Displaying publications 581 - 600 of 1243 in total

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  1. Soo YN, Tan CP, Tan PY, Khalid N, Tan TB
    J Sci Food Agric, 2021 Apr;101(6):2455-2462.
    PMID: 33034060 DOI: 10.1002/jsfa.10871
    BACKGROUND: The popularity of coffee, the second most consumed beverage in the world, contributes to the high demand for liquid non-dairy creamer (LNDC). In this study, palm olein emulsions (as LNDCs) were investigated as alternatives to the more common soybean oil-based LNDCs. LNDCs were prepared via different homogenization pressures (100-300 bar) using different types of oil (palm olein and soybean oil) and concentrations of DATEM emulsifier (5-20 g kg-1 ).

    RESULTS: Increases in homogenization pressure and emulsifier concentration were observed to have significant (P  0.05) differences between the prepared and commercial LNDCs in terms of their color, appearance, and overall acceptability.

    CONCLUSION: Shelf-stable LNDCs with qualities comparable to commercial LNDC were successfully fabricated. Valuable insights into the effects of homogenization pressure, oil type, and emulsifier concentration, as well as functionality and consumer acceptance of the LNDCs when added into black coffee, were obtained. © 2020 Society of Chemical Industry.

    Matched MeSH terms: Hydrogen-Ion Concentration
  2. Mohd Syukri MS, A Rahman R, Mohamad Z, Md Illias R, Nik Mahmood NA, Jaafar NR
    Int J Biol Macromol, 2021 Jan 01;166:876-883.
    PMID: 33144251 DOI: 10.1016/j.ijbiomac.2020.10.244
    Enzyme immobilization has been known to be one of the methods to improve the stability and reusability of enzyme. In this study, a strategy to optimize laccase immobilization on polyethylene terephthalate grafted with maleic anhydride electrospun nanofiber mat (PET-g-MAH ENM) was developed. The development involves the screening and optimization processes of the crucial factors that influence the immobilization yield such as enzyme concentration, pH values, covalent bonding (CV) time, CV temperature, crosslinking (CL) time, CL temperature and glutaraldehyde concentration using two-level factorial design and Box-Behnken design (BBD), respectively. It was found that laccase concentration, pH values and glutaraldehyde concentration play important role in enhancing the immobilization yield of laccase on PET-g-MAH ENM in the screening process. Subsequently, the optimization result showed at 0.28 mg/ml laccase concentration, pH 3 and 0.45% (v/v) glutaraldehyde concentrations gave the highest immobilization yield at 87.64% which was 81.2% increment from the immobilization yield before optimization. Under the optimum condition, the immobilized laccase was able to oxidize 2, 2-azino-bis 3-ethylbenzothiazoline-6- sulfonic acid (ABTS) in a broad range of pH (pH 3-6) and temperature (20- 70 °C). Meanwhile, the kinetic parameters for Km and Vmax were 1.331 mM and 0.041 mM/min, respectively. It was concluded that the optimization of immobilized laccase on PET-g-MAH ENM enhance the performance of this biocatalyst.
    Matched MeSH terms: Hydrogen-Ion Concentration
  3. Ahmad MN, Shuhaimen MS, Normaya E, Omar MN, Iqbal A, Ku Bulat KH
    J Texture Stud, 2020 10;51(5):810-829.
    PMID: 32401337 DOI: 10.1111/jtxs.12529
    Meat tenderness is one of the most important organoleptic properties in determining consumer acceptance in meat product marketability. Therefore, an effective meat tenderization method is sought after by exploring plant-derived proteolytic enzymes as meat tenderizer. In this study, a novel protease from Cashew was identified as a new alternative halal meat tenderizer. The extraction of cashew protease was optimized using response surface methodology (R2 = 0.9803) by varying pH, CaCl2 concentration, mixing time, and mass. pH 6.34, 7.92 mM CaCl2 concentration, 5.51 min mixing time, and 19.24 g sample mass were the optimal extraction conditions. There was no significant difference (n = 3; p 
    Matched MeSH terms: Hydrogen-Ion Concentration
  4. Okomoda VT, Mithun S, Chatterji A, Effendy MAW, Oladimeji AS, Abol-Munafi AB, et al.
    Fish Physiol Biochem, 2020 Aug;46(4):1497-1505.
    PMID: 32378001 DOI: 10.1007/s10695-020-00807-7
    This study was designed to optimize the culture conditions of juvenile Epinephelus fuscoguttatus (Forsskål, 1775) under laboratory conditions. To this effect, the rate of oxygen consumption was monitored as an index of stress under different temperature, salinity, pH, photoperiod, and urea concentrations. The result obtained after 12 h of exposure suggests the preference of the juvenile E. fuscoguttatus to a temperature range of 15-25 °C and salinity of 30 ppt. Based on this study, temperature was found to be the most lethal as 100% mortality was observed after 6 h in fish exposure to temperatures above the optimal (≥ 30 °C). However, the oxygen consumption rate was similar under the different pH, photoperiod, and urea concentration tested. It was concluded that water temperature was most critical in terms of respiration physiology of the juvenile E. fuscoguttatus given the range and levels of environmental factors tested in this study.
    Matched MeSH terms: Hydrogen-Ion Concentration
  5. Yau XH, Khe CS, Mohamed Saheed MS, Lai CW, You KY, Tan WK
    PLoS One, 2020;15(4):e0232490.
    PMID: 32353051 DOI: 10.1371/journal.pone.0232490
    Oily wastewater, especially water-oil emulsion has become serious environmental issue and received global attention. Chemical demulsifiers are widely used to treat oil-water emulsion, but the toxicity, non-recyclable and non-environmental friendly characteristic of chemical demulsifiers had limited their practical application in oil-water separation. Therefore, it is imperative to develop an efficient, simple, eco-friendly and recyclable demulsifiers for breaking up the emulsions from the oily wastewater. In this study, a magnetic demulsifier, magnetite-reduced graphene oxide (M-rGO) nanocomposites were proposed as a recyclable demulsifier to break up the surfactant stabilized crude oil-in-water (O/W) emulsion. M-rGO nanocomposites were prepared via in situ chemical synthesis by using only one type Fe salt and GO solid as precursor at room temperature. The prepared composites were fully characterized by various techniques. The effect of demulsifier dosage and pH of emulsion on demulsification efficiency (ED) has been studied in detailed. The demulsification mechanism was also proposed in this study. Results showed that M-rGO nanocomposites were able to demulsify crude O/W emulsion. The ED reaches 99.48% when 0.050 wt.% of M-rGO nanocomposites were added to crude O/W emulsion (pH = 4). Besides, M-rGO nanocomposites can be recycled up to 7 cycles without showing a significant change in terms of ED. Thus, M-rGO nanocomposite is a promising demulsifier for surfactant stabilized crude O/W emulsion.
    Matched MeSH terms: Hydrogen-Ion Concentration
  6. Nik-Pa NIM, Sobri MFM, Abd-Aziz S, Ibrahim MF, Kamal Bahrin E, Mohammed Alitheen NB, et al.
    Int J Mol Sci, 2020 May 30;21(11).
    PMID: 32486212 DOI: 10.3390/ijms21113919
    Two optimization strategies, codon usage modification and glycine supplementation, were adopted to improve the extracellular production of Bacillus sp. NR5 UPM β-cyclodextrin glycosyltransferase (CGT-BS) in recombinant Escherichia coli. Several rare codons were eliminated and replaced with the ones favored by E. coli cells, resulting in an increased codon adaptation index (CAI) from 0.67 to 0.78. The cultivation of the codon modified recombinant E. coli following optimization of glycine supplementation enhanced the secretion of β-CGTase activity up to 2.2-fold at 12 h of cultivation as compared to the control. β-CGTase secreted into the culture medium by the transformant reached 65.524 U/mL at post-induction temperature of 37 °C with addition of 1.2 mM glycine and induced at 2 h of cultivation. A 20.1-fold purity of the recombinant β-CGTase was obtained when purified through a combination of diafiltration and nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography. This combined strategy doubled the extracellular β-CGTase production when compared to the single approach, hence offering the potential of enhancing the expression of extracellular enzymes, particularly β-CGTase by the recombinant E. coli.
    Matched MeSH terms: Hydrogen-Ion Concentration
  7. Yeoh SY, Lubowa M, Tan TC, Murad M, Mat Easa A
    Food Chem, 2020 Dec 15;333:127425.
    PMID: 32683254 DOI: 10.1016/j.foodchem.2020.127425
    Zero-salted yellow alkaline noodles (YAN) were immersed in solutions of resistant starch HYLON™ VII (HC) or fruit coating Semperfresh™ (SC) containing a range of salt (NaCl) between 10 and 30% (w/v). The objective was to evaluate the effect of salt-coatings on the textural, handling, cooking, and sensory properties of YAN. Increasing salt in the coatings caused a reduction in optimum cooking time, cooking loss and increase in cooking yield. The mechanical and textural parameters, sensory hardness, springiness and overall sensory acceptability of the salt-coated noodles however decreased with increasing salt application. HC-Na10 and SC-Na10 showed the highest textural and mechanical parameters, sensory hardness and springiness. The differences in the parameters were attributed mainly to the water absorption properties of starch that was affected by salt application. Thus, the quality of salt-coated noodles was dependent mainly on the amounts of salt applied in the coatings rather than on the types of coatings used.
    Matched MeSH terms: Hydrogen-Ion Concentration
  8. Ayanda AF, Jusop S, Ishak CF, Othman R
    PLoS One, 2020;15(6):e0234045.
    PMID: 32544208 DOI: 10.1371/journal.pone.0234045
    A study was conducted to determine the impact of applying different sources of Mg, namely kieserite, ground magnesium limestone (GML) and Mg-rich synthetic gypsum (MRSG) on an acid tropical soil, oil palm growth and production. Besides high amount of Mg and Ca, MRSG contains S. Exchangeable Ca in the untreated soil of the plantation was 0.64 cmolc kg-1, but its critical level to sustain oil palm growth was 0.9 cmolc kg-1. MRSG was applied in the plantation as Mg-fertilizer; however, since Ca is also a limiting nutrient, oil palm growth was correlated (r = 0.69) with Ca supplied by the MRSG. Mg needed to sustain oil palm production is normally supplied by kieserite. Its requirement can be met at a lower cost compared to that of the kieserite by using MRSG. Due to MRSG treatment, exchangeable Ca in the soil increased steadily to satisfy the requirement of oil palm for fruit bunches production. From the glasshouse and field study, it was observed that MRSG applied at 1.5 times the recommended rate gave results comparable to that of the kieserite. MRSG treatment resulted in the increase of soil pH to >5 that precipitated Al3+ as inert Al-hydroxides, which eventually enhanced oil palm seedlings growth. Thus, MRSG can also replace GML to increase soil pH and satisfy the Ca and Mg requirement of oil palm. It can be concluded that MRSG has the potential to be used as a source of Mg as well as Ca for oil palm grown on acidic soil.
    Matched MeSH terms: Hydrogen-Ion Concentration
  9. Jenol MA, Ibrahim MF, Kamal Bahrin E, Abd-Aziz S
    Bioprocess Biosyst Eng, 2020 Nov;43(11):2027-2038.
    PMID: 32572569 DOI: 10.1007/s00449-020-02391-9
    Sago hampas is a starch-based biomass from sago processing industries consisted of 58% remaining starch. This study has demonstrated the bioconversion of sago hampas to volatile fatty acids (VFAs) by Clostridium beijerinckii SR1 via anaerobic digestion. Higher total VFAs were obtained from sago hampas (5.04 g/L and 0.287 g/g) as compared to commercial starch (5.94 g/L and 0.318 g/g). The physical factors have been investigated for the enhancement of VFAs production using one-factor-at-a-time (OFAT). The optimum condition; 3% substrate concentration, 3 g/L of yeast extract concentration and 2 g/L of ammonium nitrate enhanced the production of VFAs by 52.6%, resulted the total VFAs produced is 7.69 g/L with the VFAs yield of 0.451 g/g. VFAs hydrolysate produced successfully generated 273.4 mV of open voltage circuit and 61.5 mW/m2 of power density in microbial fuel cells. It was suggested that sago hampas provide as an alternative carbon feedstock for bioelectricity generation.
    Matched MeSH terms: Hydrogen-Ion Concentration
  10. Adeyi AA, Jamil SNAM, Abdullah LC, Choong TSY, Lau KL, Alias NH
    Molecules, 2020 Jun 07;25(11).
    PMID: 32517324 DOI: 10.3390/molecules25112650
    Proper remediation of aquatic environments contaminated by toxic organic dyes has become a research focus globally for environmental and chemical engineers. This study evaluates the adsorption potential of a polymer-based adsorbent, thiourea-modified poly(acrylonitrile-co-acrylic acid) (T-PAA) adsorbent, for the simultaneous uptake of malachite green (MG) and methylene blue (MB) dye ions from binary system in a continuous flow adsorption column. The influence of inlet dye concentrations, pH, flow rate, and adsorbent bed depth on adsorption process were investigated, and the breakthrough curves obtained experimentally. Results revealed that the sorption capacity of the T-PAA for MG and MB increase at high pH, concentration and bed-depth. Thomas, Bohart-Adams, and Yoon-Nelson models constants were calculated to describe MG and MB adsorption. It was found that the three dynamic models perfectly simulate the adsorption rate and behavior of cationic dyes entrapment. Finally, T-PAA adsorbent demonstrated good cyclic stability. It can be regenerated seven times (or cycles) with no significant loss in adsorption potential. Overall, the excellent sorption capacity and multiple usage make T-PAA polymer an attractive adsorbent materials for treatment of multicomponent dye bearing effluent in a fixed-bed column system.
    Matched MeSH terms: Hydrogen-Ion Concentration
  11. Nordin NA, Abdul Rahman N, Abdullah AH
    Molecules, 2020 Jul 06;25(13).
    PMID: 32640766 DOI: 10.3390/molecules25133081
    Heavy metal pollution, such as lead, can cause contamination of water resources and harm human life. Many techniques have been explored and utilized to overcome this problem, with adsorption technology being the most common strategies for water treatment. In this study, carbon nanofibers, polyacrylonitrile (PAN)/sago lignin (SL) carbon nanofibers (PAN/SL CNF) and PAN/SL activated carbon nanofibers (PAN/SL ACNF), with a diameter approximately 300 nm, were produced by electrospinning blends of polyacrylonitrile and sago lignin followed by thermal and acid treatments and used as adsorbents for the removal of Pb(II) ions from aqueous solutions. The incorporation of biodegradable and renewable SL in PAN/SL blends fibers produces the CNF with a smaller diameter than PAN only but preserves the structure of CNF. The adsorption of Pb(II) ions on PAN/SL ACNF was three times higher than that of PAN/SL CNF. The enhanced removal was due to the nitric acid treatment that resulted in the formation of surface oxygenated functional groups that promoted the Pb(II) ions adsorption. The best-suited adsorption conditions that gave the highest percentage removal of 67%, with an adsorption capacity of 524 mg/g, were 40 mg of adsorbent dosage, 125 ppm of Pb(II) solution, pH 5, and a contact time of 240 min. The adsorption data fitted the Langmuir isotherm and the pseudo-second-order kinetic models, indicating that the adsorption is a monolayer, and is governed by the availability of the adsorption sites. With the adsorption capacity of 588 mg/g, determined via the Langmuir isotherm model, the study demonstrated the potential of PAN/SL ACNFs as the adsorbent for the removal of Pb(II) ions from aqueous solution.
    Matched MeSH terms: Hydrogen-Ion Concentration
  12. Norizan NABM, Halim M, Tan JS, Abbasiliasi S, Mat Sahri M, Othman F, et al.
    Molecules, 2020 Jul 31;25(15).
    PMID: 32752106 DOI: 10.3390/molecules25153516
    Palm kernel cake (PKC) has been largely produced in Malaysia as one of the cheap and abundant agro-waste by-products from the palm oil industry and it contains high fiber (mannan) content. The present study aimed to produce β-mannanase by Bacillus subtilis ATCC11774 via optimization of the medium composition using palm kernel cake as substrate in semi-solid fermentation. The fermentation nutrients such as PKC, peptone, yeast extract, sodium chloride, magnesium sulphate (MgSO2), initial culture pH and temperature were screened using a Plackett-Burman design. The three most significant factors identified, PKC, peptone and NaCl, were further optimized using central composite design (CCD), a response surface methodology (RSM) approach, where yeast extract and MgSO2 were fixed as a constant factor. The maximum β-mannanase activity predicted by CCD under the optimum medium composition of 16.50 g/L PKC, 19.59 g/L peptone, 3.00 g/L yeast extract, 2.72 g/L NaCl and 0.2 g/L MgSO2 was 799 U/mL. The validated β-mannanase activity was 805.12 U/mL, which was close to the predicted β-mannanas activity. As a comparison, commercial media such as nutrient broth, M9 and Luria bertani were used for the production of β-mannanase with activities achieved at 204.16 ± 9.21 U/mL, 50.32 U/mL and 88.90 U/mL, respectively. The optimized PKC fermentation medium was four times higher than nutrient broth. Hence, it could be a potential fermentation substrate for the production of β-mannanase activity by Bacillus subtilis ATCC11774.
    Matched MeSH terms: Hydrogen-Ion Concentration
  13. Show PL, Ooi CW, Lee XJ, Yang CL, Liu BL, Chang YK
    Int J Biol Macromol, 2020 Nov 01;162:1711-1724.
    PMID: 32805284 DOI: 10.1016/j.ijbiomac.2020.08.065
    Adsorption of lysozyme on the dye-affinity nanofiber membranes was investigated in batch and dynamic modes. The membrane matrix was made of electrospun polyacrylonitrile nanofibers that were grafted with ethylene diamine (EDA) and/or chitosan (CS) for the coupling of Reactive Blue 49 dye. The physicochemical properties of these dye-immobilized nanofiber membranes (P-EDA-Dye and P-CS-Dye) were characterized microscopically, spectroscopically and thermogravimetrically. The capacities of lysozyme adsorption by the dye-affinity nanofiber membranes were evaluated under various conditions, namely pH, dye immobilized density, and loading flow rate. The adsorption of lysozyme to the dye-affinity nanofiber membranes was well fitted by Langmuir isotherm and pseudo-second kinetic models. P-CS-Dye nanofiber membrane had a better performance in the dynamic adsorption of lysozyme from complex chicken egg white solution. It was observed that after five cycles of adsorption-desorption, the dye-affinity nanofiber membrane did not show a significant loss in its capacity for lysozyme adsorption. The robustness as well as high dynamic adsorption capability of P-CS-Dye nanofiber membrane are promising for the efficient recovery of lysozyme from complex feedstock via nanofiber membrane chromatography.
    Matched MeSH terms: Hydrogen-Ion Concentration
  14. Tan JS, Abbasiliasi S, Lalung J, Tam YJ, Murugan P, Lee CK
    Prep Biochem Biotechnol, 2021;51(3):260-266.
    PMID: 32876520 DOI: 10.1080/10826068.2020.1808793
    This study aimed at purification of phycocyanin (PC) from Phormidium tergestinum using an aqueous two-phase system (ATPS) comprised of polyethylene glycol (PEG) and salts. The partitioning efficiency of PC in ATPS and the effect of phase composition, pH, crude loading, and neutral salts on purification factor and yield were investigated. Results showed that PC was selectively partitioned toward bottom phase of the system containing potassium phosphate. Under optimum conditions of 20% (w/w) PEG 4000, 10% (w/w) potassium phosphate, 20% (v/v) crude load at pH 7, with addition of 0.5% (w/w) NaCl, PC from P. tergestinum was partially purified up to 5.34-fold with a yield of 87.8%. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the molecular weight of PC was ∼19 kDa. Results from this study demonstrated ATPS could be used as a potential approach for the purification of PC from P. tergestinum.
    Matched MeSH terms: Hydrogen-Ion Concentration
  15. Chai TT, Xiao J, Mohana Dass S, Teoh JY, Ee KY, Ng WJ, et al.
    Food Chem, 2021 Mar 15;340:127876.
    PMID: 32871354 DOI: 10.1016/j.foodchem.2020.127876
    Jackfruit is a sweet tropical fruit with very pleasant aroma, and the ripe seeds are edible. In this study, jackfruit seed proteins were isolated and subjected to trypsin digestion. The resultant protein hydrolysate was then subjected to antioxidant assay-guided purification, using centrifugal filtration, C18 reverse-phase and strong cation exchange (SCX) fractionations. The purified SCX fraction was further analyzed by de novo peptide sequencing, and two peptide sequences were identified and synthesized. Peptide JFS-2 (VGPWQK) was detected with antioxidant potential, with EC50 value comparable to that of commercial GSH antioxidant peptide. Additionally, the identified peptides were tested with protein protection potential, in an albumin protein denaturation inhibitory assay. Concurrently, we also investigated the pH, temperature, and gastrointestinal-digestion stability profiles for the identified peptide. With further research efforts, the identified peptides could potentially be developed into preservative agent for protein-rich food systems or as health-promoting diet supplements.
    Matched MeSH terms: Hydrogen-Ion Concentration
  16. Xue Mei L, Mohammadi Nafchi A, Ghasemipour F, Mat Easa A, Jafarzadeh S, Al-Hassan AA
    Int J Biol Macromol, 2020 Dec 01;164:4603-4612.
    PMID: 32941902 DOI: 10.1016/j.ijbiomac.2020.09.082
    The development of intelligent packaging based on natural and biodegradable resources is getting more attention by researchers in recent years. The aim of this study was to develop and characterize a pH-sensitive films based on sago starch and incorporated with anthocyanin from torch ginger. The pH-sensitive films were fabricated by casting method with incorporation of different torch ginger extract (TGE) concentration. The surface morphology, physicochemical, barrier, and mechanical properties as well as the pH-sensitivity of films were investigated. The film with the highest concentration of TGE showed the lowest tensile strength (4.26 N/m2), toughness (2.54 MJ/m3), Young's modulus (73.96 MPa) and water vapour permeability (2.6 × 10-4 g·m/day·kPa·m2). However, its elongation at break (85.14%), moisture content (0.27%) and water solubility (37.92%) were the highest compared to other films. pH sensitivity analysis showed that the films containing TGE extract, changes in colour by changing the pH. The colour of films changed from pink to slightly green as the pH increased from pH 4 to 9. Thus, the developed pH-sensitive film with torch ginger extract has potential as intelligent packaging for detection of food freshness or spoilage to ensure their quality and safe consumption.
    Matched MeSH terms: Hydrogen-Ion Concentration
  17. Tan LF, Elaine E, Pui LP, Nyam KL, Yusof YA
    Acta Sci Pol Technol Aliment, 2021 1 16;20(1):55-66.
    PMID: 33449520 DOI: 10.17306/J.AFS.0771
    BACKGROUND: Biodegradable food packaging has improved in quality with recent research incorporating natural extracts for functionality purposes. This research aims to develop chitosan film with Chrysanthemum morifolium essential oil to improve the shelf life of fresh raw chicken and beef.

    METHODS: 1.5% (w/v) chitosan films with Chrysanthemum morifolium essential oil (0% to 6% (v/v)) were produced through homogenization, the casting of a film solution in a petri dish and convection drying. The edible film was evaluated in terms of its physical (color, thickness, water vapor permeability), mechanical (puncture strength, tensile strength, elongation at break) and chemical properties (antioxidant assay, Fourier Transform Infrared Spectroscopy (FTIR)).

    RESULTS: With an increasing concentration of Chrysanthemum morifolium in the chitosan film, the test values of physical properties such as tensile strength, puncture force, and elongation at break declined significantly. However, the thickness, water permeability, and color profile (L*, a*, b*) values of the chitosan film increased. Similarly, the scavenging effect of antioxidant assay increased (from 4.97% to 18.63%) with a rise in Chrysanthemum morifolium concentration. 2%, 3%, and 4% of Chrysanthemum morifolium in the chitosan film showed a significant inhibition zone ranging from 2.67 mm to 3.82 mm against Staphylococcus aureus, a spoilage bacterium that is commonly found in chicken and beef products. The storage and pH tests showed that 4% of Chrysanthemum morifolium in the film maintained pH level (safe to consume), and the shelf life was extended from 3 days to 5 days of meat storage.

    CONCLUSIONS: This study demonstrated that the incorporation of 4% (v/v) Chrysanthemum morifolium extract into 1.5% (w/v) chitosan film extends the storage duration of raw meat products noticeably by reducing Staphylococcus aureus activity. Therefore, it increases the quality of the edible film as an environmentally friendly food packaging material so that it can act as a substitute for the use of plastic bags. Future studies will be conducted on improving the tensile strength of the edible film to increase the feasibility of using it in the food industry. In addition, the microstructure and surface morphology of the edible film can be further determined.

    Matched MeSH terms: Hydrogen-Ion Concentration
  18. Ngatiman M, Jami MS, Abu Bakar MR, Subramaniam V, Loh SK
    Heliyon, 2021 Jan;7(1):e05931.
    PMID: 33490684 DOI: 10.1016/j.heliyon.2021.e05931
    The formation of struvite crystals or magnesium ammonium phosphate (MgNH4PO4) in palm oil mill effluent (POME) occurs as early as in the secondary stage of POME treatment system. Its growth continues in the subsequent tertiary treatment which reduces piping diameter, thus affecting POME treatment efficiency. Hypothesis. The beneficial use of the crystal is the motivation. This occurrence is rarely reported in scientific articles despite being a common problem faced by palm oil millers. The aim of this study is to characterize struvite crystals found in an anaerobic digester of a POME treatment facility in terms of their physical and chemical aspects. The compositions, morphology and properties of these crystals were determined via energy dispersive spectroscopy (EDS), elemental analysis, scanning electron microscopy (SEM) and x-ray diffraction (XRD). Solubility tests were carried out to establish solubility curve for struvite from POME. Finally, crystal growth experiment was done applying reaction crystallization method to demonstrate struvite precipitation from POME. Results showed that high phosphorous (P) (24.85 wt%) and magnesium (Mg) (21.33 wt%) content was found in the struvite sample. Elemental analysis detected carbon (C), hydrogen (H), nitrogen (N) and sulfur (S) below 4 wt%. The crystals analysed by XRD in this study were confirmed as struvite with 94.8% struvite mineral detected from its total volume. Having an orthorhombic crystal system, struvite crystals from POME recorded an average density of 1.701 g cm-3. Solubility curve of struvite from POME was established with maximum solubility of 275.6 mg L-1 at pH 3 and temperature 40 °C. Minimum solubility of 123.6 mg L-1 was recorded at pH 7 and temperature 25 °C. Crystal growth experiment utilizing POME as the source medium managed to achieve 67% reduction in phosphorous content. This study concluded that there is a potential of harnessing valuable nutrients from POME in the form of struvite. Struvite precipitation technology can be adapted in the management of POME in order to achieve maximum utilization of the nutrients that are still abundant in POME. At the same time maximization of nutrient extractions from POME will also reduce pollutants loading in the final discharge.
    Matched MeSH terms: Hydrogen-Ion Concentration
  19. Akbar, I., Jaswir, I., Jamal, P.
    MyJurnal
    Gelatine obtained from fish skin has become a potential source of preparing nanoparticles and
    encapsulation of bioactive compounds. Within these fish skin, gelatine nanoparticles show
    potent benefits for application in pharmaceutical and cosmetic industry. The encapsulated
    bioactive ingredients within nanoparticles have improved bioavailability, delivery properties,
    and solubility of the nutraceuticals within the human body and blood stream. Many of such
    bioactive peptides (biopeptides) are potent antioxidants; and as oxidative stress is the main
    cause of the onset of various chronic diseases, encapsulation of antioxidant biopeptides within
    fish gelatine nanoparticles could be a potential remedy to prevent or delay the onset of such
    diseases and for better health prospects. The purpose of the present work was to prepare a
    simple, safe, and reproducible novel food delivery nanoparticle system encapsulating a desirable antioxidant biopeptide. An optimisation study was conducted to produce a desirable size
    of gelatine nanoparticles which showed a higher encapsulation efficiency of an antioxidant
    biopeptide. Sunflower biopeptide was chosen as the antioxidant biopeptide, as the activity of
    this protein hydrolysate is quite high at DPPH of 89% and FRAP assay of 968 µm/L. Tilapia
    fish was used as gelatine source at an average yield of the process at 10% wt/wt. Effects of
    parameters such as pH, biopeptide concentration, and cross-linking agent ‘glutaraldehyde’ on
    the size, stability, and encapsulation efficiency on the nanoparticles were studied. The average
    diameter of the biopeptide loaded gelatine nanoparticle was between 228.3 and 1,305 nm.
    Encapsulation efficiency was 76% at an optimal pH of 2, glutaraldehyde concentration of 2
    mL, and biopeptide concentration of 0.1 mg/mL exhibited DPPH at 92% and FRAP assay of
    978 µm/L. To understand the absorption of sunflower biopeptide in stomach, blood stream,
    and biopeptide release of the gelatine nanoparticles, biopeptide loaded gelatine nanoparticles
    were subjected to simulated gastrointestinal conditions mimicking human stomach and
    intestine; and showed peptide release of 0.1464 and 0.277 mg/mL upon pepsin and pancreatin
    digestion, respectively.
    Matched MeSH terms: Hydrogen-Ion Concentration
  20. Law AT, Yeo ME
    Bull Environ Contam Toxicol, 1997 Mar;58(3):469-74.
    PMID: 9008059
    Matched MeSH terms: Hydrogen-Ion Concentration
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