A three-dimensional Regional Ocean Modelling System is used to study the tidal characteristics and their dynamics in the Sunda Shelf of the southern South China Sea. In this model, the outer domain is set with a 25 km resolution and the inner one, with a 9 km resolution. Calculations are performed on the inner domain. The model is forced at the sea surface by climatological monthly mean wind stress, freshwater (evaporation minus precipitation), and heat fluxes. Momentum and tracers (such as temperature and salinity) are prescribed in addition to the tidal heights and currents extracted from the Oregon State University TOPEX/Poseidon Global Inverse Solution (TPXO7.2) at the open boundaries. The results are validated against observed tidal amplitudes and phases at 19 locations. Results show that the mean average power energy spectrum (in unit m2/s/cph) for diurnal tides at the southern end of the East Coast of Peninsular Malaysia is approximately 43% greater than that in the East Malaysia region located in northern Borneo. In contrast, for the region of northern Borneo the semidiurnal power energy spectrum is approximately 25% greater than that in the East Coast of Peninsular Malaysia. This implies that diurnal tides are dominant along the East Coast of Peninsular Malaysia while both diurnal and semidiurnal tides dominate almost equally in coastal East Malaysia. Furthermore, the diurnal tidal energy flux is found to be 60% greater than that of the semidiurnal tides in the southern South China Sea. Based on these model analyses, the significant tidal mixing frontal areas are located primarily off Sarawak coast as indicated by high chlorophyll-a concentrations in the area.
Surimi refers to concentrated myofibrial protein extracted from fish flesh by washing process. Surimi powder, is normally prepared in a dried form, and potentially useful as a raw material for preparation of seafood products. Surimi powder offers many advantages in industrial application, such as easy handling, low distribution cost, and physically convenient for addition to dry mixtures. In order to prevent the denaturation of the protein during drying, dryoprotectants such as sucrose and polyols can be added. Surimi powder is classified as fish protein concentrate type A because its protein content is higher than 65%. Surimi powder has good functional properties, such as gelation, water holding capacity, and emulsifying and foaming properties. Gel-based fish products and fish snacks are common products that can be made from surimi powder.
In the current research, osmotic dehydration of red pitaya (Hylocereus polyrhizusis) cubes using sucrose solution at mild temperature (35ºC) was investigated. Sucrose solution (40, 50 and 60% w/w) was employed for osmotic dehydration process. Responses of weight reduction (WR), solid gain (SG), water loss (WL), color (L*, a* and b*) and texture (hardness) were evaluated. It was found that sucrose concentration significantly (p < 0.05) affected the mass transfer terms during osmosis process. The results obtained revealed an increase in yellowness (b*), decrease in lightness (L*) and redness (a*) as the sucrose concentration increased. Furthermore, osmotically dehydrated samples were considerably softer than untreated samples. Increasing of sucrose concentration and dehydration time caused softer tissue of dehydrated product compared with the fresh red pitaya.
Shrimp aquaculture is playing a vital role in Malaysian agriculture, especially its increasing
contribution to economic growth. White shrimp aquaculture is not only the key player in brackish
water shrimp aquaculture but also the largest contributor to Malaysian shrimp aquaculture. This
study estimates technical efficiency and investigates factors affecting technical inefficiency of
Malaysian white shrimp aquaculture. Stochastic frontier analysis with trans-log production
model is applied in this study. Malaysian white shrimp aquaculture farmers have achieved
an estimated average technical efficiency of 81.2 percent. Land ownership, shrimp seed size
and seminar are the factors having significant impacts on technical inefficiency and thereby
playing important roles in improving technical efficiency of this industry. This study suggests
that seminar should be conducted by shrimp farming extension agents to enhance knowledge
of shrimp farmers. Malaysian government should allocate lands and, provide technical and
financial supports to develop this industry. Subsidy on shrimp seed should be also given to
encourage shrimp farmers to embrace and adopt quality shrimp seed for their farms.
Changes in physical properties (weight, size, colour and weight loss) and chemical properties (proximate analysis, TSS, pH, freezing point, total acidity and sugar content) of two water apple (Syzgium samaragense) cultivars, Semarang Rose and Kristal Taiwan were evaluated during ripening at 10°C and 50% RH. The results showed that the Kristal Taiwan cultivar was larger in size and weight but smaller in length compared to Semarang Rose. The Semarang Rose cultivar was sweeter than Kristal Taiwan. In this study, data obtained suggests that the water apple fruit can be stored at cold storage until 19 days.
A study was conducted to quantitate the concentrations of heavy metals, such as Hg, Pb and Cd in eight species of marine fin fish caught off the coast of Langkawi Island in Malaysia, as well as in its waters. The same fish were also used to determine the content of nutritional minerals, such as copper (Cu), zinc (Zn), calcium (Ca), and manganese (Mn).Fish and water samples were collected from four different areas, namely (1) Main Jetty Pulau Tuba (MJPT), (2) Teluk Cempedak Jetty (TCJ), (3) Simpang Tiga Chian Lian (STCL) and (4) Main Jetty Kuah (MJK) around Langkawi Island. Results showed that for the vital elements, all species had higher concentration of Zn compared to other elements. For the toxic elements, lead (Pb) and mercury (Hg) were found to have lower concentration of the mean values than the permissible limits set by FAO/WHO (1984). However, cadmium (Cd) level was slightly higher than the permissible limit but was still acceptable according to the Malaysian Food Regulation (1985). It can be concluded that all fish species studied are safe to be consumed.
Vibrio parahaemolyticus is prevalent in tropical marine environment in all seasons and can cause seafood-borne gastroenteritis. A total of 251 suspected isolates were tested including 60 from frozen shrimp, 50 from cultured live shrimp, 67 from sediments of culture ponds and 74 from water were subjected to polymerase chain reaction (PCR) targeting the toxR gene for confirmation as V. parahaemolyticus. Of the 128 toxR positive isolates, 15% of the isolates from culture environment (from live shrimp, sediments and water) and 7% of frozen shrimp samples were positive for the tdh and trh genes. Since urease production could be a marker of trh but not tdh in V. parahaemolyticus, a total of 189 of the 251 suspected V. parahaemolyticus isolates were tested for urease production and 41% of the isolates were found to be positive for urease production. However not all urease positive strains of V. parahaemolyticus were positive for either tdh or trh genes. Detection of virulent strains in shrimp culture environment in Malaysia suggests a probable risk for health of people consuming raw shrimp.
In this study, two types of plants materials were used namely Garcinia atrovirdis and Cynometra
cauliflora to determine the proximate composition, mineral content and antioxidant activities. Total phenolic content (TPC) and ferric reducing antioxidant power (FRAP) assay had been used to determine antioxidant activity in both samples. The moisture, ash, fiber, fat, protein and carbohydrate content in both samples were determined by using Association of Official Analytical Chemists (AOAC) methods. Mineral content in the sample was determined using Atomic absorption spectrophotpmetry (AAS). The results showed higher TPC and FRAP values in Cynometra cauliflora compared to Garcinia atrovirdis. Methanol extractions gave higher TPC and FRAP values compared to water extraction. The results obtained indicated that both samples have the potential to be as a source of natural antioxidants. Further study should be conducted to explore the benefits of underutilized fruits not only in antioxidant activity but other usages as well.
The effect of the addition of different concentrations of chitosan (0–2.0% w/w) on the gelling properties of surimi gels made from African catfish (Clarias gariepinus) was tested. Lipid oxidation, total volatile basic nitrogen (TVB-N), and aerobic plate count (APC) changes during 20 days of storage at 4oC also were evaluated. Surimi gels with 1.5% (w/w) chitosan added exhibited the highest improvement in gel strength (58.92%), whiteness (13.18%), and water holding capacity (36.8%). Incorporation of 2.0% (w/w) chitosan in gels resulted in the lowest TVB-N value (36.63 mg N/100 g) at the end of the 20 days storage period. Both the peroxide values and the 2-thiobarbituric acid values increased more slowly in the chitosan-treated gels than in the control gel during the storage period. Chitosan at concentrations of 1.75% and 2.0% (w/w) conferred the best antioxidant effect on catfish surimi gels and resulted in a significant reduction in APC. Based on the microbiological acceptability limit (106 cfu/g), the shelf life
of surimi gels with 1.75% and 2.0% (w/w) chitosan was extended to 12 days in refrigerated storage at 4oC, whereas the other samples lasted only 8 days. Hence, the addition of 1.5–2.0% (w/w) chitosan is a promising approach for the preparation of catfish surimi gels, as it improves texture, prevents lipid oxidation, and inhibits microbial growth.
This study reported the extraction optimization and characterization of cobia (Rachycentron canadum) skin gelatin. Optimization study was carried out to determine the effect of CH3COOH concentration, skin to water ratio, extraction temperature and extraction time on gelatin yield (GY) and gel strength (GS) using Response Surface Methodology (RSM). The optimum conditions were 0.15mol/L for CH3COOH concentration, 82.4oC of extraction temperature, 6 h of extraction time and 1:6 of skin to water ratio, which produced cobia gelatin with GY of 20.10% and GS of 205.6 g. Characteristics of cobia skin gelatin (CG) were then compared to that of commercial bovine gelatin (BG). It was found that the most dominant amino acid in CG was glycine, proline and alanine. There was no difference in foaming and emulsifying properties of CG and BG at 1% concentration, but at 2% and 3% concentration, BG performed better. CG was found to have higher fat binding capacity but lower water holding capacity than BG. Least gelling concentration for CG was recorded at 2% while for BG at 1%. CG and BG had a pI at pH 6.05 and 4.82, respectively. This study shows that cobia skin gelatin has potential as halal alternative to bovine gelatin in food industry.
This study examines and compares the influence of pH on the functional, rheological and structural properties of eel skin (Monopterus sp.) and bovine gelatins. Functional properties studied and compared were emulsifying capacity and stability; water holding capacity; fat binding capacity; foaming capacity; and foaming stability. The rheological properties studied include gel strength and dynamic oscillatory measurements. The structural properties of eel skin and bovine gelatin were determined by Fourier transform infrared spectroscopy (FTIR). Results obtained showed that eel skin gelatin treated at pH 8 (compared to pH 5) exhibited the higher emulsifying, fat binding, foaming and viscoelasticity properties. The FTIR spectrum assay showed that eel skin gelatin presented a similar structure to that of bovine gelatin. This study demonstrated that pH levels influence functional, rheological and structural properties of eel skin gelatin and that these properties were enhanced to either equal or surpass those of bovine gelatin. Hence, this study indicates that eel skin gelatin has immense potential for use as an alternative to bovine gelatin.
Four fungal isolates: Simplicillium chinense (iso 9, accession no. KX425621), Penicillium simplicissimum (iso 10, KP713758), Trichoderma asperellum (iso 11, KP792512), and Coriolopsis sp. (1c3, KM403574) were subjected to a series of induced-tolerance training under high metal concentrations to determine if greater tolerance could be achieved from constant exposure to such conditions. Adaptive tolerance assay (Tolerance Index, TI) and Field-Emission Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX) characterized their metal tolerance. "Untrained" S. chinense, P. simplicissimum and T. asperellum showed tolerance towards 4000-4500ppm Al(III) (TI: 0.64-0.71), 1000ppm Cr(III) (0.52-0.83) and Pb(II) (0.32-0.88). With tolerance training, tolerance towards 2000-6000ppm Al(III), 500-3000ppm Pb(II) and 2000-3000ppm Cr(III) were achieved (TI: 0.01-0.82) compared to untrained cultures (0.00-0.59). In contrast, tolerance training for Coriolopsis sp. and P. simplicissimum was less successful, with TI values similar or lower than untrained cultures. SEM-EDX analysis proposed biosorption and bioaccumulation as mechanisms for metal removal. The latter was demonstrated with the removal of Cr(III) and Pb(II) by S. chinense (12.37 and 11.52mgg-1, respectively) and T. asperellum (10.44 and 7.50mgg-1). Induced-tolerance training may render benefit in the long run, but this delicate approach is suggestively species and metal dependent.
Matched MeSH terms: Water Pollutants, Chemical/isolation & purification; Water Pollutants, Chemical/metabolism; Water Pollutants, Chemical/toxicity*
The study aimed to evaluate the quality of the hybrid
layer form by three different adhesive systems. Class V
cavities were prepared on the buccal surface of fourty
extracted human premolars. The prepared teeth were
randomly assigned into four groups according to the
adhesive system and application mode. The systems
were: Optibond S (OS, total-etch); Optibond Versa (OV,
two-bottles, self-etch); Single Bond Universal (SBU,
one-bottle, self-etch) and Single Bond Universal with
etchant (SBU + etchant). All cavities were restored with
composite (Filtek Z350XT). The samples were sectioned,
polished and pretreated to remove minerals, protein
and water prior to SEM evaluation. From the images,
thickness of the hybrid layers was measured. Present of
resin tags and adaptation failure were also recorded. The
data obtained were analyzed using ANOVA, Dunnett’s
T3, Kruskal-Wallis and Mann-Whitney tests. OS group
showed the highest average hybrid layer thickness (4.34
µm), followed by SBU + etchant (3.06 µm), OV (1.91 µm)
and SBU (0.95 µm). Both adhesive and cohesive failures
were observed in SBU group. Present of prominent resin
tags were seen in both OS and OV groups. In conclusion,
all the investigated adhesive systems were able to perform
distinguishable actions as shown in micro-morphological
alteration and hybrid layer thickness. Two-bottles, selfetch
adhesive (OV) was proven to produce negligible
adaptation failure compared to other adhesive systems in
the present study. Combined all-in-one adhesive (SBU)
was found to render a superior bonding performance in
total-etch mode comparing to self-etch mode.
Agriculture residues are a promising feedstock for value-added products from lignocellulosic waste. However, pretreatment of lignocellulosic materials is essential to facilitate enzymatic
hydrolysis and improve sugar yield. The objective of this study is to evaluate the effect of acid or alkali during microwave-assisted pretreatment of dragon fruit foliage (DFF) that
would make hydrolysis process more efficient. In the present study, distilled water and three chemicals were examined for their effects on releasing monomeric sugar during microwave
treatment. Microwave-assisted pretreatment namely microwave-distilled water (M-H2O) (control); microwave-sulfuric acid (M-H2SO4); microwave-sodium hydroxide (M-NaOH); and
microwave-sodium bicarbonate (M-NaHCO3) pretreatment were performed using 5% (w/v) of DFF as substrate at 800 watt microwave power for 5 minutes exposure time. Highest yield
of monomeric sugar was found at 15.56 mg/g using M-NaOH pretreatment at 0.1N NaOH. For M-H2SO4 pretreatment, 0.1N H2SO4 produced 8.2 mg/g of monomeric sugar. Application
of M-NaHCO3 pretreatment using 0.05N NaHCO3 solution released 6.45 mg/g of monomeric sugar. While, soaking DFF in distilled water and subjecting to microwave irradiation released
6.6 mg/g of monomeric sugar. Treatments with the lowest concentration (0.01 N) of the three chemicals released only small quantities of total monomeric sugars and less than that with distilled water. The changes in the physical structure of DFF prior to and after the microwaveassisted pretreatment are also reported.
The objectives of this study were to develop composite films using various gelatin sources with corn oil (CO) incorporation (55.18%) and to investigate the mechanical and physical properties of these films as potential packaging films. There were increases (p < 0.05) in the tensile strength (TS) and puncture strength (PS) of films when the concentration of gelatin increased. The mechanical properties of these films were also improved when compared with films produced without CO. Conversely, the water barrier properties of composite films decreased (p < 0.05) when the concentration of gelatin in composite films increased. Comparing with pure gelatin films, water and oxygen barrier properties of gelatin films decreased when manufactured with the inclusion of CO.
This paper presents the enzymatic liquefaction process for honey jackfruit optimized with Pectinex® Ultra SP-L and Celluclast® 1.5 L individually or in combinations at different concentrations (0-2.5% v/w) and incubation time (0-2.5 h). Treatment with combinations of enzymes showed a greater effect in the reduction of viscosity (83.9-98.8%) as compared to single enzyme treatment (64.8-87.3%). The best parameter for enzymatic liquefaction was obtained with 1.0% (v/w) Pectinex® Ultra SP-L and 0.5% (v/w) Celluclast® 1.5 L for 1.5 h. Spray drying process was carried out using different inlet temperatures (140-180 °C) and maltodextrin concentrations (10-30% w/w). Results indicated that the spray-dried honey jackfruit powder produced at 160 °C with 30% w/w maltodextrin gave the highest product yield (66.90%) with good powder qualities in terms of water activity, solubility, moisture content, hygroscopicity, color and bulk density. The spray-dried honey jackfruit powder could potentially be incorporated into various food products.
An air exposed single-chamber microbial fuel cell (SCMFC) using microalgal biocathodes was designed. The reactors were tested for the simultaneous biodegradation of real dye textile wastewater (RTW) and the generation of bioelectricity. The results of digital image processing revealed a maximum coverage area on the biocathodes by microalgal cells of 42%. The atmospheric and diffused CO2 could enable good algal growth and its immobilized operation on the cathode electrode. The biocathode-SCMFCs outperformed an open circuit voltage (OCV), which was 18%-43% higher than the control. Furthermore, the maximum volumetric power density achieved was 123.2 ± 27.5 mW m(-3). The system was suitable for the treatment of RTW and the removal/decrease of COD, colour and heavy metals. High removal efficiencies were observed in the SCMFCs for Zn (98%) and COD (92-98%), but the removal efficiencies were considerably lower for Cr (54-80%). We observed that this single chamber MFC simplifies a double chamber system. The bioelectrochemical performance was relatively low, but the treatment capacity of the system seems encouraging in contrast to previous studies. A proof-of-concept experiment demonstrated that the microalgal biocathode could operate in air exposed conditions, seems to be a promising alternative to a Pt cathode and is an efficient and cost-effective approach to improve the performance of single chamber MFCs.
Vibrio parahaemolyticus is a main foodborne disease in seafood and generally seafood is
easily deteriorates in quality of color and flavor. In this study, clove (Syzygium aromaticum)
extract shows potent antibacterial activity against growth of antibiotics resistant Vibrio
parahaemolyticus on seafood samples (cockles and shrimps). Vibrio parahaemolyticus was
artificial contaminates on the samples with 106 CFU/ml. The samples were treated with different
concentration of cloves extract with 10 mg/ml which are 0.5%, 5% and 10% concentration
from methanol food grade extraction in 0 hr, 5 min, 10 min, 15 min, 30 min, 60 min and
120 min. Tab water and deionized water were selected as a negative control. As a result, the
amount of 10 % cloves managed to mitigates the number of V. parahaemolyticus on seafood
samples in 5 minutes and 15 min on both samples. Therefore, our results signify the fact that
cloves can be apply as natural sanitizer which could meet consumer demands for safe and
traditionally consumed either raw without any undesirable effect when applied in the seafood
system industries.
Microbial electrochemical systems (MESs) are an attracting technology for the disposal of wastewater treatment and simultaneous energy production. In MESs, at the anode microorganisms through the catalytic activity generates electrons that can be converted into electricity or other valuable chemical compounds. Microorganisms those having ability to donate and accept electrons to and from anode and cathode electrodes, respectively are recognized as 'exoelectrogens'. In the MESs, it renders an important function for its performance. In the present mini-review, we have discussed the role of microbiome including pure culture, enriched culture and mixed culture in different BESs application. The effects of operational and biological factors on microbiome development have been discussed. Further discussion about the molecular techniques for the evaluation of microbial community analysis is addressed. In addition different electrochemical techniques for extracellular electron transfer (EET) mechanism of electroactive biofilms have been discussed. This review highlights the importance of microbiome in the development of MESs, effective operational factors for exo-electrogens activities as well their key challenges and future technological aspects are also briefly discussed.
A ternary complex between germanium, Catechol Violet (CV) and cetyltrimethylanunoniuni bromide is proposed for the determination of germanium. The stoichiometric ratio Ge:CV is 1:2. Beer's law is obeyed from 0.1 to 1.0 ppm of Ge. The method is highly selective. Interference from Sn(IV), Fe(III), Bi(III), Cr(VI), Mo(VI), V(V) and Sb(III) in mg amounts is eliminated by extracting the germanium into carbon tetrachloride from 9M HC1 and then stripping into water before the photometric determination.