Published: 2018-06-28

Price risk perceptions and management strategies in Vietnamese pangasius production

Ngoc T. A. Pham, Quy D. Mai, Ha T. Dang, & Thuyen T. Pham
Electronic version: 28 Jun 2018 | DOI: 10.52997/jad.1.03.2018
Abstract | PDF (260.1K)

Abstract

Vietnamese pangasius prices have become more volatile over the past decade exposing the business to risk and uncertainty. This study explored Vietnamese pangasius farmers’ perceptions about the sources of price risk and the effectiveness of price risk management strategies through Likert scales. The relationships between farm and farmer socioeconomic characteristics and their perceptions were also examined by using Chi-square analysis. Data were obtained through a structured survey with 110 farmers in three provinces of An Giang, Can Tho, and Dong Thap. Results suggested that pangasius farmers mostly concerned the instability of input prices, the volume of input supply, the instability of output prices, and the legislation of sales contracts between farmers and processors. We further found that price risk management strategies were not perceived as less effective measures to mitigate the price risk. Gender, farmers’ experience, farm size, crop period, farm types, and access to credit are positively related to the farmers’ perceptions. Findings on the price risk perceptions and management strategies are useful to support public and private of price risk management decision towards increasing the sustainability of pangasius production.

Evaluating the growth capacity and heavy metal absorption of sweet sorghum and grain sorghum at the seedling stage

Tra T. T. Dinh
Electronic version: 28 Jun 2018 | DOI: 10.52997/jad.6.03.2018
Abstract | PDF (260.1K)

Abstract

In recent years, the use of plants for clean-up and recovery (phytoremediation) has been studied and used in many countries of the world. In this study, E-Tian sweet sorghum (ET) and BT x 623 (BT) sorghum were treated with heavy metal cadmium at 5 concentrations (0, 5, 10, 25, 50 mg/kg). The growth of plant; absorption, accumulation of cadmium (Cd) heavy metals in plant parts at the seedling stage have been identified and assessed. The results showed that Cd affected the height and number of leaves of the plant. Especially, Cd accumulation in the plant decreased in sequence: root, stem, leaf. When comparing the heavy metals accumulation in the two cultivars, the results showed that the BT cultivar had higher Cd uptake and accumulation potential than ET. Therefore, BT can be used for phytoremediation of heavy metals in soil but not for providing food and feed.

The use of water spinach (Ipomoea aquatica) in domestic wastewater treatment

Thinh V. D. Nguyen, Mai N. H. Nguyen, Thao V. Ngo, & Huong N. T. Huynh
Electronic version: 28 Jun 2018 | DOI: 10.52997/jad.7.03.2018
Abstract | PDF (260.1K)

Abstract

The main objective of this study was to examine the efficacy and capacity of using hydroponic systems in municipal pollutant removal at household scale. Three pilot scaled hydroponic systems [dimensionfor each system: 4.5 m (L) x Φ 114 mm] were installed to investigate the optimal age of vegetable, planting density and retention time for household wastewater treatment, respectively. Water spinach (Ipomoeaaquatica) planted in 27 plastic cups throughout 4.5-m-length and 114- mm-diameter uPVC pipes filled with wastewater was employed as the treating agent of pollutants. The averaged influent contained proximately 32.5 mg/L suspended solids (SS), 76.0 mg/L biological oxygen demand (BOD5), 220.5 mg/L chemical oxygen demand (COD), 26mg/L NH4+  , 5.0 mg/L NO3−  , and 8.5 mg/L PO43− at pH 7.3. Results showed that a designed system consisting of 10 plants of 15-day-old water spinach pre-planted in baked clay in each cup was capable oftreating 30 L of domestic wastewater meeting the current municipal wastewater discharge standards in Vietnam (column A standards of QCVN 14:2008/BTNMT) after 4 days of wastewater retention time. Ifoperated under conditions of the above parameters, the pilot-plant hydroponic system can achieve the removal of 65% SS, 82% BOD5, 74% COD, 90% NH4+ , 30% NO3− and 86% PO43−. The result of this studyhas provided an applicable domestic wastewater treatment system ecofriendly and suitable for small and medium household areas.

Optimization of maltodextrin and carrageenan gum concentration added in spray drying process of Pouzolzia zeylanica extract by response surface methodology

Tan D. Nguyen, & Thuy M. Nguyen
Electronic version: 28 Jun 2018 | DOI: 10.52997/jad.11.03.2018
Abstract | PDF (260.1K)

Abstract

Pouzolzia zeylanica is a kind of medicinal plant which is generally cultivated in Mekong Delta region. It owns many bioactive compounds that are known to possess antioxidant, antimicrobial and anticarcinogenic properties. This study aimed to optimize additional carrier concentration for spray drying of Pouzolzia zeylanica extract. Response Surface Methodology (RSM) with central composite design (CCD) was applied for optimization and investigation of the influence of maltodextrin (5÷15%, w/v) and carrageenan gum (0.06÷1.0%, w/v) concentration on the physicochemical characteristics of spray dried powder (bioactive compounds, moisture content as well as particle size distribution). The results showed that the optimum concentrations of maltodextrin and carrageenan gum were 8.8% w/v and 0.082% w/v, respectively. At these optimal conditions, the anthocyanin, flavonoid, polyphenol, tannin, moisture content and particle size of obtained spray dried powder were 5.77 mg cyanidin-3-glycoside equivalents (CE)/100 g; 29.49 mg quercetin equivalents (QE)/g; 28.35mg gallic acid equivalents (GAE)/g; 27.44 mg tannic acid equivalents (TAE)/g, 6.55% and 6.09 µm, respectively.

Effect of thawing methods on antioxidant capacity of frozen strawberry (Fragaria x ananassa) and mulberry (Morusnigra)

Viet B. Nguyen, Phuong H. Le, & Minh N. Nguyen
Electronic version: 28 Jun 2018 | DOI: 10.52997/jad.12.03.2018
Abstract | PDF (3.2M)

Abstract

The aim of this study was to evaluate the antioxidant capacity of thawed frozen strawberries (Fragariaananasa) and mulberries (Morusnigra). Both types of fruit were frozen in a freezer with a cooling rate of 1 0 C/min and stored at -180C in 1 week before thawed at ambient temperature, cold temperature (40C) and in a microwave oven. ANOVA, LSD test and Principal Component Analysis (PCA) were applied to compare the effect of thawing methods. Results showed that different thawing methods significantly affected (P < 0.05) drip loss, vitamin C content, total phenolic content (TPC) and antioxidant capacity of strawberries and mulberries. The strongly negative correlation was found between the drip loss and the remaining vitamin C as well as between the thawing time and the antioxidant capacity of thawed fruit. Among three thawing methods, microwave was considered as the most effective method to retain antioxidant capacity, vitamin C and total phenolic content for both strawberry and mulberry.    

Changes of total polyphenolics and vitamin C in acerola during storage and spray drying process

Thien T. Le, Quang H. Luong, Cabaltica D. Angeli, Tuan Q. Le, & Raes Katleen
Electronic version: 28 Jun 2018 | DOI: 10.52997/jad.10.03.2018
Abstract | PDF (260.1K)

Abstract

Acerola fruit is known to have a high vitamin C concentration. Polyphenolics are also natural oxidants occurring in plants. Understanding changes of these components during storage conditions and processing steps become important. Results of this research showed that there was significant difference in vitamin C and total polyphenolic concentration and three popular varieties of acerola fruits from Tien Giang province. Concentrations of both vitamin C and polyphenolics reduced rapidly during storage at room temperature. After three days, vitamin C reduced about 40% whereas total polyphenolics reduced about 70%. The losses at refrigerated temperature after 3 days were less than 15% and less than 30%, for vitamin C and total polyphenolics, respectively. Frozen storage of the fruit maintained quite well vitamin C and polyphenolics. Acerola pomace juice was concentrated before spray drying and, at the same vacuum pressure, temperatures influenced significantly the retention of vitamin C and total polyphenolics. Optimization of spray drying conditioners including inlet hot air temperatures and added ratio of maltodextrin (drying carrier) was also carried out to obtain high recovery of dry matter, total polyphenolics and vitamin C.

The science foundation for the establishment of cooperation mechanism on trans-boundary water management

Hung V. Bui, & Diep N. Nguyen
Electronic version: 28 Jun 2018 | DOI: 10.52997/jad.9.03.2018
Abstract | PDF (291.2K)

Abstract

The Mekong Delta (MD) is of socio-economic importance for both Vietnam and Cambodia. The trans-boundary dimension and respective management issues are highly relevant for the economic development and security of each country. Because the economic development of each country is different in the boundary region of MD, there are many kinds of natural hazard occurred in MD (including flood, drought, acid sulphate soils, and saltwater intrusion), the impact of upstream development, a myriad of flood controlling infrastructure, and the implications of climate change. To resolve these above problems and maintain the boundary security condition, the two countries areimplementing many cooperation and coordination mechanisms (CMs) at central and provincial levels. In this article, the current CMs between the two countries are presented to clarify the implementing status, effective and coherent level of the trans-boundary water management (TWM). From that, some recommendations will be proposed to set up a new CM closed with TWM for the boundary provinces in MD.