bluuebunny/crossref_metadata_2025_split huggingface dataset:
INFLUENCE OF FACTORS ON THE BITTERNESS AND SENSORY TASTE IN PROTEIN HYDROLYSATE FROM SPENT
Authors: Thanh Ngoc Nguyen Thi 
Published: April 2018

Spent brewer’s yeast, obtained after the main fermentation stage, is a rich- in-protein source (protein content accounts for 48 - 50 % dry matter). In order to use efficiently this protein source for using in food industry, it was hydrolysed by different methods into mixtures of peptides and amino acids. So that it has a wide range of applications in food. It can be used as emulsifying agents in a number of applications such as salad dressings, spreads, ice cream, coffee whitener, cracker, and meat products like sausages. However, bitterness in hydrolysates is one of the major undesirable aspects for various applications in food processing. In this study, influences of factors (E/S ratio, pH and temperature) on bitterness of hydrolysate were studied to choose the best hydrolysis conditions by using flavourzyme, alcalase and neutrase. The bitterness of hydrolysate was determined by intensity sensory method (using quinine standard) and amino acid content was analysed by HPLC method. The result showed that bitterness of brewer’s yeast hydrolysate by flavourzyme is the lowest and that by neutrase is the highest. In particular, the bitterness of hydrolysates have reached values of 15.2–40.42 µmol quinine/l (FH - flavourzyme hydrolysate), 21–64.99 µmol quinine/l (AH - alcalase hydrolysate) and 34.62–64.26 µmol quinine/l (NH - neutrase hydrolysate), respectively. The hydrolysis conditions in using flavourzyme were chosen at 50 oC, pH 7, E/S ratio 7.1U/g and in using alcalase - at 55 oC, pH 8, ratio E/S 7.2 U/g, respectively. At this conditions, bitterness reached values 15.44 µmol quinine/l (in FH) and 21.16 µmol quinine/l (in AH).
OPTIMIZATION FOR BATCH PROTEOLYTIC HYDROLYSIS OF SPENT BREWER’S YEAST BY USING PROTEASES
Authors: Thanh Ngoc Nguyen Thi 
Published: April 2018

The yield of proteolylic hydrolysis for spent brewer’s yeast by protease and aminoacid contents of hydrolysates (the main factors influencing in taste of hydrolysed product) depends on factors influencing in catalytic activities of enzymes as temperature, pH value, type of used enzymes and ratio enzyme/substrate. With the purpose to hydrolyse the spent brewer’s yeast for food application, bitterness of hydrolysate takes the firth consideration, and than the yield of hydrolysing process plays economic role. In this paper, it is dealt with determination of optimal conditions to obtain the highest yield of hydrolysis process and the lowest bitterness of hydrolysate (the bitterness is determined by sensory evaluation, expressed equivalently with concentration of quinine). Response surface methodology (RSM) was used to determine optimum condition for batch proteolytic hydrolysis of spent brewer’s yeast. The influencing factors were investigated as temperature (X1): 40 oC–60 oC; pH (X2): 6.0–9.0, ratio E (flavourzyme)/S (X3): 5–10 U/g and hydrolysis time (X4): 6–9 hours. The experimental responses including degree of hydrolysis (Y1) (%) and bitterness of hydrolysate (Y2) (μmol quinine/ml) are performed in second-degree model. The optimal conditions for obtaining high degree of hydrolysis and low bitterness are determined: Ratio of enzyme mixture (alcalase 7.5 U/g and flavourzyme 8.5 U/g), pH 7.5, hydrolysis temperature at 52oC and hydrolysis time 9 hours. Under the optimal conditions, the actual values obtained for the yield of hydrolysis was 40.81 ± 0.044 % and the bitterness equivalently with concentration of quinine was 16.37 ± 0.03 μmol quinine/ml.
ANTIBACTERIAL ACTIVITY OF HYDROLYZED VIRGIN COCONUT OIL BY IMMOBILIZED LIPASE
Authors: Ai Van Nguyen Thi 
Published: April 2018

The aim of this study was to investigate the hydrolysis conditionsof virgin coconut oil (VCO) by immobilized lipase (Lypozyme TL IM). Then the hydrolyzed products wereevaluated with their antibacterial activityagainst Gram – negative and Gram – positive bacteria (Escherichia coli (ATCC 25922), Salmonella enteritidis (ATCC 13076), Staphylococcus aureus (ATCC 25923) and Bacillus cereus (ATCC 25924)).The effect of four factors on hydrolysis degree of VCO was investigated: the ratio of VCO to buffer, the ratio of enzyme to substrate, pH condition, and temperature.The best reaction conditions in the case of using Lypozyme TL IM as the catalyst was determined: the ratio of VCO to buffer of 1.3 (g/g); the ratio of enzyme to substrate of 0.5 (%), pH of 8.0 and temperature of 65 oC, VCO was hydrolyzed in 28 hours, acid value achieved to 188.05 (mg/g). The products of hydrolyzed VCO (HVCO) showed activity against Salmonella enteritidis (ATCC 13076) at the concentrations of 5 % and against Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923) and Bacillus cereus (ATCC 25924) at the concentrations of 20 %.
INHIBITION OF BACTERIA ISOLATED FROM NINH THUAN GRAPES BY ORGANIC ACIDS
Authors: Hanh Nguyen Thi 
Published: April 2018

Ninh Thuan grapes are famous specialty of Vietnam. After harvesting, they are very susceptible to damage if not preserved in time. This study aimed to find the minimal inhibitory concentration and minimal bactericidal concentrations of organic acids, such as lactic acid, citric acid, and ascorbic acid towards seven bacteria previously isolated from Ninh thuan grapes (Empedobacter brevis, Citrobacter sp. Enterobacterium ludwigii, Bacillus cereus, Flavobacterium sp., Pseudomonas oryzihabitans and Bacillus thuringiensis) in order to apply in pretreatment of grapes prior to storage. The Minimal Inhibitory Concentration (MIC) was determined by the binary dilution method. 0.1 ml of each dilution of test acids with initial concentration of 3 % was mixed with 0.1 ml of bacteria (c.a. 5.105 CFU/ml), in 96-culturing-well plate. Innoculated plate was incubated for 24 hours at temperature of 37 °C. Optical density was measured at 620 nm wavelength by a Microplate reader device. For Minimal Bactericidal Concentration (MBC) determination, 0.1 ml of bacteria (c.a.5.105 CFU/ml) was mixed with 0.4 ml liquid medium of Tryptone Glucose Agar (TGA) and of 0.5 ml acid at above concentrations, culturing within 24 hours at temperature of 37 °C. After 24 hours, they were dropped onto TGA agar plates, and cultured for 24 hours at 37 °C. The results showed that, the MIC and MBC of citric acid toward Empedobacter brevis were 0.12 mg/ml and 0.12 mg/ml; Citrobacter sp. were 0.9 mg/ml and 3.8 mg/ml; Enterobacterium ludwigii were 0.45 mg/ml and 1.9 mg/ml; Bacillus cereus were 0.9 mg/ml and 0.9 mg/ml; Flavobacterium sp. were 0.12 mg/ml and 0.45 mg/ml; Pseudomonas oryzihabitans were 0.12 mg/ml and 0.45 mg/ml and Bacillus thuringiensis were 0.12 mg/ml and 0.9 mg/ml, respectively. Similarly, MIC and MBC of lactic acid toward: Empedobacter brevis were 0.12 mg/ml and 0.23 mg/ml;Citrobacter sp. were 0.9 mg/ml and 1.9 mg/ml; Enterobacterium ludwigii were 0.45 mg/ml and 0.9 mg/ml; Bacillus cereus were 0.23 mg/ml and 0.45 mg/ml; Flavobacterium sp. were 0.12 mg/ml and 1.9 mg/ml; Pseudomonas oryzihabitans were 0.23 mg/ml and 1.9 mg/ml and Bacillus thuringiensis were 0.12 mg/ml and 1.9 mg/ml, respectively. Ascorbic acid was found to be inefficient for use as antimicrobial agent against isolated bacteria. The above results suggested that citric and lactic acids could be used at maximal concentrations of 3.8 mg/ml and 1.9 mg/ml, respectively to suppress bacteria from grapes. This finding would contribute to develop method for pretreatment of grapes in fresh grape preservation techniques.
COMBINATION OF METHANE OXIDATION AND DENITRIFICATION PROCESS IN A TWO-STAGE BIOREACTOR
Authors: Thu Vu Phuong 
Published: April 2018

The importance of a combination of methane oxidation and denitrification processes in a two-stage bioreactor was investigated for the removal of nitrate using methane gas. In the configuration I, methane and oxygen were supplied separately to two columns of the two-stage bioreactor, an oxic column and an anoxic column. The nitrate removal efficiency was around 25 % and nitrite presented in the liquid medium, showing that the denitrification process was not complete. In the configuration II, methane and oxygen were supplied together to one column of the two-stage bioreactor, better results were achieved. Nitrate removal efficiency increased to almost 100 %, no nitrite was found in the liquid medium. The methane oxidation and the denitrification processes seemed to be happened simultaneously in one column of the two-stage bioreactor and demonstrated its advantages. Methane utilized concentration in the medium of the methane oxidation column increased from 1 to 2.1 mg/L, which resulted in more soluble organic carbon was created and supplied for denitrifiers. The C/N utilized ratio was lower in the Configuration II showing that the aerobic methane oxidation coupled to denitrification (AMO-D) achieved higher efficiency when methane and oxygen were supplied together.
EVALUATION OF THE IMPACT OF DYKE ON THE PRACTICE OF USING PLANT PROTECTION CHEMICALS AND THE ENVIRONMENT IMPACT QUOTATION INDEX OF RICE CULTIVATION AREAS IN THAP MUOI, DONG THAP PROVINCE
Authors: Van Ha Nguyen Thi 
Published: April 2018

This report presents the result of a survey to evaluate the use of crop protection chemicals (pesticides – HCBVTV) in rice-growing areas with dyke, semi-dyke and no embankment based on interview result with 112 interviewers such as farmers, agricultural specialists, and pesticide dealers in Thap Muoi District, Dong Thap Province and pesticide usage data recorded by three selected framers in 3 different dyke systems. It showed that dyke practice affects the use of pesticides of farmers. After dykes constructed, the pesticides used were more diverse, with higher dosage compared to before having embankments. The report also evaluates the risk of using pesticides through Environmental Impact Quotient (EIQ) index. It showed that areas with dyke and semi-dyke have much higher EIQ index than areas without embankment, 167, 145 and 54, respectively.
A STUDY FOR SYNTHESIS OF DICALCIUM PHOSPHATE FROM VARIOUS GRADES OF PHOSPHATIC MATERIALS
Authors: Huy Bui Quoc 
Published: April 2018

Anhydrous dicalcium phosphate with monetite structure plays a significant biological importance for the mineralization of bones and teeth. This compound can reconstruct the hard tissues due to its high solubility in the body than other calcium phosphate compounds. Di calcium phosphate is being used as a food - additive supplying calcium and phosphate for humans and animals. Due to the high effective P2O5 content, this compound is also used efficiently as a slowly soluble fertilizer in agriculture for all soil and crop types. This paper presents results of synthesis of di calcium phosphate monetite from Ca(OH)2 and phosphoric acid and di calcium phosphate brushite from the resulting solution after enriching of type II - Lao Cai apatite ore by phosphoric acid. The samples were examined by volumetric titration methods, XRD, SEM and EDS.
NGHIÊN CỨU ĐỘ BỀN ĐIỆN HÓA CỦA ĐIỆN CỰC ANOT BIẾN TÍNH BẰNG CÁC OXIT KIM LOẠI TRÊN NỀN TITAN
Authors: Thu Hiền Chu Thị 
Published: April 2018

Bài viết này trình bày các kết quả của nghiên cứu tính chất điện hóa và độ bền của điện cực Ti/PbO2 được phủ bởi hỗn hợp oxit kim loại SnO2 và Sb2O3. Các phương pháp phân cực liên tục và phương pháp quét theo chu kì đã được sử dụng trong nghiên cứu. Các kết quả nghiên cứu cho thấy các điện cực Ti/Sb2O3-SnO2/PbO2 có tuổi thọ dài nhất khoảng 290 giờ với lớp phủ SnO2-Sb2O3 được hình thành ở nhiệt độ nung của dung dịch muối là 480 oC. Điện cực Ti/Sb2O3-SnO2/PbO2 khả năng điện hóa tốt hơn các điện cực Ti/PbO2.
STRUCTURE OF SPAN-80 ACTIVATED DOUBLE PEROVSKITE SYSTEM La2Co1-xFexMnO6 (x = 0.00, 0.01, 0.02, 0.03)
Authors: Tan Pham The 
Published: April 2018

We report the structure and the magnetic behaviors of the Fe-doped La2Co1-xFexMnO6 family of compounds at low doping concentrations x ≤ 3 %. The substitution of Fe into the Co site induced the increase in ferromagnetism at the cost of TC. The small doping of Fe in La2Co1-xFexMnO6 (£ 3 %) led to the slight changes in the lattice constants but the symmetry of the lattice remained unchanged (Pnma). The doping also reduced TC for both transitions at around 215 K and 130 K which attribute for the different spin orderings of the magnetic ions.
DISCOVERY OF ENTOMOPATHOGENIC FUNGI Cordyceps takaomontana AT LANGBIAN MOUNTAIN, LAM DONG, VIET NAM
Authors: Hiep Dinh Minh 
Published: April 2018

The stromata of Cordyceps sp. were found on the Langbian Mountain – Da Lat, Vietnam at the height of 1.650 meter above sea level, on the larva of Lepidoptera. Stromata were lemon-yellow, clavate to elongated clavate, arising from a white pseudosclerotium. The fertile head was on the top part of stromata, darker coloured in comparison to the stipe. Perithecium was narrowly ovoid, superficial and forming dark yellow punctate on the surface of stromata. Ascus cylindrical with semi- spherical cap. Ascospores were cylindric, truncated and separately after discharge from the ascus.Pure culture was isolated on Potato Glucose Agar (PGA) medium: white colony in young and yellow in old. The isolated mycelium was not homogenous in thickness and in growth rate at the peripheral area. Conidiophores were phialide, tapering to both apexes. Conidia had elliptical shape and form into chains after maturation.DNA was isolated, then purified from pure mycelium and used to amplifying the nrLSU (nuclear ribosomal large subunit) sequence. The amplified products were used for sequencing, proof-reading by some professional solfwares before combining with other nrLSU sequences. Then this database was used to search for the suitable evolution model as well as to construct the phylogenetic trees.The results of phylogenetic analysis completely supported the morphological classification: DL0038A and DL0038B were Cordyceps takaomontana.
LEAF LITTER FUNGI ISOLATED IN BACH MA NATIONAL PARK, VIET NAM
Authors: Hoang Yen Le Thi 
Published: April 2018

A survey of fungi from leaf litter at Bach Ma National Park in Viet Nam was initiated. Using surface disinfection and moist chamber with single spore isolation methods, 102 isolates were obtained and of those, 70 isolates were selected for further morphological study. They belong to 5 classes, 9 orders, 14 families, 33 genera, and 51 species. Among them, Ceratosporella deviata, Lateriramulosa sp., Isthmolongispora ampuliformis, Polylobatispora quinquecornuta, Scolecobasidium tricladiatum, Triglyphiuma labamense, Tricladiella pulvialis, Tripospermum myrti, Triscelophorus sp., Varicosporium elodeaea are newly recorded in Viet Nam.
SCREENING OF SALT TOLERANT BACTERIA FOR PLANT GROWTH PROMOTION ACTIVITIES AND BIOLOGICAL CONTROL OF RICE BLAST AND SHEATH BLIGHT DISEASE ON MANGROVE RICE
Authors: Minh Nguyen Van 
Published: April 2018

From 22 rice, soil and water samples collected in the field of Long An and Tien Giang provinces, we isolated and screened 87 strains of bacteria around the root zone and endophytic bacteria. Through testing the ability of plant growth stimulation, the result showed 16 strains were capable of nitrogen fixation, 13 strains were capable of phosphate solubilization, 27 strains were capable of IAA production and 2 strains had all 3 activities. By the dual testing method and the percentage of inhibition method between bacterial and fungal pathogen, LD5 and LS6 strains had the highest antifungal activity against Rhizotocnia sp. CR1 at 94.02 %. TS3 and TĐ13 strains had the highest antifungal activity against Magnaporthe sp. BP3 at 81.74 ± 0.88 % and 80 ± 0.60 %, respectively. Furthermore, there were 6 strains inhibiting both Rhizotocnia sp. CR1 and Magnaporthe sp. BP3 (LĐ5, LS4, LS6, LN1, LN6, TS3). The strains were identified by biochemical methods. The results showed that LD5, LS6 and TS3 were 70.37 % similar to Bacillus thurigiensis, TD13 strain was 70.37 % similar to Bacillus pantothenticus, TD9 strain was 72.72 % similar to Azotobacter vinelandii and TD6 strain was 70.37 % similar to Bacillus subtilis. Regarding the test of activity to stimulate growth in net house model, combination of 4-strain (TD6, TD9, TD13, TS3) had the effect of increasing the length of roots, trunk and weight of rice compared with control treatment. For evaluation of biocontrol of fungal pathogen in net house model, the abilities to control sheath blight in N-2C1 and N-LĐ5 treatment were the highest (40.59 % and 39.06 %, respectively). The ability to control rice blast in N-2C2 treatment was the highest (41.26 %). The ability to biocontrol both sheath blight and rice blast in N-4C treatment was 37.89 %.
THE EFFECT OF LEATHER FIBERS ON VULCANIZATION BEHAVIOR OF NATURAL RUBBER
Authors: Hang Le Thuy 
Published: April 2018

This paper shows the primary research results of the effect of the leather fibers on the vulcanization of natural rubber (NR). The fibers used in this research were prepared by grinding waste leather scraps of Vietnam shoe making company. Leather fibers (LFs) and natural latex rubber were mixed together at various rates by a stirring machine. The obtained composites of natural rubber containing leather fibers were dried at pleasant condition prior to the analysis. Vulcanization behavior of the samples was clarified using a moving die rheometer. The vulcanization temperature as 120 °C is found to be the appropriate temperature for the NR/LFs composite. The increasing of minimum and maximum torque with the increasing of leather fiber content shows the improving in stiffness of natural rubber with the presence of leather fibers. Regarding to curing curves, 40 wt% promises to be the optimal leather fiber content to reinforce natural rubber.
FABRICATION OF CURCUMIN LOADED NANO POLYCAPROLACTONE/CHITOSAN NONWOVEN FABRIC VIA ELECTROSPINNING TECHNIQUE
Authors: Hoang Minh Son 
Published: April 2018

Cucurmin loaded poly e–caprolactone/chitosan (PCL/CTS) nanoscale nonwoven fabric was successfully fabricated using electrospinning, a facial and efficient method. The surface tensions of PCL/CTS blend solutions in various ratios were measured to evaluate the influence of PCL/CTS ratio on fibers formation. The effects of process parameter such as the applied voltage, tip–collector distance and the solution flow rate on the fiber generation and morphology of final fiber were optimized. Nanofibers morphology and structure were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. The prepared fibers had a smooth surface and fine morphology. The diameter of fibers ranges from 200 nm to 400 nm. The release kinetics of curcumin loaded samples were also analyzed via in vitro technique. Results demonstrated that the polycaprolactone/chitosan–based nanofibers encapsulate curcumin is a potential material for wound healing acceleration.
REMOVAL OF Cd(II) FROM WATER BY USING GRAPHENE OXIDE–MnFe2O4 MAGNETIC NANOHYBRIDS
Authors: Hieu Nguyen Huu 
Published: April 2018

In this work, graphene oxide–manganese ferrite (GO–MnFe2O4) magnetic nanohybrids were synthesized by co–precipitation technique. The adsorption properties of GO–MnFe2O4 for efficient removal of Cd(II) from contaminated water were investigated. The nanohybrids were characterized by using X–ray diffraction, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller specific surface area (BET), transmission electron microscopy, and vibrating sample magnetometry (VSM). VSM result showed the high saturation magnetization values Ms = 27.1 emu/g, the BET specific surface area was 84.236 m2/g. Adsorption experiments were carried out to evaluate the adsorption capacity of the GO–MnFe2O4 magnetic nanohybrids and compared with MnFe2O4 nanoparticles and GO nanosheets. The equilibrium time for adsorption of Cd(II) onto the nanohybrids was 240 minutes. Experimental adsorption data were well–fitted to the Langmuir isotherm and the pseudo–second–order kinetic equation. The experimental results showed that adsorption of Cd(II) using GO–MnFe2O4 magnetic nanohybrids was better than MnFe2O4 and GO with a maximum adsorption capacity of 121.951 mg/g at pH 8. Reusability, ease of magnetic separation, high removal capacity, and fast kinetics lead the GO–MnFe2O4 nanohybrids to be promising adsorbents for removal heavy metals from contaminated water.
SYNTHESIS OF ZINC OXIDE/GRAPHENE OXIDE NANOCOMPOSITES AS ANTIBACTERIAL MATERIALS AGAINST STAPHYLOCOCCUS AUREUS AND ESCHERICHIA COLI
Authors: Hieu Nguyen Huu 
Published: April 2018

New materials with good antibacterial activity and less toxicity to other species have attracted numerous research interests. Modified Hummers method was used for preparing graphene oxide (GO). Zinc oxide/graphene oxide (ZnO/GO) nanocomposites were synthesized with three different ratios (0.5:1, 1:1, and 2:1) by solution precipitation method. The ZnO/GO nanocomposites were characterized by Fourier transform infrared spectroscopy, X–ray diffraction, Raman spectroscopy, Brunauer–Emmett–Tellerspecific surface area, and transmission electron microscopy image. The characterization results showed that ZnO nanoparticles with a mean size of 12–18 nm were randomly decorated on the surfaces and edges of GO sheets. ZnO/GO 1:1 with a high specific surface area of 65 m2/g was obtained. The antibacterial activity of ZnO, GO, and ZnO/GO was tested against Gram negative bacteria escherichia coli (E. coli) and Gram positive bacteria staphylococcus aureus (S. aureus) using well diffusion method. The test results confirmed that antibacterial activity of ZnO/GO was higher than that of GO and ZnO. Additionally, the ZnO/GO with the ratio of 1:1 is the strongest activity and more active against S. aureus than against E. coli and minimal inhibitory concentration (MIC) value of ZnO/GO 1:1 is 80 µg/mL for S. aureus and 160 µg/mL for E. coli. This novel nanocomposite could be used as a potential material for antimicrobial application.
DIATOM COMPOSITION IN THE RED RIVER NEAR SON TAY, HA NOI
Authors: Thu Hang Hoang Thi 
Published: April 2018

This study represents data on diatom composition in water samples collected in the Red River near Son Tay town, Hanoi. Diatom samples were selected from marcophyte and stone surfaces during dry season of 2014. 79 diatom species belonging to 8 families were identified. The most species rich genera are Nitzchia (16 species), Navicula (14 species), Gomphonema (5 species). There are five diatom species which are dominant in Red River diatom community including Navicularecens (30 % of the total community), Nitzschiapalea (9.3 %), Synedra fasciculate (8.1 %), Luticola minor (5 %) and Gomphonemaparvulum (2.8 %). The Oligosaprobous and α -m esosaprobous diatom taxa make up only around 3% and to 20 % of the total community. However, polysaprobous and ß- mesosaprobous taxa dominate in the Red River accounted 13 to 51 % total community.