Development of a Water-Dispersible Phytosterol Nanodispersion System and its Application in Soy Milk Storage

This work was aimed to develop a stable water-dispersible phytosterol nanodispersion system. In the first part of this work, the formation and characterization of phytosterol nanodispersions prepared using Tween 20 was investigated. The experiment demonstrated the feasibility of phytosterol nanodispersion production using hexane as organic phase through an emulsification-evaporation technique. The mean particle diameter of phytosterol nanoparticles produced was 50 nm in diameter and had a spherical shape. The dispersed phase ratio, conventional homogenization parameters and the homogenization pressure showed significant (p < 0.05) effects on the final phytosterol particles size and their distribution profiles. High-pressure homogenization caused significant phytosterol loss (p < 0.05). Two response surface methodology (RSM) processes were applied to optimize the processing and formulation parameters for preparing phytosterol nanodispersions. The optimized processing parameters were 15.25 min of mixing time, 7000 rpm of mixing speed and a homogenization pressure of 42.4 MPa. The corresponding responses for the optimized preparation conditions were a mean particle size (PS) of 52 nm and a phytosterol concentration (Phyto) of 336 mg/l. The optimized formulation parameters determined were a phase ratio (PR) of 3.54 and a mixture ratio (MR) of 0.19, and the corresponding optimized responses were a PS of 55.4 nm and 87.6% phytosterol concentration. The PS showed no significant (p > 0.05) change over a period of 8 weeks of storage at 4 ºC. The Tween 20 was replaced by four different types of sucrose fatty acid esters (SEs), namely sucrose palmitate (P-1570), sucrose laureate (L-1695), sucrose steareate (S-1570) and sucrose oleate (OWA-1570). The physicochemical properties of SE-stabilized water-dispersible phytosterol nanodispersions were examined. The PS and the %Phyto of the prepared phytosterol nanodispersions ranged from 2.8 to 259.9 nm And from 230.4 to 504.6 mg/l. All of the prepared phytosterol nanodispersions exhibited pseudoplastic flow behavior, with a low yield stress ranging from 0.630 to 9.183 mPas and a low consistency coefficient of 0.608 to 88.710 mPas. Less than 1.5 ppm of hexane residues in the prepared nanodispersions was detected. Sucrose esters P-1570, L-1695 and S-1570 were found to be appropriate for use in preparing phytosterol nanoparticles with small PS at a monomodal distribution, with high clarity. The high phytosterol-loaded nanodispersions prepared with co-solvents ethanol and L-1695 had small spherical PS of approximately 5 nm, with low viscosity and high clarity. The solvent residue levels in the final prepared nanodispersions were acceptable. L-1695 was selected for further optimization of the production of L-1695-stabilized water-dispersible phytosterol nanodispersions through RSM. The optimized parameters were 5.5% of Ph (phytosterol concentration), 1.0% of L (L-1695 concentration), 3 C (homogenization cycle), and P(homogenization pressure) of 37 MPa. The corresponding responses for the optimized condition were a PS of 3 nm and a %Ph of 90.4%. The optimized phytosterol nanodispersions had a polydispersity index of 0.550 at a monomodal distribution. The pH value and hexane and ethanol residues concentration were 6.45, 48.2 μl/l and 930.3 μl/l, respectively. The optimized nanodispersions were stable to heat treatment up to 121 °C, chilling at 4 and 10 °C and freezing with a cryoprotectant at – 4 and – 20 °C. The stability of the optimized phytosterol nanodispersions and phytosterol-fortified soy milk (SMP) over a 12-week period was investigated. The storage resulted in increases in PS and reduced the total phytosterol concentration of the autoclaved phytosterol nanodispersions. Adding phytosterol nanodispersions increased the mean particle size of the soy milk. The fortified phytosterol nanoparticles became entrapped in the fat droplets of the soy milk. The stability of the SMP depended on the stability of the soy milk. The fortification of phytosterol nanodispersions in soy milk was feasible

Optimization of processing parameters for the preparation of phytosterol microemulsions by the solvent displacement method

The purpose of this study was to optimize the parameters involved in the production of water-soluble phytosterol microemulsions for use in the food industry. In this study, response surface methodology (RSM) was employed to model and optimize four of the processing parameters, namely, the number of cycles of high-pressure homogenization (1−9 cycles), the pressure used for high-pressure homogenization (100−500 bar), the evaporation temperature (30−70 °C), and the concentration ratio of microemulsions (1−5). All responses—particle size (PS), polydispersity index (PDI), and percent ethanol residual (%ER)—were well fit by a reduced cubic model obtained by multiple regression after manual elimination. The coefficient of determination (R2) and absolute average deviation (AAD) value for PS, PDI, and %ER were 0.9628 and 0.5398%, 0.9953 and 0.7077%, and 0.9989 and 1.0457%, respectively. The optimized processing parameters were 4.88 (approximately 5) homogenization cycles, homogenization pressure of 400 bar, evaporation temperature of 44.5 °C, and concentration ratio of microemulsions of 2.34 cycles (approximately 2 cycles) of high-pressure homogenization. The corresponding responses for the optimized preparation condition were a minimal particle size of 328 nm, minimal polydispersity index of 0.159, and <0.1% of ethanol residual. The chi-square test verified the model, whereby the experimental values of PS, PDI, and %ER agreed with the predicted values at a 0.05 level of significance

Response surface modeling of processing parameters for the preparation of phytosterol Nanodispersions using an emulsification-evaporation technique.

The purpose of this study was to optimize the production parameters for water-soluble phytosterol nanodispersions. Response surface methodology (RSM) was employed to model and optimize three of the processing parameters: mixing time (t) by conventional homogenizer (1–20 min), mixing speed (v) by conventional homogenizer (1,000–9,000 rpm) and homogenization pressure (P) by high-pressure homogenizer (0.1–80 MPa). All responses [i.e., mean particle size (PS), polydispersity index (PDI) and phytosterols concentration (Phyto, mg/l)] fitted well to a reduced quadratic model by multiple regressions after manual elimination. For PS, PDI and Phyto, the coefficients of determination (R 2) were 0.9902, 0.9065 and 0.8878, respectively. The optimized processing parameters were 15.25 min mixing time, 7,000 rpm mixing speed and homogenization pressure 42.4 MPa. In the produced nanodispersions, the corresponding responses for the optimized preparation conditions were a PS of 52 nm, PDI of 0.3390 and a Phyto of 336 mg/l

Effect of sucrose fatty acid esters on the particle characteristics and flow properties of phytosterol nanodispersions

The effect of four different types of sucrose fatty acid esters as nonionic emulsifiers on the physicochemical properties of water-soluble phytosterol nanodispersions was investigated. In general, the mean particle sizes of the prepared phytosterol nanodispersions ranged from 2.8 to 259.9 nm. The phytosterol content in the final prepared nanodispersions ranged from 230.4 to 504.6 mg/l. All of the prepared phytosterol nanodispersions exhibited pseudoplastic flow behavior, with low yield stress ranging from 0.630 to 9.183 mPa and a low consistency coefficient of 0.608–88.710 mPas. Less than 1.5 μl of hexane residues per liter of prepared nanodispersions was found in the prepared phytosterol nanodispersions. Transmission electron microscopy (TEM) demonstrated that the prepared phytosterol nanoparticles were spherical in shape. In general, the sucrose fatty acid esters P-1570, L-1695 and S-1570 are appropriate for use in the preparation of phytosterol nanoparticles with small mean particle size at monomodal distribution with high clarity in appearance

Preparation and characterisation of water-soluble phytosterol nanodispersions.

The purpose of this study was to prepare and characterise water-soluble phytosterol nanodispersions for food formulation. The effects of several factors were examined: four different types of organic phases (hexane, isopropyl alcohol, ethanol and acetone), the organic to aqueous phase ratio and conventional homogenisation vs. high-pressure homogenisation. We demonstrated the feasibility of phytosterol nanodispersions production using an emulsification–evaporation technique. The results showed that hexane was able to produce the smallest particle size at a mean diameter of approximately 50 nm at monomodal distribution. Phytosterol nanodispersions prepared with a higher homogenisation pressure and a higher organic to aqueous phase ratio resulted in significantly larger phytosterol nanoparticles (P < 0.05). Phytosterol loss after high-pressure homogenisation ranged from 3% to 28%, and losses increased with increasing homogenisation pressure. Elimination of the organic phase by evaporation resulted in a phytosterol loss of 0.5–9%

Rheological properties of modified starch-whey protein isolate stabilized soursop beverage emulsion systems

The rheological properties of soursop beverage emulsions as a function of main emulsion components, namely modified starch (5–12 % w/w), whey protein isolates (WPI) (0–2 % w/w), soursop flavor oil (5–15 % w/w), and deionized water (67.4–86.4 % w/w) were investigated using a fourcomponent with constrained extreme vertices mixture design. The apparent viscosity, flow index, yield stress, viscoelastic behavior (G′ and G′′) and consistency coefficient were evaluated. In general, analysis of variance (ANOVA) showed high coefficients of determination values (R2), ranging between 0.795 and 0.999 for the regression models, thus confirming a satisfactory adjustment of the polynomial regression models with the experimental data. Increase in both modified starch and oil phase concentration had increased the apparent viscosity of the emulsions. Contrary, higher concentrations of oil phase had negative effects on flow index and consistency coefficient, resulting in the changes of flow behavior. In addition, modified starch showed solid-like elastic properties at low concentration but behaved as liquid-like viscous as the concentration of modified starch increased. Oil phase concentration had a significant (p0.05) effect on neither the apparent viscosity nor the flow index at low concentrations but was an important element in providing elastic properties to the emulsion film

MIMS rheumatology, allergy & immunology

x, 63 hal; 15 x 21 c

An empirical comparison of structural and accounting-based credit risk models.

This paper looks into 3 types of credit risk models: Altman Z-Score (2002), KMV-Merton (1974) and Longstaff and Schwartz (1997). These models are analyzed and tested using a sample of listed industrial firms in the Standard & Poor’s 500. With the aim of finding the most reliable and predictive model even in times of economic turbulence, a number of tests were carried out to test the correlation of the outputs calculated from the models against their market rating obtained from major Credit Rating Agencies. The qualitative and quantitative tests carried out in this report showed that KMV-Merton model has the strongest positive correlation with the corresponding Credit Rating Agencies’ ratings. A sensitivity analysis was carried out to test effect of a change in asset volatility on both KMV-Merton and Longstaff and Schwartz models. A simple prediction test examined the models on their ability to generate EDPs which can accurately predict the financial status of the firms for the next fiscal year.BUSINES

A Remote Baby Surveillance System with RFID and GPS Tracking

In the 21st century, sending babies or children to daycare centres has become more and more common among young guardians. The balance between full-time work and child care is increasingly challenging nowadays. In Malaysia, thousands of child abuse cases have been reported from babysitting centres every year, which indeed triggers the anxiety and stress of the guardians. Hence, this paper proposes to construct a remote baby surveillance system with radio-frequency identification (RFID) and global positioning system (GPS) tracking. With the incorporation of the internet of things (IoT), a sensor-based microcontroller is used to detect the conditions of the baby as well as the surrounding environment and then display the real-time data as well as notifications to alert the guardians via a mobile application. These conditions include the crying and waking of the baby, as well as temperature, the mattress’s wetness, and moving objects around the baby. In addition, RFID and GPS location tracking are implemented to ensure the safety of the baby, while white noise is used to increase the comfort of the baby. In the end, a prototype has been successfully developed for functionality and reliability testing. Several experiments have been conducted to measure the efficiency of the mattress’s wetness detection, the RFID transmission range, the frequency spectrum of white noise, and also the output power of the solar panel. The proposed system is expected to assist guardians in ensuring the safety and comfort of their babies remotely as well as prevent any occurrence of child abuse

Effect of lipophilization on the distribution and reactivity of ingredients in emulsions

Hypothesis: The reactivity of small molecules in emulsions is believed to depend on their partitioning between phases, yet this is hard to verify experimentally in situ. In the present work, we use electron paramagnetic resonance (EPR) spectroscopy to simultaneously measure the distribution and reactivity of a homologous series of lipophilized spin probes in an emulsion. Experiments: 4-Hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPOL) was derivatized with saturated fatty acids to create a series of spin probes with increasing lipophilicity (C4-, C8-, C12-, and C16-TEMPO). The probes were added to a 10wt.% tetradecane-in water emulsions (d32~190nm) stabilized with sodium caseinate (1wt.% in the aqueous phase, pH 7). The distribution of the probes between phases was measured by electron paramagnetic resonance (EPR) spectroscopy. Findings: TEMPOL partitioned into the aqueous phase, C4-TEMPO distributed between the lipid and aqueous phases (69% and 31% respectively) while the more lipophilic probes dissolved exclusively within the lipid droplets. Interestingly, the more lipophilic probes initially precipitated upon their addition to the emulsion, and only slowly redistributed to the droplets over hours or days, the rate of which was dependent on their carbon chain length. The reactivity of the probes with aqueous an aqueous phase reductant (ascorbate) generally depended on the proportion in the aqueous phase (i.e., TEMPOL. >C4-TEMPO. >C8-TEMPO~C12-TEMPO~C16-TEMPO)