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  1. Tan TB, Yussof NS, Abas F, Mirhosseini H, Nehdi IA, Tan CP
    Food Chem, 2016 Mar 1;194:416-23.
    PMID: 26471574 DOI: 10.1016/j.foodchem.2015.08.045
    A solvent displacement method was used to prepare lutein nanodispersions. The effects of processing parameters (addition method, addition rate, stirring time and stirring speed) and emulsifiers with different stabilizing mechanisms (steric, electrostatic, electrosteric and combined electrostatic-steric) on the particle size and particle size distribution (PSD) of the nanodispersions were investigated. Among the processing parameters, only the addition method and stirring time had significant effects (p<0.05) on the particle size and PSD. For steric emulsifiers, Tween 20, 40, 60 and 80 were used to produce nanodispersions successfully with particle sizes below 100nm. Tween 80 (steric) was then chosen for further comparison against sodium dodecyl sulfate (SDS) (electrostatic), sodium caseinate (electrosteric) and SDS-Tween 80 (combined electrostatic-steric) emulsifiers. At the lowest emulsifier concentration of 0.1%, all the emulsifiers invariably produced stable nanodispersions with small particle sizes (72.88-142.85nm) and narrow PSDs (polydispersity index<0.40).
  2. Tan TB, Yussof NS, Abas F, Mirhosseini H, Nehdi IA, Tan CP
    Food Chem, 2016 Aug 15;205:155-62.
    PMID: 27006226 DOI: 10.1016/j.foodchem.2016.03.008
    The stability of lutein nanodispersions was evaluated during storage and when exposed to different environmental conditions. Lutein nanodispersions were prepared using Tween 80, sodium dodecyl sulfate (SDS), sodium caseinate (SC) and SDS-Tween 80 as the emulsifiers. During eight weeks of storage, all samples showed remarkable physical stability. However, only the SC-stabilized nanodispersion showed excellent chemical stability. Under different environmental conditions, the nanodispersions exhibited a varied degree of stability. All nanodispersions showed constant particle sizes at temperatures between 30 and 60°C. However, at pH 2-8, only the SC-stabilized nanodispersion was physically unstable. The addition of NaCl (300-400mM) only caused flocculation in nanodispersion stabilized by SDS-Tween 80. All nanodispersions were physically stable when subjected to different centrifugation speeds. Only Tween 80-stabilized nanodispersion was stable against the effect of freeze-thaw cycles (no phase separation observed). In this study, there was no particular emulsifier that was effective against all of the environmental conditions tested.
  3. Shariffa YN, Tan TB, Uthumporn U, Abas F, Mirhosseini H, Nehdi IA, et al.
    Food Res Int, 2017 11;101:165-172.
    PMID: 28941679 DOI: 10.1016/j.foodres.2017.09.005
    The aim of this study was to develop formulations to produce lycopene nanodispersions and to investigate the effects of the homogenization pressure on the physicochemical properties of the lycopene nanodispersion. The samples were prepared by using emulsification-evaporation technique. The best formulation was achieved by dispersing an organic phase (0.3% w/v lycopene dissolved in dichloromethane) in an aqueous phase (0.3% w/v Tween 20 dissolved in deionized water) at a ratio of 1:9 by using homogenization process. The increased level of homogenization pressure to 500bar reduced the particle size and lycopene concentration significantly (p<0.05). Excessive homogenization pressure (700-900bar) resulted in large particle sizes with high dispersibility. The zeta potential and turbidity of the lycopene nanodispersion were significantly influenced by the homogenization pressure. The results from this study provided useful information for producing small-sized lycopene nanodispersions with a narrow PDI and good stability for application in beverage products.
  4. Toopkanloo SP, Tan TB, Abas F, Alharthi FA, Nehdi IA, Tan CP
    Nanomaterials (Basel), 2020 Dec 05;10(12).
    PMID: 33291386 DOI: 10.3390/nano10122432
    This study used highly lipophilic agents with an aim to increase the oxidant inhibitory activity and enhance photothermal stability of a novel mixed soy lecithin (ML)-based liposome by changing the composition of formulation within the membrane. Specifically, the development and optimization of the liposome intended for improving Trolox equivalent antioxidant capacity (TEAC) value and %TEAC loss was carried out by incorporating a natural antioxidant, quercetin (QU). In this context, a focus was set on QU encapsulation in ML-based liposomes and the concentration-dependent solubility of QU was investigated and calculated as encapsulation efficiency (EE). To explore the combined effects of the incorporation of plant sterols on the integrity and entrapment capacity of mixed phospholipid vesicles, conjugation of two types of phytosterols (PSs), namely β-sitosterol (βS) and stigmasterol (ST), to mixed membranes at different ratios was also performed. The EE measurement revealed that QU could be efficiently encapsulated in the stable ML-based liposome using 0.15 and 0.1 g/100 mL of βS and ST, respectively. The aforementioned liposome complex exhibited a considerable TEAC (197.23%) and enhanced TEAC loss (30.81%) when exposed to ultraviolet (UV) light (280-320 nm) over a 6 h duration. It appeared that the presence and type of PSs affect the membrane-integration characteristics as well as photodamage transformation of the ML-based liposome. The association of QU with either βS or ST in the formulation was justified by their synergistic effects on the enhancement of the EE of liposomes. Parallel to this, it was demonstrated that synergistic PS effects could be in effect in the maintenance of membrane order of the ML-based liposome. The findings presented in this study provided useful information for the development and production of stable QU-loaded ML-based liposomes for food and nutraceutical applications and could serve as a potential mixed lipids-based delivery system in the disease management using antioxidant therapy.
  5. 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.

  6. Hew KS, Asis AJ, Tan TB, Yusoff MM, Lai OM, Nehdi IA, et al.
    Food Chem, 2020 Mar 01;307:125545.
    PMID: 31654951 DOI: 10.1016/j.foodchem.2019.125545
    Corresponding the high presence of 3-monochloropropane-1,2-diol esters (3-MCPDE) and glycidyl esters (GE) in refined palm oil, this paper re-evaluated degumming and bleaching processes of physical palm oil refining to reduce the amount of said contaminants. Separation-free water degumming was incorporated into the process, and this significantly (p 
  7. Lye GX, Cheng WK, Tan TB, Hung CW, Chen YL
    Sensors (Basel), 2020 Apr 08;20(7).
    PMID: 32276431 DOI: 10.3390/s20072098
    Despite advancements in the Internet of Things (IoT) and social networks, developing an intelligent service discovery and composition framework in the Social IoT (SIoT) domain remains a challenge. In the IoT, a large number of things are connected together according to the different objectives of their owners. Due to this extensive connection of heterogeneous objects, generating a suitable recommendation for users becomes very difficult. The complexity of this problem exponentially increases when additional issues, such as user preferences, autonomous settings, and a chaotic IoT environment, must be considered. For the aforementioned reasons, this paper presents an SIoT architecture with a personalized recommendation framework to enhance service discovery and composition. The novel contribution of this study is the development of a unique personalized recommender engine that is based on the knowledge-desire-intention model and is suitable for service discovery in a smart community. Our algorithm provides service recommendations with high satisfaction by analyzing data concerning users' beliefs and surroundings. Moreover, the algorithm eliminates the prevalent cold start problem in the early stage of recommendation generation. Several experiments and benchmarking on different datasets are conducted to investigate the performance of the proposed personalized recommender engine. The experimental precision and recall results indicate that the proposed approach can achieve up to an approximately 28% higher F-score than conventional approaches. In general, the proposed hybrid approach outperforms other methods.
  8. Niaz A, Adnan A, Bashir R, Mumtaz MW, Raza SA, Rashid U, et al.
    Plants (Basel), 2021 Jun 02;10(6).
    PMID: 34199333 DOI: 10.3390/plants10061128
    The Tamarix dioica (T. dioica) is widely used medicinal plant to cure many chronic ailments. T. dioica is being used to manage diabetes mellitus in traditional medicinal system; however, very little scientific evidence is available on this plant in this context. The current study involves the fractionation of crude methanolic extract of T. dioica using n-hexane, ethyl acetate, chloroform, and n-butanol. The screening for antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was carried out. The in vitro antidiabetic potential was assessed by measuring α-glucosidase inhibition. Total phenolic and flavonoid contents were also determined for each fraction. The metabolites were identified using highly sensitive and emerging 1H-NMR technique. The results revealed the ethyl acetate fraction as the most potent with DPPH scavenging activity of 84.44 ± 0.21% and α-glucosidase inhibition with IC50 value of 122.81 ± 2.05 µg/mL. The total phenolic and flavonoid content values of 205.45 ± 1.36 mg gallic acid equivalent per gram dried extract and 156.85 ± 1.33 mg quercetin equivalent per gram dried extract were obtained for ethyl acetate fraction. The bucketing of 1H-NMR spectra identified 22 metabolites including some pharmacologically important like tamarixetin, tamaridone, quercetin, rutin, apigenin, catechin, kaempferol, myricetin and isorhamnetin. Leucine, lysine, glutamic acid, aspartic acid, serine, and tyrosine were the major amino acids identified in ethyl acetate fraction. The molecular docking analysis provided significant information on the binding affinity among secondary metabolites and α-glucosidase. These metabolites were most probably responsible for the antioxidant activity and α-glucosidase inhibitory potential of ethyl acetate fraction. The study ascertained the ethnomedicinal use of T. dioica to manage diabetes mellitus and may be a helpful lead towards naturopathic mode for anti-hyperglycemia.
  9. Toopkanloo SP, Tan TB, Abas F, Azam M, Nehdi IA, Tan CP
    Molecules, 2020 Dec 11;25(24).
    PMID: 33322600 DOI: 10.3390/molecules25245873
    In order to improve the membrane lipophilicity and the affinity towards the environment of lipid bilayers, squalene (SQ) could be conjugated to phospholipids in the formation of liposomes. The effect of membrane composition and concentrations on the degradation of liposomes prepared via the extrusion method was investigated. Liposomes were prepared using a mixture of SQ, cholesterol (CH) and Tween80 (TW80). Based on the optimal conditions, liposome batches were prepared in the absence and presence of SQ. Their physicochemical and stability behavior were evaluated as a function of liposome constituent. From the optimization study, the liposomal formulation containing 5% (w/w) mixed soy lecithin (ML), 0.5% (w/w) SQ, 0.3% (w/w) CH and 0.75% (w/w) TW80 had optimal physicochemical properties and displayed a unilamellar structure. Liposome prepared using the optimal formulation had a low particle size (158.31 ± 2.96 nm) and acceptable %increase in the particle size (15.09% ± 3.76%) and %trolox equivalent antioxidant capacity (%TEAC) loss (35.69% ± 0.72%) against UV light treatment (280-320 nm) for 6 h. The interesting outcome of this research was the association of naturally occurring substance SQ for size reduction without the extra input of energy or mechanical procedures, and improvement of vesicle stability and antioxidant activity of ML-based liposome. This study also demonstrated that the presence of SQ in the membrane might increase the acyl chain dynamics and decrease the viscosity of the dispersion, thereby limiting long-term stability of the liposome.
  10. Tan TB, Chu WC, Yussof NS, Abas F, Mirhosseini H, Cheah YK, et al.
    Food Funct, 2016 Apr 20;7(4):2043-51.
    PMID: 27010495 DOI: 10.1039/c5fo01621e
    In this study, we prepared a series of lutein nanodispersions via the solvent displacement method, by using surfactants with different stabilizing mechanisms. The surfactants used include Tween 80 (steric stabilization), sodium dodecyl sulfate (SDS; electrostatic stabilization), sodium caseinate (electrosteric stabilization) and SDS-Tween 80 (electrostatic-steric stabilization). We then characterized the resulting lutein nanodispersions in terms of their particle size, particle size distribution, zeta potential, lutein content, flow behavior, apparent viscosity, transmittance, color, morphological properties and their effects on cell viability and cellular uptake. The type of surfactant used significantly (p < 0.05) affected the physical properties of the nanodispersions, but the chemical properties (lutein content) remained unaffected. Transmission electron microscopy (TEM) images obtained from this study demonstrated that the solvent displacement method was capable of producing lutein nanodispersions containing spherical particles with sizes ranging from 66.20-125.25 nm, depending on the type of surfactant used. SDS and SDS-Tween 80 surfactants negatively affected the viability of the HT-29 cells used in this study. Thus, for the cellular uptake determination, only Tween 80 and sodium caseinate surfactants were used. The cellular uptake of the lutein nanodispersion stabilized by sodium caseinate was higher than that which was stabilized by Tween 80. All things considered, the type of surfactant with different stabilizing mechanisms did produce lutein nanodispersions with different characteristics. These findings would aid in future selection of surfactants in order to produce nanodispersions with desirable properties.
  11. Tan PY, Tan TB, Chang HW, Tey BT, Chan ES, Lai OM, et al.
    Food Chem, 2018 Feb 15;241:79-85.
    PMID: 28958562 DOI: 10.1016/j.foodchem.2017.08.075
    Tocotrienol microcapsules (TM) were formed by firstly preparing Pickering emulsion containing tocotrienols, which was then gelled into microcapsules using alginate and chitosan. In this study, we examined the stability of TM during storage and when applied into a model food system, i.e. yogurt. During storage at 40°C, TM displayed remarkably lower tocotrienols loss (50.8%) as compared to non-encapsulated tocotrienols in bulk oil (87.5%). When the tocotrienols were incorporated into yogurt, the TM and bulk oil forms showed a loss of 23.5% and 81.0%, respectively. Generally, the tocotrienols were stable in the TM form and showed highest stability when these TM were added into yogurt. δ-Tocotrienol was the most stable isomer in both forms during storage and when incorporated into yogurt. The addition of TM into yogurt caused minimal changes in the yogurt's color and texture but slightly altered the yogurt's viscosity.
  12. Tan PY, Tan TB, Chang HW, Tey BT, Chan ES, Lai OM, et al.
    J Agric Food Chem, 2017 Dec 06;65(48):10651-10657.
    PMID: 29124932 DOI: 10.1021/acs.jafc.7b03521
    Considering the health benefits of tocotrienols, continuous works have been done on the encapsulation and delivery of these compounds. In this study, we encapsulated tocotrienols in chitosan-alginate microcapsules and evaluated their release profile. Generally, these tocotrienols microcapsules (TM) displayed high thermal stability. When subjected to pH adjustments (pH 1-9), we observed that the release of tocotrienols was the highest (33.78 ± 0.18%) under basic conditions. The TM were also unstable against the effect of ionic strength, with a high release (70.73 ± 0.04%) of tocotrienols even at a low sodium chloride concentration (50 mM). As for the individual isomers, δ-tocotrienol was the most sensitive to pH and ionic strength. In contrast, β-/γ-tocotrienols were the most ionic-stable isomers but more responsive toward thermal treatment. Simulated gastrointestinal model showed that the chitosan-alginate-based TM could be used to retain tocotrienols in the gastric and subsequently release them in the intestines for possible absorption.
  13. Chang HW, Tan TB, Tan PY, Abas F, Lai OM, Wang Y, et al.
    Food Res Int, 2018 03;105:482-491.
    PMID: 29433239 DOI: 10.1016/j.foodres.2017.11.034
    Fish oil-in-water emulsions containing fish oil, thiol-modified β-lactoglobulin (β-LG) fibrils, chitosan and maltodextrin were fabricated using a high-energy method. The results showed that chitosan coating induced charge reversal; denoting successful biopolymers complexation. A significantly (p<0.05) larger droplet size and lower polydispersity index value, attributed to the thicker chitosan coating at the oil-water interface, were observed. At high chitosan concentrations, the cationic nature of chitosan strengthened the electrostatic repulsion between the droplets, thus conferring high oxidative stability and low turbidity loss rate to the emulsions. The apparent viscosity of emulsions stabilized using thiol-modified β-LG fibrils-chitosan complex was higher than those stabilized using β-LG fibrils alone, resulting in the former's higher creaming stability. Under thermal treatments (63°C and 100°C), emulsions stabilized using thiol-modified β-LG fibrils-chitosan complex possessed higher heat stability as indicated by the consistent droplet sizes observed. Chitosan provided a thicker protective layer that protected the oil droplets against high temperature. Bridging flocculation occurred at low chitosan concentration (0.1%, w/w), as revealed through microscopic observations which indicated the presence of large flocs. All in all, this work provided us with a better understanding of the application of protein fibrils-polysaccharide complex to produce stable emulsion.
  14. Tan PY, Tey BT, Chan ES, Lai OM, Chang HW, Tan TB, et al.
    Foods, 2021 Feb 07;10(2).
    PMID: 33562391 DOI: 10.3390/foods10020358
    Calcium carbonate (CaCO3) has been utilized as a pH-responsive component in various products. In this present work, palm tocotrienols-rich fraction (TRF) was successfully entrapped in a self-assembled oil-in-water (O/W) emulsion system by using CaCO3 as the stabilizer. The emulsion droplet size, viscosity and tocotrienols entrapment efficiency (EE) were strongly affected by varying the processing (homogenization speed and time) and formulation (CaCO3 and TRF concentrations) parameters. Our findings indicated that the combination of 5000 rpm homogenization speed, 15 min homogenization time, 0.75% CaCO3 concentration and 2% TRF concentration resulted in a high EE of tocotrienols (92.59-99.16%) and small droplet size (18.83 ± 1.36 µm). The resulting emulsion system readily released the entrapped tocotrienols across the pH range tested (pH 1-9); with relatively the highest release observed at pH 3. The current study presents a potential pH-sensitive emulsion system for the entrapment and delivery of palm tocotrienols.
  15. Goh KM, Wong YH, Abas F, Lai OM, Mat Yusoff M, Tan TB, et al.
    Foods, 2020 Jun 04;9(6).
    PMID: 32512737 DOI: 10.3390/foods9060739
    Shortening derived from palm oil is widely used in baking applications. However, palm oil and the related products are reported to contain high levels of monochloropropandiol (MCPD) ester and glycidyl ester (GE). MCPD and glycidol are known as process contaminants, which are carcinogenic and genotoxic compounds, respectively. The objective was to evaluate the effects of antioxidant addition in palm olein and stearin to the content of MCPD esters and GE in baked cake. Butylated hydroxyanisole (BHA), rosemary extract and tocopherol were used to fortify the samples at 200 mg/kg and in combinations (400, 600 and 800 mg/kg rosemary or tocopherol combined with 200 mg/kg BHA). The MCPD esters and GE content, radical formation and the quality of the fats portion were analyzed. The results showed that palm olein fortified with rosemary extract yielded less 2-MCPD ester. The GE content was lower when soft stearin was fortified with rosemary. ESR spectrometry measurements showed that the antioxidants were effective to reduce radical formation. The synergistic effects of combining antioxidants controlled the contaminants formation. In conclusion, oxidation stability was comparable either in the single or combined antioxidants. Tocopherol in combination with BHA was more effective in controlling the MCPD esters and GE formation.
  16. Tan PY, Tan TB, Chang HW, Mwangi WW, Tey BT, Chan ES, et al.
    J Sci Food Agric, 2021 Nov;101(14):5963-5971.
    PMID: 33840091 DOI: 10.1002/jsfa.11249
    BACKGROUND: Throughout the past decade, Pickering emulsion has been increasingly utilized for the encapsulation of bioactive compounds due to its high stability and biocompatibility. In the present work, palm tocotrienols were initially encapsulated in a calcium carbonate Pickering emulsion, which was then subjected to alginate gelation and subsequent chitosan coating. The effects of wall material (alginate and chitosan) concentrations, gelation pH and time, and chitosan coating time on the encapsulation efficiency of palm tocotrienols were explored.

    RESULTS: Our findings revealed that uncoated alginate microcapsules ruptured upon drying and exhibited low encapsulation efficiency (13.81 ± 2.76%). However, the addition of chitosan successfully provided a more complex and rigid external wall structure to enhance the stability of the microcapsules. By prolonging the crosslinking time from 5 to 30 min and increasing the chitosan concentration from 0.1% to 0.5%, the oil encapsulation efficiency was increased by 28%. Under the right gelation pH (pH 4), the extension of gelation time from 1 to 12 h resulted in an increase in alginate-Ca2+ crosslinkings, thus strengthening the microcapsules.

    CONCLUSION: With the optimum formulation and process parameters, a high encapsulation efficiency (81.49 ± 1.75%) with an elevated oil loading efficiency (63.58 ± 2.96%) were achieved. The final product is biocompatible and can potentially be used for the delivery of palm tocotrienols. © 2021 Society of Chemical Industry.

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