostratigraphic, ecological, paleogeographic studies, in sedimentary lithology... Regarding stratigraphy, the characteristic of Pleistocene is the first emergence of four genera: Baculogypsina, Cymbaloporetta, Parasorites, and Schlumbergerella; for Holocene - the appearance of the following genera: Ammomassilina, Baulogypsinoides, Cymbaloporella, Falsotextularia, Fijiella, Flintina, Gyroidina, Lugdunum, Neoconorbina, Planoperculina, Ptychomiliolata, Pseudoflintina, Pseudomassilina, Sahulia, Schlumbergerina, Septotextularia, Siphoniferoides, Tawitawia and Truongsaia. These fossils are the basis for dating sediment age, Quaternary stratigraphic division and correlation. In terms of paleoecology, benthic Foraminifera in the region (1) characterize the shallow offshore environment of the continental shelf, where there are the high and stable salinity, and the relatively strong environmental dynamics; in some places there are coral reef Foraminifera populations. In the region (2), they characterize the coral reef ecosystem of shallow and warm sea areas in the belt of tropical-subtropical climate of the Earth, where the salinity is high and stable, the transparency of water is high, and the environmental dynamics is relatively strong to strong... In addition, the paper also mentioned some other issues such as paleogeography (sea-level fluctuation), value of creating sediments of Foraminifera, environmental monitoring (for modern Foraminifera)
Some results of research and forecasting of groundwater salinization in the coastal zone of Soc Trang province
Get PDFIn recent years, the situation of salinity intrusion is very complicated and becomes more serious in the coastal area of Soc Trang province. In this research, SEAWAT modified water density flow model was used to forecast the salinity intrusion for Holocene aquifer (qh) and upper Pleistocene aquifer (qp3) according to the water use planning scenario. The results show that the impact of groundwater extraction process increases the TDS content in the aquifer, the salt water/fresh water areas change over time, the trend of salinity change increases. In Holocene aquifer, salt water area is relatively large and the TDS concentration increases towards the sea, however, fresh water area changes inconsiderably: In 2015 accounting for 17.42% and by 2030 accounting for 17.77% of aquifer area. In upper Pleistocene aquifer, the fresh water area declines significantly: In 2015 accounting for 9.35% and by 2030 only accounting for 7.53% of aquifer area
Application of satellite images and VNREDSAT-1 images in study on marine environment in Truong Sa region
Get PDFThe remote sensing images, including images of MODIS, VNREDSAT-1 and altimeter, are applied for researching marine environment with the different resolutions. On the basis of different time remote sensing images, we concentrated on the assessment of several characteristics including the SST, chlorophyll-a concentration and sea surface current at the different depths in different monsoons as well. With the large areas, we used the images of MODIS and altimeter. The detailed research area focuses on the Nam Yet island, and the images of VNREDSAT-1 are used. The analysis method of environmental parameters of SST and chlorophyll-a used the regression functions based on the single and combined bands to enhance the accuracy of the analysis result. The marine parameters collected at different depths in the latest field surveys on Truong Sa archipelago in the years of 2015 and 2018 are presented in this paper. On the basis of these parameters, we can analyse the relationships and compare the real field survey data and corresponding results interpreted from remote sensing images
Vietnam geographical exploitation under the United Nations Convention on the Law of the Sea in 1982 (UNCLOS 1982)
Get PDFAs an active member of the United Nations Convention on the Law of the Sea - UNCLOS, Vietnam has completed 3 Reports on the Limits of the Continental Shelf and has submitted two of them to the Commission on the Limits of the Continental Shelf - CLCS, before the deadline 13-5-2009. Those are: (1) Outer Limits of the Vietnam’s Extended Continental Shelf: North Area (VNM-N); (2) Outer Limits of the Vietnam’s Extended Continental Shelf: Middle Area (VNM-M) and (3) Vietnam - Malaysia Joint Continental Shelf Submission. The VNM-M has not yet been submitted but it was mentioned to the CLCS and will be submitted in the appropriate time.Vietnam’s submissions were highly appreciated by CLCS; although the CLCS has not yet organized a special sub-committee to look at our reports, the secretariat of CLCS has already posted the executive reports of our submissions, with our principle claims on the continental shelf, on the website of the CLCS since May 2009. This paper presents shortly the UNCLOS and its application in Vietnam case
Environments of upper miocene sediments in the Hanoi depression interpreted from grain-size parameters
No full textThe grain-size analysis is carried out for 49 samples of Upper Miocene sediments taken from three boreholes in the Hanoi depression. The statistic parameters of the grain size distributions such as percentiles, median, graphic mean, sorting or inclusive graphic standard deviation, inclusive graphic skewness, and graphic kurtosis are used to decipher the depositional environments and transportation mechanisms of sediments. Bivariate plotting of these parameters, the discriminant functions with four basic parameters of graphics mean, sorting, inclusive graphic skewness and graphic kurtosis, and the CM pattern with the one percentile (C) and median (M) diameters are applied for this determination. The plots of graphics mean versus sorting suggest 14% of samples being the sand sheet, 46% related to rivers and 40% of the estuarine environment. The sorting - inclusive graphic skewness plot shows a river-related environment for all samples. Linear discriminant functions show the sandstone of upper Miocene in Hanoi depression are deltaic sediments formed in unstably transporting and depositional environment, impacted by turbidity current in the coastal river-mouth. The CM pattern shows sediment transportation for most of the samples in three modes: rolling, suspension and rolling, and uniform suspension. The environmental dynamics are relatively complex and change over time
A study on vegetative propagation of Huperzia serrata by cuttings in Sa Pa, Lao Cai
Get PDFHuperzia serrata is a precious medicinal plant used in medicine to support and treat Alzheimer's disease. Currently, this species is in danger of extinction due to indiscriminate exploitation for commercial purposes. Furthermore, this species reproduces slowly and is difficult to cultivate artificially. The reproduction by spores of this species is very long and takes 15−20 years from the spore germination to mature plant, whereas asexual reproduction by tissue culture is also difficult. Therefore, cutting is an effective method to propagate this species on a large scale. In this study, we surveyed the factors affecting the survival rate, the rooting and the number of new leaves of the stem cuttings, including cutting length, growing substrate, and effects of growth-regulating hormones IBA (0 ppm, 500 ppm, 1000 ppm, 2000 ppm and 3000 ppm) and α-NAA (0 ppm, 10 ppm, 20 ppm, 30 ppm and 40 ppm). The experimental results showed that using cuttings of 6 cm in length treated with IBA at a concentration of 1000 ppm for 30 mins and cultured on the substrate mixture of soil, decomposed animal manure and rice husk at a ratio of 3:1:1 was the best for cuttings of H. serrata in Sa Pa. The results of this study will contribute to the conservation and development of genetic source of H. serrata in Vietnam.