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 degrees 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 (R(2)) 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 degrees 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.
Diacylglycerol (DAG) and triacylglycerol (TAG) as responses on optimization of DAG production using a dual response approach of response surface methodology were investigated. This approach takes the molecular equilibrium of DAG into account and allows for the optimization of reaction conditions to achieve maximum DAG and minimum TAG yields. The esterification reaction was optimized with four factors using a central composite rotatable design. The following optimized conditions yielded 48 wt % DAG and 14 wt % TAG: reaction temperature of 66.29 degrees C, enzyme dosage of 4 wt %, fatty acid/glycerol molar ratio of 2.14, and reaction time of 4.14 h. Similar results were achieved when the process was scaled up to a 10 kg production in a pilot packed-bed enzyme reactor. Lipozyme RM IM did not show any significant activity losses or changes in fatty acid selectivity on DAG synthesis during the 10 pilot productions. However, lipozyme RM IM displayed higher selectivity toward the production of oleic acid-enriched DAG. The purity of DAG oil after purification was 92 wt %.
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 present study aims to design a milk fat globule membrane (MFGM)-inspired structured membrane (phospholipid- and protein-rich) for microencapsulation of docosahexaenoic acid (DHA) oil. DHA-enriched oil emulsions were prepared using different ratios of sunflower phospholipid (SPL), proteins [whey protein concentrate (WPC), soy protein isolate (SPI), and sodium caseinate (SC)], and maltodextrin and spray-dried to obtain DHA microcapsules. The prepared DHA oil emulsions have nanosized particles. SPLs were found to affect the secondary structure of WPC, which resulted in increased exposure of the protein hydrophobic site and emulsion stability. SPL also reduced the surface tension and viscosity of the DHA oil emulsions. In vitro digestion of the spray-dried DHA microcapsules showed that they were able to effectively resist gastric proteolysis and protect their bioactivity en route to the intestine. The DHA microcapsules have a high lipid digestibility in the small intestine with a high DHA hydrolysis efficiency (74.3%), which is higher than that of commercial DHA microcapsules.
Medium-chain diacylglycerol (MCD), medium-long-chain diacylglycerol (MLCD), and long-chain diacylglycerol (LCD) were prepared through enzymatic esterification using different conditions at temperatures of 55-70 °C and reaction times of 1.5-5 h and in the presence of 5-6% Novozym 435. Subsequently, purification was performed using three different techniques, namely, molecular distillation (MD), deodorization (DO), and silica gel column chromatography (SGCC). Variations in terms of the physicochemical and thermodynamic properties, crystallization properties, and kinetics of the diacylglycerols (DAGs) before and after purification were determined. Irrespective of the DAG chain lengths, SGCC was able to produce samples with high DAG purity (96-99 wt %), followed by MD (58-79 wt %) and DO (39-59 wt %). A higher 1,3-DAG/1,2-DAG ratio was recorded for all samples, with the highest ratio recorded for SGCC purified samples. Regardless of the purification techniques used, the solid fat content (SFC) profiles of crude samples with steep curves were altered post-purification, showing a gradual increment in SFC along with increasing temperature. Modification of the Avrami constant and coefficient suggested the modification of the crystal growth mechanism post-purification. Crystallization and melting temperatures of products with a higher DAG purity were shifted to a higher temperature region. Variations were also reflected in terms of the crystal polymorphism, whereby the α and β' crystals transitioned into the more stable β form in purified samples accompanied by modification in the microstructures and crystal sizes. However, there was insignificant change in the morphology of MLCD crystal after purification, except for the decrease in crystal sizes. In conclusion, synthesis of MCD, MLCD, and LCD comprising different DAG purities had distinctive SFC profiles, thermodynamic properties, crystallization kinetics, and crystal morphologies, which can be further incorporated into the preparation of a variety of fat products to obtain end products with desired characteristics.
Phospholipid composition in the milk fat globule membrane (MFGM) fluctuates during the entire lactation period in order to suit the growing needs of newborn infants. The present study elucidated and relatively quantified phospholipid molecular species extracted from human milk (HM), mature human milk (MHM), and infant formulas (with or without MFGM supplementation) using hydrophilic liquid chromatography-electrospray ionization-ion trap-time of flight-mass spectrometry (HILIC-ESI-IT-TOF-MS) system. Principal component analysis was used to clarify the differences between phospholipid composition in HM, MHM, and infant formulas. HM and MHM contained high concentrations of sphingomyeline (HM: 107.61 μg/mL, MHM: 227.18 μg/mL), phosphatidylcholine (HM: 59.96 μg/mL, MHM: 50.77 μg/mL), and phosphatidylethanolamine (PE) (HM: 25.24 μg/mL, MHM: 31.76 μg/mL). Significant concentrations (<300 ng/mL) of arachidonic, eicosapentanoic, and docosahexanoic acids were found to esterify to PE in HM and MHM. Meanwhile, all infant formulas were found to contain high concentrations of phosphatidic acids indicating the possibility of degradation of the fortified MFGM either during processing or storage of the infant formulas.
Considering the health benefits of tocotrienols, continuous works have been done on the encapsulation and delivery of these compounds. In this study, we encapsulated tocotrienols in chitosan-alginate microcapsules and evaluated their release profile. Generally, these tocotrienols microcapsules (TM) displayed high thermal stability. When subjected to pH adjustments (pH 1-9), we observed that the release of tocotrienols was the highest (33.78 ± 0.18%) under basic conditions. The TM were also unstable against the effect of ionic strength, with a high release (70.73 ± 0.04%) of tocotrienols even at a low sodium chloride concentration (50 mM). As for the individual isomers, δ-tocotrienol was the most sensitive to pH and ionic strength. In contrast, β-/γ-tocotrienols were the most ionic-stable isomers but more responsive toward thermal treatment. Simulated gastrointestinal model showed that the chitosan-alginate-based TM could be used to retain tocotrienols in the gastric and subsequently release them in the intestines for possible absorption.
During high-temperature refining of vegetable oils, 3-monochloropropanediol (3-MCPD) esters, possible carcinogens, are formed from acylglycerol in the presence of a chlorine source. To investigate organochlorine compounds in vegetable oils as possible precursors for 3-MCPD esters, we tested crude palm, soybean, rapeseed, sunflower, corn, coconut, and olive oils for the presence of organochlorine compounds. Having found them in all vegetable oils tested, we focused subsequent study on oil palm products. Analysis of the chlorine isotope mass pattern exhibited in high-resolution mass spectrometry enabled organochlorine compound identification in crude palm oils as constituents of wax esters, fatty acid, diacylglycerols, and sphingolipids, which are produced endogenously in oil palm mesocarp throughout ripening. Analysis of thermal decomposition and changes during refining suggested that these naturally present organochlorine compounds in palm oils and perhaps in other vegetable oils are precursors of 3-MCPD esters. Enrichment and dose-response showed a linear relationship to 3-MCPD ester formation and indicated that the sphingolipid-based organochlorine compounds are the most active precursors of 3-MCPD esters.
Edible bird's nest (EBN) is recognized as a nourishing food among Chinese people. The efficacy of EBN was stated in the records of traditional Chinese medicine and its activities have been reported in many researches. Malaysia is the second largest exporter of EBNs in the world, after Indonesia. For many years, EBN trade to China was not regulated until August 2011, when a safety alert was triggered for the consumption of EBNs. China banned the import of EBNs from Malaysia and Indonesia due to high level of nitrite. Since then, the Malaysia government has formulated Malaysia Standards for swiftlet farming (MS 2273:2012), edible bird's nest processing plant design and management (MS 2333:2010), and edible bird's nest product quality (MS 2334:2011) to enable the industry to meet the specified standards for the export to China. On the other hand, Indonesia's EBN industry formulated a standard operating procedure (SOP) for exportation to China. Both countries can export EBNs to China by complying with the standards and SOPs. EBN contaminants may include but not limited to nitrite, heavy metals, excessive minerals, fungi, bacteria, and mites. The possible source of contaminants may come from the swiftlet farms and the swiftlets or introduced during processing, storage, and transportation of EBNs, or adulterants. Swiftlet house design and management, and EBN processing affect the bird's nest color. Degradation of its optical quality has an impact on the selling price, and color changes are tied together with nitrite level. In this review, the current and future prospects of EBNs in Malaysia and Indonesia in terms of their quality, and the research on the contaminants and their effects on EBN color changes are discussed.
An extractive bioconversion conducted on soluble starch with cyclodextrin glycosyltransferase (CGTase) enzyme in ethylene oxide-propylene oxide (EOPO)/potassium phosphates liquid biphasic system (LBS) to extract gamma-cyclodextrin (γ-CD) was examined. A range of EOPO (with potassium phosphates) molecular weights was screen to investigate the effect of the latter on the partioning efficency of CGTase and γ-CD. The results show that the optimal top phase γ-CD yield (74.4%) was reached in 35.0% (w/w) EOPO 970 and 10.0% (w/w) potassium phosphate with 2.0% (w/w) sodium chloride. A theoretical explanation for the effect of NaCl on γ-CD was also presented. After a 2 h bioconversion process, a total of 0.87 mg/mL concentration of γ-CD was produced in the EOPO/ phosphates LBS top phase. After the extraction of top phase from LBS, four continuous repetitive batches were successfully conducted with relative CGTase activity of 1.00, 0.86, 0.45, and 0.40 respectively.
The present study focused on investigating the storage stability of oil-in-water (O/W) emulsions with high oil volume fractions prepared with palm olein-based diacylglycerol oil (POL-DAG)/soybean oil (SBO) blends at 25 °C. The incorporation of different ratios of oil blends significantly influenced (p < 0.05) the texture, color, droplet size distribution, and rheological parameters of the emulsions. Only emulsions incorporated with 10% to 20% POL-DAG in oil phase exhibited pseudoplastic behavior that fitted the Power Law model well. Furthermore, the O/W emulsions prepared with POL-DAG/SBO blends exhibited elastic properties, with G' higher than G". During storage, the emulsion was found to be less solid-like with the increase in tan δ values. All emulsions produced with POL-DAG/SBO blends also showed thixotropic behavior. Optical microscopy revealed that the POL-DAG incorporation above 40% caused aggregated droplets to coalesce and flocculate and, thus, larger droplet sizes were observed. The current results demonstrated that the 20% POL-DAG substituted emulsion was more stable than the control emulsion. The valuable insights gained from this study would be able to generate a lot more possible applications using POL-DAG, which could further sustain the competitiveness of the palm oil industry.
The stability of refined, bleached, and deodorized palm olein (RBDPO) was studied under controlled heating conditions. RBDPO was heated continuously for 24 h at 160, 170, and 180 °C, with oil sampled at four hour intervals. Thermo-oxidative alterations were measured through various parameters, such as monomeric oxidized triacylglycerols (oxTAG), total polar compounds (TPC), polymerized triacylglycerols (PTG), oxidative stability, and fatty acid composition. After 24 h of heating, the TPC and triacylglycerol oligomers showed a linear increase with heating time at all heating temperatures. At the end of the heating study, more epoxy acids were formed than keto and hydroxy acids. Moreover, caprylic acid, which was not present in fresh oil, was formed in significant amounts. The increase in oxTAG was strongly correlated with the increase in the p-anisidine value and total oxidation value. The decreases in diacylglycerol and free fatty acids were strongly correlated with an increase in PTG.
Calcium carbonate (CaCO3) has been utilized as a pH-responsive component in various products. In this present work, palm tocotrienols-rich fraction (TRF) was successfully entrapped in a self-assembled oil-in-water (O/W) emulsion system by using CaCO3 as the stabilizer. The emulsion droplet size, viscosity and tocotrienols entrapment efficiency (EE) were strongly affected by varying the processing (homogenization speed and time) and formulation (CaCO3 and TRF concentrations) parameters. Our findings indicated that the combination of 5000 rpm homogenization speed, 15 min homogenization time, 0.75% CaCO3 concentration and 2% TRF concentration resulted in a high EE of tocotrienols (92.59-99.16%) and small droplet size (18.83 ± 1.36 µm). The resulting emulsion system readily released the entrapped tocotrienols across the pH range tested (pH 1-9); with relatively the highest release observed at pH 3. The current study presents a potential pH-sensitive emulsion system for the entrapment and delivery of palm tocotrienols.
Shortening derived from palm oil is widely used in baking applications. However, palm oil and the related products are reported to contain high levels of monochloropropandiol (MCPD) ester and glycidyl ester (GE). MCPD and glycidol are known as process contaminants, which are carcinogenic and genotoxic compounds, respectively. The objective was to evaluate the effects of antioxidant addition in palm olein and stearin to the content of MCPD esters and GE in baked cake. Butylated hydroxyanisole (BHA), rosemary extract and tocopherol were used to fortify the samples at 200 mg/kg and in combinations (400, 600 and 800 mg/kg rosemary or tocopherol combined with 200 mg/kg BHA). The MCPD esters and GE content, radical formation and the quality of the fats portion were analyzed. The results showed that palm olein fortified with rosemary extract yielded less 2-MCPD ester. The GE content was lower when soft stearin was fortified with rosemary. ESR spectrometry measurements showed that the antioxidants were effective to reduce radical formation. The synergistic effects of combining antioxidants controlled the contaminants formation. In conclusion, oxidation stability was comparable either in the single or combined antioxidants. Tocopherol in combination with BHA was more effective in controlling the MCPD esters and GE formation.
β-Lactoglobulin (β-lg) can produce fibrils that have multi-functional properties. Impacts of different stirring speeds on characteristics of β-lg fibrils as a stable form in β-lg fibril solutions were investigated. Fibril concentration, fibril morphology, turbidity, particle size distribution, zeta potential, and rheological behavior of solutions were studied. Stirring enhanced fibril formation and stability of a fibril solution, in comparison with unstirred solutions. Increasing the stirring speed produced more turbidity and a greater distribution of particle sizes, higher viscosity values, but no differences in zeta potential values of β-lg fibril solutions. However, a high stirring speed is not feasible due to reduction of the fibril yield and changes in fibril morphology.
An optimized refining process for kenaf seed oil was conducted. The 3-monochloro-1,2-propanediol (3-MCPD) contents, triacylglycerol composition, fatty acids composition, bioactive compounds, phosphorus contents, and oxidation indexes of the kenaf seed oil during each stage of the refining process were determined. The results showed that there was no detected 3-MCPD ester in kenaf seed oil throughout the refining process. Deodorization had slightly increased the 2-MCPD ester (9.0 μg/kg) and glycidyl ester (54.8 μg/kg). Oleic (36.53%) and linoleic acids (36.52%) were presented in the largest amount in the refined kenaf seed oil, and triacylglycerols contributed to 99.96% in the oil. There was a removal of 31.6% of phytosterol content and 17.1% of tocopherol and tocotrienol contents in kenaf seed oil after refining. The refining process was totally removed the hydroperoxides, 93% of free fatty acids and 98.8% of phosphorus content in kenaf seed oil.
Present study prepared curcumin liposomes with high encapsulation efficiency (>70%) using bovine milk and krill phospholipids; and investigated the effects of phospholipids composition on storage stability, in-vitro bioavailability, antioxidative and anti-hyperglycemic properties of the curcumin liposomes. Curcumin liposomes prepared from bovine milk phospholipids have smaller particle sizes (163.1 ± 6.42 nm) and greater negative zeta potentials (-26.7 mv) as compared to that prepared from krill phospholipids (particle size: 212.2 ± 4.1 nm, zeta potential: -15.23 mv). In addition, curcumin liposomes from bovine milk phospholipids demonstrated better stability under harsh storage conditions (alkaline conditions, oxygen, high temperature and relative humidity). Nevertheless, curcumin-loaded liposomes prepared from bovine milk phospholipids have inferior bioavailability compared to that prepared from krill phospholipids. No significant differences can be observed in terms of anti-oxidative and anti-hyperglycemic properties of liposomes prepared from both bovine milk and krill phospholipids. Findings from present study will open up new opportunities for development of stable curcumin liposomes with good functional properties (high digestibility, bioavailability and pharmacological effects).
The rheological properties, microstructure, textural properties, colour and droplet size distribution of mayonnaise-like emulsion models prepared using 10-30wt.% of palm olein-based diacylglycerol (POL-DAG) oil were compared with those of the control (100wt.% VCO) model. There were significant (P<0.05) differences in the particle size distribution of the oil droplets, the textural properties, and the rheological properties of the various emulsion models. The rheological analysis included the determination of the flow curves, yield stress, thixotropy, apparent viscosity, and viscoelastic parameters. The concentrated oil-in-water (O/W) emulsion with 30wt.% POL-DAG substitution exhibited high thixotropy. The POL-DAG content had a substantial effect on the rheological properties of yield stress, storage modulus (G') and loss modulus (G″). The pseudoplastic behaviour of the emulsions was demonstrated. The size of the particles in the 30% POL-DAG-substituted emulsion was dramatically increased after one day and 30days of storage. All of the emulsion samples with POL-DAG substituted for VCO showed a relatively non-uniform bimodal droplet size distribution after one day of storage. In general, substitution of 10-20wt.% POL-DAG oil is appropriate for preparing O/W emulsions that had flow curves and textural properties similar to those of the control sample.
The detection of 3- and 2-MCPD ester and glycidyl ester was transformed from selected ion monitoring (SIM) mode to multiple reaction monitoring (MRM) mode by gas chromatography triple quadrupole spectrometry. The derivatization process was adapted from AOCS method Cd 29a-13. The results showed that the coefficient of determination (R2) of all detected compounds obtained from both detection mode was comparable, which falls between 0.997 and 0.999. The limit of detection and quantification (LOD and LOQ) were improved in MRM mode as compared to SIM mode. In MRM mode, the LOD of 3- and 2-MCPD ester was achieved 0.01 mg/kg while the LOQ was 0.05 mg/kg. Besides, LOD and LOQ of glycidyl ester were 0.024 and 0.06 mg/kg respectively. A blank spiked with MCPD esters (0.03, 0.10 and 0.50 mg/kg) and GE (0.06, 0.24 and 1.20 mg/kg) were chosen for repeatability and recovery tests. MRM mode showed better repeatability in area ratio and recovery with relative standard deviation (RSD %)
Fish oil-in-water emulsions containing fish oil, thiol-modified β-lactoglobulin (β-LG) fibrils, chitosan and maltodextrin were fabricated using a high-energy method. The results showed that chitosan coating induced charge reversal; denoting successful biopolymers complexation. A significantly (p<0.05) larger droplet size and lower polydispersity index value, attributed to the thicker chitosan coating at the oil-water interface, were observed. At high chitosan concentrations, the cationic nature of chitosan strengthened the electrostatic repulsion between the droplets, thus conferring high oxidative stability and low turbidity loss rate to the emulsions. The apparent viscosity of emulsions stabilized using thiol-modified β-LG fibrils-chitosan complex was higher than those stabilized using β-LG fibrils alone, resulting in the former's higher creaming stability. Under thermal treatments (63°C and 100°C), emulsions stabilized using thiol-modified β-LG fibrils-chitosan complex possessed higher heat stability as indicated by the consistent droplet sizes observed. Chitosan provided a thicker protective layer that protected the oil droplets against high temperature. Bridging flocculation occurred at low chitosan concentration (0.1%, w/w), as revealed through microscopic observations which indicated the presence of large flocs. All in all, this work provided us with a better understanding of the application of protein fibrils-polysaccharide complex to produce stable emulsion.