Lactic Acid Fermentation of Radish and Cucumber in Rice Bran Bed

The Lactobacillus plantarum (L. plantarum) strain XK1.4 isolated from pickled vegetables was applied for cucumber and radish fermentation using rice bran. Fermented radish and cucumber pickles are the lactic acid fermentation products formed through the influence of microorganisms present in the environment. The main objective of the study is to select the appropriate rice bran type (white/yellow rice bran) and treatment methods (roasting time), and also choose suitable fermentation conditions (initial microbial population and added salt content) for traditional pickled cucumber and white radish with appropriate lactic acid content and high acceptability by consumers. The results showed that the quality of white bran was better than yellow bran and less oxidized, the total free fatty acid was also much lower than that of yellow bran. It was found that the lactic acid content analyses provided significant different results for the samples, compared to the control (without inoculant addition). The pickled samples for which L. plantarum strain XK 1.4 was used displayed a better fermentation process. The lower concentration of bacteria added in the initial stage, the lower the acid content of the rice bran medium and the fermented products where L. plantarum strains were added. L. plantarum grew rapidly in rice bran fermenting bed of 10 CFU g at 25-26 °C and 3% NaCl. With the appropriate selection of fermentation parameters, it only takes about 4 days for the fermentation process (2 days of preparing rice bran medium and 2 days of fermenting white radish and cucumber) with high lactic acid content and consumer’s acceptability

Lactic Acid Fermentation of Radish and Cucumber in Rice Bran Bed

The Lactobacillus plantarum (L. plantarum) strain XK1.4 isolated from pickled vegetables was applied for cucumber and radish fermentation using rice bran. Fermented radish and cucumber pickles are the lactic acid fermentation products formed through the influence of microorganisms present in the environment. The main objective of the study is to select the appropriate rice bran type (white/yellow rice bran) and treatment methods (roasting time), and also choose suitable fermentation conditions (initial microbial population and added salt content) for traditional pickled cucumber and white radish with appropriate lactic acid content and high acceptability by consumers. The results showed that the quality of white bran was better than yellow bran and less oxidized, the total free fatty acid was also much lower than that of yellow bran. It was found that the lactic acid content analyses provided significant different results for the samples, compared to the control (without inoculant addition). The pickled samples for which L. plantarum strain XK 1.4 was used displayed a better fermentation process. The lower concentration of bacteria added in the initial stage, the lower the acid content of the rice bran medium and the fermented products where L. plantarum strains were added. L. plantarum grew rapidly in rice bran fermenting bed of 10 CFU g at 25-26 °C and 3% NaCl. With the appropriate selection of fermentation parameters, it only takes about 4 days for the fermentation process (2 days of preparing rice bran medium and 2 days of fermenting white radish and cucumber) with high lactic acid content and consumer’s acceptability

A quantitative study of spin-flip co-tunneling transport in a quantum dot

We report detailed transport measurements in a quantum dot in a spin-flip co-tunneling regime, and a quantitative comparison of the data to microscopic theory. The quantum dot is fabricated by lateral gating of a GaAs/AlGaAs heterostructure, and the conductance is measured in the presence of an in-plane Zeeman field. We focus on the ratio of the nonlinear conductance values at bias voltages exceeding the Zeeman threshold, a regime that permits a spin flip on the dot, to those below the Zeeman threshold, when the spin flip on the dot is energetically forbidden. The data obtained in three different odd-occupation dot states show good quantitative agreement with the theory with no adjustable parameters. We also compare the theoretical results to the predictions of a phenomenological form used previously for the analysis of non-linear co-tunneling conductance, specifically the determination of the heterostructure g-factor, and find good agreement between the two.Comment: 5 pages, 5 figure

Impact of foaming conditions on quality for foam-mat drying of Butterfly pea flower by multiple regression analysis

In recent years, the Butterfly pea flower has been increasingly interested in its color and function. However, the preservation of the extract faced many difficulties; therefore, foam drying technology was applied to solve this problem. The study was conducted to determine the effect of foaming conditions, including albumin ratio, carboxymethyl cellulose (CMC) ratio, and whipping time on foam characteristics. At the same time, the multi-dimensional regression method was also used to determine the most suitable foaming conditions for the following process. The research results showed that all 3 factors strongly influenced the foaming process of pea flower extract. It could be concluded that the most suitable condition for foaming is to use 9.3% albumin, 0.79% CMC and stir for 19 min. Under these conditions, the foam expansion and stability were 584.79% and 96.44% respectively. The powder obtained from the foam drying of Butterfly pea flower extract was also analyzed for quality. The temperature of 65 oC for 4 hrs gave relatively high-quality powder with protein content, anthocyanin and antioxidant activity of 9.89 g/100g, 1.15 mg/g and 87.34% respectively. In conclusion, the foam-mat dried powder from butterfly pea flower extract is suitable for other processing processes, especially in the processing of folk cakes, pasta and bread industry

Evaluation of water loss and solute uptake during osmotic treatment of white radishes (Raphanus sativus L.) in salt-sucrose solution

White radish, scientifically known as Raphanus sativus L., is a yearly vegetable. Currently, it was being grown and widely used in the world, including Vietnam. These plants have been used as food or food processing. The osmotic treatment of vegetables involves the removal of water from plants in which the solids from the osmotic solution are transported to the plant material by osmosis. By this procedure, sucrose and saline solution are usually performed. White radishes were dehydrated in different hypertonic solutions by combined sucrose and NaCl at three different concentrations, including 9 runs. Mass transfer behaviour was applied according to three common models such as Fick’s second law, Weibull and Peleg’s equations based on the change of moisture and solid content of white radish during osmotic dehydration. The obtained results showed that the mass transfer was fast at initial stage and became slowly at the later stage. The effective moisture (Dm) and solid diffusivities (Ds) were ranged from 1.0186 to 1.2826x10-8 and from 1.0692 to 2.3322x10-8 (m2/s) respectively. The Peleg’s equation was found to be the best fitting for water loss and solid uptake thanks to the high determination coefficient (>97.64%) and the low average relative error (<3.174%). Raised up solution concentration resulted in higher water loss and mass gain

First record of Cantharellus minor from Vietnam with identification support from a combination of nrLSU and nrSSU phylogenetic analysis

Background: A previously identified sample XC02, which was collected from a pine forest (Pinus kesiya Royle ex Gordon), in Xuan Tho Commune, Da Lat, Lam Dong Province, Vietnam, was identified as Cantharellus minor based on morphology and nrLSU phylogeny analysis. Sequence analysis of multiple genes are becoming more and more common for phylogenetic analysis of mushrooms.Method: Total DNA was isolated from sample XC02. The primer NS1, NS4 were applied to amplify the target gene the nuclear ribosomal small subunit DNA (nrSSU). For phylogenetic analysis, individual and concatenated datasets (nrSSU and nrLSU-nrSSU) were constructed. Phylogenetic tree was constructed with MEGA 6.0 with a 1000 replicate bootstrap based on the neighbor joining, maximum likelihood, maximum parsimony method.  Results: A concatenated dataset containing a total of 14 sequences from Cantharellus, Craterellus (Cantharellaceae, Canthraellales) and Hydnum (Hydnaceae, Cantharellales) were constructed. For the specimen XC02, the phylogenies based on the first, second, and third datasets (nrLSU, nrSSU, and nrLSU-nrSSU) and the morphological analysis, reported in our previous study, strongly confirmed the identity of XC02 as Cantharellus minor.Conclusion: The combination between the morphological analysis and phylogenetic analysis is confirmed as the best approach for the identification of Cantharellus and other mushroom species that we collected in the Central Highlands, Vietnam.Keywords: nrLSU; Cantharellus, Cantharellus minor; nrSSU; nrLSU; phylogeny analysis; Vietna

Preliminary study on phytogeography of Dipterocarpaceae Blume family in Vietnam

Biogeographically mapping flora of Vietnam requires the studies on the distribution of some important species groups for identifying the typical species composition of each phytochorion. The Dipterocarpaceae family contains taxa originated in tropical Asia and its subfamily of Dipterocarpoideae is proved to have Southeast Asia origin. In Vietnam, this family includes 43 species in 7 genera. In this study, Dipterocarpaceae species from 645 sites in Vietnam are assessed and compared to those in over the world. In Vietnam, this family distributes in tropical and/or slightly passing to subtropical climate but none of its species is naturally found in the Red River and the Mekong River deltas. In the world, the Dipterocarpaceae species found in Vietnam concentrated distributes in Indochina floristic region, corresponding to the originative area of South Myanmar. Statistically, there are 12 endemic species for the Indochinese floristic region and five of them are endemic for four provinces of this region related to Vietnam, respectively as follows: South China - 1, North Indochina - 1, South Indochina - 2 and Annam - 1. Additionally, some species distribute in East Asia floristic region of Holarctic Kingdom because of expanding the distribution area from the Indochinese floristic region. All genera of this family in Vietnam were originated in the Indochinese floristic region. Moreover, the floristic data and phytogeographical phylogeny diagram, based on analyses of phytogeography and DNA, would be better to use for finding out the distributional source or the forming time of species or genus, then the phylogenetic diagram.ReferencesAngiosperm Phylogeny Group, 2009. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III. Botanical Journal of the Linnean Society, 161(2), 105-121. Ashton P.S., 1982. Dipterocarpaceae. In: Van Steenis C.G.G.J., 1979-1983, Flora Malesiana. Dipterocarpaceae. Martinus Nijhoff Publisher, The Hague, London, 9(2), 250p. Averyanov L.V., Phan K.L., Nguyen T.H., Harder D.K., 2003. Phytogeographic review of Vietnam and adjacent areas of Eastern Indochina, Komarovia, Saint Petersburg, 3, 1-83. Kress W.J., DeFilipps R.A., Farr E. and Yin D.Y.K., 2003. A checklist of the trees, shrubs, herbs and climbers of Myanmar. National Museum of Nature History, Washington DC, 45, 1-590. Le Tran Chan (Editor), 1999. Some characteristics of the flora of Vietnam. Science and Technique publishing house, Hanoi, 305p (Vietnamese). Li X.W., Li J., Ashton P.S., 2007. Dipterocarpaceae. In: Wu Z.Y., Raven P.H. (Hrsg.). Flora of China. Missouri Botanical Garden Press, St. Louis, 13, 48-54. Nguyen Hoang Nghia, 2005. Dipterocarps of Vietnam. Agriculture Publishing House, Hanoi, 100p. Nguyen Kim Dao, 2003. “Dipterocarpceae Blume, 1825” in Checklist Plant species of Vietnam. Agricultural Publishing House, Hanoi, 2, 328-340 (Vietnamese). Nguyen Nga Phi, 2009. Molecular phylogeny of Southeast-Asian Dipterocarps belonging to tribe Dipterocarpeae (family Dipterocarpaceae) based on non-coding sequence data of chloroplast and nuclear DNA. Department of Forest Genetics and Georest Tree Breeding, Büsgen Institute, Faculty of Forest Science and Forest Ecology, Georg-August University of Göttingen. Göttingen, 142p. Nguyen Nghia Thin, 2004. Methods in Botanical Research. HNU publishing house, Hanoi, 172p (Vietnamese). Pham Hoang Ho, 2001. Illustration Flora of Vietnam, Youth Publishing House. Ho Chi Minh City, 2, 1022p (Vietnamese). Smitinand T., 1969. The distribution of Dipterocarpaceae in Thailand. National History Bull. Siam Soci., 23, 67-75. Smitinand T., J.E. Vidal, P.H. Ho, 1990. Flore du Cambodge, du Laos et du Vietnam, 25, Diptérocarpacées. Muséum National d’Histoire Naturelle, Paris, 123p (French). Takhtajan A. (Translated by Theodore J. Crovello), 1986. Floristic Regions of the World. University of California Press, 544p. Thai Van Trung, 1978. Tropical Forest Ecology systems of Vietnam. Science and Technique publishing house, Hanoi, 314p (Vietnamese). The Plant List (Version 1.1.), 2013. Dipterocarpaceae. http://www.theplantlist.org

Anticaries activity of mangiferin isolated from Mangifera indica leaves in Vietnam

Mangiferin (1) was isolated from Vietnamese Mangifera indica leaves. Its antimicrobial activities against the oral bacterium Streptococcus mutans GS-5 were evaluated in terms of inhibition of acid production and biofilm formation. The obtained results indicated that mangiferin at the concentration of 0.5 mM clearly inhibited acid production by this organism with a final pH value of 5.2 compared to 3.9 of the control. The reduction in biofilm biomass was found up to 92 % when it was treated with 1.0 mM mangiferin. Thus, mangiferin possesses moderate anticaries activity against S. mutans GS-5. Keywords. Mangifera indica, mangiferin, Streptococcus mutans, anticaries activity

Spatiotemporal evolution of SARS-CoV-2 Alpha and Delta variants during large nationwide outbreak of COVID-19, Vietnam, 2021

We analyzed 1,303 SARS-CoV-2 whole-genome sequences from Vietnam, and found the Alpha and Delta variants were responsible for a large nationwide outbreak of COVID-19 in 2021. The Delta variant was confined to the AY.57 lineage and caused >1.7 million infections and >32,000 deaths. Viral transmission was strongly affected by nonpharmaceutical interventions