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Optimization of Pectin Extraction and Effect of Extraction Conditions on Esterification of Pectin from Purple Passion Fruit Peel (Passiflora edulisSims.)

Nguyen Trong Thang, Le Minh Nguyet

Received: 03-03-2021 / Accepted: 10-05-2021
Passion fruitpeel accounts for a very high percentageof the total fruit weight. Therefore, taking advantage of this by-product source to extract pectin will both create valuable products for application in the food industry and contribute to solving environmental problems. This study aimed to find the optimal conditions for extracting pectin from the peelsof purple passion fruit and to evaluate the effect of extraction conditions on the degree of esterification of pectin. Using a central composite design (CCD) with a response surface methodology (RSM), the results showedthat the generated quadratic model adequately explained the data variation and significantly represented the actual relationship between the independent variables and the responses. This study also found the optimal conditions to extract pectin from passion fruit peelsas follows: citric axit concentration of 8.00%, temperature of 82.14C and extraction time of 81.07 min for the highest yield of pectin (24.42%). Thepectin extracted under the optimum conditions had the followingphysicochemical properties: equivalent weight (EW) of 586.92± 17.55; degree of esterification (DE) of 38.76± 1.52 %; methoxyl index (MI) of 3.94± 0.13 %; total anhydrouronic acid content (AUA) of 76.58± 1.19 %. Thesecharacteristics are suitable for the purpose of edible film making, opening up a potential application for this pectin. In addition, the extraction conditions had a marked effect on the degree of esterification of pectin from purple passion fruit peel.
ImpactsofConstructionandDevelopmentofEconomicZoneon landuseManagementinSouth - East NgheAnEconomicZone

Truong Quang Ngan, Nguyen KhacThoi , Tran Trong Phuong

Received: 25-02-2020 / Accepted: 25-05-2020
The study aimed to determine the impacts of construction and development of economic zone on a number of land use management factors in Southeastern Economic Zone, Nghe An province. The study used method of surveying, comparing and analyzing secondary data, method of interviewing 148 officials and 480 households in 3 survey areas. The study uses Likert's 5-level scale to evaluate the process of building and developing economic zone, managing land use, using T-Test to check the differences in some indicators between objects and among 3 groups of households, use the correlation coefficient r (Spearman Ranking) to determine the impact level. The process of building and developing the economic zone with five selected criteria has been assessed at a high level by the people and management officials, there has been a difference between the two groups. The planning for construction of economic zones and development of functional zones has a major impact on land use management elements in region 1. Economic zone construction planning; functional area development; infrastructure development; attracting investment project capital and labor force that has a great impact on the land use rights transfer market, agricultural land prices and agricultural land use in region 2. Planning for construction of economic zones, development of functional areas and development of facilities. The infrastructure has a great impact on the transfer market of residential land use rights and the rights of land users in area 3.
Developinga Multiple-Choice Test System on Computers

Ngo Cong Thang, Do Thi Nham

Received: 17-12-2019 / Accepted: 10-02-2020
Our research was conducted to develop a multiple-choice test systemon Computers, because this system is necessary to increase the effectiveness of evaluatingstudents' achievement. We studied new technologies such as NoteJS, MongoDB, AngularJS, and performed the stepsof the software development life cyclesuch as analysis, design, installation, testand deployment of the multiple-choice test system. After the testing process, our system has achieved very good results in theevaluating students’achievement. The results of our experiments haveconfirmed that our system can be effectively applied in practice.
Smart Agriculture: Issues and Recommendations for Research and Training

Do Kim Chung

Received: 26-07-2018 / Accepted: 20-08-2018
Smart Agriculture (SA) is one of the outcomes of the fourth industrial revolution. This paper highlights concepts, interrelated elements and technology tendencies and curent situations of SA in the world and Vietnam. The paper also points out the benefits, challenges and training and research issues for Vietnam to adopt SA. Finally, the paper suggests some viewpoints and orientations for renovating research and training agriculture’s human resource in the country including renovation of training and research approaches; continuation of restructuring agriculture sector by renovating public investment and services in agriculture research and training and moving from resource-based development strategy to renovation and innovation-based one; prioritizing SA where applicable but still considering traditional farming; implemetation of SA’s R and D program; encouraging start-ups in development and application of SA’s technologies; renovation of training program by closely meeting society’s demand, overcoming market failures in training, renewing training contents and training modes, strengthening linkages with other stakeholders; updating technologies of the industry 4.0 for training human resource in digital physical, biological and operational technologies; more attention for training in knowledge and skills for current agriculture labor force
Study on the Production of Perilla Seed Oil

Nguyen Thi Hoang Lan, Bui Quang Thuat, Le Danh Tuyen

Received: 20-05-2018 / Accepted: 02-07-2018
The study was carried out on perilla seeds (containing 30.09%oil) harvested from plants cultivated in Dong Dư (Gia Lam-Ha Noi)to select the most suitable processing methods andto optimize the processing techniques of seed oil extraction. Two- time dynamic extraction was selected as the most suitable method to extract oil from perilla seeds. The main processing factors were examined in order to enhance the oil extraction yield and oil quality. The optimised processing conditions were identified. The seeds were ground into powder with particle size of 0.2 mm. The ground materials were then extracted 2 times by n-hexan at 60 oC and at a solid/liquid ratio of 1/6 in 5 hours for the first extraction and 1/5 in 4 hours for the second one. The obtained perilla seed oil had good nutritional quality with high levels of essential polyunsaturated fattyacids, especially omega-3 which accounted for 58.3% of total fattyacids.
Productive Efficiency of Intensive White-Leg Shrimp Farming Households in Phu Yen Province

Le Kim Long

Received: 15-03-2017 / Accepted: 19-05-2017
Shrimp is the major commodityin the annual export turnover of Vietnam. This paper analyzedproductive efficiencyof the intensive white-leg shrimp farming households in Phu Yen. A total of 59 shrimp farming households practicing intensive aquaculture with the area of 45 ha (about 24% of the intensive white-leg shrimp farming in Phu Yen province) were randomly surveyed. The result showedthat although the intensive white-leg shrimp farming in Phu Yen is still profitable,but the interest for investment in shrimpfarming is rather low due to high risk and high productive capital. Moreover, this aquaculture is only profitable if its negative impact on the environment is neglected. The saturation state due to open-access mechanism for aquaculture has, however, been reached. Toward a sustainable aquaculture, it requires a further revision and issuing policies that step by step endogenize the environmental costs into the production process. Farmers’supports such as technology development, technique training and credit acess are also important.
Development of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) on Different FeedPlants

Nguyen Thi Huong, Ho Thi Thu Giang, Pham Van Lam

Received: 28-12-2015 / Accepted: 05-05-2016
The development and life cycle of the beet armyworm, Spodoptera exigua(Hübner), were determined in the laboratoryusing six feedplants: welsh onion(Allium fistulosum); amaranth(Amaranthus viridis); mustard greens(Brassica integrifolia); mung bean(Vigna radiata); cabbage(Brassica oleracea capitata); and turmeric(Curcuma longa). The life cycle of S. exiguawas shortest on amaranth (24.2 days) and longest on turmeric (34.7 days). Feedplantsdid not significantly affectthe percentage of egg hatching or pupal survival. However, larval survival differed among feedplants, being highest on amaranth (87.6%) and lowest on turmeric (50.0%). The highest percentage of female progeny was recorded from S. exiguareared on welsh onion (46.7%) and the lowest for larvae reared on turmeric (36.1%). The fecundity of S. exiguafemales ranged from 174.3 eggs on turmeric to 453.8 eggs on amaranth. Within each feedplant, the increased pupal weight resulted in increasedfecundity. It means that the fecundity was significantly related tothefemale pupal weight ofS. exiguareared on test feedplants(r = 0,883 - 0,965).
ANALYSIS OF FACTORS AFFECTING DEMAND OF PORK CONSUMPTION IN VINH CITY, NGHE AN PROVINCE

Do Truong Lam, Tran The Cuong, Nguyen Thi Thu Huyen, Vu Khac Xuan, Nguyen Anh Duc

Received: 07-05-2013 / Accepted: 28-06-2013
Demand for pork consumption is highly fluctuated and depended on many factors. Thus, the estimation and analysis of factors affecting pork demand would contribute to stabilize the market for pork in particular and the whole market for consumption goods. The study used econometrics model and ANOVA analysis to analyze key factors affecting the demand for pork consumption in Vinh city, Nghe An province. Results showed that key factors such as price of pork meat, fish, and chicken, as well as real income of household have affected to the demand for pork consumption. On the other hand, some factors such as price of beef, personal background of consumers (like source of income, age, gender, and current living place of household) do not have any effect on the demand (of pork). In order to stabilize the market for pork, some measures are required such as controlling the supply of pork meat, developing the retail system (for pork), and planning for pig production in associated with poultry and fish production.
Building a Procedure for Adding Cashew Nut in Cookie Making Process

Dinh Thi Hien, Nguyen Thi Thanh Thuy, Nguyen Duc Quyet

Received: 15-07-2013 / Accepted: 22-10-2013
The aim of the study was to build a recipe and procedure for cookies making with cashew supplement in order to produce a tasty, nutritive and convenient fast food to market. The best proportion of cashew added to flour is 10% of the total powder weight. The procedure suggested includes the following steps. Firstly, shortening and butter is l mixed for 3-5 minutes before adding powder milk, sugar, salt and vanilla, then mixing is continued until homogeneous dough is obtained. Secondly, flour and cashew are added and blended in 12-15 minutes afterward. The dough temperature is in range from 19 to 25oC and the moisture is between 16 and 20%. Thirdly, the dough is shaped in to small pieces with 4-5cm in diameter and 3-4mm in thickness. Baking step is carried out at 160oC for 5 minutes followed by 240oC for 3 minutes. The new “cashew cookies” has better nutrient components, higher calories as well as specific characteristics.
Study on Genetic Diversity in Taro (Colocasia esculenta) by DNA Markers

Nguyen Van Giang, Vu Ngoc Lan, Tong Van Hai

Received: 08-12-2012 / Accepted: 23-01-2013
In this study, we used DNA markers (5 RAPD markersand 5 SSR markers) to screen genetic diversity in 60 samples of taro(Colocasia esculenta)that collected. Total 67 alleleswere amplified by RAPD markers, in that has 47 polymorphic alleles. 20 alleleswere amplified by SSRmarkersand 9 alleles were polymorphic. From the electrophoresis PCR products of these two directives, 60 taro accessions were grouped into 12 clusters with similarity coefficients of 0.8 by NTSYSpc 2.1 software. The information found in this study may be used for taro conservation and breeding programs.
Study on In vitroPropagation of Miltoniasp.

Phan Xuan Huyen, Hoang Van Cuong, Nguyen Thi Phuong Hoang

Received: 25-07-2014 / Accepted: 09-10-2015
In the present study, 3 -4 protocormsderived from meristem of red and white-pink Miltoniasp. were used as material source for all invitro culture experiments. Effect of MS medium concentration, coconut waterandBA alone or in combination with αNAA on protocorm formation and shoot growth were studied. After 90 days of culture, the results showed that half MS medium supplemented with 15% coconut water, 1.5 mg/l BA in combination with αNAA of 0.1 mg/l, 30 g/l sucrose, 8 g/l agar, 1 g/l activated charcoal,andpH 5.8 was the best for protocorm inductionand shoot growth (25.60 shoots/explant, height of 1.95cm). Half MS medium containing 0.1 - 1 mg/l αNAA or 0.1 - 1 mg/l IBA, 30 g/l sucrose, 8 g/l agar, 1 g/l activated charcoal,andpH 5.8 was suitable for in vitroroot formationafter 40 days of cultureandthe rate of shoot formation was 100%.Coconut fiber and fern fiber were suitablesubstratesfor plantlet growth in the greenhouse, with coconut fiber beingbetter in terms of number of roots/explant, root length andsurvival ratecomapred tofern fiber substrate.
Anti-Bacterial Activity of Myrtle Leaf and Myrtle Seed (Rhodomyrtus tomentosa) Extracts on Bacterial Strains Causing Acute Hepatopancreas Necrosis Disease (AHPND) in Shrimp

Dang Thi Lua, Lai Thi Ngoc Ha, Nguyen Thanh Hai

Received: 14-07-2015 / Accepted: 12-10-2015
Acute hepatopancreas necrosis disease (AHPND) has been considered as a major constraint for the sustainable development of shrimp culture industry. This study was carried out to examine in vitroanti-bacterial effects of herbal extracts derived from leaves and seeds of myrtle (Rhodomyrtus tomentosa) on bacterial strains caused AHPND, Vibrio parahaemolyticusKC12.02.0, V. parahaemolyticusKC13.14.2, andVibrio sp.KC13.17.5. Results showed that although both myrtle leafand seed extracts had anti-bacterial effects against in vitro AHPND-causingVibriostrains, the myrtle seed extract showed higher antibacterial activities. The inhibition zone diameters of myrtle seed extract reached17,67 mm for V.parahaemolyticusKC13.14.2; 18,00 mm for V.parahaemolyticusKC12.02.0and 19,33 mm for Vibriosp.KC13.17.5. These results suggested myrtle seed extract can potentially be used as a material for development of herbal medicine for AHPND control.
X.ent Package for Extraction of Entities, Relationships between Entities and Support Data Analysis in Epidemiological Journals in French Agriculture

Phan Trong Tien, Ngo Cong Thang

Received: 22-07-2015 / Accepted: 03-09-2015
Entity extraction is a task of information extraction and element classification in text such as the names of persons, organizations, locations, times, etc. and to find relationship between entities such as the relationship between the names of persons with the organizations. The X.ent tool was built solve this task. It uses dictionaries matching and hand - crafted rules to extract. In extracting the relationship between the entities, we applied two methods: analysis of text structures and unsupervised learning approach called coo – ccurrence analysis. This tool is available on the site of R at the links: http: //cran.r - project.org/web/packages/x.ent/index.html.
Assessing Genetic Diversity Tomato and Yellow Leaf Curl Virus (TYLCV) Resistance Gene ofTomato Varieties by DNAMarkers

Doan Xuan Canh, Tong Van Hai, Nguyen Hong Minh, Doan Thi Thanh Thuy

Received: 15-08-2014 / Accepted: 22-01-2015
Tomato is apopularly important vegetable in the world and Vietnam. Assessing genetic diversity and detcetion of genes for disease resistance of the existing germplasm of tomato are usefull for development ofnew varieties with high yield, good qualityand disease resistance. In this study,10 SSR markersand four markers related to TYLCV resistance genes (Ty1, Ty2and Ty3) were usedto analyse genetic diversityand identify the TYLCV genes, respectively, of26 of tomatoes accessions available at food crops research institute. The results showed, that only 5 marker showedpolymorphism.26 accessions were grouped into 5 clusters with similarity coefficients threshold of 0.7 by using NTSYSpc 2.1 software. The information found in this study is very important fornew tomato hybrid breeding programs.Only four of 26 accessions carriedTy1andthe genesTy2 and Ty3 were not detected
Assessmentof The ResultsonImplementation of Supportive Policiesfor Enterprise Development in Nghe An Province

Trinh Thi Huyen Thuong, Do Kim Chung

Received: 05-10-2014 / Accepted: 20-01-2015
Goverment’s supportive policy is important leverage to promote the enterprise development, especially in the economy slow-down period. However, in the course of policy implementation severalproblemsarise. With theinformation collected by interview methods using a set of questionaireforimplementingagenciesandthe beneficiary enterprises, this article showedthat gorverment’s supportive policy in Nghe An province has brought positive impacts on enterprise development,contributing to increasing capital, reduction ofproduction costs, and relievingbusiness problems in therecessionperiod; thereby promotingthe development of enterprises in the province.In addition, the article pointed out shortcomings of policy mechanisms, such ascomplicated procedures for receiving support, inadequatelevels of support, low enterprises’ accessibilityto the support… From these evaluations, the authorsmade a number of proposals to improve the effectiveness of policy support in the future.
Isolation and Evaluation of Antibiotic Activity of Endophytic Actinobacteria on May Chang Tree (Litsea cubeba) against Pathogenic Bacteria Causing Diseases on Common Carp and Tilapia

Trinh Thi Trang, Kim Van Van, Truong Dinh Hoai, Nguyen Thanh Hai, Nguyen Van Giang, Nguyen Ngoc Tuan

Received: 02-11-2016 / Accepted: 28-12-2016
Tilapia and common carp are two main cultured species with high annual production annually in freshwater aquaculture in northern Vietnam. , hHowever, there are serious problems caused by bacterial infection. The use of antibiotics is not sufficient to mitigate outbreaks of the diseases due to antibiotic resistance of the causal agentsrate are increasing. Therefore, antimicrobial compounds are potential as a new approach to overcome the challenges of antibiotic resistance. The aim of this study is to isolate and evaluate antibiotic activity of endophytic actinobacteria from May Chang tree (Litsea cubeba) against three pathogenic bacterial species Aeromonas hydrophila GL14, Aeromonas caviaeHD60 và S. agalactiaeHY10. The results showed that 9/32 (28,2%) endophytic actinobacteria isolates could inhibit at least one target pathogenic bacteria. Three isolates MTR711, MTR622 and MTL121 showed the highest antibacterial response with minimium inhibitory concentration (MIC) ranged from 93,3 to 300,0 µl/mL, amongst these the lowest value is for MTR711 and MTR622 without significant difference. When combining three individual actinobacteria mentioned above for fractional inhibitory concentration (FIC) test, the synergistic effect was found for the pair of MTR711-MTR622 against three pathogenic bacteria chosen in this study with ∑FIC ≤0,5. The combination of two actinobacteria MTR711 and MTR622 improved bacterial inhibitory effect at least 4 times compared to individual treatment. The results are motivating enough to conduct further studies on use of endophytic actinobacteria for treating pathogenic bacteria in aquatic animals.
Identify the Effectiveness of Some Soybean Rust Resistant GenesonVietnam and Their Linkage Molecular Markers

Nguyen Van Khoi, Duong Xuan Tu, Nguyen Thanh Tuan, Nguyen Van Lam, Nguyen Huy Chung, Dinh Xuan Hoan, Le Thi Thanh, Nguyen Thi Thu, Phan Huu Ton

Received: 10-03-2016 / Accepted: 15-08-2016
Five genes Rpp1, Rpp2, Rpp3, Rpp4 & Rpp5 conferringresistancetoPhakopsora pachyrhiziSydow in soybean were identtified. Resistance evaluation of the soybean linescarryingresistant genes shows that genes Rpp2and Rpp4are highlyresistanttosoybean rust in Vietnam while Rpp5ishigh resistanttothe isolatesof rustpathogencollected from Southvietnam. The selection of molecular markers linkedto the above-mentionedresistance genes based on the analysisofcrossing populationsbetween resistant and susceptible cultivars shows that the markers Satt620, Satt288 and Sat_275 are closely linkedto Rpp2, Rpp4and Rpp5with the genetic distance of3.33cM, 2.50cM and4.16cM,respectively. Thesemarkers may beused to identify and select resistancegenes ingermplasm andresistant individuals in segregating populations.
Effect of ExtractionConditions on Polyphenol Content and Antioxidant Activityof the Extract from Gynura Procumbens(Lour) Merr. Leaves

Nguyen The Han, Pham Thi Kim Quyen, Nguyen Van Minh

Received: 18-03-2016 / Accepted: 15-07-2016
Gynura procumbens(Lour.) Merr.is a well- known traditional herb in South East Asia and it is widely used to treat inflammation, high cholesterol level, high blood pressure and diabetes. In the present study, the effects of various extractionconditionswere investigated:solvent, solvent concentration, materialto solvent ratio, extraction temperature, extraction time and extraction techniques (maceration and ultrasonic- assisted) on total phenolic content (TPC) and antioxidant activity of the extract fromleaves of Gynura procumbens(Lour) Merr. cultivated in Khánh Hoa province.Folin- Ciocalteu’s method was used for the determination of TPC, while theantioxidant activity was determined by 2,2’ - diphenyl - 1 - picrylhydrazyl (DPPH) radicalscavenging activity and reducing power assays. The best extraction conditions were as follows: 50% aqueous methanolas the extraction solvent,1: 50 materialto solvent ratio, the extraction temperature at60C and the extraction time of30 min, using ultrasonic- assisted extraction. The total phenolic content, DPPH radical scavenging activity (EC50) and reducing power (EC50) under suitable condition, were 48.49 mg GAE/g dry extract, 0.13 and 0.06 mg/ml, respectively. The present study suggested that the Gynura procumbens extract could be a promising source of natural antioxidants.
Evaluation of Feature Selection Methods for Gene Expression Data Classifcation

Phan Thi Thu Hong, Nguyen Thi Thuy

Received: 11-08-2015 / Accepted: 08-03-2016
Selection of relevant genes that have effects in some diseases is a challenging task in gene expression studies. Most gene selection studies focused on assessing the association between individual gene and the disease. In fact, diseases are thought to involve a complex etiology including complicated interactions between many genes and the disease. Random Forest (RF) method has recently been successfully used for identifying genetic factors that have effects in some complex diseases. In spite of performing well in some data sets with moderate size, RF still suffers from working for selecting informative genes and building accurate prediction models. In this paper, we investigatedsome methods in learning advanced random forests that allow one to select a sub-set of informative genes (most relevant to disease). The method can therefore reduce the dimensionality and can perform well in prediction high-dimensional data sets. The performance of these methods has been analyzed for finding the robust one for each interest objective (the accuracy of the prediction model or the smallest possible set of relevant genes) based on experiments results on 8 available public data sets of gene expression from the repository of biomedical data sets (Kent Ridge) and bioinformatics data sets(Bioinformatics).
Biological Age Determination for Tomato cv'Savior' Grown in Spring-Summer Season by Modeling Approach

Tran Thi Dinh, Tran Thi LanHuong

Received: 15-10-2015 / Accepted: 11-03-2016
In the curent study, the biological age of tomato cv 'Savior' grown in spring summer season was determined using modeling approach. The model was calibrated based on two input variables: mass and fruit color changes during fruit development and ripening. The model was successfully validated using a single point estimation method. The data in this study canbe combined with the quality attributes at diferent physiological stages to calibrate the model for predicting the optimal harvest timeof tomato cv Savior in further research.
Selection of Lactic Acid Bacteria with Bioactive Characteristics for Application in Agricultural Waste Treatment forMaking FeedforRuminants

Nguyen Thi Lam Doan, Luu Thi Thuy Duong

Received: 16-10-2017 / Accepted: 26-12-2017
After the harvest, most by-products from rice straws, plant roots, and stems etc are burned by farmers. This activity causes environmental pollution. The use of variable source of agricultural by-products as feed for livestock is considered as one of the alternative reduce waste. Agricultural by products have high fiber content, low digestibility and energy value. This study aimrd to select lactic acid bacteria with biological characteristics such as high lactic acid production, production of some extracellular enzymes (amylase, cellulase, xylanase) and antibacterial activity against pathogenic bacteria for treatment of agricultural by-product as cattle feed. Results of this study showed that from 61 strains lactic bacteria isolated, 27 strains were selected with high lactic acid production (200-263ºT) and good growth at 37ºC. From 27 strains, 8 strains were identified with extracellular enzyme production of amylase, cellulase, and xylanase with ring diameter of substrate resolution of 7-33 mm. In addition, this study revealed 3 strains with antibacterial properties such as T6.2 strain against gram positive Listeria monocytogenesand two strains, C3.15 and C3.19, against gram-negative (E. coli). Three strains were capable of decomposing straws, but the C3.19 showed strongest decomposition.
In VitroAnti-Bacterial Activity of Herbal Extracts against Staphylococcusspp. and Streptococcus spp. Isolated from the Metritis in Cows

Nguyen Thi Thanh Ha, Nguyen Thanh Hai, Nguyen Nam Phuong, Nguyen Van Thanh

Received: 18-04-2017 / Accepted: 26-07-2017
The use of antibioticsfor the cow metritis treatment has many advantages, however, raises concerns about antibiotic residues in the meat and dairy products as well as increasing antibiotic resistance of pathogenic bacteria. Herbs have been increasingly demonstrated their significant role in the pharmaceutical industry as a biosafety solutionandan alternative to synthetic chemical drugs. The present study aimed to examine the anti-bacterial activity of herbal extracts(Polyalthia longifolia var.Pendula, Lignum Caesalpiniae sappari, Excoecaria cochinchinensis Lour.,Clerodendron fragrans Vent, Wedelia calendulaceae Less, Cudrania tricuspidata, Pseuderanthemum (Ness)Radik, Lactuca indica L)against Staphylococcusspp. and Streptococcusspp.isolated from cow metritis. The resultsshowed that the extractionefficiency varied from 9.60% (Lignum Caesalpiniae sappari) to 14.32% (Wedelia calendulaceae Less). At the concentration of 100 mg/ml, all the extracts showed good anti-bacterial activity against Staphylococcusspp. and Streptococcusspp. For Streptococcusspp., the bacterial inhibition zone varied from 11.80 mm (Cudrania tricuspidata(Carr) to 25.00 mm (Clerodendron fragrans Vent). The diameter of the bacterial inhibition zone of Staphylococcusspp. varied from 10.28 mm (Cudrania tricuspidata(Carr)) to 25.30 mm (Wedelia calendulaceae Less). The extract solution of Clerodendron fragransVent and Wedelia calendulaceaeLess showed the highest anti-bacterial activity. This extract remained its anti-bacterial activity against Staphylococcus spp. and Streptococcusspp. at concentration of 0.20mg/ml.
Manufacturing Protocol for the Starter Culture from Mold Mucor elegans

Le Minh Nguyet, Phan Thi Phuong Thao

Received: 29-05-2012 / Accepted: 15-09-2012
Starter culture is a source of pure microorganisms that are used for controlled fermentationto produce traditional fermented products with high quality, stability, and safety. The starter culture derived from mold contains spores and hydrolytic enzymes. This study was conducted to determine the optimal culture conditions for spore formation and the protease biosynthesis of mold Mucor elegans, to set up a manufacturing protocol for the starter culture that can be applied for producing the fermented soybean product “Chao”. It was identified that the medium with soybean meal and rice flour in a 50/50 ratio was the best for start culture production.
Effect of Time Destroying the Growing Point on Propagation Efficiency of Pineapple (Ananas comosus) cv. MD2

Le Vinh Hung, Nguyen Thi Ngoc Diem

Received: 25-03-2024 / Accepted: 21-06-2024 / Published: 25-07-2024
The pineapple variety MD2 has low, prolonged and ununiform shoot production under natural conditions. Therefore, it is very necessary to process buds simultaneously by destroying the growth tip to improve propagation efficiency for production. In this study, shoot tip/growing point was destroyed at time points (3.5, 4.5, 5.5, 6.5, 7.5 and 8.5 months after planting) and shoots of different sizes (4cm and 3 true leaves; 6cm and 4 true leaves; 8cm and 5 true leaves; 10cm and 6 true leaves; 12cm and ≥ 6 true leaves) were recorded. Research results show that mother plants shoots of 8.5 months after planting were treated and suckerss with a height of 4cm and 3 true leaves yielded 48.87 suckers/year. However, the plants were treated 7.5 months after planting combined yielded suckers with 8cm and 5 true leaves. The treatment time points and the size of the buds collected did not affect the sucker formation time ranging from 40.90 to 45.76 days and the survival rate after transplanting from 84.56 to 99.87%.
DOI: https://doi.org/10.1234/1fxw2a37
Reproductive Performance and Egg Quality ofVan Linh chickens raised at Vietnam National University of Agriculture

Duong Thu Huong, Nguyen Thi Chau Giang, Nguyen Van Thong, Nguyen Khanh Toan, Pham Van Son, Nguyen Hoang Thinh

Received: 11-12-2023 / Accepted: 23-05-2024
The study was carried out to determine reproductive performance and egg quality of Van Linh chicken from 17 to 40 weeks raised at the Faculty of Animal Science, Vietnam National University of Agriculture. A total of 40 hens and 6 roosters were randomly divided into 2 groups to monitor reproductive performance, feed consumption per ten eggs, egg quality and egg hatching rate. The results showed that Van Linh chickens attained sexual maturity at 120 days of age and the highest of laying egg rate at 193 days of age. In theperiod from 17-40 weeks of age, the egg yield was 66.93 eggs/hen, laying rate was 39.81%, feedconsumption/10 eggs was 3.24kg. The eggs of Van Linh chickens had an average weight of 43.81 g/egg, morphological index of 1.33; Haugh unit was 80.12. The rate of fertile eggs, hatched/fertile eggsand the rate of type I chicks/hatched eggswere 83.17; 86.98 and 90.48% respectively.

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