Displaying publications 1 - 20 of 49 in total

  1. Cheong SK, Lim YC, Mok KL
    Malays J Pathol, 1991 Jun;13(1):51-2.
    PMID: 1795563
    Mixed reagents for the Glucose-6-phosphate dehydrogenase (G6PD) deficiency fluorescent screening test were freeze-dried in plastic tubes. The reagents were then reconstituted with distilled water and the test was performed in the usual way. Initial testing with the freeze-dried mixed reagents gave consistent positive reaction to 12 normal blood samples and negative reaction to 9 G6PD deficient blood samples. This will enable a laboratory with freeze-drying facilities to prepare reagent tubes in bulk. As these tubes can be kept at 4 degrees C and do not require to be stored at -20 degrees C, a major laboratory can prepare these tubes and supply small laboratories for screening purposes.
    Matched MeSH terms: Freeze Drying*
  2. Mediani A, Abas F, Tan CP, Khatib A
    Antioxidants (Basel), 2014 May 07;3(2):358-70.
    PMID: 26784876 DOI: 10.3390/antiox3020358
    The present study was conducted to determine the effect of air (AD), oven (OD) and freeze drying (FD) on the free radical scavenging activity and total phenolic content (TPC) of Cosmos caudatus and the effect of storage time by the comparison with a fresh sample (FS). Among the three drying methods that were used, AD resulted in the highest free radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) (IC50 = 0.0223 mg/mL) and total phenolic content (27.4 g GAE/100 g), whereas OD produced the lowest scavenging activity and TPC value. After three months of storage, the dried samples showed a high and consistent free radical scavenging activity when compared to stored fresh material. The drying methods could preserve the quality of C. caudatus during storage and the stability of its bioactive components can be maintained.
    Matched MeSH terms: Freeze Drying
  3. Maitland HB
    Med J Malaya, 1965 Sep;20(1):8-10.
    PMID: 4221441
    Matched MeSH terms: Freeze Drying*
  4. Kang, O.L., Yong, P.F., Ma’aruf, A.G., Osman, H., Nazaruddin, R.
    In this work, oven-dried, freeze-dried and spray-dried agaro-oligosaccharide powders were characterized to investigate their physicochemical and antioxidant properties. Agaro-oligosaccharide powders were shown to exhibit high water solubility index (88.73 – 95.88%), water absorption capacity (0.96 – 2.57 g/g) and oil absorption capacity (0.40 – 0.45 g/g). Agaro-oligosaccharide powders were shown to possess moderate DPPH radical scavenging activity (10.65 – 14.59%), ABTS radical scavenging activity (44 .47 – 65.61%) and ferric reducing antioxidant activity (0.165 – 0.353). Agaro-oligosaccharide powders were further characterized with respect to thermal and pH stability. Agaro-oligosaccharide powders were shown to exhibit high temperature resistance (≤ 100oC) and acid/alkaline resistance.
    Matched MeSH terms: Freeze Drying
  5. Ahmad Razi Othman, Intan Safinar Ismail, Norhani Abdullah, Syahida Ahmad
    Jatropha curcas is a multipurpose plant that has been suggested as a possible cure to
    inflammation. It can be used as a source of animal feed, live fence, biodiesel and in traditional
    medicine. Practitioners have used various extraction techniques to extract the active components
    of the plant. This article compares the efficiency of three methods of drying technique for the
    extraction of the total phenolic content from the plant. The freeze-drying method was the best
    method compared to oven dry and air dry. The freeze-drying method dries J. curcas root sample
    faster and preserve the total phenolic content better than the other methods.
    Matched MeSH terms: Freeze Drying
  6. Rabeta MS, Lin S
    Sains Malaysiana, 2015;44:275-280.
    This study aimed to assess the effects of fresh, thermal drying method (vacuum oven drying), and nonthermal drying method (freeze drying) on the antioxidant activities of leaves and berries of Cayratia trifolia using ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-1-picrylhydrazyl radical scavenging capacity (DPPH) assays. The total phenolic content (TPC) and flavonoid content (TFC) of the leaves and berries of C. trifolia were also measured. Based on the results obtained, the TPC, TFC, and antioxidant activities of the leaves and berries were arranged in the following order: freeze-dried sample with methanol extraction > vacuum-dried sample with methanol extraction > freeze-dried sample with water extraction > vacuum-dried sample with water extraction > fresh sample with methanol extraction > fresh sample with water extraction. The results showed a significant difference (p<0.05) between the fresh and dried samples. In conclusion, freeze drying was found to be a good method for maintaining TPC, TFC, and antioxidant activities by FRAP and DPPH methods in the leaves and berries of C. trifolia.
    Matched MeSH terms: Freeze Drying
  7. Mirhosseini H, Amid BT
    Chem Cent J, 2013 Jan 04;7(1):1.
    PMID: 23289739 DOI: 10.1186/1752-153X-7-1
    BACKGROUND: A natural carbohydrate biopolymer was extracted from the agricultural biomass waste (durian seed). Subsequently, the crude biopolymer was purified by using the saturated barium hydroxide to minimize the impurities. Finally, the effect of different drying techniques on the flow characteristics and functional properties of the purified biopolymer was investigated. The present study elucidated the main functional characteristics such as flow characteristics, water- and oil-holding capacity, solubility, and foaming capacity.

    RESULTS: In most cases except for oven drying, the bulk density decreased, thus increasing the porosity. This might be attributed to the increase in the inter-particle voids of smaller sized particles with larger contact surface areas per unit volume. The current study revealed that oven-dried gum and freeze-dried gum had the highest and lowest compressibility index, thus indicating the weakest and strongest flowability among all samples. In the present work, the freeze-dried gum showed the lowest angle of repose, bulk, tapped and true density. This indicates the highest porosity degree of freeze dried gum among dried seed gums. It also exhibited the highest solubility, and foaming capacity thus providing the most desirable functional properties and flow characteristics among all drying techniques.

    CONCLUSION: The present study revealed that freeze drying among all drying techniques provided the most desirable functional properties and flow characteristics for durian seed gum.

    Matched MeSH terms: Freeze Drying
  8. Michelle Wong Tzeling J, Yean Yean C
    Analyst, 2016 Feb 21;141(4):1246-9.
    PMID: 26783560 DOI: 10.1039/c5an01741f
    A shelf-stable loop-mediated isothermal amplification (LAMP) reagent for Burkholderia pseudomallei detection is described. The coupling of LAMP reagents with the indirect colorimetric indicator and consequently its lyophilization enable the simple evaluation of results without the need for any advance laboratory instruments. The reagents were found to have a stable shelf life of at least 30 days with well-maintained sensitivity and specificity.
    Matched MeSH terms: Freeze Drying
  9. Tan NH, Tan CS
    Toxicon, 1987;25(11):1249-53.
    PMID: 3433296
    The enzymatic activities of four samples of Malayan cobra venom were investigated. There was significant variation in the contents of L-amino acid oxidase, alkaline phosphomonoesterase, acetylcholinesterase, phospholipase A, 5'-nucleotidase and hyaluronidase. The phosphodiesterase content was, however, constant. Storage of the lyophilized venom powder at 25 degrees C for 1 month did not affect the enzymatic activities. The venom enzymatic activities were generally also stable at 4 degrees C in 0.85% saline solution. After incubation at 37 degrees C for 39 days in 0.85% saline solution, the venom still retained considerable amounts of enzymatic activities. SP-Sephadex C-25 ion-exchange chromatography of the venom showed that the phospholipase A, L-amino acid oxidase, 5'-nucleotidase, phosphodiesterase and alkaline phosphomonoesterase exist in multiple forms.
    Matched MeSH terms: Freeze Drying
  10. Baharuddin, N.A., Kamin, S., Samsuddin, A.R.
    Ann Dent, 2003;10(1):-.
    This study evaluated the effectiveness of demineralized freeze-dried bone xenograft in reducing post-surgical pocket depth in moderate to advanced adult periodontitis in patients. Nine patients with a total of eighteen intrabony defects were selected for this study. The bony defects were matched for tooth type, location and pocket depth. Following an initial non-surgical treatment, only pockets of 5 to 7 mm deep were indicated for surgery. Periodontal pockets were measured pre-operatively and at 3, 6 and 9 months post-surgically. The study protocol included a split mouth design, where surgical treatment was carried out at both test and control sites. The test sites were assigned demineralized freeze-dried bone xenograft and the control sites were subjected to debridement alone without the use of demineralized freeze-dried bone xenograft. The results from this study showed a statistically significant difference in the mean pocket depth at 6 and 9 months post-operatively for both test and control groups, but there was no statistically significant difference at 3 months. In conclusion, demineralized freeze-dried bone xenograft was ineffective in reducing periodontal pocket depth in patients with moderate to severe periodontitis, as compared to surgical debridement alone.
    Matched MeSH terms: Freeze Drying
  11. Rabeta, M.S., Lai, S.Y.
    Antioxidant capacity of Ocimum tenuiflorum L. or ‘ruku’ were determined in this study. Fresh
    leaves of Ocimum tenuiflorum was subjected to freeze drying, vacuum drying and processed
    into fermented and unfermented tea. The samples were extracted using distilled water and the
    total phenolics, total flavonoids, condensed tannin content, anthocyanins and total antioxidant
    capacity (TAC) were assessed, measured with ferric reducing antioxidant power (FRAP)
    and 1,1-diphenyl-1-picrylhydrazyl radical scavenging capacity (DPPH) assays. The results
    showed that drying the fresh leaves of Ocimum tenuiflorum and processing them into tea leaves
    significantly increase (P < 0.05) the antioxidant capacity, total phenolic content, total flavonoid
    content, and condensed tannin content. However, anthocyanins content showed reduction
    after drying. In the present study, it can be concluded that the vacuum drying method seem
    to produce a product with higher quality of antioxidant properties than freeze drying. Hence,
    vacuum drying can be used to replace freeze drying as it is also cheaper than freeze drying.
    Matched MeSH terms: Freeze Drying
  12. Aishah, B., Nursabrina, M., Noriham, A., Norizzah, A.R., Mohamad Shahrimi, H.
    There are many factors influencing the stability and color variation of natural colorant anthocyanin and pH is among the most significant factor. This study aims to determine the stability of the anthocyanins in freeze-dried Hibiscus sabdariffa, Melastoma malabathricum and Ipomoea batatas in various acidic pH (pH 2.0, 2.5, 3.0, 3.5, 4.0 and 4.5). Total monomeric anthocyanin, degradation index, color density and percent polymeric color were analyzed to determine anthocyanins degradation and their color variations. Among the samples, H.sabdariffa contain the highest monomeric anthocyanins (163.3 mg/L) followed by M. malabathricum (49.9 mg/L) and the lowest is I.batatas (13.8 mg/L). Monomeric anthocyanins from I.batatas were found to be very stable and not affected by changes in pH than in H. sabdariffa and M. malabathricum. However, degradation index (DI) of H. sabdariffa was the lowest with value of 0.365 ± 0.049 at pH 3.5. The lowest percentage of polymeric color (4.94 ± 0.64) was also shown by H. sabdariffa at pH 2.5 and maintained a deep red color with increasing pH indicating higher color stability compared to M. malabathricum and I. batatas. Overall, natural pigment in H. sabdariffa was found to be the most stable in both monomeric anthocyanin content and chromaticity properties. These results provided information that will further proven the potential usage of H. sabdariffa, M. malabathricum and I. batatas as natural coloring agents to replace the synthetic colorant in food and beverage industries.
    Matched MeSH terms: Freeze Drying
  13. Baharuddin, N.A., Kamin, S., Samsuddin, A.R.
    Ann Dent, 2005;12(1):-.
    The aim of this study was to determine the effectiveness of demineralized freeze-dried bone xenograft (DFDBBX) in minimizing post-surgical recession in moderate to advanced adult periodontitis in patients. Nine patients with a total of eighteen intrabony defects were matched for the tooth type, location of defects and periodontal pocket depth (5 to 7mm). Following an initial nonsurgical treatment, recession at defects indicated for surgery was measured pre-operatively. Surgical treatment was carried out by split mouth design, where the test sites were assigned DFDBBX and the control sites were subjected to debridement without the use of DFDBBX. Recessions were measured at 3 months, 6 months and 9 months post-operatively. The results showed no statistically significant difference in mean recession at 3, 6 and 9 months post-operatively compared to baseline for both test and control groups. Thus, DFDBBX was ineffective in minimizing recession on patients with moderate to severe periodontitis, as compared to surgical debridement alone.
    Matched MeSH terms: Freeze Drying
  14. Chen D, Xia X, Wong TW, Bai H, Behl M, Zhao Q, et al.
    Macromol Rapid Commun, 2017 Apr;38(7).
    PMID: 28196300 DOI: 10.1002/marc.201600746
    Device applications of shape memory polymers demand diverse shape changing geometries, which are currently limited to non-omnidirectional movement. This restriction originates from traditional thermomechanical programming methods such as uniaxial, biaxial stretching, bending, or compression. A solvent-modulated programming method is reported to achieve an omnidirectional shape memory behavior. The method utilizes freeze drying of hydrogels of polyethylene glycol networks with a melting transition temperature around 50 °C in their dry state. Such a process creates temporarily fixed macroporosity, which collapses upon heating, leading to significant omnidirectional shrinkage. These shrunken materials can swell in water to form hydrogels again and the omnidirectional programming and recovery can be repeated. The fixity ratio (R f ) and recovery ratio (R r ) can be maintained at 90% and 98% respectively upon shape memory multicycling. The maximum linear recoverable strain, as limited by the maximum swelling, is ≈90%. Amongst various application potentials, one can envision the fabrication of multiphase composites by taking advantages of the omnidirectional shrinkage from a porous polymer to a denser structure.
    Matched MeSH terms: Freeze Drying
  15. Muhamad Haikal Zainal, Khairul Baqir Alkhair Khairul Amin, Oskar Hasdinor Hassan, Sharifah Aminah Syed Mohamad, Abd Malik Marwan Ali, Fathiah Abdullah, et al.
    Many kinds of substrates have been used to investigate bioelectricity production with Microbial Fuel Cell (MFC). Dry algae biomass has the highest maximum power density compared to other substrates due to high carbon sources from its lipid. However, the bacterial digestion of algae biomass is not simple because of the complexity and strength of the algal cell wall structure. An algae biomass extraction is needed to break the cell wall structure and facilitate digestion. Spray drying method is commonly used in highvalue products but may degrade some algal components which are crucial for microbial degradation in MFC, while the freeze-drying method is able to preserve algal cell constituents. The MFC was fed with freeze dried and spray dried algae biomass to produce energy and determine the degradation efficiency. Results showed the average voltage generated was 739 mV and 740 mV from freeze dried and spray dried algae biomass, respectively. The maximum power density of freeze dried algae biomass is 159.9 mW/m2 and spray dried algae biomass is 152.3 mW/m2. Freeze dried algae biomass has 54.2% of COD removal and 28.4% of Coulombic Efficiency while spray dried algae biomass has 50.1% of COD removal and 24.9% of Coulombic Efficiency.
    Matched MeSH terms: Freeze Drying
  16. Norhayati Pa'e, Nur Idayu Abd Hamid, Norzieana Khairuddin, Khairul Azly Zahan, Kok FS, Bazlul Mobin Siddique, et al.
    Sains Malaysiana, 2014;43:767-773.
    Nata de coco or bacterial cellulose produced by Acetobacter xylinum is a unique type of biocellulose. It contains more than 90% of water. Dried nata was preferred compared to wet form since it is more convenient and portable with stable properties. Therefore, drying process is necessary in order to produce dried nata de coco. Drying method is a key factor that influenced the properties of dried nata de coco produced. The aim of this study was to investigate the effect of different drying methods on morphology, crystallinity, swelling ability and tensile strength of dried nata de coco. Nata de coco samples were dried using three physical drying methods such as oven, tray dryer or freeze dryer until it achieved 3-5% moisture content. Obviously, the three drying techniques produced web-like structured nata de coco and quite similar crystallinity which was in range between 87 and 89%. Freeze dried sample showed the largest swelling capacity and tensile strength which was found to be 148 MPa. Different drying method gave different properties of nata de coco. Therefore, the present work proposed the most suitable drying method can be utilized based on the properties of end product needed.
    Matched MeSH terms: Freeze Drying
  17. Tee WF, Nazaruddin R, Tan YN, Ayob MK
    Food Sci Technol Int, 2014 Sep;20(6):399-404.
    PMID: 23774606 DOI: 10.1177/1082013213488775
    This study investigated the survival of encapsulated potential probiotic Lactobacillus plantarum which isolated from fermented cocoa beans. κ-Carrageenan was used to encapsulate the probiotic. Encapsulation techniques such as emulsification, freeze-drying or extrusion were adopted to encapsulate the probiotic. Freeze-drying and extrusion methods showed higher (p 
    Matched MeSH terms: Freeze Drying*
  18. Abdualkader AM, Ghawi AM, Alaama M, Awang M, Merzouk A
    Pak J Pharm Sci, 2013 May;26(3):525-35.
    PMID: 23625426
    The medicinal Malaysian leeches have been used in traditional medicine to treat many different ailments. In this study, leech saliva extract (LSE) was collected from the medicinal Malaysian leech Hirudinaria manillensis. Gel electrophoresis of LSE was carried out to estimate the peptide and protein molecular weights of its content. Results showed that LSE contains more than 60 peptides and proteins with molecular masses ranging from 1.9-250kDa. Thrombin time assay in vitro was employed to assess the collected LSE antithrombin activity. First, to study its stability, LSE was lyophilized under the following different conditions: pre-freezing temperature, type of container and lyophilization cycle. Pre-freezed LSE sample at -20°C and lyophilized for 24 hours retained about 100-95% of its original biological activities. Second, the LSE antithrombin activity was monitored for a period of six months. Storage temperature, type of the container and photosensitivity effects on antithrombin activity of the lyophilized (solid state) and non-lyophilized (liquid state) were investigated. Results showed that storage temperature drastically affected the biological activity of LSE with -20 °C as the optimum temperature. Samples stored at ambient temperature and +4 °C were light photosensitive and adversely affected when stored in polypropylene tubes. Lyophilized samples were more stable than non-lyophilized ones over the period of study. To sum up, in order to have a biologically active stock of LSE, it has to be lyophilized for no more than 24 hours following freezing at -20°C and has to be stored at -20°C in glass tubes protected from light.
    Matched MeSH terms: Freeze Drying/methods
  19. Mehrnoush A, Mustafa S, Yazid AM
    Int J Mol Sci, 2012;13(3):2939-50.
    PMID: 22489134 DOI: 10.3390/ijms13032939
    Response surface methodology (RSM) along with central composite design (CCD) was applied to optimize the freeze drying conditions for purified pectinase from mango (Mangifera indica cv. Chokanan) peel. The effect of pectinase content (-2.66, 62.66 mg/mL), Arabic gum (-1.21, 10.21%, w/v), and maltodextrin (0.73, 7.26%, w/v) as independent variables on activity, yield, and storage stability of freeze-dried enzyme was evaluated. Storage stability of pectinase was investigated after one week at 4 °C and yield percentage of the enzyme after encapsulation was also determined. The independent variables had the most significant (p < 0.05) effect on pectinase activity and yield of the enzyme. It was observed that the interaction effect of Arabic gum and maltodextrin improved the enzymatic properties of freeze-dried pectinase. The optimal conditions for freeze-dried pectinase from mango peel were obtained using 30 mg/mL of pectinase content, 4.5 (%, w/v) of Arabic gum, and 4 (%, w/v) of maltodextrin. Under these conditions, the maximum activity (11.12 U/mL), yield (86.4%) and storage stability (84.2%) of encapsulated pectinase were achieved.
    Matched MeSH terms: Freeze Drying/methods*
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