Structural and physicochemical characteristics of modified amylopectin produced by bacterial branching enzymes

Phuong Lan Tran,Il-Nam Oh,Phu Cuong Nguyen,Kyu-Been Park,Cheul-Soon Yim,Eun-Ji Park,Nan-Young Lee,Jong-Tae Park 한국당과학회 2017 한국당과학회 학술대회 Vol.2017 No.01

Glycogen branching enzymes (GBEs) from Escherichia coli (EcBE), Deinococcus geothermalis (DgBE) and Vibrio vulnificus (VvBE) have different characteristics for branching activities, especially in chain-length transferred. In this study, the three GBEs were used to produce cluster-starches from amylopectin, and physicochemical properties of the cluster-starches were intensively analyzed in relation to their molecular structures. Side chain distribution of these cluster-starches obviously shifted to short and medium chains that made a significant decrease in their molecular weight and size. They thereby increased water-solubility without exhibiting viscosity. There was no retrogradation of DgBE- and VvBE-clusters during storage at 4℃ for 17 days. Catalytic efficiency of porcine pancreatic α-amylase (PPA) was lowest for VvBE-cluster. In conditions mimicking the human intestine, EcBE, DgBE and VvBE cluster-starches were digested 100%, 67.1% and 73.0%, respectively, in comparison with that of amylopectin. Consequently, the modified clusters from amylopectin produced by DgBE and especially VvBE may be new functional materials for food and pharmaceutical industries.

Physicochemical properties of native and partially gelatinized high-amylose jackfruit (<i>Artocarpus heterophyllus</i> Lam.) seed starch

Tran, Phuong Lan,Nguyen, Dang Hai Dang,Do, Viet Ha,Kim, Young-Lim,Park, Sunghoon,Yoo, Sang-Ho,Lee, Suyong,Kim, Yong-Ro Elsevier 2015 LWT- Food science and technology Vol.62 No.2

<P><B>Abstract</B></P> <P>Jackfruit seed starch (JFSS) cultivated in Vietnam had a high amylose content (∼44%). Differential scanning calorimetry thermogram of JFSS consisted of two separate endothermic peaks with distinct onset and conclusion temperatures. When JFSS was heated at 70?°C, the first endothermic peak disappeared, whereas the second endotherm remained. The partially-gelatinized JFSS still possessed A-type X-ray diffraction pattern. SEM images showed that the rim of the starch granule at the hollow bottom of the bell shape first melted during the partial gelatinization at 70?°C. Both native and partially-gelatinized JFSS produced soft and highly elastic gels, but their moduli differed slightly. Additionally, the partially-gelatinized JFSS was successfully used to produce genistin–cycloamylose (CA) and amylose–lysolecithin complexes with and without 4-α-glucanotransferase. Water sorption isotherms of partially gelatinized JFSS showed higher water-holding capacity than that of the native starch.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Vietnamese Jackfruit seed starch had two separate DSC gelatinization endotherms. </LI> <LI> JFSS heated at 70?°C showed one endotherm with crystallinity and granular integrity. </LI> <LI> Vietnamese Jackfruit seed starch produced a soft but highly elastic gel. </LI> <LI> High amylose JFSS was used to enzymatically produce genistin-cycloamylose complex. </LI> </UL> </P>

Molecular Structure and Rheological Character of High-amylose Water Caltrop (Trapa bispinosa Roxb.) Starch

Phuong Lan Tran,이진실,박관화 한국식품과학회 2013 Food Science and Biotechnology Vol.22 No.4

The molecular structure and rheological properties of high-amylose water caltrop (Trapa bispinosa Roxb.)starch cultivated in Vietnam were investigated. The water caltrop starch had 47.1% amylose and its molecular weight (Mw) was (4.77±0.27)×106 g/mol, whereas the Mw was (2.07±0.10)×107 g/mol for amylopectin. The average chain length of amylopectin was DPn=19.0 and the proportions of A, B1, B2, and B3 chains were 28.2, 50.3, 13.1, and 8.5%, respectively. The DSC thermogram of the water caltrop starch was broadly endothermic, with 2 distinct endothermic peaks at 73.6 and 80.7oC. Gel formation of water caltrop starch occurred rapidly, with an extremely high storage modulus up to approximately 1,200 Pa. Highamylose water caltrop starch paste had an extremely high final viscosity compared to that of other cereal starches. These rheological behaviors may have been due to the extremely high amylose content.

Detection of Vibrio cholerae O1 by Using Cerium Oxide Nanowires - Based Immunosensor with Different Antibody Immobilization Methods

Phuong Dinh Tam,Nguyen Luong Hoang,Hoang Lan,Pham Hung Vuong,Ta Thi Nhat Anh,Tran Quang Huy,Nguyen Thanh Thuy 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.10

In this work, we evaluated the effects of different antibody immobilization strategies on the response of a CeO2-nanowires (NWs)-based immunosensor for V ibrio cholerae O1 detection. Accordingly, the changes in the electron-transfer resistance (Ret) from before to after cells bind to an antibody-modified electrode prepared by using three different methods of antibody immobilization were determined. The values were 16.2%, 8.3%, and 6.65% for the method that utilized protein A, antibodies activated by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC)/Nhydroxysuccinimide (NHS), and absorption, respectively. Cyclic voltammetry confirmed that the change in the current was highest for the immunosensors prepared using protein A (11%), followed by those prepared with EDC/NHS-activated antibodies (9%), and finally, those prepared through absorption (7.5%). The order of the antibody immobilization strategies in terms of resulting immunosensor detection limit and sensitivity was as follows order: absorption (3.2 × 103 CFU/mL; 45.1 /CFU·mL−1) < EDC/NHS-activated antibody (1.0 × 103 CFU/mL; 50.6 /CFU·mL−1) < protein A (1.0 × 102 CFU/mL; 65.8 /CFU·mL−1). Thus, we confirmed that the protein A - mediated method showed significantly high cell binding efficiencies compared to the random immobilization method.

Presence of β-Amylase in Ramie Leaf and its Anti-staling Effect on Rice Cake

Dang Hai Dang Nguyen,Phuong Lan Tran,하현숙,이진실,홍완수,Quang Tri Le,오병철,박성훈 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.1

Presence of β-amylase in ramie leaf and its anti-staling effect on starch-based foods were assessed. The ammonium sulfate fractionate (80% saturation) of the ramie leaf extracts showed a β-amylase activity, giving maltose (Glc2) as a major product, exclusively, when incubating with maltopentaose (Glc5) or soluble starch at 45oC, pH 6.0. The starch-based food product (rice cake) prepared with freeze-dried ramie leaf enzyme revealed that the linear maltooligosaccharides ranging from Glc2 to Glc6 significantly increased and the shorter branch chains (DP<15) of amylopectin increased whereas the longer branch chains (DP>16) decreased in the product. These results demonstrated that maltosyl residue was released from the non-reducing end of the longer branch chains of amylopectin by β-amylase. The ramie leaf-treatment sample significantly reduced the retrogradation rate during 48 h storage at 4℃. As an alternative plant-origin enzyme, the ramie leaf β-amylase has potential for a novel anti-staling additive.

Synthesis, bioevaluation and docking study of 5-substitutedphenyl-1,3,4-thiadiazole-based hydroxamic acids as histone deacetylase inhibitors and antitumor agents

Nam, Nguyen-Hai,Huong, Tran Lan,Dung, Do Thi Mai,Dung, Phan Thi Phuong,Oanh, Dao Thi Kim,Park, Sang Ho,Kim, Kyungrok,Han, Byung Woo,Yun, Jieun,Kang, Jong Soon,Kim, Youngsoo,Han, Sang-Bae Informa UK Ltd. 2014 Journal of enzyme inhibition and medicinal chemist Vol.29 No.5

<P>Since the first histone deacetylase (HDAC) inhibitor (Zolinza®, widely known as suberoylanilide hydroxamic acid; SAHA) was approved by the Food and Drug Administration for the treatment of T-cell lymphoma in 2006, the search for newer HDAC inhibitors has attracted a great deal of interest of medicinal chemists worldwide. As a continuity of our ongoing research in this area, we designed and synthesized a series of 5-substitutedphenyl-1,3,4-thiadiazole-based hydroxamic acids as analogues of SAHA and evaluated their biological activities. A number of compounds in this series, for example, <I>N<SUP>1</SUP></I>-hydroxy-<I>N</I><SUP>8</SUP>-(5-(2-chlorophenyl)-1,3,4-thiadiazol-2-yl)octandiamide (<B>5b</B>), <I>N<SUP>1</SUP></I>-hydroxy-<I>N</I><SUP>8</SUP>-(5-(3-chlorophenyl-1,3,4-thiadiazol-2-yl)octandiamide (<B>5c</B>) and <I>N<SUP>1</SUP></I>-hydroxy-<I>N</I><SUP>8</SUP>-(5-(4-chlorophenyl)-1,3,4-thiadiazol-2-yl)octandiamide (<B>5d</B>), were found to possess potent anticancer cytotoxicity and HDAC inhibition effects. Compounds <B>5b</B>-<B>d</B> were generally two- to five-fold more potent in terms of cytotoxicity compared to SAHA against five cancer cell lines tested. Docking studies revealed that these hydroxamic acid displayed higher affinities than SAHA toward HDAC8.</P>

Determinants of Operational Self-Sustainability of Microfinance Institutions in Vietnam

LE, Thanh Tam,DAO, Lan Phuong,DO, Ngoc Mai,TRUONG, Thi Hoai Linh,NGUYEN, Thi Thuy Duong,TRAN, Chung Thuy Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.10

The purpose of this paper is to investigate the determinants of the Operational Self-Sustainability (OSS) of Vietnamese microfinance institutions (MFIs). This research uses both qualitative and quantitative research methods: (i) qualitative research was via in-depth interviews with ten microfinance practitioners, policymakers and researchers; (ii) quantitative research was conducted by using panel data of 34 MFIs in the period 2011-2015 with binary logistics and OLS regressions. Results are as follows: (i) MFIs' OSS in Vietnam are mainly determined by five key factors: portfolio at risk (PAR>30), capital structure, gross loan portfolio, scope of activities and legal form; (ii) OSS are most affected by legal status (social organizations have better OSS than formal MFIs or programs/projects), location (MFIs focus in one province have higher OSS than working nationwide or just in one district), capital structure (MFIs with more equity proportion have higher OSS); (iii) surprisingly, average loan size per borrower and age of MFIs do not have statistically significant correlation with OSS. The key recommendations are: (i) MFIs should focus on its professionality and increase its equity; (ii) related stakeholders such as State Bank of Vietnam should promote the enabling ecosystem for microfinance development to enhance poverty reduction and economic development.

Comparison of Catalyzing Properties of Bacterial 4-α-Glucanotransferases Focusing on Their Cyclizing Activity

( Jung-eun Kim ),( Phuong Lan Tran ),( Jae-min Ko ),( Sa-rang Kim ),( Jae-han Kim ),( Jong-tae Park ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.1

A newly cloned 4-α-glucanotransferase (αGT) from Deinococcus geothermalis and two typical bacterial αGTs from Thermus scotoductus and Escherichia coli (MalQ) were investigated. Among 4 types of catalysis, the cyclization activity of αGTs that produces cycloamylose (CA), a valuable carbohydrate making inclusion complexes, was intensively studied. The new αGT, DgαGT, showed close protein sequence to the αGT from T. scotoductus (TsαGT). MalQ was clearly separated from the other two αGTs in the phylogenetic and the conserved regions analyses. The reaction velocities of disproportionation, cyclization, coupling, and hydrolysis of three αGTs were determined. Intriguingly, MalQ exhibited more than 100-fold lower cyclization activity than the others. To lesser extent, the disproportionation activity of MalQ was relatively low. DgαGT and TsαGT showed similar kinetics results, but TsαGT had nearly 10-fold lower hydrolysis activity than DgαGT. Due to the very low cyclizing activity of MalQ, DgαGT and TsαGT were selected for further analyses. When amylose was treated with DgαGT or TsαGT, CA with a broad DP range was generated immediately. The DP distribution of CA had a bimodal shape (DP 7 and 27 as peaks) for the both enzymes, but larger DPs of CA quickly decreased in the DgαGT. Cyclomaltopentaose, a rare cyclic sugar, was produced at early reaction stage and accumulated as the reactions went on in the both enzymes, but the increase was more profound in the TsαGT. Taken together, we clearly demonstrated the catalytic differences between αGT groups from thermophilic and pathogenic bacteria that and showed that αGTs play different roles depending on their lifestyle.

Characterization of the Transglycosylation Reaction of 4-α-Glucanotransferase (MalQ) and Its Role in Glycogen Breakdown in Escherichia coli

( Dang Hai Dang Nguyen ),( Sung-hoon Park ),( Phuong Lan Tran ),( Jung-wan Kim ),( Quang Tri Le ),( Winfried Boos ),( Jong-tae Park ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.3

We first confirmed the involvement of MalQ (4-α-glucanotransferase) in Escherichia coli glycogen breakdown by both in vitro and in vivo assays. In vivo tests of the knock-out mutant, ΔmalQ, showed that glycogen slowly decreased after the stationary phase compared to the wild-type strain, indicating the involvement of MalQ in glycogen degradation. In vitro assays incubated glycogen-mimic substrate, branched cyclodextrin (maltotetraosyl-β-CD: G4-β-CD) and glycogen phosphorylase (GlgP)-limit dextrin with a set of variable combinations of E. coli enzymes, including GlgX (debranching enzyme), MalP (maltodextrin phosphorylase), GlgP and MalQ. In the absence of GlgP, the reaction of MalP, GlgX and MalQ on substrates produced glucose-1-P (glc-1-P) 3-fold faster than without MalQ. The results revealed that MalQ led to disproportionate G4 released from GlgP-limit dextrin to another acceptor, G4, which is phosphorylated by MalP. In contrast, in the absence of MalP, the reaction of GlgX, GlgP and MalQ resulted in a 1.6-fold increased production of glc-1-P than without MalQ. The result indicated that the G4-branch chains of GlgP-limit dextrin are released by GlgX hydrolysis, and then MalQ transfers the resultant G4 either to another branch chain or another G4 that can immediately be phosphorylated into glc-1-P by GlgP. Thus, we propose a model of two possible MalQ-involved pathways in glycogen degradation. The operon structure of MalP-defecting enterobacteria strongly supports the involvement of MalQ and GlgP as alternative pathways in glycogen degradation.

E-commerce Adoption in Distribution: An Empirical Study on Household Businesses in Food and Beverage Industry

Xuan Truong NGUYEN,Thai Ha NGUYEN,Huynh Phuong DANG,Thi Lan Phuong PHAM,Thi Thanh BUI,Nhat Minh TRAN,Tri An HUYNH,Nam Phong NGUYEN 한국유통과학회 2022 유통과학연구 Vol.20 No.2

Purpose: This study aims to identify factors affecting the adoption of e-commerce by household businesses in Vietnam s food and beverage industry. Research design, data and methodology: The integrated TAM and TOE frameworks and ten hypotheses were developed to test the relationship between relevant factors. A cross-sectional survey was conducted to collect valid data from 992 respondents who run F&B household businesses in Vietnam. Results: The empirical research results confirm all proposed hypotheses that e-commerce adoption is affected by the perceived usefulness, the perceived ease of use, vendor support partners, social expectancy, competitive pressure, subjective norm, and household resources. Meanwhile, technical readiness, environment readiness, and organization readiness are intermediate variables that influence the implementation of e-commerce in food and beverage distribution. Conclusions: The findings suggest effective orientations to foster the food and beverage e-trading practice for household businesses in developing countries. Accordingly, to encourage private household businesses to adopt e-commerce, it is necessary to focus on improving business resources, technology readiness, environment readiness, and organization readiness through raising awareness of usefulness, benefits, perceived ease of use, and increased support of vendor partners. Future research can focus on improving the efficiency of e-commerce applications in F&B distribution for both household businesses and larger-scale enterprises.