Displaying publications 1 - 20 of 44 in total

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  1. Fulltext Towards producing novel fish gelatin films by combination treatments of ultraviolet radiation and sugars (ribose and lactose) as cross-linking agents
    Bhat R, Karim AA
    J Food Sci Technol, 2014 Jul;51(7):1326-33.
    PMID: 24966426 DOI: 10.1007/s13197-012-0652-9
    Developing novel fish gelatin films with better mechanical properties than mammalian gelatin is a challenging but promising endeavor. Studies were undertaken to produce fish gelatin films by combining treatments with different sugars (ribose and lactose) followed 'by' 'and' ultraviolet (UV) radiation, as possible cross-linking agents. Increase in tensile strength and percent elongation at break was recorded, which was more significant in films without sugars that were exposed to UV radiation. Films with added ribose showed decreased solubility after UV treatment and exhibited higher swelling percentage than films with added lactose, which readily dissolved in water. FTIR spectra of all the films showed identical patterns, which indicated no major changes to have occurred in the functional groups as a result of interaction between gelatin, sugars and UV irradiation. The results of this study could be explored for commercial use, depending on industrial needs for either production of edible films or for food packaging purposes.
  2. Tongkat Ali (Eurycoma longifolia Jack): a review on its ethnobotany and pharmacological importance
    Bhat R, Karim AA
    Fitoterapia, 2010 Oct;81(7):669-79.
    PMID: 20434529 DOI: 10.1016/j.fitote.2010.04.006
    Eurycoma longifolia Jack is an herbal medicinal plant of South-East Asian origin, popularly recognized as 'Tongkat Ali.' The plant parts have been traditionally used for its antimalarial, aphrodisiac, anti-diabetic, antimicrobial and anti-pyretic activities, which have also been proved scientifically. The plant parts are rich in various bioactive compounds (like eurycomaoside, eurycolactone, eurycomalactone, eurycomanone, and pasakbumin-B) among which the alkaloids and quassinoids form a major portion. Even though toxicity and safety evaluation studies have been pursued, still a major gap exists in providing scientific base for commercial utilization and clearance of the Tongkat Ali products with regard to consumer's safety. The present review aims at reviewing the research works undertaken till date, on this plant in order to provide sufficient baseline information for future works and for commercial exploitation.
  3. Effect of ionizing radiation on some quality attributes of nutraceutically valued lotus seeds
    Bhat R, Karim AA
    Int J Food Sci Nutr, 2009;60 Suppl 4:9-20.
    PMID: 19462319 DOI: 10.1080/09637480802241626
    Radiation processing has been employed successfully for value addition of food and agricultural products. Preliminary studies were undertaken to evaluate the changes induced by ionizing radiation (up to 30 kGy), in the form of gamma irradiation and electron beam irradiation, on some quality attributes and nutritive values of nutraceutically valued lotus seeds. Significant loss in seed firmness was recorded between control and irradiated seeds, irrespective of radiation source. Similarly, the specific viscosity of irradiated lotus seeds decreased significantly up to a dose of 7.5 kGy. Starch increased after exposure to gamma or electron beam irradiation, whereas the total phenolic contents were decreased. Gamma irradiation revealed an enhancement in protein, while the electron beam showed a decrease. Partial oxidation of the seeds during radiation treatments might have occurred as evidenced from the decomposition profiles (thermogravimetry) during heating. It is evident that ionizing radiation brought about significant and variable changes in the quality and nutritive values of lotus seed. Further exploration of this technology for safety and quality is warranted.
  4. Fulltext Fruit pod extracts as a source of nutraceuticals and pharmaceuticals
    Karim AA, Azlan A
    Molecules, 2012 Oct 10;17(10):11931-46.
    PMID: 23052712 DOI: 10.3390/molecules171011931
    Fruit pods contain various beneficial compounds that have biological activities and can be used as a source of pharmaceutical and nutraceutical products. Although pods or pericarps are usually discarded when consuming the edible parts of fruits, they contain some compounds that exhibit biological activities after extraction. Most fruit pods included in this review contain polyphenolic components that can promote antioxidant effects on human health. Additionally, anti-inflammatory, antibacterial, antifungal and chemopreventive effects are associated with these fruit pod extracts. Besides polyphenolics, other compounds such as xanthones, carotenoids and saponins also exhibit health effects and can be potential sources of nutraceutical and pharmaceutical components. In this review, information on fruit pods or pericarp of Garcinia mangostana, Ceratonia siliqua, Moringa oleifera, Acacia nilotica, Sapindus rarak and Prosopis cineraria is presented and discussed with regard to their biological activity of the major compounds existing in them. The fruit pods of other ethno- botanical plants have also been reviewed. It can be concluded that although fruit pods are considered as being of no practical use and are often being thrown away, they nevertheless contain compounds that might be useful sources of nutraceutical and other pharmaceutical components.
  5. Hydrolysis of native and heat-treated starches at sub-gelatinization temperature using granular starch hydrolyzing enzyme
    Uthumporn U, Shariffa YN, Karim AA
    Appl Biochem Biotechnol, 2012 Mar;166(5):1167-82.
    PMID: 22203397 DOI: 10.1007/s12010-011-9502-x
    The effect of heat treatment below the gelatinization temperature on the susceptibility of corn, mung bean, sago, and potato starches towards granular starch hydrolysis (35°C) was investigated. Starches were hydrolyzed in granular state and after heat treatment (50°C for 30 min) by using granular starch hydrolyzing enzyme for 24 h. Hydrolyzed heat-treated starches showed a significant increase in the percentage of dextrose equivalent compared to native starches, respectively, with corn 53% to 56%, mung bean 36% to 47%, sago 15% to 26%, and potato 12% to 15%. Scanning electron microscopy micrographs showed the presence of more porous granules and surface erosion in heat-treated starch compared to native starch. X-ray analysis showed no changes but with sharper peaks for all the starches, suggested that hydrolysis occurred on the amorphous region. The amylose content and swelling power of heat-treated starches was markedly altered after hydrolysis. Evidently, this enzyme was able to hydrolyze granular starches and heat treatment before hydrolysis significantly increased the degree of hydrolysis.
  6. Emulsifying and foaming properties of ultraviolet-irradiated egg white protein and sodium caseinate
    Kuan YH, Bhat R, Karim AA
    J Agric Food Chem, 2011 Apr 27;59(8):4111-8.
    PMID: 21401213 DOI: 10.1021/jf104050k
    The physicochemical and functional properties of ultraviolet (UV)-treated egg white protein (EW) and sodium caseinate (SC) were investigated. UV irradiation of the proteins was carried out for 30, 60, 90, and 120 min. However, the SC samples were subjected to extended UV irradiation for 4 and 6 h as no difference was found on the initial UV exposure time. Formol titration, SDS-PAGE, and FTIR analyses indicated that UV irradiation could induce cross-linking on proteins and led to improved emulsifying and foaming properties (P < 0.05). These results indicated that the UV-irradiated EW and SC could be used as novel emulsifier and foaming agents in broad food systems for stabilizing and foaming purposes.
  7. Physicochemical and functional properties of ozone-oxidized starch
    Chan HT, Bhat R, Karim AA
    J Agric Food Chem, 2009 Jul 8;57(13):5965-70.
    PMID: 19489606 DOI: 10.1021/jf9008789
    The effects of oxidation by ozone gas on some physicochemical and functional properties of starch (corn, sago, and tapioca) were investigated. Starch in dry powder form was exposed to ozone for 10 min at different ozone generation times (OGTs). Carboxyl and carbonyl contents increased markedly in all starches with increasing OGTs. Oxidation significantly decreased the swelling power of oxidized sago and tapioca starches but increased that of oxidized corn starch. The solubility of tapioca starch decreased and sago starch increased after oxidation. However, there was an insignificant changed in the solubility of oxidized corn starch. Intrinsic viscosity [eta] of all oxidized starches decreased significantly, except for tapioca starch oxidized at 5 min OGT. Pasting properties of the oxidized starches followed different trends as OGTs increased. These results show that under similar conditions of ozone treatment, the extent of starch oxidation varies among different types of starch.
  8. Late presentation of esophageal cancer: observations in a multiracial South-East Asian population
    Abdullah M, Karim AA, Goh KL
    J Dig Dis, 2010 Feb;11(1):28-33.
    PMID: 20132428 DOI: 10.1111/j.1751-2980.2009.00410.x
    Esophageal cancer (ECA) is an important cancer in Malaysia. The aim of the study is to review the demographic data and clinical presentation of patients with ECA seen at the University of Malaya Medical Centre, Kuala Lumpur.
  9. Antibacterial activity and mechanical properties of partially hydrolyzed sago starch-alginate edible film containing lemongrass oil
    Maizura M, Fazilah A, Norziah MH, Karim AA
    J Food Sci, 2007 Aug;72(6):C324-30.
    PMID: 17995673
    Edible films were prepared from a mixture of partially hydrolyzed sago starch and alginate (SA). Lemongrass oil (0.1% to 0.4%, v/w) and glycerol (0% and 20%, w/w) were incorporated in the films to act as natural antimicrobial agent and plasticizer, respectively. The films were characterized for antimicrobial activity, water vapor permeability (WVP), tensile strength (TS), percent elongation at break (%E), and water solubility (WS). Fourier transform infrared (FTIR) spectroscopy was conducted to determine functional group interactions between the matrix and lemongrass oil. The zone of inhibition was increased significantly (P < 0.05) by addition of lemongrass oil at all levels in the presence and the absence of glycerol. This indicates that the film containing lemongrass oil was effective against Escherichia coli O157:H7 at all levels. In the absence of glycerol, the tensile strength of film decreased as the oil content increased, but there was no significant (P > 0.05) difference in percent elongation. The percent elongation at break and WVP values for film with 20% glycerol was found to be increased significantly (P < 0.05) with an increase in lemongrass oil content. Addition of lemongrass oil did not have any interaction with the functional groups of films as measured by FTIR.
  10. Mycotoxins in Food and Feed: Present Status and Future Concerns
    Bhat R, Rai RV, Karim AA
    Compr Rev Food Sci Food Saf, 2010 Jan;9(1):57-81.
    PMID: 33467806 DOI: 10.1111/j.1541-4337.2009.00094.x
      Disease outbreaks due to the consumption of contaminated food and feedstuff are a recurring problem worldwide. The major factor contributing to contamination are microorganisms, especially fungi, which produce low-molecular-weight compounds as secondary metabolites, with confirmed toxic properties referred to as mycotoxins. Several mycotoxins reported to date are cosmopolitan in distribution and incur severe health-associated risks (including cancer and neurological disorders). Hence, creating awareness among consumers, as well as developing new methods for detection and inactivation is of great importance for food safety. In this review, the focus is on the occurrence of various types of mycotoxins in food and feed associated with risks to humans and livestock, as well as legislation put forth by various authorities, and on presently practiced detoxification methods. Brief descriptions on recent developments in mycotoxin detection methodology are also inlcuded. This review is meant to be informative not only for health-conscious consumers but also for experts in the field to pave the way for future research to fill the existing gaps in our knowledge with regard to mycotoxins and food safety.
  11. Fulltext Protective effects of Ficus racemosa stem bark against doxorubucin-induced renal and testicular toxicity
    Ahmed F, Urooj A, Karim AA
    Pharmacogn Mag, 2013 Apr;9(34):130-4.
    PMID: 23772108 DOI: 10.4103/0973-1296.111265
    BACKGROUND: Ficus racemosa Linn. (Moraceae) bark is a rich source of phenolic compounds known to possess potential antioxidant activity offering numerous health benefits.

    MATERIALS AND METHODS: The present study evaluated the protective effects of sequential acetone extract of Ficus racemosa bark at two doses (FR250; 250 mg kg(-1) and FR500; 500 mg kg(-1) p.o.) against doxorubicin-induced renal and testicular toxicity in rats.

    RESULTS: Doxorubicin administration resulted in significant decrease (P ≤ 0.05) in total protein and glutathione concentrations, while increased (P ≤ 0.05) serum urea, creatinine and thiobarbituric acid reactive substances (TBARS). Extract pretreatment restored biochemical parameters toward normalization. FR250 and FR500 decreased serum creatinine levels by 22.5% and 44%, while serum urea levels were decreased by 30.4% and 58.8%, respectively. Extract pretreatment (500 mg kg(-1)) decreased TBARS and increased glutathione levels in the kidney and testis to control levels. These observations were substantiated by histopathological studies, wherein normal renal and testicular architecture was restored in FR500 group.

    CONCLUSION: Doxorubicin exposure results in pronounced oxidative stress, and administration of F. racemosa stem bark extract offers significant renal and testicular protection by inhibiting lipidperoxidation-mediated through scavenging free radicals.

  12. Functional, thermal and molecular behaviours of ozone-oxidised cocoyam and yam starches
    Oladebeye AO, Oshodi AA, Amoo IA, Karim AA
    Food Chem, 2013 Nov 15;141(2):1416-23.
    PMID: 23790933 DOI: 10.1016/j.foodchem.2013.04.080
    Ozone-oxidised starches were prepared from the native starches isolated from white and red cocoyam, and white and yellow yam cultivars. The native and oxidised starches were evaluated for functional, thermal and molecular properties. The correlations between the amount of reacted ozone and carbonyl and carboxyl contents of the starches were positive, as ozone generation time (OGT) increased. Significant differences were obtained in terms of swelling power, solubility, pasting properties and textural properties of the native starches upon oxidation. The DSC data showed lower transition temperatures and enthalpies for retrograded gels compared to the gelatinized gels of the same starch types. The native starches showed CB-type XRD patterns while the oxidised starches resembled the CA-type pattern. As amylose content increased, amylopectin contents of the starches decreased upon oxidation. Similarly, an increase in Mw values were observed with a corresponding decrease in Mn values upon oxidation.
  13. Electroporation enhances the ability of lactobacilli to remove cholesterol
    Lye HS, Karim AA, Rusul G, Liong MT
    J Dairy Sci, 2011 Oct;94(10):4820-30.
    PMID: 21943733 DOI: 10.3168/jds.2011-4426
    The objective of the present study was to evaluate the effect of electroporation on the membrane properties of lactobacilli and their ability to remove cholesterol in vitro. The growth of lactobacilli cells treated at 7.5 kV/cm for 4 ms was increased by 0.89 to 1.96 log(10) cfu/mL upon fermentation at 37 °C for 20 h, the increase being attributed to the reversible and transient formation of pores and defragmentation of clumped cells. In addition, an increase of cholesterol assimilation as high as 127.2% was observed for most cells electroporated at a field strength of 7.5 kV/cm for 3.5 ms compared with a lower field strength of 2.5 kV/cm. Electroporation also increased the incorporation of cholesterol into the cellular membrane, as shown by an increased cholesterol:phospholipids ratio (50.0-59.6%) upon treatment at 7.5 kV/cm compared with treatment at 2.5 kV/cm. Saturation of cholesterol was observed in different regions of the membrane bilayer such as upper phospholipids, apolar tail, and polar heads, as indicated by fluorescence anisotropy using 3 fluorescent probes. Electroporation could be a useful technique to increase the ability of lactobacilli to remove cholesterol for possible use as cholesterol-lowering adjuncts in the future.
  14. Sonication improves kasturi lime (Citrus microcarpa) juice quality
    Bhat R, Kamaruddin NS, Min-Tze L, Karim AA
    Ultrason Sonochem, 2011 Nov;18(6):1295-300.
    PMID: 21550834 DOI: 10.1016/j.ultsonch.2011.04.002
    Freshly squeezed kasturi lime fruit juice was sonicated (for 0, 30 and 60min at 20°C, 25kHz frequency) to evaluate its impact on selected physico-chemical and antioxidant properties, such as pH, °Brix, titratable acidity, Hunter color values (L(∗), a(∗), b(∗)), ascorbic acid, DPPH radical scavenging activity, total phenolics, antioxidant capacity, flavonoids and flavonols. Additionally, the effect of sonication treatments on the microbial load (TPC, yeast and mold) were also evaluated. Sonication of juice samples for 60min showed enhancement in most of the bioactive compounds compared to samples treated for 30min and control samples (untreated). Significant reductions in the microbial load corresponding to sonication time were also recorded. Results of the present study indicate that sonication may be employed as a suitable technique for kasturi lime juice processing, where antioxidant and other bioactive compound retention or enhancement is desired, along with the achievement of safety and quality standards.
  15. Ultrasound enhanced growth and cholesterol removal of Lactobacillus fermentum FTDC 1311 in the parent cells but not the subsequent passages
    Lye HS, Khoo BY, Karim AA, Rusul G, Liong MT
    Ultrason Sonochem, 2012 Jul;19(4):901-8.
    PMID: 22265020 DOI: 10.1016/j.ultsonch.2011.12.018
    The aim of this study was to evaluate the effect of ultrasound on the intestinal adherence ability, cell growth, and cholesterol removal ability of parent cells and subsequent passages of Lactobacillus fermentum FTDC 1311. Ultrasound significantly decreased the intestinal adherence ability of treated parent cells compared to that of the control by 11.32% (P<0.05), which may be due to the protein denaturation upon local heating. Growth of treated parent cells also decreased by 4.45% (P<0.05) immediately upon ultrasound (0-4h) and showed an increase (P<0.05) in the viability by 2.18-2.34% during the later stage of fermentation (12-20 h) compared to that of the control. In addition, an increase (P<0.05) in assimilation of cholesterol (>9.74%) was also observed for treated parent cells compared to that of the control, accompanied by increased (P<0.05) incorporation of cholesterol into the cellular membrane. This was supported by the increased ratio of membrane cholesterol:phospholipids (C:P), saturation of cholesterol in the apolar regions, upper phospholipids regions, and polar regions of membrane phospholipids of parent cells compared to that of the control (P<0.05). However, such traits were not inherited by the subsequent passages of treated cells (first, second, and third passages). Our data suggested that ultrasound treatment could be used to improve cholesterol removal ability of parent cells without inducing permanent damage/defects on treated cells of subsequent passages.
  16. Antioxidant capacity and phenolic composition of fermented Centella asiatica herbal teas
    Ariffin F, Heong Chew S, Bhupinder K, Karim AA, Huda N
    J Sci Food Agric, 2011 Dec;91(15):2731-9.
    PMID: 21987075 DOI: 10.1002/jsfa.4454
    C. asiatica was exposed to various fermentations: no fermentation (0 min), partial fermentation (120 min) and full fermentation (24 h). Total phenolic content (TPC) and ferric-reducing antioxidant power (FRAP) of C. asiatica infusions were studied as a function of water temperature (60, 80 or 100 °C), the brewing stage (one, two or three) and the brewing time (1, 3, 5, 10, 15 or 20 min). The optimum brewing procedure was adopted to study the antioxidant properties and phenolic compounds in C. asiatica infusions.
  17. Exploring the antioxidant potential of lignin isolated from black liquor of oil palm waste
    Bhat R, Khalil HP, Karim AA
    C. R. Biol., 2009 Sep;332(9):827-31.
    PMID: 19748457 DOI: 10.1016/j.crvi.2009.05.004
    This study was conducted to evaluate the potential antioxidant activity of lignin obtained from black liquor, a hazardous waste product generated during the extraction of palm oil. Antioxidant potential of the extracted lignin was evaluated by dissolving the extracted samples in 2 different solvent systems, namely, 2-methoxy ethanol and DMSO. Results revealed high percent inhibition of the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical in the lignin sample dissolved in 2-methoxy ethanol over DMSO (concentration range of 1-100 microg/ml). Lignin extracted in 2-methoxy ethanol exhibited higher inhibition percentage (at 50 microg/ml, 84.2%), whereas a concentration of 100 microg/ml was found to be effective in the case of the DMSO solvent (69.8%). Fourier transform infrared (FTIR) spectrometry revealed that the functional groups from the extracted lignin and commercial lignin were highly similar, indicating the purity of the lignin extracted from black liquor. These results provide a strong basis for further applications of lignin in the food industry and also illustrate an eco-friendly approach to utilize oil palm black liquor.
  18. Physicochemical properties of hydrothermally treated hemicellulose from oil palm frond
    Fazilah A, Azemi MN, Karim AA, Norakma MN
    J Agric Food Chem, 2009 Feb 25;57(4):1527-31.
    PMID: 19166335 DOI: 10.1021/jf8028013
    Hemicelluloses from oil palm frond (OPF) were extracted using 3 M potassium hydroxide (KOH) for 4 h at 40 degrees C with stirring at 400 rpm to obtain hemicelluloses A and B. The total yield of the hemicellulose isolated from OPF was 33% (dry weight). Both hemicelluloses A and B were then subjected to hydrothermal treatment at 121 degrees C and 1.03 x 10(5) Pa for 10, 30, and 50 min. Physicochemical characterizations of hydrothermally treated hemicelluloses, such as Klason lignin content and reducing sugar content, were performed to study the effect of autohydrolysis processing on OPF-derived hemicelluloses. It was shown that Klason lignin content in hemicellulose A was higher than that in hemicellulose B and decreased after hydrothermal treatment. Hydrothermal treatment enhanced the solubility of hemicelluloses, which reflects their higher reducing sugar content. Monosaccharide analysis using HPLC showed that xylose was the predominant monosaccharide for both hemicelluloses A and B.
  19. Dual modification of starch via partial enzymatic hydrolysis in the granular state and subsequent hydroxypropylation
    Karim AA, Sufha EH, Zaidul IS
    J Agric Food Chem, 2008 Nov 26;56(22):10901-7.
    PMID: 18975963 DOI: 10.1021/jf8015442
    The effect of enzymatic pretreatment on the degree of corn and mung bean starch derivatization by propylene oxide was investigated. The starch was enzymatically treated in the granular state with a mixture of fungal alpha-amylase and glucoamylase at 35 degrees C for 16 h and then chemically modified to produce enzyme-hydrolyzed-hydroxypropyl (HP) starch. Partial enzyme hydrolysis of starch in the granular state appeared to enhance the subsequent hydroxypropylation, as judged from the significant increase in the molar substitution. A variable degree of granule modification was obtained after enzyme hydrolysis, and one of the determinants of the modification degree appeared to be the presence of natural pores in the granules. Enzyme-hydrolyzed-HP starch exhibited significantly different functional properties compared to hydroxypropyl starch prepared from untreated (native) starch. It is evident that the dual modification of starch using this approach provides a range of functional properties that can be customized for specific applications.
  20. Nonmeat Protein Alternatives as Meat Extenders and Meat Analogs
    Asgar MA, Fazilah A, Huda N, Bhat R, Karim AA
    Compr Rev Food Sci Food Saf, 2010 Sep;9(5):513-529.
    PMID: 33467834 DOI: 10.1111/j.1541-4337.2010.00124.x
      The direct consumption of vegetable proteins in food products has been increasing over the years because of animal diseases, global shortage of animal protein, strong demand for wholesome and religious (halal) food, and economic reasons. The increasing importance of legume and oilseed proteins in the manufacturing of various functional food products is due to their high-protein contents. However, the greatest obstacle to utilizing these legumes and oilseeds is the presence of antinutrients; but these antinutrients can be successfully removed or inactivated by employing certain processing methods. In contrast, the potential negative impact of the antinutrients is partially balanced by the fact that they may have a health-promoting role. Legumes and oilseeds provide well-balanced amino acid profiles when consumed with cereals. Soybean proteins, wheat gluten, cottonseed proteins, and other plant proteins have been used for texturization. Texturized vegetable proteins can extend meat products while providing an economical, functional, and high-protein food ingredient or can be consumed directly as a meat analog. Meat analogs are successful because of their healthy image (cholesterol free), meat-like texture, and low cost. Mycoprotein is fungal in origin and is used as a high-protein, low-fat, health-promoting food ingredient. Mycoprotein has a good taste and texture. Texturized vegetable proteins and a number of mycoprotein products are accepted as halal foods. This article summarizes information regarding the molecular, nutritional, and functional properties of alternative protein sources to meat and presents current knowledge to encourage further research to optimize the beneficial effects of alternative protein sources.
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