Displaying publications 1 - 20 of 27 in total

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  1. Gan CY, Cheng LH, Easa AM
    J Food Sci, 2009 Mar;74(2):C141-6.
    PMID: 19323728 DOI: 10.1111/j.1750-3841.2009.01053.x
    Soy protein isolate (SPI) gels were produced using single cross-linking agents (SCLA) of microbial transglutaminase (MTG) via incubation for 5 or 24 h (SCLA-MTG). When powdered SCLA-MTG gels were heated for 2 h with ribose (R2) (2 g/100 mL), dark brown gels were formed, and these were designated as combined cross-linking agent (CCLA) gels: MTG5(R2) and MTG24(R2). The results showed that the levels of Maillard-derived browning and cross-links of MTG5(R2) and MTG24(R2) gels were significantly (P < 0.05) lower than a control gel produced without MTG (SCLA-R2) even though the percentage of ribose remaining after heating of these gels was similar, indicating that a similar amount of ribose was consumed during heating. epsilon-(gamma-glutamyl)lysine bonds formed during incubation of SPI with MTG may have reduced the free amino group of SPI to take part in the Maillard reaction; nevertheless, ribose took part in the Maillard reaction and initiated the Maillard cross-linkings within the CCLA gels.
  2. Abbas Alkarkhi FM, Ismail N, Easa AM
    J Hazard Mater, 2008 Feb 11;150(3):783-9.
    PMID: 17590506
    Cockles (Anadara granosa) sample obtained from two rivers in the Penang State of Malaysia were analyzed for the content of arsenic (As) and heavy metals (Cr, Cd, Zn, Cu, Pb, and Hg) using a graphite flame atomic absorption spectrometer (GF-AAS) for Cr, Cd, Zn, Cu, Pb, As and cold vapor atomic absorption spectrometer (CV-AAS) for Hg. The two locations of interest with 20 sampling points of each location were Kuala Juru (Juru River) and Bukit Tambun (Jejawi River). Multivariate statistical techniques such as multivariate analysis of variance (MANOVA) and discriminant analysis (DA) were applied for analyzing the data. MANOVA showed a strong significant difference between the two rivers in term of As and heavy metals contents in cockles. DA gave the best result to identify the relative contribution for all parameters in discriminating (distinguishing) the two rivers. It provided an important data reduction as it used only two parameters (Zn and Cd) affording more than 72% correct assignations. Results indicated that the two rivers were different in terms of As and heavy metal contents in cockle, and the major difference was due to the contribution of Zn and Cd. A positive correlation was found between discriminate functions (DF) and Zn, Cd and Cr, whereas negative correlation was exhibited with other heavy metals. Therefore, DA allowed a reduction in the dimensionality of the data set, delineating a few indicator parameters responsible for large variations in heavy metals and arsenic content. Taking into account of these results, it can be suggested that a continuous monitoring of As and heavy metals in cockles be performed in these two rivers.
  3. Lubowa M, Yeoh SY, Easa AM
    Food Sci Technol Int, 2018 Sep;24(6):476-486.
    PMID: 29600879 DOI: 10.1177/1082013218766984
    This study investigated the influence of pregelatinized high-amylose maize starch and chilling treatment on the physical and textural properties of canned rice noodles thermally processed in a retort. Rice noodles were prepared from rice flour partially substituted with pregelatinized high-amylose maize starch (Hylon VII™) in the ratios 0, 5, 10, and 15% (wt/wt). High-amylose maize starch improved the texture and brightness of fresh (not retorted) noodles. Chilling treatment led to significant (P ≤ 0.05) improvement in the texture of fresh noodles at all levels of substitution with high-amylose starch. The highest hardness was recorded at 15% amylose level in chilled nonretorted noodles. Retort processing induced a major loss of quality through water absorption, retort cooking loss, decreased noodle hardness, and lightness. However, the results showed that amylose and chilling treatment positively reduced the impact of retorting. For each level of amylose substitution, a low retort cooking loss and increased noodle hardness were associated with a chilling treatment. For both chilled and nonchilled noodles, retort cooking loss and hardness increased with increasing levels of amylose substitution.
  4. Ojukwu M, Tan JS, Easa AM
    J Food Sci, 2020 Sep;85(9):2720-2727.
    PMID: 32776580 DOI: 10.1111/1750-3841.15357
    A process for enhancing textural and cooking properties of fresh rice flour-soy protein isolate noodles (RNS) to match those of yellow alkaline noodles (YAN) was developed by incorporating microbial transglutaminase (RNS-MTG), glucono-δ-lactone (RNS-GDL), and both MTG and GDL into the RNS noodles (RNS-COM). The formation of γ-glutamyl-lysine bonds in RNS-COM and RNS-MTG was shown by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Scanning electron microscope showed that compared to others, the structure of RNS-COM was denser, smoother with extensive apparent interconnectivity of aggregates. The optimum cooking time was in the order: YAN > RNS-COM > RNS-MTG > RNS-GDL > RN (rice flour noodles); tensile strength was in the order: YAN > RNS-COM > RNS-MTG > RNS-GDL > RN; and elasticity were in the order: YAN > RNS-COM > RNS-MTG, RNS-GDL > RN. Overall, RNS-COM showed similar textural and structural breakdown parameters as compared to those of YAN. Changes in microstructures and improvement of RNS-COM in certain properties were likely due to enhanced crosslinking of proteins attributed to MTG- and GDL-induced cold gelation of proteins at reduced pH value. It is possible to use the combination of MTG and GDL to improve textural and mechanical properties of RNS comparable to those of YAN. PRACTICAL APPLICATION: Combined MTG and GDL yield rice flour noodles with improved textural properties. The restructured rice flour noodles have the potential to replace yellow alkaline noodles.
  5. Reihani SF, Tan TC, Huda N, Easa AM
    Food Chem, 2014 Jul 15;155:17-23.
    PMID: 24594148 DOI: 10.1016/j.foodchem.2014.01.027
    In Malaysia, fresh ulam raja leaves (Cosmos caudatus) are eaten raw with rice. In this study, beef patties incorporated with extracts of ulam raja (UREX) and commercial green tea extract (GTE) added individually at 200 and 500 mg/kg were stored at -18°C for up to 10 weeks. Lipid oxidation, cooking yield, physicochemical properties, textural properties, proximate composition and sensory characteristics of the beef patties were compared between those incorporated with UREX, GTE and the control (pure beef patty). Incorporation of UREX or GTE at 500 mg/kg into beef patties reduced the extent of lipid oxidation significantly (P<0.05). UREX showed a strong lipid oxidation inhibitory effect, comparable with GTE. In addition, a significant improvement (P<0.05) in cooking yield and textural properties was also recorded. However, incorporation of UREX and GTE into beef patties showed no significant influence (P>0.05) on the colour, pH, proximate composition and overall sensory acceptability of the patties.
  6. Nopianti R, Huda N, Ismail N, Ariffin F, Easa AM
    J Food Sci Technol, 2013 Aug;50(4):739-46.
    PMID: 24425976 DOI: 10.1007/s13197-011-0394-0
    Physicochemical properties of threadfin bream surimi with different levels of polydextrose (3%, 6%, 9% and 12%), raw surimi, raw surimi with addition sodium tripolyphosphate and commercial surimi (sucrose) during 6 months of frozen storage were investigated. The analyses included the measurement of Ca(2+)-ATPase, sulfhydryl contents, protein solubility, sodium dodecyl sulfate polyacrylamide gel electrophoresis, differential scanning calorimetry and scanning electron microscopy. The Ca(2+)-ATPase, sulfhydryl content and protein solubility levels added with 3%, 6%, 9% and 12% polydextrose can be maintained until the 6 months of storage by 47.33%, 41.60% and 51.41%, respectively. Differential scanning calorimetry showed decreases in thermal stabilization of myosin with regard to transition termperature. Analysis by scanning electron microscopy demonstrated that the number of pores formed was increased after storage. This study suggested that surimi stored with the polydextrose as a cryoprotectant was able to maintain physicochemical of surimi better compared to raw surimi with no additives or raw surimi with sodium tripolyphosphate.
  7. Yeoh SY, Alkarkhi AF, Ramli SB, Easa AM
    Int J Food Sci Nutr, 2011 Jun;62(4):410-7.
    PMID: 21306189 DOI: 10.3109/09637486.2010.539555
    Yellow alkaline noodles (YAN) prepared by partial substitution of wheat flour with soy protein isolate and treated with microbial transglutaminase (MTG) and ribose were investigated during cooking. Cooking caused an increase in lightness but a decrease in redness and yellowness, pH, tensile strength and elasticity values of noodles. The extents of these changes were influenced by formulation and cross-linking treatments. The pH and lightness for YAN-ribose were lowest but the yellowness and redness were the highest whilst the tensile strength and elasticity values remained moderate. For YAN-MTG, the color and pH values were moderate, but tensile strength and elasticity values were the highest. YAN prepared with both cross-linking agents had physical values between YAN-ribose and YAN-MTG. Although certain sensory parameters showed differences in score, the overall acceptability of all 10-min-cooked YAN was similar. It is possible to employ cross-linking agents to improve physical properties of cooked YAN.
  8. Lew LC, Bhat R, Easa AM, Liong MT
    J Sci Food Agric, 2011 Jun;91(8):1406-15.
    PMID: 21384373 DOI: 10.1002/jsfa.4325
    Probiotics are live micro-organisms that exert beneficial effects on their host. A high survival rate during gastrointestinal transit and storage is often desirable. The main aim of this study was to develop protective carriers for probiotics via the use of enzymatically crosslinked soy protein isolate incorporated with agrowastes such as banana peel, banana pulp, cempedak rind and cocoa rind.
  9. Wai WW, Alkarkhi AF, Easa AM
    J Food Sci, 2009 Oct;74(8):C637-41.
    PMID: 19799660 DOI: 10.1111/j.1750-3841.2009.01331.x
    Response surface methodology (RSM) was carried out to study the effect of temperature, pH, and heating time as input variables on the yield and degree of esterification (DE) as the output (responses). The results showed that yield and DE of extracted pectin ranged from 2.27% to 9.35% (w/w, based on dry weight of durian rind) and 47.66% to 68.6%, respectively. The results also showed that a 2nd-order model adequately fitted the experimental data for the yield and DE. Optimum condition for maximum yield and DE was achieved at 85 degrees C, a time of either 4 or 1 h, and a pH of 2 or 2.5.
  10. Gan CY, Alkarkhi AF, Easa AM
    J Biosci Bioeng, 2009 Apr;107(4):366-72.
    PMID: 19332294 DOI: 10.1016/j.jbiosc.2008.12.007
    D-optimal design was employed to optimize the mixture of cross-linking agents formulation: microbial transglutaminase (MTGase) and ribose, and the processing parameters (i.e. incubation and heating time) in the mixture in order to obtain combined-cross-linked bovine serum albumin gels that have high gel strength, pH close to neutral and yet medium in browning. Analysis of variance (ANOVA) showed that the contribution of quadratic term to the model over the linear was significant for pH and L* value, whereas linear model was significant for gel strength. Optimization study using response surface methodology (RSM) was performed to the mixture components and process variables and the optimum conditions obtained were: MTGase of 1.34-1.43 g/100 mL, ribose of 1.07-1.16 g/100 mL, incubation time of 5 h at 40 degrees C and heating time of 3 h at 90 degrees C.
  11. Gan CY, Cheng LH, Azahari B, Easa AM
    Int J Food Sci Nutr, 2009;60 Suppl 7:99-108.
    PMID: 19194813 DOI: 10.1080/09637480802635090
    Cross-linked soy protein isolate (SPI) gels were produced via single-treatment of SPI with microbial transglutaminase (MTG) for 5 h or 24 h, or with ribose for 2 h, or via combined-treatments of SPI with MTG followed by heating with ribose. Assessment of gel strength and solubility concluded that measures which increased protein cross-links resulted in improved gel strength; however, in most cases the digestibility and amino acid content of the gels were reduced. The combined treated gel of SPI/MTG for 24 h/ribose was more easily digested by digestive enzymes and retained higher amounts of amino acids compared with the control Maillard gels of SPI with ribose. MTG consumed lysine and glutamine and reduced the availability of amino acids for the Maillard reaction with ribose. MTG was able to preserve the nutritional value of SPI against the destructive effect of the Maillard reaction and cross-links.
  12. Alkarkhi AF, Ismail N, Ahmed A, Easa Am
    Environ Monit Assess, 2009 Jun;153(1-4):179-85.
    PMID: 18504644 DOI: 10.1007/s10661-008-0347-x
    Statistical analysis of heavy metal concentrations in sediment was studied to understand the interrelationship between different parameters and also to identify probable source component in order to explain the pollution status of selected estuaries. Concentrations of heavy metals (Cu, Zn, Cd, Fe, Pb, Cr, Hg and Mn) were analyzed in sediments from Juru and Jejawi Estuaries in Malaysia with ten sampling points of each estuary. The results of multivariate statistical techniques showed that the two regions have different characteristics in terms of heavy metals selected and indicates that each region receives pollution from different sources. The results also showed that Fe, Mn, Cd, Hg, and Cu are responsible for large spatial variations explaining 51.15% of the total variance, whilst Zn and Pb explain only 18.93 of the total variance. This study illustrates the usefulness of multivariate statistical techniques for evaluation and interpretation of large complex data sets to get better information about the heavy metal concentrations and design of monitoring network.
  13. Alkarkhi AF, Ramli SB, Easa AM
    Int J Food Sci Nutr, 2009;60 Suppl 4:116-25.
    PMID: 19115121 DOI: 10.1080/09637480802609368
    Major (sodium, potassium, calcium, magnesium) and minor elements (iron, copper, zinc, manganese) and one heavy metal (lead) of Cavendish banana flour and Dream banana flour were determined, and data were analyzed using multivariate statistical techniques of factor analysis and discriminant analysis. Factor analysis yielded four factors explaining more than 81% of the total variance: the first factor explained 28.73%, comprising magnesium, sodium, and iron; the second factor explained 21.47%, comprising only manganese and copper; the third factor explained 15.66%, comprising zinc and lead; while the fourth factor explained 15.50%, comprising potassium. Discriminant analysis showed that magnesium and sodium exhibited a strong contribution in discriminating the two types of banana flour, affording 100% correct assignation. This study presents the usefulness of multivariate statistical techniques for analysis and interpretation of complex mineral content data from banana flour of different varieties.
  14. Alkarkhi AF, Ahmad A, Ismail N, Easa AM
    Environ Monit Assess, 2008 Aug;143(1-3):179-86.
    PMID: 17899414
    Multivariate statistical techniques such as multivariate analysis of variance (MANOVA) and discriminant analysis (DA) were applied for analyzing the data obtained from two rivers in the Penang State of Malaysia for the concentration of heavy metal ions (As, Cr, Cd, Zn, Cu, Pb, and Hg) using a flame atomic absorption spectrometry (F-AAS) for Cr, Cd, Zn, Cu, Pb, As and cold vapor atomic absorption spectrometry (CV-AAS) for Hg. The two locations of interest with 20 sampling points of each location were Kuala Juru (Juru River) and Bukit Tambun (Jejawi River). MANOVA showed a strong significant difference between the two rivers in terms of heavy metal concentrations in water samples. DA gave the best result to identify the relative contribution for all parameters in discriminating (distinguishing) the two rivers. It provided an important data reduction as it used four parameters (Zn, Pb, Cd and Cr) affording 100% correct assignations. Results indicated that the two rivers were different in terms of heavy metals concentrations in water, and the major difference was due to the contribution of Zn. A negative correlation was found between discriminate functions (DF) and Cr and As, whereas positive correlation was exhibited with other heavy metals. Therefore, DA allowed a reduction in the dimensionality of the data set, delineating a few indicator parameters responsible for large variations in heavy metal concentrations. Correlation matrix between the parameters exhibited a strong evidence of mutual dependence of these metals.
  15. Tan TC, AlKarkhi AF, Easa AM
    Food Chem, 2012 Oct 15;134(4):2430-6.
    PMID: 23442706 DOI: 10.1016/j.foodchem.2012.04.049
    The addition of ribose to bovine or porcine gelatine solutions followed by heating at 95 °C yielded brown solutions with different pH, colour (CIE L(*) and b(*)) and absorbance (A(420*) values. These differences were used for gelatine powder identification, differentiation and quality control. Differentiation analysis of the Maillard reaction parameters was conducted using cluster analysis (CA) and confidence intervals (CI). The potential use of the method as a quality control procedure was evaluated by using statistical process control (SPC). CA revealed that the two types of gelatine could be classified into two different groups. CI (95% confidence) revealed that the absorbance and colour values could be used as indicators for differentiation between the two types of gelatine because the intervals between the Maillard reaction parameters of the samples were far apart. The methodology demonstrated good reproducibility because it behaved predictably based on the X¯-S charts generated from the SPC charts.
  16. Zzaman W, Bhat R, Yang TA, Easa AM
    J Sci Food Agric, 2017 Oct;97(13):4429-4437.
    PMID: 28251656 DOI: 10.1002/jsfa.8302
    BACKGROUND: Roasting is one of the important unit operations in the cocoa-based industries in order to develop unique flavour in products. Cocoa beans were subjected to roasting at different temperatures and times using superheated steam. The influence of roasting temperature (150-250°C) and time (10-50 min) on sugars, free amino acids and volatile flavouring compounds were investigated.

    RESULTS: The concentration of total reducing sugars was reduced by up to 64.61, 77.22 and 82.52% with increased roasting temperature at 150, 200 and 250°C for 50 min, respectively. The hydrophobic amino acids were reduced up to 29.21, 36.41 and 48.87% with increased roasting temperature at 150, 200 and 250°C for 50 min, respectively. A number of pyrazines, esters, aldehydes, alcohols, ketones, carboxyl acids and hydrocarbons were detected in all the samples at different concentration range. Formation of the most flavour active compounds, pyrazines, were the highest concentration (2.96 mg kg-1 ) at 200°C for 10 min.

    CONCLUSION: The superheated steam roasting method achieves the optimum roasting condition within a short duration Therefore, the quality of cocoa beans can be improved using superheated steam during the roasting process. © 2017 Society of Chemical Industry.

  17. Chong WK, Mah SY, Easa AM, Tan TC
    J Food Sci Technol, 2019 Sep;56(9):4371-4379.
    PMID: 31478006 DOI: 10.1007/s13197-019-03905-4
    Time and temperature parameters of superheated steam (SHS) treatment were optimised using response surface methodology (RSM) for specific lipoxygenase (LOX) activity in soya beans and crude protein content in soya milk. The optimal SHS treatment was obtained at 9.3 min and 119 °C. The predicted values of specific LOX activity and crude protein content by RSM were 0.0098 μmol/(min mg protein) and 3.2%, respectively. These values were experimentally verified to be 0.0081 ± 0.0002 μmol/(min mg protein) and 3.0 ± 0.1%, respectively. Sensory evaluation showed that the beany flavour of soya milk produced from SHS treated soya beans was significantly weaker (P 
  18. Alkarkhi AFM, Ramli SB, Yong YS, Easa AM
    Food Chem, 2011 Nov 15;129(2):312-318.
    PMID: 30634232 DOI: 10.1016/j.foodchem.2011.04.060
    Banana pulp and peel flour prepared from green and ripe Cavendish banana were assessed for physicochemical properties such as pH, total soluble solids (TSS), water holding capacity (WHC) and oil holding capacity (OHC) at 40, 60 and 80°C, colour values L∗, a∗ and b∗, back extrusion force (BEF) and viscosity. Data obtained were analysed by MANOVA, discriminant analysis and cluster analysis. All statistical analyses showed that physicochemical properties of flour prepared from pulp and peel, and green and ripe banana were different from each other. TSS, WHC40, WHC60 and BEF can be used to discriminate between peel and pulp flour, whilst TSS and viscosity can be used to discriminate between flour prepared from green and ripe banana.
  19. Ojukwu M, Ofoedu C, Seow EK, Easa AM
    J Sci Food Agric, 2021 Jul;101(9):3732-3741.
    PMID: 33301191 DOI: 10.1002/jsfa.11004
    BACKGROUND: Rice flour does not contain gluten and lacks cohesion and extensibility, which is responsible for the poor texture of rice noodles. Different technologies have been used to mitigate this challenge, including hydrothermal treatments of rice flour, direct addition of protein in noodles, use of additives such as hydrocolloids and alginates, and microbial transglutaminase (MTG). Recently, the inclusion of soy protein isolate (SPI), MTG, and glucono-δ-lactone (GDL) in the rice noodles system yielded rice noodles with improved texture and more compact microstructure, hence the need to optimize the addition of SPI, MTG, and GDL to make quality rice noodles.

    RESULTS: Numerical optimization showed that rice noodles prepared with SPI, 68.32 (g kg-1 of rice flour), MTG, 5.06 (g kg-1 of rice flour) and GDL, 5.0 (g kg-1 of rice flour) gave the best response variables; hardness (53.19 N), springiness (0.76), chewiness (20.28 J), tensile strength (60.35 kPa), and cooking time (5.15 min). The pH, sensory, and microstructure results showed that the optimized rice noodles had a more compact microstructure with fewer hollows, optimum pH for MTG action, and overall sensory panelists also showed the highest preference for the optimized formulation, compared to other samples selected from the numerical optimization and desirability tests.

    CONCLUSION: Optimization of the levels of SPI, MTG, and GDL yielded quality noodles with improved textural, mechanical, sensory, and microstructural properties. This was partly due to the favourable pH value of the optimized noodles that provided the most suitable conditions for MTG crosslinking and balanced electrostatic interaction of proteins. © 2020 Society of Chemical Industry.

  20. Ramli S, Ismail N, Alkarkhi AF, Easa AM
    Trop Life Sci Res, 2010 Aug;21(1):91-100.
    PMID: 24575193 MyJurnal
    Banana peel flour (BPF) prepared from green or ripe Cavendish and Dream banana fruits were assessed for their total starch (TS), digestible starch (DS), resistant starch (RS), total dietary fibre (TDF), soluble dietary fibre (SDF) and insoluble dietary fibre (IDF). Principal component analysis (PCA) identified that only 1 component was responsible for 93.74% of the total variance in the starch and dietary fibre components that differentiated ripe and green banana flours. Cluster analysis (CA) applied to similar data obtained two statistically significant clusters (green and ripe bananas) to indicate difference in behaviours according to the stages of ripeness based on starch and dietary fibre components. We concluded that the starch and dietary fibre components could be used to discriminate between flours prepared from peels obtained from fruits of different ripeness. The results were also suggestive of the potential of green and ripe BPF as functional ingredients in food.
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