Klebsiella pneumoniae is a pathogen associated with various infection types, which often exhibits multiple antibiotic resistance. Phages, or bacterial viruses, have an ability to specifically target and destroy K. pneumoniae, offering a potential means of combatting multidrug-resistant infections. Phage enzymes are another promising therapeutic agent that can break down bacterial capsular polysaccharide, which shields K. pneumoniae from the immune response and external factors. In this study, Klebsiella phage K5 was isolated; this phage is active against Klebsiella pneumoniae with the capsular type K21. It was demonstrated that the phage can effectively lyse the host culture. The adsorption apparatus of the phage has revealed two receptor-binding proteins (RBPs) with predicted polysaccharide depolymerising activity. A recombinant form of both RBPs was obtained and experiments showed that one of them depolymerised the capsular polysaccharide K21. The structure of this polysaccharide and its degradation fragments were analysed. The second receptor-binding protein showed no activity on capsular polysaccharide of any of the 31 capsule types tested, so the substrate for this enzyme remains to be determined in the future. Klebsiella phage K5 may be considered a useful agent against Klebsiella infections.
The aim of this study was to determine the effects of xanthan gum and carrageenan on the
oil uptake and acceptability of banana (Musa acuminate) fritters during repeated deep fat
frying. Banana namely ‘Pisang Awak’ at maturity stage 6 were peeled, cut and dipped into 3
batter formulations containing 1% carrageenan, 1% xanthan gum and a control. The bananas
were deep fried at 170±5°C for 3 minutes in 2.5L cooking oil without oil replenishment for
3 consecutive days. The moisture, oil content, texture, colour and acceptability of the banana
fritters were evaluated at first and every 10th frying cycles. Results indicated that the oil and
moisture content of fried bananas were dependent on frying cycles. The oil content increased
while the moisture decreased with increased in frying cycles. There was significant reduction
(p0.05) in terms of overall acceptance between
treated and untreated. Hence, 1% xanthan gum was effective in reducing oil absorption of
banana fritters without affecting the overall sensory acceptability
Food manufacturers are interested in developing emulsion-based products into nutritional foods by using beneficial oils, such as fish oil and virgin coconut oil (VCO). In this study, the physicochemical properties of a VCO oil-in-water emulsion was investigated and compared to other commercial oil-in-water emulsion products (C1, C2, C3, and C4). C3 exhibited the smallest droplet size of 3.25 µm. The pH for the emulsion samples ranged from 2.52 to 4.38 and thus were categorised as acidic. In a texture analysis, C2 was described as the most firm, very adhesive and cohesive, as well as having high compressibility properties. From a rheological viewpoint, all the emulsion samples exhibited non-Newtonian behaviour, which manifested as a shear-thinning property. The G'G'' crossover illustrated by the VCO emulsion in the amplitude sweep graph but not the other commercial samples illustrated that the VCO emulsion had a better mouthfeel. In this context, the VCO emulsion yielded the highest zeta potential (64.86 mV), which was attributed to its strong repulsive forces, leading to a good dispersion system. C2 comprised the highest percentage of fat among all emulsion samples, followed by the VCO emulsion, with 18.44% and 6.59%, respectively.
Geobacillus sp. WSUCF1 is a Gram-positive, spore-forming, aerobic and thermophilic bacterium, isolated from a soil sample obtained from a compost facility. Strain WSUCF1 demonstrated EPS producing capability using different sugars as the carbon source. The whole-genome analysis of WSUCF1 was performed to disclose the essential genes correlated with nucleotide sugar precursor biosynthesis, assembly of monosaccharide units, export of the polysaccharide chain, and regulation of EPS production. Both the biosynthesis pathway and export mechanism of EPS were proposed based on functional annotation. Additionally, the genome description of strain WSUCF1 suggests sophisticated systems for its adaptation under thermophilic conditions. The presence of genes associated with CRISPR-Cas system, quorum quenching lactonase, polyketide synthesis and arsenic resistance makes this strain a potential candidate for various applications in biotechnology and biomedicine. The present study indicates that strain WSUCF1 has promise as a thermophilic EPS producer for a broad range of industrial applications. To the best of our knowledge, this is the first report on genome analysis of a thermophilic Geobacillus species focusing on its EPS biosynthesis and transportation, which will likely pave the way for both enhanced yield and tailor-made EPS production by thermophilic bacteria.
The purpose of this study was to simultaneously predict the drug release and skin permeation of Piroxicam (PX) topical films based on Chitosan (CTS), Xanthan gum (XG) and its Carboxymethyl derivatives (CMXs) as matrix systems. These films were prepared by the solvent casting method, using Tween 80 (T80) as a permeation enhancer. All of the prepared films were assessed for their physicochemical parameters, their in vitro drug release and ex vivo skin permeation studies. Moreover, deep learning models and machine learning models were applied to predict the drug release and permeation rates. The results indicated that all of the films exhibited good consistency and physicochemical properties. Furthermore, it was noticed that when T80 was used in the optimal formulation (F8) based on CTS-CMX3, a satisfactory drug release pattern was found where 99.97% of PX was released and an amount of 1.18 mg/cm2 was permeated after 48 h. Moreover, Generative Adversarial Network (GAN) efficiently enhanced the performance of deep learning models and DNN was chosen as the best predictive approach with MSE values equal to 0.00098 and 0.00182 for the drug release and permeation kinetics, respectively. DNN precisely predicted PX dissolution profiles with f2 values equal to 99.99 for all the formulations.
The effects of xanthan gum (XG) and hydroxypropyl methylcellulose (HPMC) in sponge cakes were studied. Hydrocolloids enhanced the thickening effect in batter that affected the textural attributes of sponge cakes. During storage, the structural changes in XG-cake resulted in higher hardness compared to HPMC-cake. Similar to XG, HPMC also contributed moistness to cake. The moisture loss of cake containing XG was slower than HPMC-cake. FTIR study showed absorption of OH at region of 3600-2900 cm-1 that explained the strong interaction of water in cake containing XG compared to other cake formulations.
Bacterial cellulose (BC) is a biopolymer with significant potential for the development of novel materials. This work aimed to prepare and characterize BC powders from nata de coco, and assess the possible enhancement of the powder properties by spray drying. Therefore, BC powders prepared by acid treatment and mechanical processing were spray-dried, and characterized according to their morphology, flowability, thermal stability, water retention capacity, and compared with commercial microcrystalline cellulose (MCC). The powders redispersibility and suspensions rheology were also evaluated. SEM showed that spray-dried BC microparticles exhibited semispherical shape and had flow rate of 4.23 g s(-1) compared with 0.52 g s(-1) for MCC. Particle size analysis demonstrated that spray-dried BC microparticles could be redispersed. TGA showed that BC samples had higher thermal stability than MCC. Water retention capacities of BC samples were greater than MCC. These findings provide new insight on the potential applications of spray-dried BC as a promising pharmaceutical excipient.
Acrylated abietic acid (acrylated AbA) and acrylated abietic acid-grafted bacterial cellulose pH sensitive hydrogel (acrylated AbA-g-BC) were prepared by a one-pot synthesis. The successful dimerization of acrylic acid (AA) and abietic acid (AbA) and grafting of the dimer onto bacterial cellulose (BC) was confirmed by 13C solid state NMR as well as FT-IR. X-ray diffraction analysis showed characteristic peaks for AbA and BC; further, there was no effect of increasing amorphous AA content on the overall crystallinity of the hydrogel. Differential scanning calorimetry revealed a glass transition temperature of 80°C. Gel fraction and swelling studies gave insight into the features of the hydrogel, suggesting that it was suitable for future applications such as drug delivery. Scanning electron microscopy observations showed an interesting interpenetrating network within the walls of hydrogel samples with the lowest levels of AA and gamma radiation doses. Cell viability test revealed that the synthesized hydrogel is safe for future use in biomedical applications.
The purpose of this research was to study processing variables at the laboratory and pilot scales that can affect hydration rates of xanthan gum matrices containing diclofenac sodium and the rate of drug release. Tablets from the laboratory scale and pilot scale proceedings were made by wet granulation. Swelling indices of xanthan gum formulations prepared with different amounts of water were measured in water under a magnifying lens. Granules were thermally treated in an oven at 60 degrees C, 70 degrees C, and 80 degrees C to study the effects of elevated temperatures on drug release from xanthan gum matrices. Granules from the pilot scale formulations were bulkier compared to their laboratory scale counterparts, resulting in more porous, softer tablets. Drug release was linear from xanthan gum matrices prepared at the laboratory scale and pilot scales; however, release was faster from the pilot scales. Thermal treatment of the granules did not affect the swelling index and rate of drug release from tablets in both the pilot and laboratory scale proceedings. On the other hand, the release from both proceedings was affected by the amount of water used for granulation and the speed of the impeller during granulation. The data suggest that processing variables that affect the degree of wetness during granulation, such as increase in impeller speed and increase in amount of water used for granulation, also may affect the swelling index of xanthan gum matrices and therefore the rate of drug release.
Olive oil-entrapped diethanolamine-modified high-methoxyl pectin (DMP)-gellan gum (GG)-bionanofiller composites were developed for controlled intragastric delivery of metformin HCl (MFM). DMP had a degree of amidation of 48.7% and was characterized further by FTIR, XRD and DSC analyses. MFM-loaded composites were subsequently accomplished by green synthesis via ionotropic gelation technique using zinc acetate as cross-linker. The thermal, X-ray and infrared analyses suggested an environment in the composites compatible with the drug, except certain degree of attenuation in drug's crystallinity. Scanning electron microscopy revealed almost spherical shape of the composites. Depending upon the mass ratios of GG:DMP, types of nanofiller (neusilin/bentonite/Florite) and oil inclusion, the composites exhibited variable drug encapsulation efficiency (DEE, 50-85%) and extended drug release behaviours (Q8h, 69-94%) in acetate buffer (pH 4.5). The optimized oil-entrapped Florite R NF/GG: DMP (1:1) composites eluted MFM via case-II transport mechanism and its drug release data was best fitted in zero-order kinetic model. The optimized formulation demonstrated excellent gastroretentive properties and substantial hypoglycemic effect in streptozotocin-induced diabetic rats. These novel hybrid matrices were thus found suitable for controlled intragastric delivery of MFM for the management of type 2 diabetes.
The impacts on both rheological parameters; Casson yield stress and Casson viscosity were determined. The interactions among blend’s components; xanthan gum (XG), corn starch (CS), glycerin (GL) and their relationship with both flow parameters were also investigated by using D-Optimal mixture design. Three levels of cocoa butter substitution assigned in chocolate production were at 5%, 10% and 15% level with random proportions of each component generated by Design Expert software. An appropriate mathematical model was applied to evaluate each response as a function of the proportions of the components enabling in prediction of future response by using any blend of components. As the incorporation of the blends (XG/CS/GL) in chocolate production was elevated from 5% to 15%, both parameters; viscosity and yield stress of chocolate were gradually increased, as in range 7.819 to 10.529 Pa, and 2.372 to 3.727 Pa.s, respectively. Neither binary nor ternary component-component interaction exhibited synergistic effect. Nevertheless, strongest antagonistic effect on both rheological parameters of substituted chocolate at 5% level and 10% level were respectively observed at ternary interaction region for the former, and at binary interaction area of CS:GL, closer to CS corner as for the latter. This study somehow provides ideas on how component-component interactions influence experimented response.
The aim of this work is to study the effect of hydrocolloids (guar gum, xanthan gum and carboxymethyl cellulose (CMC) on the physical properties and sensory evaluation of ice cream produced in order to investigate the potential of applying fermented glutinous rice (tapai pulut) as a value-added ingredient. The addition of 25% fermented glutinous rice was the most reliable amount to enhance the physical and sensory properties of ice cream when incorporating hydrocolloids. The addition of hydrocolloids significantly (p < 0.05) increased the pH, firmness, overrun, and melting rate of fermented glutinous rice ice cream. The addition of guar gum scored the highest firmness value (5403 g) followed by CMC (4630 g) and xanthan gum (3481g). Fermented glutinous rice ice cream with xanthan gum added, induced a noticeable change in overrun value (62%) while the addition of CMC decreased the melting rate compared to the control. The FTIR spectrum of fermented glutinous rice ice cream with different hydrocolloids containing carboxyl, amide and carbonyl group was appeared at 3362-3379 cm-1 , 1639-1640 cm-1 and 1026-1064 cm-1, respectively. In conclusion, the addition of xanthan gum presented great potential to improve the quality of fermented glutinous rice ice cream produced in terms of its firmness, overrun and melting rate.
Impacts and relationships on physicochemical properties in dark chocolate produced from different substitution for cocoa butter by Xanthan gum (XG) and Guar gum (GG) blends were determined using D-optimal mixture design. This study involved three levels of substitution which are 5%, 10% and 15% with constrained cocoa butter content and random blend of gums. Linear design models were applied to analyze parameters including texture (hardness) measurement and melting profile of fat crystal. Products experienced undesirable raises of hardness jointly with the increment of gums incorporation across the level of cocoa butter replacement from 5% to 15%. Similar trend was also agreed with the melting behavior of products as their melting point increased with the gradual diminution of cocoa butter. After all, the replacement of cocoa butter using hydrocolloids was deemed possible as there were products whose melting point and hardness fell in the acceptable range.
The aim of this work was to investigate the effect of glycerol concentration on mechanical
and physical properties of gellan gum (GG) biofilm. The biofilm was prepared using solvent
casting method and the effective glycerol concentration was found to be within 30-50%
w/w (based on GG weight). At 60 and 70 w/w% of glycerol, the films started to distort
because the films was flexible and brittle. As glycerol concentration was increased the tensile
strength (TS) and Youngs modulus (E) of films decreased. Somehow, elongation at break
(EAB), water vapor transmission rate (WVTR) and swelling of films was increased. Glycerol
plasticized GG biofilm was thermally stable and flexible, proposed its can be exploited as
film-forming material and with optimized glycerol concentration it has good mechanical and
physical properties for edible biofilm.
Xanthan integrated graphene oxide functionalized by titanium dioxide was successfully prepared through facile, eco-friendly and cost effective ice-templating technique. The three-dimensional (3D) graphene composite demonstrated relatively high temperature stability, chemical functionalities and porous sponge-like structure. The adsorption of lead was favored by high initial concentration and shaking speed at the operational solution pH. The process equilibrium and kinetic adhered to the Langmuir and pseudo-second-order correlations, respectively. The biomass integrated graphene composite showed maximum adsorption capacities ranging from 132.18 to 199.22 mg/g for 30-70 °C. Moreover, it was highly regenerable under mild conditions (0.1 M hydrochloric acid, 30 °C) and used repeatedly while retaining 84.78% of its initial adsorption capacity at the fifth adsorption-regeneration cycle. With comparatively high lead adsorption capacities, adequate recyclability and environmentally friendliness, the as-prepared 3D graphene composite has high application potential in heavy metal-wastewater separation for protection of the environment and human health.
Gellan gum incorporating titanium dioxide nanoparticles biofilm was synthesized and characterized using UV, FTIR and XRD to study their physical and chemical properties. The mechanical properties were measured using universal mechanical testing. Meanwhile, the biological properties were investigated towards for antibacterial and cell proliferation. This comprehensive data are relevant with the research article entitled "Gellan gum incorporating titanium dioxide nanoparticles biofilm as wound dressing: Physicochemical, mechanical, antibacterial properties and wound healing studies" [1].
The effects of alginate-based [sodium alginate, 0-2% (w/v), glycerol, 0-2% (w/v) and sunflower oil 0.025% (w/v)] and gellan-based [gellan, 0-1% (w/v), glycerol, 0-1% (w/v) and sunflower oil 0.025% (w/v)] edible coatings on fresh-cut pineapple were evaluated by response surface methodology (RSM). Weight loss, firmness and respiration rate were considered as response variables. The results showed that for all response variables the RSM models were significantly (p0.05) difference between predicted and experimental values. The overall optimum region predicted by RSM indicated that alginate and gellan-based coatings containing 1.29% (w/v) sodium alginate, 1.16% (w/v) glycerol and 0.56% (w/v) gellan gum, 0.89% (w/v) glycerol were optimized formulations respectively.
Dough mixing and thermal properties including the pasting profiles of various commercial wheat flour (WF)-banana pseudostem flour (BP)-hydrocolloid blends were determined using a farinograph, differential scanning calorimetry (DSC) and a rapid-visco analyser (RVA). The prepared blends were WF, WF substituted with 10% BP (10BP) and 10BP with added 0.8% w/w (flour weight basis) xanthan gum (XG) or sodium carboxymethylcellulose (CMC) (10BPX and 10BPC, respectively). The dough of 10BP and the doughs containing XG or CMC reduced stability and breakdown time compared with the WF dough. All dough containing BP demonstrated greater water absorption and mixing tolerance index values than the WF dough. The substitution of 10% BP into WF and the addition of hydrocolloids did not significantly affect the conclusion temperature (Tc) of the mixture, but did increased the onset temperature (To), peak temperature (Tp) and decreased the gelatinisation enthalpy change (ΔHg) of the blends. Samples of 10BP, 10BPX and 10BPC significantly decreased (p
Starch and hydrocolloids were often used together in food industry to modify the rheological properties with the aim to enhance the starch tolerance to processing conditions. As such, the rheological properties of xanthan gum (XG), carrageenan, high (HMP) and low methoxyl pectin (LMP), with native corn starch (NCS) and modified corn starch (MCS) at different temperature were evaluated in this study. The flow behavior index (n) of corn starch-hydrocolloid mixtures were observed in the range from 0.160 to 0.604 where indicated the shear thinning behavior. The addition of hydrocolloids increased the apparent viscosity of the starch system. NCS mixtures showed consistency index (K) and apparent viscosities (na,100) decreased with increase in the temperature. The addition of XG and carrageenan increased the storage (G’) and loss (G”) moduli. Among the hydrocolloids, the XG addition to the NCS exhibited superior viscoelastic properties as evidenced by the highest G’ and lowest tan δ values. XG was observed capable to increase while pectin reduced the solid-like starch system. This result provides pragmatic data for food engineer in process design and food product development by minimizing the cost of trial and error.