Min-Tze Liong

University of Science, Malaysia, George Town, Pulau Pinang, Malaysia

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Publications (45)82.69 Total impact

  • Article: Bioactives from probiotics for dermal health: functions and benefits.
    Lee-Ching Lew, Min-Tze Liong
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    ABSTRACT: Probiotics have been extensively reviewed for decades, emphasizing on improving general gut health. Recently, more studies showed that probiotics may exert other health promoting effects beyond gut well-being, attributed to the rise of the gut-brain-axis correlations. Some of these new benefits include skin health such as improving atopic eczema, atopic dermatitis, healing of burn and scars, skin rejuvenating properties, and improving skin innate immunity. Increasing evidences have also showed that bacterial compounds such as cell wall fragments, their metabolites and dead bacteria can elicit certain immune responses on the skin and improve skin barrier functions. This review aimed to underline the mechanisms or the exact compounds underlying the benefits of bacterial extract on the skin based on evidences from in vivo and in vitro studies. This review could be of help in screening of probiotic strains with potential dermal enhancing properties for topical applications. © 2013 The Authors Journal of Applied Microbiology © 2013 The Society for Applied Microbiology.
    Journal of Applied Microbiology 01/2013; · 2.34 Impact Factor
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    Article: Effects and applications of sub-lethal ultrasound, electroporation and UV radiations in bioprocessing
    Siok-Koon Yeo, Min-Tze Liong
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    ABSTRACT: Advances in bioprocess technology involving microbial cells have led to increased and improved pro-duction of beneficial new products and bioactive com-pounds. However, the semipermeable barrier of the cell membrane often retards the efficient productivity or reac-tion rate of the cells. Physical treatments such as ultra-sound, electroporation and UV radiation provide an efficient approach to increase membrane permeability, leading to enhanced productivity of microbial cells. It is important to note that extensive membrane permeabiliza-tion by these physical treatments could be detrimental to cell viability leading to lower yield. An appropriate selec-tion of sublethal dosage and intensity of these physical treatments are critical to preserve the viability of cells and at the same time maintain their bioprocess applications. Despite the promising applications of these physical treat-ments, safety issues related to possible genotoxicity or mutation of cells upon treatments have been raised. This genotoxic effect of physical treatments could be prevented if appropriate measures are taken, without compromising their bioprocess potentials. The current review highlights the effect of sublethal physical treatments such as ultra-sound, electroporation and UV radiation on the viability of cells, their potential bioprocess applications, and the pos-sibility of mutations.
    Annals of Microbiology 10/2012; · 0.69 Impact Factor
  • Article: Growth optimization of Lactobacillus rhamnosus FTDC 8313 and the production of putative dermal bioactives in the presence of manganese and magnesium ions.
    Lee-Ching Lew, Min-Tze Liong
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    ABSTRACT: AIMS: The study aimed to optimize the growth and evaluate the production of putative dermal bioactives from Lactobacillus rhamnosus FTDC 8313 using response surface methodology, in the presence of divalent metal ions namely manganese and magnesium. METHODS AND RESULTS: A central composite design matrix (alpha value of ± 1.414) was generated with two independent factors namely, manganese sulphate (MnSO(4) ) and magnesium sulphate (MgSO(4) ). The second-order regression model indicated that the quadratic model was significant (P < 0.01), suggesting that the model accurately represented the data in the experimental region. Three dimensional response surfaces predicted an optimum point with maximum growth of 10.59 log(10) CFU ml(-1) . The combination that produced the optimum point was 0.80 mg ml(-1) MnSO(4) and 1.09 mg ml(-1) MgSO(4) . A validation experiment was performed and data obtained showed a deviation of 0.30 % from the predicted value, ascertaining the predictions and the reliability of the regression model used. Effects of divalent metal ions on the production of putative dermal bioactives, namely hyaluronic acid, diacetyl, peptidoglycan, lipoteichoic acid and organic acids in the region of optimized growth were evaluated using 3D response surfaces generated. Evaluation based on the individual and interaction effects showed both manganese and magnesium played an important role on the production of these putative bioactives. CONCLUSIONS: Optimum growth of L. rhamnosus FTDC 8313 in reconstituted skimmed milk was achieved at 10.59 log(10) CFU ml(-1) in the presence of MnSO(4) (0.80 mg ml(-1) ) and MgSO(4) (1.09 mg ml(-1) ). Production of putative dermal bioactive and inhibitory compounds including hyaluronic acid, diacetyl, peptidoglycan, lipoteichoic acid and organic acids at the regions of optimized growth showed potential dermal applications. SIGNIFICANT AND IMPACTS OF STUDY: This research can serve as a fundamental study to further evaluate the potential of Lactobacillus strains in non-gut related roles such as dermal applications. © 2012The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.
    Journal of Applied Microbiology 10/2012; · 2.34 Impact Factor
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    Article: Effect of Ultrasound on Bioconversion of Isoflavones and Probiotic Properties of Parent Organisms and Subsequent Passages of Lactobacillus
    Siok-Koon Yeo, Min-Tze Liong
    LWT - Food Science and Technology. 10/2012;
  • Article: Effect of electroporation on viability and bioconversion of isoflavones in mannitol-soymilk fermented by lactobacilli and bifidobacteria.
    Siok-Koon Yeo, Min-Tze Liong
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    ABSTRACT: BACKGROUND: The aim of this study was to evaluate the effect of electroporation (2.5-7.5 kV cm(-1) for 3.0-4.0 ms) on the growth of lactobacilli and bifidobacteria, membrane properties and bioconversion of isoflavones in mannitol-soymilk. RESULTS: The viability of lactobacilli and bifidobacteria decreased immediately after electroporation. This was attributed to lipid peroxidation, which led to alterations in the membrane phospholipid bilayer, specifically at the polar head, interface and apolar tail regions. Such alterations also resulted in decreased membrane fluidity and increased membrane permeability upon electroporation (P < 0.05). However, the effect was reversible and treated cells showed better growth than the control upon fermentation for 24 h at 37 °C (P < 0.05). Additionally, electroporation increased the bioconversion of glucosides to bioactive aglycones in mannitol-soymilk, which was attributed to increased intracellular and extracellular β-glucosidase activities of cells upon treatment (P < 0.05). CONCLUSION: Application of electroporation on lactobacilli and bifidobacteria could be beneficial for the development of fermented soymilk with enhanced bioactivity. Considering the enhanced bioactive aglycones, this soymilk could be useful for the prevention of hormone-dependent disorders. Copyright © 2012 Society of Chemical Industry.
    Journal of the Science of Food and Agriculture 07/2012; · 1.44 Impact Factor
  • Article: Growth properties and cholesterol removal ability of electroporated Lactobacillus acidophilus BT 1088.
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    ABSTRACT: This study aimed to evaluate the effects of electroporation on the cell growth, cholesterol removal, and adherence abilities of L. acidophilus BT 1088 and their subsequent passages. The growth of electroporated parent cells increased (P<0.05) by 4.49-21.25% compared with that of the control. This may be attributed to the alteration of cellular membrane. However, growth of first, second, and third passages of treated cells was comparable with that of the control, which may be attributed to the resealing of transient pores on the cellular membrane. Electroporation also increased (P<0.05) assimilation of cholesterol by treated parent cells (>185.40%) and first passage (>21.72%) compared with that of the control. Meanwhile, incorporation of cholesterol into the cellular membrane was also increased (P<0.05) in the treated parent cells (>108.33%) and first passage (>26.67%), accompanied by increased ratio of cholesterol:phospholipids (C:P) in these passages. Such increased ratio was also supported by increased enrichment of cholesterol in the hydrophilic heads, hydrophobic tails, and the interface regions of the membrane phospholipids of both parent and first passage cells compared with that of the control. However, such traits were not inherited by the subsequent second and third passages. Parent cells also showed decreased intestinal adherence ability (P<0.05; decreased by 1.45%) compared with that of the control, without inheritance by subsequent passages of treated cells. Our data suggest that electoporation could be a potential physical treatment to enhance the cholesterol removal ability of lactobacilli that was inherited by the first passage of treated cells without affecting their intestinal adherence ability.
    Journal of Microbiology and Biotechnology 07/2012; 22(7):981-9. · 1.38 Impact Factor
  • Article: Bioconversion of isoflavones and the probiotic properties of the electroporated parent and subsequent three subcultures of Lactobacillus fermentum BT 8219 in biotin-soymilk.
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    ABSTRACT: This study was aimed at an evaluation of the potential inheritance of electroporation effects on Lactobacillus fermentum BT 8219 through to three subsequent subcultures, based on their growth, isoflavone bioconversion activities, and probiotic properties, in biotin-supplemented soymilk. Electroporation was seen to cause cell death immediately after treatment, followed by higher growth than the control during fermentation in biotin-soymilk (P<0.05). This was associated with enhanced intracellular and extracellular beta-glucosidase specific activity, leading to increased bioconversion of isoflavone glucosides to aglycones (P<0.05). The growing characteristics, enzyme, and isoflavone bioconversion activities of the first, second, and third subcultures of treated cells in biotin-soymilk were similar to the control (P>0.05). Electroporation affected the probiotic properties of parent L. fermentum BT 8219, by reducing its tolerance towards acid (pH 2) and bile, lowering its inhibitory activities against selected pathogens, and reducing its ability for adhesion, when compared with the control (P<0.05). The first, second, and third subcultures of the treated cells showed comparable traits with that of the control (P>0.05), with the exception of their bile tolerance ability, which was inherited to the treated cells of the first and second subcultures (P<0.05). Our results suggest that electroporation could be used to increase the bioactivity of biotin-soymilk via fermentation with probiotic L. fermentum BT 8219, with a view towards the development of functional foods.
    Journal of Microbiology and Biotechnology 07/2012; 22(7):947-59. · 1.38 Impact Factor
  • Article: Effects of ultrasound on growth, bioconversion of isoflavones and probiotic properties of parent and subsequent passages of Lactobacillus fermentum BT 8633 in biotin-supplemented soymilk.
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    ABSTRACT: This study aimed to evaluate the effects of ultrasound on Lactobacillus fermentum BT 8633 in parent and subsequent passages based on their growth and isoflavone bioconversion activities in biotin-supplemented soymilk. The treated cells were also assessed for impact of ultrasound on probiotic properties. The growth of ultrasonicated parent cells increased (P<0.05) by 3.23-9.14% compared to that of the control during fermentation in biotin-soymilk. This was also associated with enhanced intracellular and extracellular (8.4-17.0% and 16.7-49.2%, respectively; P<0.05) β-glucosidase specific activity, leading to increased bioconversion of isoflavones glucosides to aglycones during fermentation in biotin-soymilk compared to that of the control (P<0.05). Such traits may be credited to the reversible permeabilized membrane of ultrasonicated parent cells that have facilitated the transport of molecules across the membrane. The growing characteristics of first, second and third passage of treated cells in biotin-soymilk were similar (P>0.05) to that of the control, where their growth, enzyme and isoflavone bioconversion activities (P>0.05) were comparable. This may be attributed to the temporary permeabilization in the membrane of treated cells. Ultrasound affected probiotic properties of parent L. fermentum, by reducing tolerance ability towards acid (pH 2) and bile; lowering inhibitory activities against selected pathogens and reducing adhesion ability compared to that of the control (P<0.05). The first, second and third passage of treated cells did not exhibit such traits, with the exception of their bile tolerance ability which was inherited to the first passage (P<0.05). Our results suggested that ultrasound could be used to increase bioactivity of biotin-soymilk via fermentation by probiotic L. fermentum FTDC 8633 for the development of functional food.
    Ultrasonics Sonochemistry 07/2012; 19(4):890-900. · 3.57 Impact Factor
  • Article: Physical, chemical and physicochemical characterization of rice husk
    Chiu-Yin Kuan, Kay-Hay Yuen, Min-Tze Liong
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    ABSTRACT: Purpose – This paper aims to investigate the physical, chemical and physicochemical characteristics of rice husk on alkaline treatment. Design/methodology/approach – Rice husk (RM) was alkaline treated to produce soluble (SR) and insoluble residues (IR). Each fraction was characterized and soluble fraction was used to produce nanofibres using electrospinning method. Findings – Alkaline treatment was effective in isolating insoluble dietary fibre rich IR from the other interfering substances such as soluble dietary fibre, protein and lipids that originally present in RM and leached into SR. The problem of silica induced toxicity and indigestibility of rice husk was overcome by alkaline treatment. Alkaline treatment altered the inherent mineral content (calcium, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, zinc) of rice husk, and increased physicochemical properties such as emulsification ability and stability, water holding ability, mineral binding capacity (calcium, copper, iron, zinc), and antioxidant activity. SR had been successfully electrospun into nanofibres with the addition of polyvinyl alcohol. Originality/value – The paper investigated the characteristic of rice husk (RM and IR) for the development of functional foods, pharmaceutical products and new bioactives delivery system at the expense of reducing environmental liability.
    British Food Journal 06/2012; 114(6):853-867. · 0.70 Impact Factor
  • Article: Probiotic properties of bifidobacteria and lactobacilli isolated from local dairy products
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    ABSTRACT: Fourteen strains of lactobacilli and bifidobacteria were isolated from raw milk and fermented dairy products produced by local traditional industries. These strains were evaluated for potential use as probiotics based on their adhesion to intestinal epithelial cells, resistance towards acidic and bile conditions, and antimicrobial activities. All strains exhibited varying levels of adhesion properties on mucin that were strain-dependent. Although most strains tolerated acidic conditions of pH 2, 3, and 4, the viability of the Lactobacillus and Bifidobacterium strains was significantly (P < 0.05) reduced at pH 2. Most strains also tolerated bile conditions similar to that of the gastrointestinal tract. A higher inhibition was observed in the presence of deconjugated bile, such as cholic acid, compared to deconjugated bile, such as taurocholic acid. In addition, most strains also showed antimicrobial activity towards intestinal pathogens, such as Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Salmonella typhimurium, Bacillus subtilis, and Pseudomonas aeruginosa. The findings from this study show that strains of lactobacilli and bifidobacteria isolated from local dairy products may be promising probiotics for use as dietary adjuncts or the development of new functional foods. KeywordsProbiotics–Mucin–Acid–Bile–Antimicrobial
    Annals of Microbiology 05/2012; · 0.69 Impact Factor
  • Article: Growth characteristics and bioactivity of probiotics in tofu-based medium during storage
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    ABSTRACT: Lactobacillus acidophilus FTCC 0291,Lactobacillus bulgaricus FTCC 0411Lactobacillus casei FTCC 0442,Lactobacillus fermentum FTD 13 andBifidobacterium bifidum BB 12 were screened for their α-galactosidase activity over 24 h.Lactobacillus bulgaricus FTCC 0411 andL. fermentum FTD 13 showed highest α-galactosidase specific activity and were selected to be incorporated into tofufa for a storage study of 9 days at 25 and 4 °C. The viability of both probiotics in tofufa exceeded 106 CFU/g and was maintained over storage, mainly contributed by their ability to hydrolyse oligosaccharides and to utilise the reducing sugars produced. The presence of probiotics in tofufa showed an increase in the concentrations of organic acids which led to a decrease in pH levels. This exhibited a preservative effect, where total aerobes and total anaerobes were 2 log10 CFU/g lower than the control. Probiotics in tofufa also liberated peptides with angiotensin-converting enzyme (ACE) inhibitory properties. Consistent viability and high proteolytic activity of probiotics in tofufa during storage suggested that tofufa is a suitable carrier for live probiotics with bioactive potential.
    Annals of Microbiology 04/2012; 58(3):477-487. · 0.69 Impact Factor
  • Article: Growth, bioconversion of isoflavones and probiotic properties of parent and subsequent passages of Lactobacillus upon ultraviolet radiation.
    Siok-Koon Yeo, Min-Tze Liong
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    ABSTRACT: The objective of this study was to evaluate the effects of ultraviolet (UV) radiation (UVB; 90 J/m(2)) on growth, bioconversion of isoflavones and probiotic properties of parent and subsequent passages of L. casei FTDC 2113. UV radiation significantly enhanced (P < 0.05) the growth of parent cells in mannitol-soymilk fermented at 37°C for 24 h. This had led to an enhanced intracellular and extracellular β-glucosidase activity with a subsequent increase in bioconversion of isoflavones in mannitol-soymilk (P < 0.05). UV radiation also promoted (P < 0.05) the tolerance of parent cells towards acidic condition (pH 2 and 3) and intestinal bile salts (oxgall, taurocholic and cholic acid). In addition, parent treated cells also exhibited better (P < 0.05) adhesion ability to mucin and antimicrobial activity compared to that of the control. All these positive effects of UV radiation were only prevalent in the parent cells without inheritance by first, second and third passage of cells. Although temporary, our results suggested that UV radiation could enhance the bioactive and probiotic potentials of L. casei FTDC 2113, and thus could be applied for the production of probiotic products with enhanced bioactivity.
    International Journal of Food Sciences and Nutrition 01/2012; 63(7):821-31. · 1.15 Impact Factor
  • Article: Nanotech: propensity in foods and bioactives.
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    ABSTRACT: Nanotechnology is seeing higher propensity in various industries, including food and bioactives. New nanomaterials are constantly being developed from both natural biodegradable polymers of plant and animal origins such as polysaccharides and derivatives, peptides and proteins, lipids and fats, and biocompatible synthetic biopolyester polymers such as polylactic acid (PLA), polyhydroxyalkonoates (PHA), and polycaprolactone (PCL). Applications in food industries include molecular synthesis of new functional food compounds, innovative food packaging, food safety, and security monitoring. The relevance of bioactives includes targeted delivery systems with improved bioavailability using nanostructure vehicles such as association colloids, lipid based nanoencapsulator, nanoemulsions, biopolymeric nanoparticles, nanolaminates, and nanofibers. The extensive use of nanotechnology has led to the need for parallel safety assessment and regulations to protect public health and adverse effects to the environment. This review covers the use of biopolymers in the production of nanomaterials and the propensity of nanotechnology in food and bioactives. The exposure routes of nanoparticles, safety challenges, and measures undertaken to ensure optimal benefits that outweigh detriments are also discussed.
    Critical reviews in food science and nutrition 01/2012; 52(1):55-71. · 3.73 Impact Factor
  • Article: Enhanced growth of lactobacilli and bioconversion of isoflavones in biotin-supplemented soymilk upon ultrasound-treatment.
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    ABSTRACT: This study aimed at utilizing ultrasound treatment to further enhance the growth of lactobacilli and their isoflavone bioconversion activities in biotin-supplemented soymilk. Strains of lactobacilli (Lactobacillus acidophilus BT 1088, L. fermentum BT 8219, L. acidophilus FTDC 8633, L. gasseri FTDC 8131) were treated with ultrasound (30 kHz, 100 W) at different amplitudes (20%, 60% and 100%) for 60, 120 and 180 s prior to inoculation and fermentation in biotin-soymilk. The treatment affected the fatty acids chain of the cellular membrane lipid bilayer, as shown by an increased lipid peroxidation (P<0.05). This led to increased membrane fluidity and subsequently, membrane permeability (P<0.05). The permeabilized cellular membranes had facilitated nutrient internalization and subsequent growth enhancement (P<0.05). Higher amplitudes and longer durations of the treatment promoted growth of lactobacilli in soymilk, with viable counts exceeding 9 log CFU/mL. The intracellular and extracellular β-glucosidase specific activities of lactobacilli were also enhanced (P<0.05) upon ultrasound treatment, leading to increased bioconversion of isoflavones in soymilk, particularly genistin and malonyl genistin to genistein. Results from this study show that ultrasound treatment on lactobacilli cells promotes (P<0.05) the β-glucosidase activity of cells for the benefit of enhanced (P<0.05) isoflavone glucosides bioconversion to bioactive aglycones in soymilk.
    Ultrasonics Sonochemistry 01/2012; 19(1):160-73. · 3.57 Impact Factor
  • Article: Enhanced growth of lactobacilli and bioconversion of isoflavones in biotin-supplemented soymilk by electroporation.
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    ABSTRACT: This study aimed at utilizing electroporation to further enhance the growth of lactobacilli and their isoflavone bioconversion activities in biotin-supplemented soymilk. Strains of lactobacilli were treated with different pulsed electric field strength (2.5, 5.0 and 7.5 kV/cm) for 3, 3.5 and 4 ms prior to inoculation and fermentation in biotin-soymilk at 37°C for 24 h. Electroporation triggered structural changes within the cellular membrane of lactobacilli that caused lipid peroxidation (p < 0.05) and alteration of membrane fluidity (p < 0.05). This was due to the application of electric potential difference across membrane that induced pores formation and subsequently increased membrane permeability. Reversible permeabilized cells resumed growth to >9 log CFU/ml after fermentation in biotin-soymilk (p < 0.05). Lactobacilli cells treated at electric field strength of 7.5 kV/cm for 3.5 ms also showed enhanced β-glucosidase activity (p < 0.05) compared to lower doses and control, leading to increased bioconversion of isoflavones glucosides to aglycones in biotin-soymilk (p < 0.05). Results from this study show that electroporation could be used to produce biotin-soymilk with increased bioactive aglycones.
    International Journal of Food Sciences and Nutrition 12/2011; 63(5):580-96. · 1.15 Impact Factor
  • Article: Enhanced growth and bioconversion of isoflavones in prebiotic-soymilk fermented by UV-treated lactobacilli and bifidobacteria.
    Siok-Koon Yeo, Min-Tze Liong
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    ABSTRACT: The aim of this study was to evaluate the effects of ultraviolet (UV) radiation (ultraviolet A (UVA), ultraviolet B (UVB) and ultraviolet C (UVC) at 30-90 J/m²) on the membrane properties of lactobacilli and bifidobacteria, and their bioconversion of isoflavones in prebiotic-soymilk. UV treatment caused membrane permeabilization and alteration at the acyl chain, polar head and interface region of membrane bilayers via lipid peroxidation. Such alteration subsequently led to decreased (p < 0.05) viability of lactobacilli and bifidobacteria immediately after the treatment. However, the effect was transient where cells treated with UV, particularly UVA, grew better in prebiotic-soymilk than the control upon fermentation at 37°C for 24 h (p < 0.05). In addition, UV treatment also increased (p < 0.05) the intracellular and extracellular β-glucosidase activity of lactobacilli and bifidobacteria. This was accompanied by an increased (p < 0.05) bioconversion of glucosides to bioactive aglycones in prebiotic-soymilk. Our present study illustrated that treatment of lactobacilli and bifidobacteria with UV could develop a fermented prebiotic-soymilk with enhanced bioactivity.
    International Journal of Food Sciences and Nutrition 12/2011; 63(5):566-79. · 1.15 Impact Factor
  • Article: Ultrasound treatment enhances cholesterol removal ability of lactobacilli.
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    ABSTRACT: This study aimed to evaluate the effect of ultrasound treatment on the cholesterol removing ability of lactobacilli. Viability of lactobacilli cells was significantly increased (P < 0.05) immediately after treatment, but higher intensity of 100 W and longer duration of 3 min was detrimental on cellular viability (P < 0.05). This was attributed to the disruption of membrane lipid bilayer, cell lysis and membrane lipid peroxidation upon ultrasound treatment at higher intensity and duration. Nevertheless, the effect of ultrasound on membrane properties was reversible, as the viability of ultrasound-treated lactobacilli was increased (P < 0.05) after fermentation at 37 °C for 20 h. The removal of cholesterol by ultrasound-treated lactobacilli via assimilation and incorporation of cholesterol into the cellular membrane also increased significantly (P < 0.05) upon treatment, as observed from the increased ratio of membrane C:P. Results from fluorescence anisotropies showed that most of the incorporated cholesterol was saturated in the regions of phospholipids tails, upper phospholipids, and polar heads of the membrane bilayer.
    Ultrasonics Sonochemistry 08/2011; 19(3):632-41. · 3.57 Impact Factor
  • Chapter: Carriers of Probiotic Microorganisms
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    ABSTRACT: There is a growing market potential for probiotic foods as an alternative to enhance human health. Milk-based products including milk beverage, yogurts, cheese and ice cream are conventionally used as the most suitable delivery vehicle for probiotics. Despite being an ideal substrate for probiotics, the growth of probiotics in these products is often inhibited due to excessive acidification, antagonistic effect of starter culture and the presence of oxygen during processing. Various means are evaluated to enhance the viability of probiotics, including supplementation with growth enhancer and protection by microencapsulation. The drawbacks of milk-based carrier associated with cholesterol contents and lactose intolerance have prompted the development of alternative carriers for probiotics. Currently, new foods such as soy-based products, cereal-based products, fruits, vegetables and meat products are developed as potential carriers. These nondairy-based products contain reasonable amounts of carbohydrates, fibers, proteins and vitamins that support the growth of probiotics. In addition, some components of these products are able to protect probiotics during transit through the harsh condition of gastrointestinal tract and during storage. However, growths in nondairy products such as sausage and fruit juices are inhibited by the presence of inhibitory substances such as nisin, organic acids and curing salts. Therefore, appropriate selection of culture used in these products is crucial in maintaining the viability of cells, without affecting the sensory and organoleptic property of the final products.
    07/2011: pages 191-220;
  • Article: Agrowaste-based nanofibers as a probiotic encapsulant: fabrication and characterization.
    Wai-Yee Fung, Kay-Hay Yuen, Min-Tze Liong
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    ABSTRACT: This study explored the potential of soluble dietary fiber (SDF) from agrowastes, okara (soybean solid waste), oil palm trunk (OPT), and oil palm frond (OPF) obtained via alkali treatment, in the nanoencapsulation of Lactobacillus acidophilus . SDF solutions were amended with 8% poly(vinyl alcohol) to produce nanofibers using electrospinning technology. The spinning solution made from okara had a higher pH value at 5.39 ± 0.01 and a higher viscosity at 578.00 ± 11.02 mPa·s (P < 0.05), which resulted in finer fibers. FTIR spectra of nanofibers showed the presence of hemicellulose material in the SDF. Thermal behavior of nanofibers suggested possible thermal protection of probiotics in heat-processed foods. L. acidophilus was incorporated into the spinning solution to produce nanofiber-encapsulated probiotic, measuring 229-703 nm, visible under fluorescence microscopy. Viability studies showed good bacterial survivability of 78.6-90% under electrospinning conditions and retained viability at refrigeration temperature during the 21 day storage study.
    Journal of Agricultural and Food Chemistry 06/2011; 59(15):8140-7. · 2.82 Impact Factor
  • Article: Development of a probiotic delivery system from agrowastes, soy protein isolate, and microbial transglutaminase.
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    ABSTRACT: Probiotic delivery system was developed via the use of microbial transglutaminase (MTG) cross-linked soy protein isolate (SPI) incorporated with agrowastes such as banana peel (BE), banana pulp (BU), and pomelo rind (PR). Inoculums of Lactobacillus bulgaricus FTDC 1511 were added to the cross-linked protein matrix. The incorporation of agrowastes had significantly (P<0.05) reduced the strength, pH value, and the lightness of the SPI gel carriers, while sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles revealed that the occurring cross-links within the SPI gel carriers were attributed to the addition of MTG. Scanning electron microscope micrographs illustrated that SPI carriers containing agrowastes have exhibited a less-dense protein matrix. All the SPI carriers possessed maximum swelling ratio at 4 to 4.5 within 15 min in simulated gastric fluid (SGF), whereas the maximum swelling ratios of SPI/BE, SPI/BU, and SPI/PR were higher compared to that of control in simulated intestinal fluid (SIF). Additionally, SPI carriers in SGF medium did not show degradation of structure, whereas a major collapse of network was observed in SIF medium, indicating controlled-release in the intestines. The addition of agrowastes into SPI carriers led to a significantly (P<0.0001) lower release of L. bulgaricus FTDC 1511 in SGF medium and a higher release in SIF medium, compared to that of the control. SPI carriers containing agrowastes may be useful transports for living probiotic cells through the stomach prior to delivery in the lower intestines. PRACTICAL APPLICATION:  Agrowastes could be utilized as a new probiotic carrier for enhanced gastrointestinal transit and during storage. This also reduces the amount of agrowastes accumulated.
    Journal of Food Science 04/2011; 76(3):H108-15. · 1.66 Impact Factor