Displaying publications 61 - 80 of 125 in total

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  1. Fulltext Stability of glycated haemoglobin (HbA1c) measurements from whole blood samples kept at -196°C for seven to eight years in The Malaysian Cohort study
    Abdullah N, Goh YX, Othman R, Ismail N, Jalal N, Wan Sallam WAF, et al.
    J Clin Lab Anal, 2023 Apr;37(8):e24898.
    PMID: 37243371 DOI: 10.1002/jcla.24898
    OBJECTIVE: Glycated haemoglobin (HbA1c) is a standard indication for screening type 2 diabetes that also has been widely used in large-scale epidemiological studies. However, its long-term quality (in terms of reproducibility) stored in liquid nitrogen is still unknown. This study is aimed to evaluate the stability and reproducibility of HbA1c measurements from frozen whole blood samples kept at -196°C for more than 7 years.

    METHODS: A total of 401 whole blood samples with a fresh HbA1c measurement were randomly selected from The Malaysian Cohort's (TMC) biobank. The HbA1c measurements of fresh and frozen (stored for 7-8 years) samples were assayed using different high-performance liquid chromatography (HPLC) systems. The HbA1c values of the fresh samples were then calculated and corrected according to the later system. The reproducibility of HbA1c measurements between calculated-fresh and frozen samples was assessed using a Passing-Bablok linear regression model. The Bland-Altman plot was then used to evaluate the concordance of HbA1c values.

    RESULTS: The different HPLC systems highly correlated (r = 0.99) and agreed (ICC = 0.96) with each other. Furthermore, the HbA1c measurements for frozen samples strongly correlate with the corrected HbA1c values of the fresh samples (r = 0.875) with a mean difference of -0.02 (SD: -0.38 to 0.38). Although the mean difference is small, discrepancies were observed within the diabetic and non-diabetic samples.

    CONCLUSION: These data demonstrate that the HbA1c measurements between fresh and frozen samples are highly correlated and reproducible.

  2. Docking of noncompetitive inhibitors into dengue virus type 2 protease: understanding the interactions with allosteric binding sites
    Othman R, Kiat TS, Khalid N, Yusof R, Newhouse EI, Newhouse JS, et al.
    J Chem Inf Model, 2008 Aug;48(8):1582-91.
    PMID: 18656912 DOI: 10.1021/ci700388k
    A group of flavanones and their chalcones, isolated from Boesenbergia rotunda L., were previously reported to show varying degrees of noncompetitive inhibitory activities toward Dengue virus type 2 (Den2) protease. Results obtained from automated docking studies are in agreement with experimental data in which the ligands were shown to bind to sites other than the active site of the protease. The calculated K(i) values are very small, indicating that the ligands bind quite well to the allosteric binding site. Greater inhibition by pinostrobin, compared to the other compounds, can be explained by H-bonding interaction with the backbone carbonyl of Lys74, which is bonded to Asp75 (one of the catalytic triad residues). In addition, structure-activity relationship analysis yields structural information that may be useful for designing more effective therapeutic drugs against dengue virus infections.
  3. Bioassay-Guided Isolation and in Silico Study of Antibacterial Compounds From Petroleum Ether Extract of Peperomia blanda (Jacq.) Kunth
    Al-Madhagi WM, Hashim NM, Awadh Ali NA, Taha H, Alhadi AA, Abdullah AA, et al.
    J Chem Inf Model, 2019 05 28;59(5):1858-1872.
    PMID: 31117526 DOI: 10.1021/acs.jcim.8b00969
    Bioassay-guided isolation protocol was performed on petroleum ether extract of Peperomia blanda (Jacq.) Kunth using column chromatographic techniques. Five compounds were isolated and their structures were elucidated via one-dimensional (1D) and two-dimensional (2D) NMR, gas chromatography mass sectroscopy (GCMS), liquid chromatography mass spectroscopy (LCMS), and ultraviolet (UV) and infrared (IR) analyses. Dindygulerione E (a new compound), and two compounds isolated from P. blanda for the first time-namely, dindygulerione A and flavokawain A-are reported herein. Antimicrobial activity was screened against selected pathogenic microbes, and minimum inhibitory concentrations (MIC) were recorded within the range of 62-250 μg/mL. Assessment of the pharmacotherapeutic potential has also been done for the isolated compounds, using the Prediction of Activity spectra for Substances (PASS) software, and different activities of compounds were predicted. Molecular docking, molecular dynamics simulation and molecular mechanics/Poisson-Boltzmann Surface Area (MM-PBSA) calculations have proposed the binding affinity of these compounds toward methylthioadenosine phosphorylase enzyme, which may explain their inhibitory actions.
  4. High level expression of Glomerella cingulata cutinase in dense cultures of Pichia pastoris grown under fed-batch conditions
    Seman WM, Bakar SA, Bukhari NA, Gaspar SM, Othman R, Nathan S, et al.
    J Biotechnol, 2014 Aug 20;184:219-28.
    PMID: 24910973 DOI: 10.1016/j.jbiotec.2014.05.034
    A Pichia pastoris transformant carrying the cutinase cDNA of Glomerella cingulata was over-expressed in a 5L bioreactor (2.0L working volume) under fed-batch conditions. Bioreactor experiments rely on varying selected parameters in repeated rounds of optimisation: here these included duration of induction, pH and temperature. Highest cell densities (320gL(-1) wet cell weight) with a cutinase production of 3800mgL(-1) and an activity of 434UmL(-1) were achieved 24h after induction with methanol in basal salt medium (at pH 5 and 28°C). Characterisation of the cutinase showed that it was stable between pH 6 and pH 11, had an optimum pH of 8.0 and retained activity for 30min at 50°C (optimum temperature 25°C).The preferred substrates of G. cingulata cutinase were the medium- to long-chain ρ-nitrophenyl esters of ρ-nitrophenylcaprylate (C8), ρ-nitrophenyllaurate (C12) and ρ-nitrophenylmyristate (C14), with the highest catalytic efficiency, kcat/Km of 7.7±0.7mM(-1)s(-1) for ρ-nitrophenylcaprylate. Microscopic analyses showed that the G. cingulata cutinase was also capable of depolymerising the high molecular weight synthetic polyester, polyethylene terephthalate.
  5. Nanoporous biomaterials for uremic toxin adsorption in artificial kidney systems: A review
    Cheah WK, Ishikawa K, Othman R, Yeoh FY
    J Biomed Mater Res B Appl Biomater, 2017 07;105(5):1232-1240.
    PMID: 26913694 DOI: 10.1002/jbm.b.33475
    Hemodialysis, one of the earliest artificial kidney systems, removes uremic toxins via diffusion through a semipermeable porous membrane into the dialysate fluid. Miniaturization of the present hemodialysis system into a portable and wearable device to maintain continuous removal of uremic toxins would require that the amount of dialysate used within a closed-system is greatly reduced. Diffused uremic toxins within a closed-system dialysate need to be removed to maintain the optimum concentration gradient for continuous uremic toxin removal by the dialyzer. In this dialysate regenerative system, adsorption of uremic toxins by nanoporous biomaterials is essential. Throughout the years of artificial kidney development, activated carbon has been identified as a potential adsorbent for uremic toxins. Adsorption of uremic toxins necessitates nanoporous biomaterials, especially activated carbon. Nanoporous biomaterials are also utilized in hemoperfusion for uremic toxin removal. Further miniaturization of artificial kidney system and improvements on uremic toxin adsorption capacity would require high performance nanoporous biomaterials which possess not only higher surface area, controlled pore size, but also designed architecture or structure and surface functional groups. This article reviews on various nanoporous biomaterials used in current artificial kidney systems and several emerging nanoporous biomaterials. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1232-1240, 2017.
  6. Macroporous bioceramics: a remarkable material for bone regeneration
    Lew KS, Othman R, Ishikawa K, Yeoh FY
    J Biomater Appl, 2012 Sep;27(3):345-58.
    PMID: 21862511 DOI: 10.1177/0885328211406459
    This review summarises the major developments of macroporous bioceramics used mainly for repairing bone defects. Porous bioceramics have been receiving attention ever since their larger surface area was reported to be beneficial for the formation of more rigid bonds with host tissues. The study of porous bioceramics is important to overcome the less favourable bonds formed between dense bioceramics and host tissues, especially in healing bone defects. Macroporous bioceramics, which have been studied extensively, include hydroxyapatite, tricalcium phosphate, alumina, and zirconia. The pore size and interconnections both have significant effects on the growth rate of bone tissues. The optimum pore size of hydroxyapatite scaffolds for bone growth was found to be 300 µm. The existence of interconnections between pores is critical during the initial stage of tissue ingrowth on porous hydroxyapatite scaffolds. Furthermore, pore formation on β-tricalcium phosphate scaffolds also allowed the impregnation of growth factors and cells to improve bone tissues growth significantly. The formation of vascularised tissues was observed on macroporous alumina but did not take place in the case of dense alumina due to its bioinert nature. A macroporous alumina coating on scaffolds was able to improve the overall mechanical properties, and it enabled the impregnation of bioactive materials that could increase the bone growth rate. Despite the bioinertness of zirconia, porous zirconia was useful in designing scaffolds with superior mechanical properties after being coated with bioactive materials. The pores in zirconia were believed to improve the bone growth on the coated system. In summary, although the formation of pores in bioceramics may adversely affect mechanical properties, the advantages provided by the pores are crucial in repairing bone defects.
  7. The NADI program and the JOICFP integrated project: partners in delivering primary health care
    Arshat H, Othman R, Kuan Lin Chee, Abdullah M
    JOICFP Rev, 1985 Oct;10:10-5.
    PMID: 12313881
    PIP:
    The NADI program (pulse in Malay) was initially launched as a pilot project in 1980 in Kuala Lumpur, Malaysia. It utilized an integrated approach involving both the government and the private sectors. By sharing resources and expertise, and by working together, the government and the people can achieve national development faster and with better results. The agencies work through a multi-level supportive structure, at the head of which is the steering committee. The NADI teams at the field level are the focal points of services from the various agencies. Members of NADI teams also work with urban poor families as well as health groups, parents-teachers associations, and other similar groups. The policy and planning functions are carried out by the steering committee, the 5 area action committees and the community action committees, while the implementation function is carried out by the area program managers and NADI teams. The chairman of each area action committee is the head of the branch office of city hall. Using intestinal parasite control as the entry point, the NADI Integrated Family Development Program has greatly helped in expanding inter-agency cooperation and exchange of experiences by a coordinated, effective and efficient resource-mobilization. The program was later expanded to other parts of the country including the industrial and estate sectors. Services provided by NADI include: comprehensive health services to promote maternal and child health; adequate water supply, proper waste disposal, construction of latrines and providing electricity; and initiating community and family development such as community education, preschool education, vocational training, family counseling and building special facilities for recreational and educational purposes.
  8. Fulltext Flavonoid biosynthesis genes putatively identified in the aromatic plant Polygonum minus via Expressed Sequences Tag (EST) analysis
    Roslan ND, Yusop JM, Baharum SN, Othman R, Mohamed-Hussein ZA, Ismail I, et al.
    Int J Mol Sci, 2012;13(3):2692-706.
    PMID: 22489118 DOI: 10.3390/ijms13032692
    P. minus is an aromatic plant, the leaf of which is widely used as a food additive and in the perfume industry. The leaf also accumulates secondary metabolites that act as active ingredients such as flavonoid. Due to limited genomic and transcriptomic data, the biosynthetic pathway of flavonoids is currently unclear. Identification of candidate genes involved in the flavonoid biosynthetic pathway will significantly contribute to understanding the biosynthesis of active compounds. We have constructed a standard cDNA library from P. minus leaves, and two normalized full-length enriched cDNA libraries were constructed from stem and root organs in order to create a gene resource for the biosynthesis of secondary metabolites, especially flavonoid biosynthesis. Thus, large-scale sequencing of P. minus cDNA libraries identified 4196 expressed sequences tags (ESTs) which were deposited in dbEST in the National Center of Biotechnology Information (NCBI). From the three constructed cDNA libraries, 11 ESTs encoding seven genes were mapped to the flavonoid biosynthetic pathway. Finally, three flavonoid biosynthetic pathway-related ESTs chalcone synthase, CHS (JG745304), flavonol synthase, FLS (JG705819) and leucoanthocyanidin dioxygenase, LDOX (JG745247) were selected for further examination by quantitative RT-PCR (qRT-PCR) in different P. minus organs. Expression was detected in leaf, stem and root. Gene expression studies have been initiated in order to better understand the underlying physiological processes.
  9. Fulltext Validation of quantitative structure-activity relationship (QSAR) model for photosensitizer activity prediction
    Frimayanti N, Yam ML, Lee HB, Othman R, Zain SM, Rahman NA
    Int J Mol Sci, 2011;12(12):8626-44.
    PMID: 22272096 DOI: 10.3390/ijms12128626
    Photodynamic therapy is a relatively new treatment method for cancer which utilizes a combination of oxygen, a photosensitizer and light to generate reactive singlet oxygen that eradicates tumors via direct cell-killing, vasculature damage and engagement of the immune system. Most of photosensitizers that are in clinical and pre-clinical assessments, or those that are already approved for clinical use, are mainly based on cyclic tetrapyrroles. In an attempt to discover new effective photosensitizers, we report the use of the quantitative structure-activity relationship (QSAR) method to develop a model that could correlate the structural features of cyclic tetrapyrrole-based compounds with their photodynamic therapy (PDT) activity. In this study, a set of 36 porphyrin derivatives was used in the model development where 24 of these compounds were in the training set and the remaining 12 compounds were in the test set. The development of the QSAR model involved the use of the multiple linear regression analysis (MLRA) method. Based on the method, r(2) value, r(2) (CV) value and r(2) prediction value of 0.87, 0.71 and 0.70 were obtained. The QSAR model was also employed to predict the experimental compounds in an external test set. This external test set comprises 20 porphyrin-based compounds with experimental IC(50) values ranging from 0.39 μM to 7.04 μM. Thus the model showed good correlative and predictive ability, with a predictive correlation coefficient (r(2) prediction for external test set) of 0.52. The developed QSAR model was used to discover some compounds as new lead photosensitizers from this external test set.
  10. Fulltext Biomolecular characterization of diazotrophs isolated from the tropical soil in Malaysia
    Naher UA, Othman R, Latif MA, Panhwar QA, Amaddin PA, Shamsuddin ZH
    Int J Mol Sci, 2013 Aug 30;14(9):17812-29.
    PMID: 23999588 DOI: 10.3390/ijms140917812
    This study was conducted to evaluate selected biomolecular characteristics of rice root-associated diazotrophs isolated from the Tanjong Karang rice irrigation project area of Malaysia. Soil and rice plant samples were collected from seven soil series belonging to order Inceptisol (USDA soil taxonomy). A total of 38 diazotrophs were isolated using a nitrogen-free medium. The biochemical properties of the isolated bacteria, such as nitrogenase activity, indoleacetic acid (IAA) production and sugar utilization, were measured. According to a cluster analysis of Jaccard's similarity coefficients, the genetic similarities among the isolated diazotrophs ranged from 10% to 100%. A dendogram constructed using the unweighted pair-group method with arithmetic mean (UPGMA) showed that the isolated diazotrophs clustered into 12 groups. The genomic DNA rep-PCR data were subjected to a principal component analysis, and the first four principal components (PC) accounted for 52.46% of the total variation among the 38 diazotrophs. The 10 diazotrophs that tested highly positive in the acetylene reduction assay (ARA) were identified as Bacillus spp. (9 diazotrophs) and Burkholderia sp. (Sb16) using the partial 16S rRNA gene sequence analysis. In the analysis of the biochemical characteristics, three principal components were accounted for approximately 85% of the total variation among the identified diazotrophs. The examination of root colonization using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) proved that two of the isolated diazotrophs (Sb16 and Sb26) were able to colonize the surface and interior of rice roots and fixed 22%-24% of the total tissue nitrogen from the atmosphere. In general, the tropical soils (Inceptisols) of the Tanjong Karang rice irrigation project area in Malaysia harbor a diverse group of diazotrophs that exhibit a large variation of biomolecular characteristics.
  11. Rapid detection of α-thalassaemia variants using droplet digital PCR
    Lee TY, Lai MI, Ramachandran V, Tan JA, Teh LK, Othman R, et al.
    Int J Lab Hematol, 2016 Aug;38(4):435-43.
    PMID: 27349818 DOI: 10.1111/ijlh.12520
    INTRODUCTION: Alpha thalassaemia is a highly prevalent disease globally and is a well-known public health problem in Malaysia. The deletional forms of the mutation are the most common forms found in alpha thalassaemia. The three most common deletional alpha thalassaemia found in this region include --(SEA) deletion, -α(3.7) rightward and -α(4.2) leftward deletions. The prevalence rate of triplication alpha cases such as ααα(anti3.7) and ααα(anti4.2) is not known in Malaysia although it plays a role in exacerbating the clinical phenotypes in beta thalassaemia carriers. Recently, there have been more reported cases of rare alpha thalassaemia mutations due to the advancement of molecular techniques involved in thalassaemia detections. Therefore, it is essential to develop a new method which allows the detection of different alpha thalassaemia mutations including the rare ones simultaneously and accurately.

    METHODS: The purpose of this study was to design an assay for the detection of triplications, common and rare deletional alpha thalassaemia using droplet digital PCR (ddPCR).

    RESULTS: This is a quantitative detection method to measure the changes of copy number which can detect deletions, duplications and triplications of the alpha globin gene simultaneously.

    CONCLUSION: In conclusion, ddPCR is an alternative method for rapid detection of alpha thalassaemia variants in Malaysia.

  12. Fulltext Participants Attrition in a Longitudinal Study: The Malaysian Cohort Study Experience
    Abdullah N, Kamaruddin MA, Goh YX, Othman R, Dauni A, Jalal NA, et al.
    Int J Environ Res Public Health, 2021 07 06;18(14).
    PMID: 34299667 DOI: 10.3390/ijerph18147216
    The attrition rate of longitudinal study participation remains a challenge. To date, the Malaysian Cohort (TMC) study follow-up rate was only 42.7%. This study objective is to identify the cause of attrition among TMC participants and the measures to curb it. A total of 19,343 TMC participants from Kuala Lumpur and Selangor that was due for follow-up were studied. The two most common attrition reasons are undergoing medical treatment at another government or private health center (7.0%) and loss of interest in participating in the TMC project (5.1%). Those who were inclined to drop out were mostly Chinese, aged 50 years and above, unemployed, and had comorbidities during the baseline recruitment. We have also contacted 2183 participants for the home recruitment follow-up, and about 10.9% agreed to join. Home recruitment slightly improved the overall follow-up rate from 42.7% to 43.5% during the three-month study period.
    Study name: The Malaysian Cohort (TMC) project
  13. Fulltext Factors Associated with the Acceptability of Mass Drug Administration for Filariasis: A Systematic Review
    Abdul Halim AFN, Ahmad D, Miaw Yn JL, Masdor NA, Ramly N, Othman R, et al.
    Int J Environ Res Public Health, 2022 Oct 10;19(19).
    PMID: 36232271 DOI: 10.3390/ijerph191912971
    Mass drug administration (MDA) has been implemented as a tool to eliminate lymphatic filariasis. Acceptability among susceptible populations is crucial to achieving MDA effective coverage. This systematic review aims to present and systematically determine the factors associated with the acceptability of MDA. Articles related to factors associated with acceptability were collected electronically from three different databases (Scopus, Web of Science, and PubMed). Four pairs of independent reviewers screened the titles and abstracts of the collected data, stored in EndnoteX7, against the inclusion criteria. Afterwards, the included articles have been critically appraised to assess the quality of the studies using the Mixed Method Appraisal Tool (MMAT). Of the 68 articles identified, 11 were included in the final review. Knowledge, awareness, attitude and perceptions, communications, delivery and accessibility of MDA, gender, and age are the factors associated with MDA acceptability. Community acceptance remains a challenge in the implementation of MDA. To expand MDA coverage in all endemic countries, there is a strong need to address the factors influencing community acceptance of MDA.
  14. Fulltext A Novel, Homozygous c.1502T>G (p.Val501Gly) Mutation in the Thyroid peroxidase Gene in Malaysian Sisters with Congenital Hypothyroidism and Multinodular Goiter
    Lee CC, Harun F, Jalaludin MY, Heh CH, Othman R, Mat Junit S
    Int J Endocrinol, 2013;2013:987186.
    PMID: 23737781 DOI: 10.1155/2013/987186
    Congenital hypothyroidism (CH) with multinodular goiter (MNG) is uncommonly seen in children. However, CH associated with goiter is often caused by defective Thyroid peroxidase (TPO) gene. In this study, we screened for mutation(s) in the TPO gene in two siblings with CH and MNG and their healthy family members. The two sisters, born to consanguineous parents, were diagnosed with CH during infancy and received treatment since then. They developed MNG during childhood despite adequate L-thyroxine replacement and negative thyroid antibody screening. PCR-amplification of all exons using flanking primers followed by DNA sequencing revealed that the two sisters were homozygous for a novel c.1502T>G mutation. The mutation is predicted to substitute valine for glycine at a highly conserved amino acid residue 501 (p.Val501Gly). Other healthy family members were either heterozygotes or mutation-free. The mutation was not detected in 50 healthy unrelated individuals. In silico analyses using PolyPhen-2 and SIFT predicted that the p.Val501Gly mutation is functionally "damaging." Tertiary modeling showed structural alterations in the active site of the mutant TPO. In conclusion, a novel mutation, p.Val501Gly, in the TPO gene was detected expanding the mutation spectrum of TPO associated with CH and MNG.
  15. Fulltext Scheme of obtaining β-carotene standard from pumpkin (Cucurbita moschata) flesh
    Norshazila, S., Irwandi, J., Othman, R., Yumi Zuhanis, H.H.
    International Food Research Journal, 2012;19(2):531-535.
    MyJurnal
    Characterization and quantification of carotenoid compound is complicated, costly and timeconsuming. The accuracy and reliability of the data depend solely on the standard and to High Performance Liquid Chromatography (HPLC) analysis but the major constraint is to acquire and to maintain the pure standards. Carotenoid standards are commercially available but they are expensive and are prone to isomerization and oxidation. Thus, the purpose of this study is to establish an analytical method for isolating β-carotene by using open column chromatography (OCC) from pumpkin (Cucurbita moschata) to be used as one of the carotenoid standards for determination of total and individual carotenoid. Pumpkin with orange flesh has been chosen due to the non-seasonal nature and its availability all year-round. This study demonstrated that the purity of β-carotene standard; determined by HPLC was ranged from 92.21 to 97.95%. The standard curves with five different concentrations of β-carotene extract from pumpkins in triplicate were constructed by plotting the peak area against the concentration. The coefficient of correlation was 0.9936. Therefore, this study established that pumpkin can be a reliable source of beta-carotene standard as it is cheap and commonly available throughout the year.
  16. Fulltext Antioxidant and Antimicrobial activities of Astaxanthin from Penaeus Monodon in comparison between chemical extraction and High Pressure Processing (HPP)
    Irna, C., Jaswir, I., Othman, R., Jimat, D.N.
    International Food Research Journal, 2017;24(101):508-513.
    MyJurnal
    The use of High Pressure Processing as an extraction method was studied by evaluating the yield of astaxanthin from shrimp carapace as a model. Previous studies have demonstrated the antioxidant and antimicrobial properties of astaxanthin. The aim of this research was to compare these properties of astaxanthin as a surrogate for its yield from High Pressure Processing (HPP) extraction with the effect of hydrostatic pressure, holding time and amount of solvents versus chemical extraction method. A solvent mixture of acetone and methanol 7:3 (v/v) was used in both methods. The pressure treated was at 238 MPa with 16.29 min of holding time and 6.59 ml of solvents for HPP method. Antioxidant activity was evaluated using scavenging activity of DPPH radical, the reducing activity of Ferrum redox reaction and oxygen radical absorption capacity. Antimicrobial activity was evaluated using a zone of inhibition test against four strain of bacteria: E. coli, E. aerogenes, S. aureus and B. subtilis. The sample of astaxanthin demonstrated a significant increase in DPPH radical scavenging activity (25.47% to 87.90%), reducing activity of Ferrum redox reaction (2.86 µmol TE/g to 8.13 µmol TE/g) and oxygen radical absorption capacity (2,000 µmol TE/100 g to 4,000 µmol TE/100 g) compared to the chemical extraction sample. The antimicrobial activity of the astaxanthin from the HPP sample produced a greater zone of inhibition against all four strains of bacteria when compared to the chemically extracted sample. A higher quality of astaxanthin was achieved with the HPP extraction method compared to chemical extraction.
  17. Fulltext Effect of abiotic stress on carotenoids accumulation in orange sweet potato callus under light and dark conditions
    Othman, R., Kammona, S., Jaswir, I., Jamal, P., Mohd Hatta, F.A.
    International Food Research Journal, 2017;24(101):0-0.
    MyJurnal
    Abiotic stress factors are the main limitation to plant growth and yield in agriculture. Orange sweet potatoes may become major sources of carotenoids in the diet, but the extent of environmental and genetic influences on plant carotenoid biosynthesis are poorly understood. Carotenoid biosynthesis is regulated by several factors such as water, light, pathogen, salinity, nutrients and is susceptible to geometric isomerisation in the presence of oxygen, light and heat which causes colour loss and oxidation. The main problems associated with carotenoid accumulation arise from the inherent instability of pigments. In this study carotenoid biogenesis is investigated in sweet potato callus culture as a potential model system for carotenogenesis by analysing the effects of environmental stress agents such as NaCl (for salt tolerance), PEG (for drought tolerance), salicylic acid (for pathogen stress or disease resistance) and nutrient strength towards carotenoid content and composition. Results of this study revealed that the bioactive compounds detected in orange sweet potato callus were α-carotene, β-carotene, lutein and zeaxanthin. Not surprisingly, the response of sweet potato callus culture to such environments appeared to be highly light dependent. Another factor is the activity of functional enzymes and candidate enzymes that regulate carotenoid biosynthesis, which will determine type and quantity of individual carotenoids. By understanding the environmental factors that affected carotenoid biosynthesis, it should be possible to enhance the amount and type of carotenoid that accumulates in sweet potato tubers. In conclusion, in vitro callus culture is suggested as a successful new alternative approaches to enhance or enrich certain carotenoids through controlled environment.
  18. Fulltext Determination of natural carotenoid pigments from freshwater green algae as potential halal food colorants
    Othman, R., Noh, N., Nurrulhidayah, A.F., Anis Hamizah, H., Jamaludin, M. A.
    International Food Research Journal, 2017;24(101):0-0.
    MyJurnal
    It is noted that nowadays, halal products are gaining wider recognition as a new benchmark for safety and quality assurance. As a consequence of these additional pigment needs, the demand in isolated natural colorants has increased as compared with synthetic dyes. The aim of the research is to explore new sources of pigments to be used as halal food colorants. This quest is not only directed in finding natural alternatives for synthetic dyes, but also with the aim to discover new taxons for the pigment production, for instance from microalgae. Therefore, a total of six freshwater algae species were evaluated quantitative and qualitatively using HPLC for carotenoids pigment. Three main carotenoids were identified in Chlorella fusca, Chlorella vulgaris, Selenastrum capricornutum, Pandorina morum, Botryococcus sudeticus and Chlorococcum sp. which are lutein, β-cryptoxanthin and β-carotene. The ratio of these carotenoids varies between species where lutein was detected substantially higher in Chlorella fusca (69.54±11.29µg/g DW); β-cryptoxanthin in Pandorina morum (1.24±0.33 µg/g DW) whereas β-carotene in Chlorella vulgaris (18.42±9.2 ug/g DW). The significant outcome of the research will be new findings of new natural carotenoid pigment sources as potential food colorants and bioactive compounds which can be beneficial to halal health promoting products industry, food products and dye technology which covers not only the Shariah requirement, but also the hygiene, purification and safety aspects.
  19. Fulltext Influence of growing location, harvesting season and post-harvest storage time on carotenoid biosynthesis in orange sweet potato (Ipomoea batatas) tuber flesh
    Othman, R., Kammona, S., Jaswir, I., Jamal, P., Mohd Hatta, F.A.
    International Food Research Journal, 2017;24(101):0-0.
    MyJurnal
    Carotenoid content in plants differs due to several factors such as cultivar, maturity, climate, locality and storage. Improving the nutritional values of sweet potato is an important breeding goal and understanding the regulation, genetics and inheritance of carotenoid biosynthesis are vital to achieve this. Environmental conditions can have a marked influence on the accumulation of carotenoids in sweet potato tubers. Little is known about the effects of location, post-harvest storage time and harvesting season particularly on carotenoid biosynthesis. Therefore, this study aimed to investigate the effects of growing location, harvesting season and storage time on carotenoid biosynthesis in orange sweet potato tuber flesh. The results showed that orange sweet potato tubers contained α-carotene and β-carotene in the first and second harvesting season (year 2011 and 2012), whereas lutein and zeaxanthin were detected only in the third harvesting season (year 2013). Analysis of carotenoid profiles of the orange sweet potato tubers grown in three different locations confirmed that the harvesting season had a major effect on the total carotenoid content and the individual carotenoid compounds. The post-harvest storage time of sweet potato tubers also appears to have distinct effects on carotenoid biosynthesis, the magnitude of the effects being dependent on the storage time, harvesting season and location. The results of this study will help to understand the effects of location, year of harvesting season and storage time on carotenoid accumulation in orange sweet potato tubers.
  20. Fulltext Study on physiochemical properties and the halalness of commercially marketed vinegar in Malaysia
    Jamaludin, M.A., Amin, A., Fadzlillah, N. A., Kartika, B., Othman, R., Sani, S., et al.
    International Food Research Journal, 2017;24(101):0-0.
    MyJurnal
    Vinegar is very popular as traditional ingredient for cooking, pickling, and preservation. It is made from sugar or starch by an alcoholic and acetous fermentation and produces ethanol as a by-product. Alcohol is prohibited to be consumed for Muslim or used as ingredient if it is exceeding the allowable limit as stated by Islamic Council in Malaysia. According to Fatwa Committee National Council of Islamic Religious Affairs Malaysia, natural occurrences of ethanol in food products are acceptable if the ethanol contents are less than 1% in beverages and 0.5% for flavoring or coloring substances for the purpose of stabilization. On the other hand, for specific vinegar product, as stated by Malaysian Food Act and Regulation, acetic acid content must be at least 4%. According to FAO/WHO, a product is to be labelled as vinegar if the acetic acid content is 6% and with a maximum residual alcohol content of 0.5%v/v for wine vinegar and 1%v/v for other vinegars. This study investigated the physiochemical properties of the vinegar from different sources of raw materials. Total solubility (TA) by using Brix method, pH, and alcohol and acetic acid content by GC-TOF/MS of 12 commercial vinegars from Malaysia and abroad were studied. The result shown that for pH value of commercial vinegar are ranged from 2.51-3.14°Brix from 2.10-40.73°Brix, acetic acid is ranged from 0.0253-0.1276% and ethanol content from 0-0.5911%. Thus, this study will come out with the clear observation on ethanol content in fermented product which is vinegar in order to categories the halalness of the product that available in Malaysia market especially the ones that are produced internationally. Lastly, as shown by the profiling study, vinegar that are imported internationally may contain some amount of alcohol in contrast with the one that locally produced in Malaysia and has Halal certification.
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