Diacylglycerol (DAG) and monoacylglycerol (MAG) are two natural occurring minor components found in most edible fats and oils. These compounds have gained increasing market demand owing to their unique physicochemical properties. Enzymatic glycerolysis in solvent-free system might be a promising approach in producing DAG and MAG-enriched oil. Understanding on glycerolysis mechanism is therefore of great importance for process simulation and optimization. In this study, a commercial immobilized lipase (Lipozyme TL IM) was used to catalyze the glycerolysis reaction. The kinetics of enzymatic glycerolysis reaction between triacylglycerol (TAG) and glycerol (G) were modeled using rate equation with unsteady-state assumption. Ternary complex, ping-pong bi-bi and complex ping-pong bi-bi models were proposed and compared in this study. The reaction rate constants were determined using non-linear regression and sum of square errors (SSE) were minimized. Present work revealed satisfactory agreement between experimental data and the result generated by complex ping-pong bi-bi model as compared to other models. The proposed kinetic model would facilitate understanding on enzymatic glycerolysis for DAG and MAG production and design optimization of a pilot-scale reactor.
The reduction of 3-monochloropropane-1,2-diol (3-MCPD) ester formation in refined palm oil was achieved by incorporation of additional processing steps in the physical refining process to remove chloroester precursors prior to the deodorization step. The modified refining process was optimized for the least 3-MCPD ester formation and acceptable refined palm oil quality using response surface methodology (RSM) with five processing parameters: water dosage, phosphoric acid dosage, degumming temperature, activated clay dosage, and deodorization temperature. The removal of chloroester precursors was largely accomplished by increasing the water dosage, while the reduction of 3-MCPD esters was a compromise in oxidative stability and color of the refined palm oil because some factors such as acid dosage, degumming temperature, and deodorization temperature showed contradictory effects. The optimization resulted in 87.2% reduction of 3-MCPD esters from 2.9 mg/kg in the conventional refining process to 0.4 mg/kg, with color and oil stability index values of 2.4 R and 14.3 h, respectively.
The formation of 3-monochloropropane-1,2-diol (3-MCPD) esters in refined palm oil during deodorisation is attributed to the intrinsic composition of crude palm oil. Utilising D-optimal design, the effects of the degumming and bleaching processes on the reduction in 3-MCPD ester formation in refined palm oil from poor-quality crude palm oil were studied relative to the palm oil minor components that are likely to be their precursors. Water degumming remarkably reduced 3-MCPD ester formation by up to 84%, from 9.79 mg/kg to 1.55 mg/kg. Bleaching with synthetic magnesium silicate caused a further 10% reduction, to 0.487 mg/kg. The reduction in 3-MCPD ester formation could be due to the removal of related precursors prior to the deodorisation step. The phosphorus content of bleached palm oil showed a significant correlation with 3-MCPD ester formation.
Several binary and ternary medium- and long-chain triacylglycerol (MLCT)-enriched margarine formulations were examined for their solid fat content, heating profile, polymorphism and textural properties. MLCT feedstock was produced through enzymatic esterification of capric and stearic acids with glycerol. The binary formulations were produced by mixing MLCT feedstock blend (40%–90%) and palm olein (10%–60%) with 10% increments (w/w). Solid fat profiles of commercial margarines were used as a reference to determine the suitability of the formulations for margarine production. The solid fat content of the binary formulations of MO 82 and MO 91 (M, MLCT, O, palm olein) were similar to the commercial margarines at 25°C which met the basic requirement for efficient dough consistency. Ternary formulations using reduced MLCT feedstock blend proportion (from 80%–90% to 60%–70%) were also developed. The reduction of MLCT feedstock blend was
done as it had the highest production cost (3USD/kg) in comparison to palm olein (0.77USD/kg) and palm stearin (0.7USD/kg). The proportions of 5%–15% of palm stearin were substituted with palm olein in MO 64 and MO 73 (M, MLCT; O, palm olein) formulations with 5% increment (w/w). As a result, MOS 702010 and MOS 603010 (M, MLCT; O, palm olein; S, palm stearin) margarine formulations showed similar SFC % to the commercial margarines at 25ºC. These formulations were subsequently chosen to produce margarines. The onset melting and complete melting points of MLCT-enriched margarine formulations were high (51.04ºC –57.93ºC) due to the presence of a high amount of long chain saturated fatty acids. Most of the formulations showed β΄- crystals. MOS 702010 was selected as the best formulation due to values for textural parameters comparable (P
Comparative whole-genome sequencing enables the identification of specific mutations during adaptation of bacteria to new environments and allelic replacement can establish their causality. However, the mechanisms of action are hard to decipher and little has been achieved for epistatic mutations, especially at the metabolic level. Here we show that a strain of Escherichia coli carrying mutations in the rpoC and glpK genes, derived from adaptation in glycerol, uses two distinct metabolic strategies to gain growth advantage. A 27-bp deletion in the rpoC gene first increases metabolic efficiency. Then, a point mutation in the glpK gene promotes growth by improving glycerol utilization but results in increased carbon wasting as overflow metabolism. In a strain carrying both mutations, these contrasting carbon/energy saving and wasting mechanisms work together to give an 89% increase in growth rate. This study provides insight into metabolic reprogramming during adaptive laboratory evolution for fast cellular growth.
This paper reports the effects of glyceryl ether specifically mono-tert-butoxypropanediol on oil in water emulsion system.
Based on 12 HLB value, screening for stable emulsions was carried out without the presence of glyceryl ether. A stable
emulsion was used as a control. Then the effects of glyceryl ether on the emulsion system were investigated. The emulsions
prepared were analyzed for stability, viscosity, pH value, particle size, in vitro dermal irritation potential, in vitro ocular
irritation potential and also moisturizing property. The incorporation of glycerol in the emulsion system was also done
for comparison. Emulsions with glyceryl ether showed lower viscosity values than emulsions with glycerol. Furthermore,
the emulsions also exhibited moisturizing property compared to the control emulsion. Glyceryl ether is suitable to be
used in cosmetic products which require reduced viscosity but retain its skin hydration property.
In recent years, increasing environmental concerns focused greater attention on the development of biodegradable materials. A thermoplastic starch derived from bioresources, sugar palm tree was successfully developed in the presence of biodegradable glycerol as a plasticizer. Sugar palm starch (SPS) was added with 15-40 w/w% of glycerol to prepare workable bioplastics and coded as SPS/G15, SPS/G20, SPS/G30 and SPS/G40. The samples were characterized for thermal properties, mechanical properties and moisture absorption on exposure to humidity were evaluated. Morphological studies through scanning electron microscopy (SEM) were used to explain the observed mechanical properties. Generally, the addition of glycerol decrease the transition temperature of plasticized SPS. The mechanical properties of plasticized SPS increase with the increasing of glycerol but up to 30 w/w%. Meanwhile, the water absorption of plasticized SPS decrease with increasing of glycerol.
Momordica charantia bioactive polysaccharide (MCBP) was used as an alternative source for the production of bio-based plastics (BPs) with choline chloride/glycerol-based deep eutectic solvent (DES) as a plasticizer. In this study, MCBP was initially extracted using 0.1 M citric acid at temperature 80 °C for 2 h, precipitated using ethanol, and then lyophilized. Subsequently, seven BPs were prepared: MCBP without plasticizer (MCBP), with 1% (w/w) of glycerol (MCBP-G), or with 1% (w/w) of DES at different choline chloride/glycerol molar ratios (i.e. 1.5:1, 1:1, 1:1.5, 1:2, and 1:3). The properties of these BPs were then investigated. Results showed that the tensile strains, stresses and moduli were in the range of 1.3-13.3%, 4.8-19.1 MPa and 132-2487 MPa, respectively. The melting temperatures were found in the range of 92.6-111.4 °C whereas the moisture absorptions and water vapour transmission rates (WVTR) of BPs were 1.4-6.5% and 3.6-5.4 mg/m2·s, respectively. The results also showed that these BPs exhibited bioactivities, such as microbial inhibitory activity (19.5-32.3 mm), free radical scavenging activity (10.3-18.3%) and ferric reducing antioxidant power (FRAP, 16.1-20.0 mM). In addition, it was observed that using DES as a plasticizer had improved the properties of BP, such as tensile strain (354.7-937.5%), melting temperature (4.6-20.3%), radical scavenging activity (0.6-88.6%), FRAP (0.9-18.7%) and antimicrobial activity (12.3-33.6%) compared to MCBP, due to the fact DES has caused different degrees of plasticization via hydrogen bonds and ionic bonds with the polymer chains, and induced a lower pH condition. Therefore, it was suggested that these BPs with DES could contribute to food preservation properties.
Response surface methodology (RSM) was used to optimize the concentrations of chitosan and glycerol for coating Berangan banana (Musa sapientum cv. Berangan). The effects of main edible coating components, chitosan (0.5-2.5%, w/w) and glycerol (0-2%, w/w) on weight loss, firmness, total colour difference, total soluble solids content (TSS) and titratable acidity (TA) of coated banana were studied during 10 days of storage at 26±2°C and 40-50% relative humidity. Results showed that the experimental data could be adequately fitted into a second-order polynomial model with coefficient of determination (R 2 ) ranging from 0.745 to 0.930 for all the variables studied. In general, the chitosan concentration appeared to be the most significant (P< 0.1) factor influencing all variables except for TSS. The optimum concentration of chitosan and glycerol were predicted to be 2.02% and 0.18%, respectively. Statistical assessment showed insignificant difference between experimental and predicted values.
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.
Calcium carbonate was evaluated as a replacement for the base during the fermentation of glycerol by a highly productive strain of 1,3-propanediol (PDO), viz., Clostridium butyricum JKT37. Due to its high specific growth rate (µmax=0.53h(-1)), 40g/L of glycerol was completely converted into 19.6g/L of PDO in merely 7h of batch fermentation, leaving only acetate and butyrate as the by-products. The accumulation of these volatile fatty acids was circumvented with the addition of calcium carbonate as the pH neutraliser before the fermentation was inoculated. An optimal amount of 15g/L of calcium carbonate was statistically determined from screening with various glycerol concentrations (20-120g/L). By substituting potassium hydroxide with calcium carbonate as the pH neutraliser for fermentation in a bioreactor, a similar yield (YPDO/glycerol=0.6mol/mol) with a constant pH was achieved at the end of the fermentation.
Many studies have investigated natural convection heat transfer from the outside surface of horizontal and vertical cylinders in both constant heat flux and temperature conditions. However, there are poor studies in natural convection from inclined cylinders. In this study, free convection heat transfer was examined experimentally from the outside surface of a cylinder for glycerol and water at various heat fluxes. The tests were performed at 10 different inclination angles of the cylinder, namely, φ = 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, and 90°, measured from the horizon. Our results indicated that the average Nusselt number reduces with the growth in the inclination of the cylinder to the horizon at the same heat flux, and the average Nusselt number enhanced with the growth in heat flux at the same angle. Also, the average Nusselt number of water is greater than that of glycerol. A new experimental model for predicting the average Nusselt number is suggested, which has a satisfactory accuracy for experimental data.
Response surface methodology (RSM) was utilized to investigate the influence of the main emulsion composition; mixture of palm and medium-chain triglyceride (MCT) oil (6%-12% w/w), lecithin (1%-3% w/w), and Cremophor EL (0.5%-1.5% w/w) as well as the preparation method; addition rate (2-20 mL/min), on the physicochemical properties of palm-based nanoemulsions. The response variables were the three main emulsion properties; particle size, zeta potential and polydispersity index. Optimization of the four independent variables was carried out to obtain an optimum level palm-based nanoemulsion with desirable characteristics. The response surface analysis showed that the variation in the three responses could be depicted as a quadratic function of the main composition of the emulsion and the preparation method. The experimental data could be fitted sufficiently well into a second-order polynomial model. The optimized formulation was stable for six months at 4 °C.
In the present study, response surface methodology (RSM) based on central composite design (CCD) was employed to investigate the influence of main emulsion composition variables, namely drug loading, oil content, emulsifier content as well as the effect of the ultrasonic operating parameters such as pre-mixing time, ultrasonic amplitude, and irradiation time on the properties of aspirin-loaded nanoemulsions. The two main emulsion properties studied as response variables were: mean droplet size and polydispersity index. The ultimate goal of the present work was to determine the optimum level of the six independent variables in which an optimal aspirin nanoemulsion with desirable properties could be produced. The response surface analysis results clearly showed that the variability of two responses could be depicted as a linear function of the content of main emulsion compositions and ultrasonic processing variables. In the present investigation, it is evidently shown that ultrasound cavitation is a powerful yet promising approach in the controlled production of aspirin nanoemulsions with smaller average droplet size in a range of 200-300 nm and with a polydispersity index (PDI) of about 0.30. This study proved that the use of low frequency ultrasound is of considerable importance in the controlled production of pharmaceutical nanoemulsions in the drug delivery system.
Oxygenated fuel additives can be produced by acetylation of glycerol. A 91% glycerol conversion with a selectivity of 38%, 28% and 34% for mono-, di- and triacetyl glyceride, respectively, was achieved at 120 °C and 3 h of reaction time in the presence of a catalyst derived from activated carbon (AC) treated with sulfuric acid at 85 °C for 4h to introduce acidic functionalities to its surface. The unique catalytic activity of the catalyst, AC-SA5, was attributed to the presence of sulfur containing functional groups on the AC surface, which enhanced the surface interaction between the glycerol molecule and acyl group of the acetic acid. The catalyst was reused in up to four consecutive batch runs and no significant decline of its initial activity was observed. The conversion and selectivity variation during the acetylation is attributed to the reaction time, reaction temperature, catalyst loading and glycerol to acetic acid molar ratio.
Purpose:To investigate the feasibilty of using processed human amniotic membrane (HAM) to support the attachment and proliferation of chondrocytes in vitro which it turn can be utilised as a cell delivery vehicle in tissue engineering applications. Methods: Fresh HAM obtained from patients undergoing routine elective ceasarean sections was harvested., processed and dried using either freez drying (FD) or air drying (AD) methods prior to sterilisation by gamma irradiation. Isolated, processed and characterised rabbit autologous chondrolytes were seeded on processsed HAM and cultured for up to three weeks. Cell attachment and proliferation were examined qualitatively using inverted brightfield microcospy. Results: Processed HAM appeared to allow cell attachment when implanted with chrondocytes. Although cells seeded on AD and FD HAM did not appear to attach as strongly as those seeded on glycerol preserved intact human amniotic membrane, these cells to be proliferated in cell culture conditions. Conclusion: Prelimanary results show that processed HAM chondrocyte attachment and proliferation.
A biodegradable composite (PLA/KBF blends) was prepared using melt blending technique in a brabender mixer and characterized with FTIR and TGA analyzer. Five percent of triacetin and glycerol contents were used as plasticizers to plasticise PLA matrix. KBF was treated with 4% NaOH solution, while 30 wt% of fibre loading was used constantly for all the composite samples. From the FTIR analysis, the additions of triacetin and glycerol to PLA composites did not produce any significant difference, and there were no chemical changes in both the plasticized PLA with the treated and untreated KBF, respectively. Observation done on the TGA analysis revealed that both plasticizers did improve the thermal stability of the composites, and this might be due to the modification on the fibre surfaces, which further led to the delay in the degradation of the PLA matrix and to significant stabilization effect.
The aim of this study was to determine the efficiency of different human amniotic membrane (HAM) processing methods on the concentration, purity and integrity of RNA. Two different techniques (Technique1 andTechnique2) were employed for the processing of HAM, which differed in terms of washing solution, sample storage conditions and processing time. Based on preservation of HAM, three groups were formed under each technique. In Technique 1, the groups were fresh frozen 1 (F1), glycerol preserved (GP) and gamma irradiated glycerol preserved (IGP); where else in Technique 2, the groups were fresh frozen 2 (F2), 50%glycerol/Dulbecco’s modified Eagle medium (DMEM) cryopre served HAM diluted with phosphate buffered saline(GB) and 50% glycerol/DMEM cryop reserved HAM diluted with diethyl procarbonate water (GD). Total RNA was extracted from the samples and their concentration, purity and integrity were examined. The F2 sample of which there was no pre-washing step and involved direct sample storage at-80oC, shorter processing time and chilled processing conditions had yielded better quality of RNA compared to the others.
The growth and production of biosurfactant by P. seudomonas aeruginosa (181) was dependant on nutritional factors. Among the eleven carbon sources tested, glucose supported the maximum growth (0.25 g/L) with the highest biosurfactant yield and this was followed by glycerol. Glucose reduced the surface tension to 35.3 dyne/cm and gave an E24 reading of 62.7%. Butanol gave the lowest growth and had no biosurfactant production. For the nitrogen sources tested, casamino acid supported a growth of 0.21 g/L which reduced the surface tension to 41.1 dyne/cm and gave an E24 reading of 56%. Soytone was assimilated similarly, with good growth and high biosurfactant production. Corn steep liquor gave the lowest growth and did not show any biosurfactant activity.