Displaying publications 1 - 20 of 63 in total

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  1. Sago starch and its utilisation
    Abd-Aziz S
    J Biosci Bioeng, 2002;94(6):526-9.
    PMID: 16233345
    The importance and development of industrial biotechnology processing has led to the utilisation of microbial enzymes in various applications. One of the important enzymes is amylase, which hydrolyses starch to glucose. In Malaysia, the use of sago starch has been increasing, and it is presently being used for the production of glucose. Sago starch represents an alternative cheap carbon source for fermentation processes that is attractive out of both economic and geographical considerations. Production of fermentable sugars from the hydrolysis of starches is normally carried out by an enzymatic processes that involves two reaction steps, liquefaction and saccharification, each of which has different temperature and pH optima with respect to the maximum reaction rate. This method of starch hydrolysis requires the use of an expensive temperature control system and a complex mixing device. Our laboratory has investigated the possibility of using amylolytic enzyme-producing microorganisms in the continuous single-step biological hydrolysis of sago flour for the production of a generic fermentation medium. The ability of a novel DNA-recombinated yeast, Saccharomyces cerevisiae strain YKU 107 (expressing alpha-amylase production) to hydrolyse gelatinised sago starch production has been studied with the aim of further utilizing sago starch to obtain value-added products.
    Matched MeSH terms: Yeast, Dried
  2. Fulltext Effect of postharvest storage of whole fruit on physico-chemical and microbial changes of fresh-cut cantaloupe (Cucumis melo L. reticulatus cv. Glamour)
    Zainal Abidin, M., Shamsudin, R., Othman, Z., Abdul Rahman, R.
    International Food Research Journal, 2013;20(2):953-960.
    MyJurnal
    Cantaloupes continue to ripen after harvesting which is caused by ethylene production due to climacteric behaviour during postharvest storage. In this study, the cantaloupe fruits harvested at commercial maturity were evaluated for quality attributes during three weeks of storage at 10°C and a relative humidity (RH) of 90±5%. In addition, fresh-cut samples were stored for a further 19 days at 2°C and 87% RH. The fresh-cut samples were prepared on a weekly basis by dipping into deionised water (control) at 2°C for 1 minute. The effect of postharvest storage of cantaloupe on the physico-chemical properties and microbial activity was observed prior to fresh-cut processing. It was found that firmness, luminosity (L*), and titratable acidity (TA) decreased, while total soluble solids (TSS), pH, TSS:TA ratio, microbial activity (total plate count (TPC) and yeast and mould (YM)) of the fresh-cut increased over the postharvest storage period of the fruit. Meanwhile, the orange colour and the intensity (hue angle, hab, and chromaticity) of the flesh did not differ significantly during storage. The cantaloupe stored for three weeks at a low temperature indicated a successful potential for fresh-cut processing due to good maintenance of the product quality.
    Matched MeSH terms: Yeast, Dried
  3. Multiobjective optimization to reconstruct biological networks
    Naef A, Abdullah R, Abdul Rashid N
    Biosystems, 2018 Sep 17;174:22-36.
    PMID: 30236951 DOI: 10.1016/j.biosystems.2018.09.003
    Automated methods for reconstructing biological networks are becoming increasingly important in computational systems biology. Public databases containing information on biological processes for hundreds of organisms are assisting in the inference of such networks. This paper proposes a multiobjective genetic algorithm method to reconstruct networks related to metabolism and protein interaction. Such a method utilizes structural properties of scale-free networks and known biological information about individual genes and proteins to reconstruct metabolic networks represented as enzyme graph and protein interaction networks. We test our method on four commonly-used protein networks in yeast. Two are networks related to the metabolism of the yeast: KEGG and BioCyc. The other two datasets are networks from protein-protein interaction: Krogan and BioGrid. Experimental results show that the proposed method is capable of reconstructing biological networks by combining different omics data and structural characteristics of scale-free networks. However, the proposed method to reconstruct the network is time-consuming because several evaluations must be performed. We parallelized this method on GPU to overcome this limitation by parallelizing the objective functions of the presented method. The parallel method shows a significant reduction in the execution time over the GPU card which yields a 492-fold speedup.
    Matched MeSH terms: Yeast, Dried
  4. Cloning, Production and Characterization of a Glycoside Hydrolase Family 7 Enzyme from the Gut Microbiota of the Termite Coptotermes curvignathus
    Woon JS, King PJH, Mackeen MM, Mahadi NM, Wan Seman WMK, Broughton WJ, et al.
    Mol Biotechnol, 2017 Jul;59(7):271-283.
    PMID: 28573450 DOI: 10.1007/s12033-017-0015-x
    Coptotermes curvignathus is a termite that, owing to its ability to digest living trees, serves as a gold mine for robust industrial enzymes. This unique characteristic reflects the presence of very efficient hydrolytic enzyme systems including cellulases. Transcriptomic analyses of the gut of C. curvignathus revealed that carbohydrate-active enzymes (CAZy) were encoded by 3254 transcripts and that included 69 transcripts encoding glycoside hydrolase family 7 (GHF7) enzymes. Since GHF7 enzymes are useful to the biomass conversion industry, a gene encoding for a GHF7 enzyme (Gh1254) was synthesized, sub-cloned and expressed in the methylotrophic yeast Pichia pastoris. Expressed GH1254 had an apparent molecular mass of 42 kDa, but purification was hampered by its low expression levels in shaken flasks. To obtain more of the enzyme, GH1254 was produced in a bioreactor that resulted in a fourfold increase in crude enzyme levels. The purified enzyme was active towards soluble synthetic substrates such as 4-methylumbelliferyl-β-D-cellobioside, 4-nitrophenyl-β-D-cellobioside and 4-nitrophenyl-β-D-lactoside but was non-hydrolytic towards Avicel or carboxymethyl cellulose. GH1254 catalyzed optimally at 35 °C and maintained 70% of its activity at 25 °C. This enzyme is thus potentially useful in food industries employing low-temperature conditions.
    Matched MeSH terms: Yeast, Dried
  5. Fulltext Cellobiohydrolase B of Aspergillus niger over-expressed in Pichia pastoris stimulates hydrolysis of oil palm empty fruit bunches
    Woon JS, Mackeen MM, Illias RM, Mahadi NM, Broughton WJ, Murad AMA, et al.
    PeerJ, 2017;5:e3909.
    PMID: 29038760 DOI: 10.7717/peerj.3909
    BACKGROUND: Aspergillus niger, along with many other lignocellulolytic fungi, has been widely used as a commercial workhorse for cellulase production. A fungal cellulase system generally includes three major classes of enzymes i.e., β-glucosidases, endoglucanases and cellobiohydrolases. Cellobiohydrolases (CBH) are vital to the degradation of crystalline cellulose present in lignocellulosic biomass. However, A. niger naturally secretes low levels of CBH. Hence, recombinant production of A. niger CBH is desirable to increase CBH production yield and also to allow biochemical characterisation of the recombinant CBH from A. niger.

    METHODS: In this study, the gene encoding a cellobiohydrolase B (cbhB) from A. niger ATCC 10574 was cloned and expressed in the methylotrophic yeast Pichia pastoris X-33. The recombinant CBHB was purified and characterised to study its biochemical and kinetic characteristics. To evaluate the potential of CBHB in assisting biomass conversion, CBHB was supplemented into a commercial cellulase preparation (Cellic(®) CTec2) and was used to hydrolyse oil palm empty fruit bunch (OPEFB), one of the most abundant lignocellulosic waste from the palm oil industry. To attain maximum saccharification, enzyme loadings were optimised by response surface methodology and the optimum point was validated experimentally. Hydrolysed OPEFB samples were analysed using attenuated total reflectance FTIR spectroscopy (ATR-FTIR) to screen for any compositional changes upon enzymatic treatment.

    RESULTS: Recombinant CBHB was over-expressed as a hyperglycosylated protein attached to N-glycans. CBHB was enzymatically active towards soluble substrates such as 4-methylumbelliferyl-β-D-cellobioside (MUC), p-nitrophenyl-cellobioside (pNPC) and p-nitrophenyl-cellobiotrioside (pNPG3) but was not active towards crystalline substrates like Avicel(®) and Sigmacell cellulose. Characterisation of purified CBHB using MUC as the model substrate revealed that optimum catalysis occurred at 50 °C and pH 4 but the enzyme was stable between pH 3 to 10 and 30 to 80 °C. Although CBHB on its own was unable to digest crystalline substrates, supplementation of CBHB (0.37%) with Cellic(®) CTec2 (30%) increased saccharification of OPEFB by 27%. Compositional analyses of the treated OPEFB samples revealed that CBHB supplementation reduced peak intensities of both crystalline cellulose Iα and Iβ in the treated OPEFB samples.

    DISCUSSION: Since CBHB alone was inactive against crystalline cellulose, these data suggested that it might work synergistically with other components of Cellic(®) CTec2. CBHB supplements were desirable as they further increased hydrolysis of OPEFB when the performance of Cellic(®) CTec2 was theoretically capped at an enzyme loading of 34% in this study. Hence, A. niger CBHB was identified as a potential supplementary enzyme for the enzymatic hydrolysis of OPEFB.

    Matched MeSH terms: Yeast, Dried
  6. Common microorganisms causing onychomycosis in tropical climate
    Leelavathi M, Tzar M, Adawiah J
    Sains Malaysiana, 2012;41:697-700.
    Onychomycosis is the infection of nail apparatus by dermatophytes, yeasts or non-dermatophyte moulds and is responsible for 50% of all nail disorders. A five year retrospective study was conducted at Universiti Kebangsaan Malaysia to identify the common pathogens responsible for onychomycosis and to describe the epidemiology of the affected patients. A total of 278 abnormal nails were cultured, out of which 231 were positive for fungus. Females constituted 50.2% (n=116) while males 49.8% (n=115). The majority (51.9%, n=120) were between ages 50-69 years. The Malay ethnic group was most commonly affected (44.2%, n=102) followed by Chinese (33.8%, n=78), Indians (18.2%, n=42) and other ethnic groups (3.8%, n=9). The most common fungal element isolated was non-dermatophyte moulds (45.4%, n=105) followed by yeast (34.6%, n=80) and dermatophytes (1.3%, n=3). Aspergillus spp. was the commonest (59.8%,n=81) non-dermatophyte mould, while Candida spp. was the commonest yeast (74.3%, n=89) isolated. In this study, non-dermatophyte moulds are the most common microorganisms implicated to cause onychomysosis. Treatment for non-dermatophyte mould is challenging as the current available antifungal agents are more effective against dermatophytes and yeasts.
    Matched MeSH terms: Yeast, Dried
  7. Fulltext Saprophytic yeasts: effective biocontrol agents against Aspergillus flavus
    Afsah-Hejri, L.
    International Food Research Journal, 2013;20(6):3403-3409.
    MyJurnal
    Aflatoxins are carcinogenic, mutagenic and teratogenic fungal toxins predominantly produced by Aspergillus flavus (A. flavus) and Aspergillus parasiticus (A. parasiticus). Members of the Aspergillus family are wound-invading pathogens that can infect pistachio trees and nuts. The pistachio nut is a favorite tree nut worldwide, and more than half of the world’s pistachio production is from Iran. Pistachio nuts can easily be infected with Aspergillus spp. due to early splitting or due to animal, insect or physical damage. Any established infection of Aspergillus under high relative humidity and temperature results in the production and rapid accumulation of aflatoxins in pistachio nuts. It is impractical to remove aflatoxins from pistachio nuts after they are produced. Some microorganisms (such as saprophytic yeasts) have been reported to have an antagonistic effect against Aspergillus spp. This study aimed to isolate saprophytic yeasts from pistachio fruits and leaves and investigate their biocontrol activities against a toxigenic strain of Aspergillus flavus (A. flavus). Saprophytic yeasts were identified based on their morphological properties and biochemical tests. In total, 24 yeast isolates were obtained from pistachio fruits and leaves, and their antagonistic effect on A. flavus (PTCC 5006) was investigated. Five saprophytic yeast isolates, displaying the highest biocontrol activities against A. flavus (PTCC 5006), were identified as Pseudozyma fusiformata, Cryptococcus albidus, Rhodotorula fragaria, Cryptococcus hungaricus and Rhodotorula hinula. The biocontrol activities of these yeast isolates were evaluated by their inhibitory effects on sporulation, colony expansion, biomass production and prevention of aflatoxin B1 (AFB1) production. Pseudozyma fusiformata was the most effective yeast isolate in terms of spore reduction (84.6%) and inhibition of AFB1 production (89.1%). Cryptococcus albidus produced the maximum reduction in fungal dry weight (77.9%). Based on these results, isolated saprophytic yeasts from pistachio fruits and leaves can be used as effective biocontrol agents against the growth of Aspergillus and aflatoxin production.
    Matched MeSH terms: Yeast, Dried
  8. Fulltext Numerical Analysis of Hydrodynamic Flow in Microfluidic Biochip for Single-Cell Trapping Application
    Khalili AA, Ahmad MR
    Int J Mol Sci, 2015;16(11):26770-85.
    PMID: 26569218 DOI: 10.3390/ijms161125987
    Single-cell analysis has become the interest of a wide range of biological and biomedical engineering research. It could provide precise information on individual cells, leading to important knowledge regarding human diseases. To perform single-cell analysis, it is crucial to isolate the individual cells before further manipulation is carried out. Recently, microfluidic biochips have been widely used for cell trapping and single cell analysis, such as mechanical and electrical detection. This work focuses on developing a finite element simulation model of single-cell trapping system for any types of cells or particles based on the hydrodynamic flow resistance (Rh) manipulations in the main channel and trap channel to achieve successful trapping. Analysis is carried out using finite element ABAQUS-FEA™ software. A guideline to design and optimize single-cell trapping model is proposed and the example of a thorough optimization analysis is carried out using a yeast cell model. The results show the finite element model is able to trap a single cell inside the fluidic environment. Fluid's velocity profile and streamline plots for successful and unsuccessful single yeast cell trapping are presented according to the hydrodynamic concept. The single-cell trapping model can be a significant important guideline in designing a new chip for biomedical applications.
    Matched MeSH terms: Yeast, Dried
  9. Fulltext Research progress in Bioflocculants from bacteria
    Abdullah, A.M., Hamidah, H., Alam, M.Z.
    International Food Research Journal, 2017;24(101):0-0.
    MyJurnal
    Although one of the major users of flocculants are water and wastewater treatment industries, flocculants are also used in various food industries. The chemical flocculants are preferred widely in these industries due to low production cost and fast production ability. However, the negative effects of the chemical flocculants should not be neglected to gain the economic benefits only. Therefore, the researchers are working to discover efficient and economical flocculants from biological sources. Several attempts have been made and are still being made to extract or produce bioflocculants from natural sources such as plants, bacteria, fungi, yeast, algae, etc. The review revealed that significant amount of work have been done in the past, in search of bioflocculant. However, commercially viable bioflocculants are yet to be marketed widely. With the advent of new biotechnologies and advances in genetic engineering, the researchers are hopeful to discover or develop commercially viable, safe and environmentfriendly bioflocculants.
    Matched MeSH terms: Yeast, Dried
  10. Fulltext Effect of glycerol feed in methanol induction phase for Hepatitis B surface antigen expression in Pichia pastoris strain KM71
    Morvarid, A.R., Zeenathul, N.A., Tam, Y.J., Zuridah, H., Mohd-Azmi, M.L., Azizon, B.O.
    Pertanika Journal of Science & Technology, 2012;20(1):31-42.
    MyJurnal
    This study describes expression of HBs Ag in methylotrophic yeast, Pichia Pastoris under alcohol oxidase promoter. A single copy number of HBs Ag gene was transformed into pichia strain of KM 71, a Muts type, by using pA0815 pichia expression vector. The recombinant was cultivated in a shake flask either using methanol or a mixed feed of glycerol -methanol for induction. The HBs Ag gene integrity was justified using direct PCR method. The expressed products in the soluble cell extracts were analyzed by Western blot, SDS page, Bradford assay and ELISA tests. The recombinant HBs Ag was expressed successfully in Pichia pastoris strain KM71 at a high level of HBs Ag protein expression. Thus, an addition of glycerol in the ratio of glycerol per methanol 1/1 (g g-1) consistently produced 2-fold increment in both biomass accumulation and HBs Ag productivity.
    Matched MeSH terms: Yeast, Dried
  11. Fulltext Thermal and dynamic mechanical properties of frozen wheat flour dough added with selected food gums
    Sim, S.Y., Noor Aziah, A.A., Teng, T.T., Cheng, L.H.
    International Food Research Journal, 2012;19(1):333-340.
    MyJurnal
    The effects of food gums addition on wheat dough freeze-thaw and frozen storage stability were studied. Thermal and dynamic mechanical properties of frozen wheat dough without yeast addition were
    determined by means of Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA).
    DSC results revealed that food gums showed the ability to increase freeze-thaw stability in frozen-stored
    samples wherein lower difference in melting enthalpy between first and second freeze-thaw cycle was shown. Based on DMA results, in general, difference between Tg’ and storage temperature (- 18°C) of dough became smaller upon addition of food gums. This may have a practical implication whereby the unfrozen phase could be better protected against physical degradation.
    Matched MeSH terms: Yeast, Dried
  12. Antimicrobial activity of fungal endophytes from vaccinium dunalianum var. Urophyllum
    Xin Tong, Xiao-ye Shen, Cheng-lin Hou
    Sains Malaysiana, 2018;47:1685-1692.
    Fungi associated with Vaccinium species play important roles in plant growth and disease control, especially in the final
    blueberry production. Vaccinium dunalianum var. urophyllum (Ericaceae) is a well-known medicinal plant in Southern
    China used to treat inflammation and microbial infections. The endophytic fungi from these plants are therefore anticipated
    as potential new sources of antimicrobials. In this report, the inhibitory effects of endophytes against clinical bacteria
    and yeast were comprehensively screened and 11 isolates indicated high bioactivity by the agar diffusion method. The
    corresponding crude extracts of these fungi under submerged fermentation also demonstrated distinct differences and
    n-butyl alcohol displayed the lowest extraction efficiency among the extracts. The ethyl acetate and dichloromethane
    extracts of filtrates from the Colletotrichum sp. VD001, Epicoccum nigrum VD021 and E. nigrum VD022 strains
    displayed good properties against pathogenic microorganisms according to disc diffusion assays and minimal inhibitory
    concentration (MIC). This study is the first indicating that cultivable endophytic fungi associated with blueberry plants
    produce potential compounds against clinical pathogens.
    Matched MeSH terms: Yeast, Dried
  13. Fulltext Evaluation of injury to Saccharomyces rouxii YSa40 cells in low water activity/pH glycerol/CPB stress system
    Yeoh, T.K., Cheah, Y.K., Davies, R.
    International Food Research Journal, 2012;19(1):95-99.
    MyJurnal
    Mid-exponential phase Saccharomyces rouxii YSa40 cells subsequently stressed at low aw/pH in the 0.64 aw/pH 3.5 glycerol/CPB system became injured. Such injury was detected by the loss of ability of the
    stressed population to form colonies on secondary-stress plating medium (glycerol/BM agar at 0.94 aw
    /pH 3.5 (lactic acid)) while colony forming ability on secondary non-stress plating medium (sugars/BM agar at 0.94 aw/pH 3.5 (lactic) was unaffected. The injury was shown to be due to sensitivity to glycerol/lactic acid. Results of the present study will be useful for achieving complete decontamination of ‘Intermediate Moisture Foods’ against xerotolerant molds and yeast.
    Matched MeSH terms: Yeast, Dried
  14. Physicochemical, antioxidant and microbial properties of fresh black stem sugarcane juice with addition of calamansi juice
    Noor Afiqah Md Noor, Maizura Murad, Effarizah Mohd Esah
    Sains Malaysiana, 2018;47:2047-2054.
    This study was designed to determine the physicochemical, antioxidant and microbial properties of fresh sugarcane juice
    with calamansi juice addition. The sugarcane that was used in the experiments was the black cane variety (Saccharum
    officinarum). Sugarcane pressed with and without their peel was juiced and added with calamansi juice before analysis
    was carried out. Standard method was used to analyse physicochemical properties such as pH, total soluble solids,
    acidity and colour of sugarcane juice. Total phenolic content (TPC), DPPH and FRAP assay were conducted for antioxidant
    properties. Total plate count and yeast and mould count were carried out for the microbiological analyses. Two way
    analysis of variance (ANOVA) shows significant (p<0.05) difference on colour of sugarcane juiced after extraction with and
    without peel. There were no significant (p>0.05) difference shown for pH, acidity and total soluble solids of sugarcane
    juice pressed with and without peel. Sugarcane juice pressed with peel produced higher antioxidant value compared
    to sugarcane pressed without peel. However, sugarcane juice pressed without peeled showed a lower microbial count
    compared to sugarcane juice pressed with peel. The addition of calamansi juice proved to have significant (p<0.05)
    effect on colour, antioxidant and microbial count of the sugarcane juices.
    Matched MeSH terms: Yeast, Dried
  15. Lipid biosynthesis in Cunninghamella bainieri 2A1 in N-limited and N-excess media
    Taha EM, Omar O, Yusoff WM, Hamid AA
    Annals of microbiology, 2010 Dec;60(4):615-622.
    PMID: 21125005
    Lipid biosynthesis and fatty acids composition of oleaginous zygomycetes, namely Cunninghamella bainieri 2A1, cultured in media with excess or limited nitrogen were quantitatively determined at different times of culture growth. Accumulation of lipids occurred even when the activity of NAD(+)-ICDH (β-Nicotinamide adenine dinucleotide-isocitrate dehydrogenase) was still detectable in both media. In C. bainieri 2A1, under nitrogen limitation, the ratio of lipids was around 35%, whereas in nitrogen excess medium (feeding media supplemented with ammonium tartarate), the lipid ratio decreased. The amount of this decrease depended on the level of ammonium tartarate in the media. The main findings in this paper were that C. bainieri 2A1 has the ability to accumulate lipid although nitrogen concentration detected inside the media and that NAD-ICDH was active in all culture periods. These results proved that the strain C. bainieri 2A1 has an alternative behavior in lipid biosynthesis that differs from yeast. According to the old hypotheses, yeasts could not accumulate lipid more than 10% when nitrogen was detected inside the media. Nitrogen-limited and excess media both contained the same fatty acids (palmitic acid, stearic acid, olic acid, linoleic acid and γ-linolenic acid), but at different concentrations. The C:N ratio was also studied and showed no effects on total lipid accumulation, but a significant effect on γ-linolenic acid concentration.
    Matched MeSH terms: Yeast, Dried
  16. Fulltext Whole genome sequencing of Rhodotorula mucilaginosa isolated from the chewing stick (Distemonanthus benthamianus): insights into Rhodotorula phylogeny, mitogenome dynamics and carotenoid biosynthesis
    Gan HM, Thomas BN, Cavanaugh NT, Morales GH, Mayers AN, Savka MA, et al.
    PeerJ, 2017;5:e4030.
    PMID: 29158974 DOI: 10.7717/peerj.4030
    In industry, the yeast Rhodotorula mucilaginosa is commonly used for the production of carotenoids. The production of carotenoids is important because they are used as natural colorants in food and some carotenoids are precursors of retinol (vitamin A). However, the identification and molecular characterization of the carotenoid pathway/s in species belonging to the genus Rhodotorula is scarce due to the lack of genomic information thus potentially impeding effective metabolic engineering of these yeast strains for improved carotenoid production. In this study, we report the isolation, identification, characterization and the whole nuclear genome and mitogenome sequence of the endophyte R. mucilaginosa RIT389 isolated from Distemonanthus benthamianus, a plant known for its anti-fungal and antibacterial properties and commonly used as chewing sticks. The assembled genome of R. mucilaginosa RIT389 is 19 Mbp in length with an estimated genomic heterozygosity of 9.29%. Whole genome phylogeny supports the species designation of strain RIT389 within the genus in addition to supporting the monophyly of the currently sequenced Rhodotorula species. Further, we report for the first time, the recovery of the complete mitochondrial genome of R. mucilaginosa using the genome skimming approach. The assembled mitogenome is at least 7,000 bases larger than that of Rhodotorula taiwanensis which is largely attributed to the presence of large intronic regions containing open reading frames coding for homing endonuclease from the LAGLIDADG and GIY-YIG families. Furthermore, genomic regions containing the key genes for carotenoid production were identified in R. mucilaginosa RIT389, revealing differences in gene synteny that may play a role in the regulation of the biotechnologically important carotenoid synthesis pathways in yeasts.
    Matched MeSH terms: Yeast, Dried
  17. Fulltext Disinfectant of pummelo (Citrus Grandis L. Osbeck) fruit juice using gaseous ozone
    Shah NNAK, Supian NAM, Hussein NA
    J Food Sci Technol, 2019 Jan;56(1):262-272.
    PMID: 30728568 DOI: 10.1007/s13197-018-3486-2
    This work studied the effectiveness of gaseous ozone disinfection on pummelo (Citrus Grandis L. Osbeck) fruit juice components. Unfiltered and filtered pummelo fruit juices were treated with gaseous ozone for up to 50 min with ozone concentration fixed at 600 mg/h. A microbiological and physicochemical properties analysis were conducted on the ozone-treated fruit juices samples. It was found that the survival rate of aerobic bacteria, yeast and mold in unfiltered pummelo fruit juice were higher compared to filtered juice, as the juice components acted as protective barriers to the microorganisms. The microorganisms' inactivation in pummelo fruit juices was also observed to have increased as the ozone treatment time increased. Significant effects on total colour difference, ascorbic acid content, and total phenolic content were also observed over increased ozone-treatment time. However, ozone was shown to be ineffective in activating PME activity in both types of juice. The experimental results of this study indicated that pummelo fruit juice components had significant effects on the effectiveness of gaseous ozone, however, the degree of the effects depends on the different fruit components (total soluble solids, total phenolic content). As a conclusion, filtered juice showed better quality characteristics in comparison to unfiltered juice post-ozone treatment.
    Matched MeSH terms: Yeast, Dried
  18. Fulltext Antimicrobial activity of Emilia sonchifolia DC., Tridax procumbens L. and Vernonia cinerea L. of Asteracea family: potential as food preservatives
    Yoga Latha, L., Darah, I., Sasidharan, S., Jain, K.
    Malays J Nutr, 2009;15(2):223-231.
    MyJurnal
    Chemical preservatives have been used in the food industry for many years. However, with increased health concerns, consumers prefer additive-free products or food preservatives based on natural products. This study evaluated antimicrobial activities of extracts from Emilia sonchifolia L. (Common name: lilac tassel flower), Tridax procumbens L. (Common name: tridax daisy) and Vernonia cinerea L. (Common name: Sahadevi), belonging to the Asteracea family, to explore their potential for use against general food spoilage and human pathogens so that new food preservatives may be developed. Three methanol extracts of these plants were tested in vitro against 20 bacterial species, 3 yeast species, and 12 filamentous fungi by the agar diffusion and broth dilution methods. The V. cinerea extract was found to be most effective against all of the tested organisms and the methanol fraction showed the most significant (p < 0.05) antimicrobial
    activity among all the soluble fractions tested. The minimum inhibitory concentrations (MICs) of extracts determined by the broth dilution method ranged from 1.56 to 100.00mg/mL. The MIC of methanol fraction was the lowest in comparison to the other four extracts. The study findings indicate that bioactive natural products from these plants may be isolated for further testing as leads in the development of new pharmaceuticals in food preservation as well as natural plant-based medicine.
    Matched MeSH terms: Yeast, Dried
  19. Fulltext Effect of fennel (Foeniculum vulgare Mill.) and coriander (Coriandrum sativum L.) on microbial quality and sensory acceptability of frozen paratha
    Rosli, N.A., Azilan, N A., Mahyudin, N.A., Mahmud Ab Rashid, N.K., Meon, F.N.S., Ismail, Z., et al.
    International Food Research Journal, 2019;26(3):945-952.
    MyJurnal
    Fennel (Foeniculum vulgare Mill.) and coriander (Coriandrum sativum L.) are known to possess good antimicrobial properties. In the present work, spice-infused frozen parathas were formulated to investigate the effect of fennel and coriander on microbial (aerobic mesophilic bacteria, yeast and mould, and Bacillus cereus) reduction and sensory acceptability of frozen paratha throughout the storage at -18°C. The present work was also aimed at determining the relationship between spice concentrations and storage durations on microbiological quality of the samples. Fennel and coriander seed powder were used at concentrations of 2, 4 and 6% of wheat flour (w/w). The microbiological analysis was performed by total plate count, yeast and mould count, and Bacillus cereus count after 9, 12 and 15 weeks of storage. Sensory evaluation was conducted using hedonic scales at the end of storage durations. Results showed that spice infusion in frozen paratha significantly delayed the growth of aerobic mesophilic bacteria, yeasts and moulds, and Bacillus cereus during storage. The lowest log count was demonstrated by coriander at 6% in total plate count (3.85, 3.90 and 3.91 log10 CFU/g), and yeast and mould count (2.54, 2.59 and 2.60 log10 CFU/g) after 9, 12 and 15 weeks, respectively. Bacillus cereus was not detected throughout the storage durations. Fennel exhibited minimum activity against Bacillus cereus with no significant difference on log count reduction when compared with control. Coriander showed the highest decrease in both total plate count and Bacillus cereus count during the storage duration. Sensory evaluation result indicated that control sample exhibited the highest preference over all attributes when compared with fennel and coriander. Coriander-infused paratha was slightly darker in colour due to high concentration of 6%. Fennel yielded the lowest score in terms of taste among all samples. Fennel and coriander showed no significant difference for sensory acceptability. Overall, all frozen parathas were in good quality after 15 weeks of frozen storage. It can thus be concluded that fennel and coriander can be used as potential natural preservatives to inhibit the growth of microorganisms in paratha during frozen storage. Nevertheless, the optimum spice concentration should be determined to minimise the effects on the sensory attributes.
    Matched MeSH terms: Yeast, Dried
  20. Fulltext Antimicrobial Effect of Malaysian Honey on Some Human Pathogens: an in vitro Study
    Hassanain, A.T., Alyaa, A.K., Karim, A.J.
    International Medical Journal Malaysia, 2010;9(2):15-18.
    MyJurnal
    Introduction: Honey has potent bactericidal activity against many pathogenic organisms, including various Gram-negative and Gram-positive bacteria. This study aimed to determine the antimicrobial effect of Malaysian honey against different species of human pathogens using optimized honey broth media. Materials and Methods: The antimicrobial activity of honey against standard strains of Gram-negative and Grampositive bacteria and yeast was tested in vitro by the broth dilution method using 10%-100% w/v concentrations prepared in tryptic soy broth. Results: Streptococcus pyogenes was the most sensitive pathogen, it was completely inhibited by 30% honey broth medium. The most resistant were E. faecalis, S. aureus and MRSA, but they were all completely inhibited by 80% honey broth medium. Conclusion: Honey is shown to possess antimicrobial activity against human Gram-positive and negative medically important bacteria.
    Matched MeSH terms: Yeast, Dried
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