Displaying publications 81 - 100 of 298 in total

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  1. Jaffri JM, Mohamed S, Ahmad IN, Mustapha NM, Manap YA, Rohimi N
    Food Chem, 2011 Sep 15;128(2):433-41.
    PMID: 25212153 DOI: 10.1016/j.foodchem.2011.03.050
    Catechin-rich oil palm (Elaeis guineensis) leaf extract (OPLE) possesses good ex vivo vasodilation, antioxidant and cardiovascular properties. This study evaluated the beneficial or toxic effects of OPLE on the liver and kidneys of normal and hypertensive rats. The OPLE (500mg/kg body weight) were administered orally to normal Wistar Kyoto rats, spontaneously hypertensive rats (SHR) and N-ω-nitro-l-arginine methyl ester (l-NAME)-induced NO-deficient hypertensive rats. The OPLE reduced hypertension in NO-deficient rats, but not in SHR. Hepatocytes or glomeruli injury and oxidative markers were high in hypertensive rats compared to normal rats, and they were reduced (p<0.05) by OPLE supplementation, even when there was no blood pressure reduction. Unlike the hypertensive drug captopril, the OPLE showed no toxicity to normal rats. The dose reported is equivalent 0.5g of catechins/day for humans or 2.5cups of tea. The catechins are from an abundant alternative source for potential use as functional food.
  2. Bhat R, Ameran SB, Voon HC, Karim AA, Tze LM
    Food Chem, 2011 Jul 15;127(2):641-4.
    PMID: 23140712 DOI: 10.1016/j.foodchem.2011.01.042
    Starfruit juice were exposed to ultraviolet (UV-C) light for 0, 30 and 60min at room temperature (25±1°C). On exposure, the titratable acidity significantly decreased, while the decrease in °Brix and pH were not significant. With regard to colorimetric parameters, L(∗) value increased significantly with a subsequent decrease in a(∗) and b(∗) values corresponding to UV treatment time. Except for the ascorbic acid, other antioxidants measured (% DPPH inhibition, total phenols, flavonols, flavonoids and antioxidant capacity) showed enhancement on expsoure to UV (significant at 60min). Microbial studies showed reduction in APC, yeasts and mould counts by 2-log cycle on UV treatments. These results supports the application of UV as a measure of non-thermal and physical food preservation technique for starfruit juice that can be explored commercially to benefit both the producers and consumers.
  3. Chua LS, Latiff NA, Lee SY, Lee CT, Sarmidi MR, Aziz RA
    Food Chem, 2011 Aug 1;127(3):1186-92.
    PMID: 25214112 DOI: 10.1016/j.foodchem.2011.01.122
    Both total phenolic content (TPC) and total flavonoid content (TFC) of Labisia pumila extracts were determined spectrophotometrically. L. pumila leaves extracted in 60% methanol (MeOH) were fractionated on C18 cartridge and the antioxidant property of each fraction was determined by measuring free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity. The 40% MeOH fraction exhibited the highest scavenging activity. Nine flavonols (quercetin, myricetin and kaempferol), two flavanols (catechin and epigallocatechin) and nine phenolic acids were identified from this active fraction by UPLC-ESI-MS/MS, and confirmed by comparison with the mass spectra of standard aglycones, theoretical fragments generated from MS Fragmenter software, and literature values.
  4. Saberi AH, Kee BB, Oi-Ming L, Miskandar MS
    Food Chem, 2011 Aug 1;127(3):1031-8.
    PMID: 25214093 DOI: 10.1016/j.foodchem.2011.01.076
    Palm-based diacylglycerol (P-DAG) oils were produced through enzymatic glycerolysis of palm kernel oil (PKO), palm oil (PO), palm olein (POL), palm mid fraction (PMF) and palm stearin (PS). High purity DAG (83-90%, w/w) was obtained and compared to palm-based oils (P-oil) had significantly (P<0.05) different fatty acid composition (FAC), iodine value (IV) and slip melting point (SMP). Solid fat content (SFC) profiles of P-DAG oils as compared to P-oils had less steep curves with lower SFC at low temperature range (5-10°C) and the higher complete melting temperatures. Also, P-DAG oils in contrast with P-oils showed endothermic as well as exothermic peaks with higher transition temperatures and significantly (P<0.05) higher crystallisation onsets, heats of fusion, and heats of crystallisation. Crystal forms for P-DAG oils were mostly in the β form.
  5. Loi CC, Boo HC, Mohammed AS, Ariffin AA
    Food Chem, 2011 Sep 1;128(1):223-6.
    PMID: 25214353 DOI: 10.1016/j.foodchem.2010.12.108
    A modified steam distillation method was developed to extract furfural from crude palm oil (CPO). The collected distillates were analysed using high performance liquid chromatography (HPLC) coupled with an ultraviolet diode detector at 284nm. The HPLC method allowed identification and quantification of furfural in CPO. The unique thermal extraction of CPO whereby the fresh fruit bunches (FFB) are first subjected to steam treatment, distinguishes itself from other solvent-extracted or cold-pressed vegetable oils. The presence of furfural was also determined in the fresh palm oil from FFB (without undergoing the normal extraction process), palm olein, palm stearin, olive oil, coconut oil, sunflower oil, soya oil and corn oil. The chromatograms of the extracts were compared to that of standard furfural. Furfural was only detected in CPO. The CPO consignments obtained from four mills were shown to contain 7.54 to 20.60mg/kg furfural.
  6. Mehrnoush A, Tan CP, Hamed M, Aziz NA, Ling TC
    Food Chem, 2011 Sep 1;128(1):158-64.
    PMID: 25214343 DOI: 10.1016/j.foodchem.2011.03.012
    This study investigated the possible relationship between the encapsulation variables, namely serine protease content (9-50mg/ml, X1), Arabic gum (0.2-10%(w/w), X2), maltodextrin (2-5%(w/w), X3) and calcium chloride (1.3-5.5%(w/w), X4) on the enzymatic properties of encapsulated serine protease. The study demonstrated that Arabic gum, maltodextrin and calcium chloride, as coating agents, protected serine protease from activity loss during freeze-drying. The overall optimum region resulted in a suitable freeze drying condition with a yield of 92% for the encapsulated serine protease, were obtained using 29.5mg/ml serine protease content, 5.1%(w/w) Arabic gum, 3.5%(w/w) maltodextrin and 3.4%(w/w) calcium chloride. It was found that the interaction effect of Arabic gum and calcium chloride improved the serine protease activity, and Arabic gum was the most effective amongst the examined coating agents. Thus, Arabic gum should be considered as potential protection in freeze drying of serine protease.
  7. Nor FM, Mohamed S, Idris NA, Ismail R
    Food Chem, 2008 Sep 15;110(2):319-27.
    PMID: 26049222 DOI: 10.1016/j.foodchem.2008.02.004
    The potential uses of Pandanus amaryllifolius leaf extract as a natural antioxidant were evaluated in refined, bleached and deodorized (RBD) palm olein, using accelerated oxidation and deep frying studies at 180°C from 0 to 40h. The extracts (optimum concentration 0.2%) significantly retarded oil oxidation and deterioration (P<0.05), comparably to 0.02% BHT in tests such as peroxide value, anisidine value, iodine value, free fatty acid, oxidative stability index (OSI), polar and polymer compound contents. In sensory evaluation studies, different batches of French fries were not significantly different (P<0.05) from one another for oiliness, crispiness, taste and overall acceptability when the same oil was used for up to the 40th hour of frying. P. amaryllifolius leaf extract, which had a polyphenol content of 102mg/g, exhibited an excellent heat-stable antioxidant property and may be a good natural alternative to existing synthetic antioxidants in the food industry.
  8. Palanisamy U, Cheng HM, Masilamani T, Subramaniam T, Ling LT, Radhakrishnan AK
    Food Chem, 2008 Jul 1;109(1):54-63.
    PMID: 26054264 DOI: 10.1016/j.foodchem.2007.12.018
    The rind of rambutan, which is normally discarded was found to contain extremely high antioxidant activity when assessed using several methods. Although having a yield of only 18%, the ethanolic rambutan rind extract had a total phenolic content of 762±10mg GAE/g extract, which is comparable to that of a commercial preparation of grape seed extract. Comparing the extract's pro-oxidant capabilities with vitamin C, α-tocopherol, grape seed and green tea, the rind had the lowest pro-oxidant capacity. In addition, the extract at 100μg/ml was seen to limit oxidant-induced cell death (DPPH at 50μM) by apoptosis to an extent similar to that of grape seed. The extracts were not cytotoxic to normal mouse fibroblast cells or splenocytes while the powderised rind was seen to have heavy metals contents far below the permissible levels for nutraceuticals. Our study for the first time reveals the high phenolic content, low pro-oxidant capacity and strong antioxidant activity of the extract from rind of Nephelium lappaceum. This extract, either alone or in combination with other active principles, can be used in cosmetic, nutraceutical and pharmaceutical applications.
  9. Fauzi SH, Rashid NA, Omar Z
    Food Chem, 2013 Apr 15;137(1-4):8-17.
    PMID: 23199984 DOI: 10.1016/j.foodchem.2012.09.086
    Blends of palm stearin (PS), palm kernel oil (PKO) and soybean oil (SBO) at certain proportions were formulated using a mixture design based on simplex-lattice (Design Expert 8.0.4 Stat-Ease Inc., Minneapolis, 2010). All the 10 oil blends were subjected to chemical interesterification (CIE) using sodium methoxide as the catalyst. The solid fat content (SFC), triacylglycerol (TAG) composition, thermal properties (DSC), polymorphism and microstructural properties were studied. Palm-based trans-free table margarine containing ternary mixture of PS/PKO/SBO [49/20/31 (w/w)], was optimally formulated through analysis of multiple isosolid diagrams and was found to have quite similar SMP and SFC profile as compared to the commercial table margarine. This study has shown chemical interesterification are effective in modifying the physicochemical properties of palm stearin, palm kernel oil, soybean oil and their mixtures.
  10. Muhamad H, Zainudin BH, Abu Bakar NK
    Food Chem, 2012 Oct 15;134(4):2489-96.
    PMID: 23442715 DOI: 10.1016/j.foodchem.2012.04.095
    Solid phase extraction (SPE) and dispersive solid-phase extraction (d-SPE) were compared and evaluated for the determination of λ-cyhalothrin and cypermethrin in palm oil matrices by gas chromatography with an electron capture detector (GC-ECD). Several SPE sorbents such as graphitised carbon black (GCB), primary secondary amine (PSA), C(18), silica, and florisil were tested in order to minimise fat residues. The results show that mixed sorbents using GCB and PSA obtained cleaner extracts than a single GCB and PSA sorbents. The average recoveries obtained for each pesticide ranged between 81% and 114% at five fortification levels with the relative standard deviation of less than 7% in all cases. The limits of detection for these pesticides were ranged between 0.025 and 0.05 μg/g. The proposed method was applied successfully for the residue determination of both λ-cyhalothrin and cypermethrin in crude palm oil samples obtained from local mills throughout Malaysia.
  11. Ngah CW, Yahya MA
    Food Chem, 2012 Oct 15;134(4):2406-10.
    PMID: 23442702 DOI: 10.1016/j.foodchem.2012.04.032
    The microwave digestion method was developed and verified for the determination of arsenic in shrimp paste samples. Experimental design for five factors (HNO(3) and H(2)O(2) volumes, sample weight, microwave power and digestion time) were used for the optimisation of sample digestion. For this purpose, two level half factorial design, which involves 16 experiments, was adopted. The concentration of arsenic was analysed by graphite furnace atomic absorption spectrometry. Design Expert® 7.0 software was used to interpret all data obtained. The combination of 2 mL HNO(3) and 1 mL H(2)O(2) volumes, 0.1g sample weight, 1400 W power and 5 min digestion time was found to be the optimum parameters required to digest the shrimp paste samples. Tests with spiked samples presented good recoveries with relative standard deviations between 0.32% and 5.35%.
  12. 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.
  13. Thoo YY, Abas F, Lai OM, Ho CW, Yin J, Hedegaard RV, et al.
    Food Chem, 2013 Jun 1;138(2-3):1215-9.
    PMID: 23411234 DOI: 10.1016/j.foodchem.2012.11.013
    The synergistic antioxidant effects of ethanolic extracts of Centella asiatica (CE), and α-tocopherol have been studied. The types of interactions exhibited by CE and α-tocopherol combined at different ratios were measured using three assays: 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical-scavenging capacity, the β-carotene bleaching system and liposome peroxidation assays. Fixed-fraction isobolographic analysis was used to detect any inducement of the antioxidant activity compared with the individual activities of CE and α-tocopherol. Of all synergistic combinations of CE and α-tocopherol, only fraction 2/3 showed the synergistic combination that fits well in three different assays and can be explained by the regeneration of α-tocopherol by CE despite the interaction effect of β-carotene present in the analytical assay. This phenomenon involved complex interactions between CE and α-tocopherol to exhibit different degrees of interactions that eventually increased antioxidant activity.
  14. 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).
  15. Musa KH, Abdullah A, Al-Haiqi A
    Food Chem, 2016 Mar 1;194:705-11.
    PMID: 26471610 DOI: 10.1016/j.foodchem.2015.08.038
    A new computational approach for the determination of 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity (DPPH-RSA) in food is reported, based on the concept of machine learning. Trolox standard was mix with DPPH at different concentrations to produce different colors from purple to yellow. Artificial neural network (ANN) was trained on a typical set of images of the DPPH radical reacting with different levels of Trolox. This allowed the neural network to classify future images of any sample into the correct class of RSA level. The ANN was then able to determine the DPPH-RSA of cinnamon, clove, mung bean, red bean, red rice, brown rice, black rice and tea extract and the results were compared with data obtained using a spectrophotometer. The application of ANN correlated well to the spectrophotometric classical procedure and thus do not require the use of spectrophotometer, and it could be used to obtain semi-quantitative results of DPPH-RSA.
  16. Noor NS, Tan LL, Heng LY, Chong KF, Tajuddin SN
    Food Chem, 2016 Sep 15;207:132-8.
    PMID: 27080889 DOI: 10.1016/j.foodchem.2016.03.088
    A new optosensor for visual quantitation of nitrite (NO2(-)) ion has been fabricated by physically immobilizing Safranine O (SO) reagent onto a self-adhesive poly(n-butyl acrylate) [poly(nBA)] microspheres matrix, which was synthesized via facile microemulsion UV lithography technique. Evaluation and optimization of the optical NO2(-) ion sensor was performed with a fiber optic reflectance spectrophotometer. Scanning electron micrograph showed well-shaped and smooth spherical morphology of the poly(nBA) microspheres with a narrow particles size distribution from 0.6μm up to 1.8μm. The uniform size distribution of the acrylic microspheres promoted homogeneity of the immobilized SO reagent molecules on the microspheres' surfaces, thereby enhanced the sensing response reproducibility (<5% RSD) with a linear range obtained from 10 to 100ppm NO2(-) ion. The micro-sized acrylic immobilization matrix demonstrated no significant barrier for diffusion of reactant and product, and served as a good solid state ion transport medium for reflectometric nitrite determination in food samples.
  17. Kazemi M, Karim R, Mirhosseini H, Abdul Hamid A
    Food Chem, 2016 Sep 1;206:156-66.
    PMID: 27041311 DOI: 10.1016/j.foodchem.2016.03.017
    Pomegranate peel is a rich source of phenolic compounds (such as punicalagin and hydroxybenzoic acids). However, the content of such bioactive compounds in the peel extract can be affected by extraction type and condition. It was hypothesized that the optimization of a pulsed ultrasound-assisted extraction (PUAE) technique could result in the pomegranate peel extract with higher yield and antioxidant activity. The main goal was to optimize PUAE condition resulting in the highest yield and antioxidant activity as well as the highest contents of punicalagin and hydroxybenzoic acids. The operation at the intensity level of 105W/cm(2) and duty cycle of 50% for a short time (10min) had a high efficiency for extraction of phenolics from pomegranate peel. The application of such short extraction can save the energy and cost of the production. Punicalagin and ellagic acid were the most predominant phenolic compounds quantified in the pomegranate peel extract (PPE) from Malas variety. PPE contained a minor content of gallic acid.
  18. 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.
  19. Nor Qhairul Izzreen MN, Hansen SS, Petersen MA
    Food Chem, 2016 Nov 1;210:566-76.
    PMID: 27211683 DOI: 10.1016/j.foodchem.2016.04.110
    The influence of fermentation temperatures (8°C, 16°C, and 32°C) and yeast levels (2%, 4%, and 6% of the flour) on the formation of volatile compounds in the crust of whole meal wheat bread was investigated. The fermentation times were regulated to optimum bread height for each treatment. The volatile compounds were extracted by dynamic headspace extraction and analyzed by gas chromatography-mass spectrometry. The results were evaluated using multivariate data analysis and ANOVA. In all crust samples 28 volatile compounds out of 58 compounds were identified and the other 30 compounds were tentatively identified. Higher fermentation temperatures promoted the formation of Maillard reaction products 3-methyl-1-butanol, pyrazine, 2-ethylpyrazine, 2-ethyl-3-methylpyrazine, 2-vinylpyrazine, 3-hydroxy-2-butanone, 3-(methylsulfanyl)-propanal, and 5-methyl-2-furancarboxaldehyde whereas at lower temperature (8°C) the formation of 2- and 3-methylbutanal was favored. Higher levels of yeast promoted the formation of 3-methyl-1-butanol, 2-methyl-1-propanol and 3-(methylsulfanyl)-propanal, whereas hexanal was promoted in the crust fermented with lower yeast level.
  20. Iqbal SZ, Asi MR, Hanif U, Zuber M, Jinap S
    Food Chem, 2016 Nov 1;210:135-40.
    PMID: 27211631 DOI: 10.1016/j.foodchem.2016.04.104
    In present study aflatoxins (AFs) and ochratoxin A (OTA) were analysed in 208 samples of rice and products collected from central areas of Punjab, Pakistan. The analysis was carried out using HPLC equipped with fluorescence detector. The results have shown that 35% of the samples were found contaminated with AFs, out of which 19% and 24% samples were found to be above the European Union (EU) maximum content for AFB1 and total AFs, respectively. About 19% samples were found contaminated with OTA and 14% samples were found to be above the EU maximum content. The highest mean level of AFB1 and total AFs were found in brown rice samples i.e. 8.91 and 12.4μg/kg, respectively. However, white rice samples have shown the highest mean level of OTA (8.50μg/kg) with highest level of 24.9μg/kg. The high mean dietary exposure 22.2 and 24.2ngkg(-1)bwday(-1) to AFB1 and OTA, respectively poses significant health hazard for local population.
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