Physical properties of dressing-type oil in water emulsions as affected by okra gum-xanthan gum-corn starch interactions

Okra gum is one of potential hydrocolloids due to its’ suspending and emulsifying abilities and blending it with other gums shall widen its application in emulsion-based food products. Therefore, interaction effects of okra gum (OG), xanthan gum (XG) and corn starch (CS) on the physical properties of dressing-type emulsions were investigated in this study using a simplex-centroid mixture design. Application of OG:CS blend resulted in smaller droplet size range (5.40 – 11.22 μm) compared to XG:CS (4.82 – 13.97 μm) with the same gum ratio (i.e. 1:1), due to emulsifying property of OG. Emulsion prepared with this blend also exhibited better viscosity (30.43 ± 9.81 Pa.s) and turbidity (Absorbance value = 0.95 ± 0.12) compared to other emulsions with individual OG or CS. Regression modelling further confirmed the occurrence of synergistic interaction in OG:CS blend which positively affected these emulsion properties. Droplet size and turbidity responses were successfully fitted with a special cubic model while viscosity response was successfully fitted with quadratic model (no lackof- fit, p > 0.05). The models are useful for predicting the respective responses to any blend combination of the components. Results of this study signify that OG is a promising hydrocolloid showing synergism with CS and this synergism can be manipulated to overcome lack of OG performance in food emulsion

Physical properties and stability evaluation of fish oil-in-water emulsions stabilized using thiol-modified β-lactoglobulin fibrils-chitosan complex

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

Formation and characterization of thiol-modified fibrillated whey protein isolate solution with enhanced functionalities

The effect of thiolation using propanethiol on the functionalities of fibrillated whey protein isolate (WPI) solution at different pH values was studied. Fibrillated WPI solutions were thiolated at different molar ratios of propanethiol:carboxyl group (0.5:1, 1:1, 2:1, 3:1, 4:1) and the highest esterification extent ratio was obtained at 4:1 (pH 9). We also found that the thiolation process improved the foaming capacity and foam stability. TEM micrographs evidenced aggregation of thiol-modified fibrillated WPI. A network of shortened fibrils attached to each other was formed upon thiolation, suggesting good physical interaction. This was coherent with the increment of zeta potential values, indicating a greater repulsion force to retard fibrils aggregation. Thiolation enhanced emulsifying stability index of thiol-modified fibrillated WPI solution (pH 8) and diminished its susceptibility to pH changes. This has broadened the potential application of fibrils as food ingredients

Stabilization and release of palm tocotrienol emulsion fabricated using pH-sensitive calcium carbonate

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

Effects of environmental stresses and in vitro digestion on the release of tocotrienols encapsulated within chitosan-alginate microcapsules

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

Effects of storage and yogurt matrix on the stability of tocotrienols encapsulated in chitosan-alginate microcapsules

Tocotrienol microcapsules (TM) were formed by firstly preparing Pickering emulsion containing tocotrienols, which was then gelled into microcapsules using alginate and chitosan. In this study, we examined the stability of TM during storage and when applied into a model food system, i.e. yogurt. During storage at 40 °C, TM displayed remarkably lower tocotrienols loss (50.8%) as compared to non-encapsulated tocotrienols in bulk oil (87.5%). When the tocotrienols were incorporated into yogurt, the TM and bulk oil forms showed a loss of 23.5% and 81.0%, respectively. Generally, the tocotrienols were stable in the TM form and showed highest stability when these TM were added into yogurt. δ-Tocotrienol was the most stable isomer in both forms during storage and when incorporated into yogurt. The addition of TM into yogurt caused minimal changes in the yogurt’s color and texture but slightly altered the yogurt’s viscosity

Performance of Detecting IgM Antibodies against Enterovirus 71 for Early Diagnosis

Enterovirus 71 (EV71) infection is more likely to induce severe complications and mortality than other enteroviruses. Methods for detection of IgM antibody against EV71 had been established for years, however, the performance of the methods in the very early diagnosis of EV71 infection had not been fully evaluated, which is especially meaningful because of the short incubation period of EV71 infection. In this report, the performance of an IgM anti-EV71 assay was evaluated using acute sera collected from 165 EV71 infected patients, 165 patients infected with other enteroviruses, and more than 2,000 sera from healthy children or children with other infected diseases. The results showed a 90% sensitivity in 20 patients who were in their first illness day, and similar sensitivity remained till 4 days after onset. After then the sensitivity increased to 95% to 100% for more than one month. The specificity of the assay in non-HFMD children is 99.1% (95% CI: 98.6–99.4), similar as the 99.9% specificity in healthy adults. The cross-reaction rate in patients infected with other non-EV71 enteroviruses was 11.4%. In conclusion, the data here presented show that the detection of IgM anti-EV71 by ELISA affords a reliable, convenient, and prompt diagnosis of EV71 infection

Formation, characterization and application of thiol-modified beta-lactoglobulin fibrils complex with chitosan

β-lactoglobulin (β-LG) fibrils have diverse functionalities that make them good emulsifiers and promising foaming agents. However, fabrication of β-LG fibrils under highly acidic conditions (pH 2) has limited their application in food matrixes for food consumption. In addition, β-LG fibrils become unstable when the pH changes and are prone to aggregation. Hence, this study examined the effect of the thiol-modification on β-LG fibrils to improve their functionalities and provide stability against pH changes. Thiol-modified β-LG fibrils were further incorporated into fish oil emulsions by complexing them with chitosan, followed by microencapsulation. In the first stage, the effect of thiol-modification on β-LG fibrils was examined by modifying the carboxyl side groups. The results showed that the highest esterification was obtained at molar ratios of 4:1 (propanethiol:carboxyl groups) under pH 9. Thiolmodification significantly (p < 0.05) enhanced the foaming capacity (550.0 ± 16.7% to 727.8 ± 9.6%), foam stability and emulsifying stability index of the β-LG fibrils. In the second stage, complexation of thiol-modified β-LG fibrils with chitosan was carried out and incorporated into a fish oil emulsion. The results showed that the emulsion droplet size increased with smaller polydispersity indexes upon increasing the chitosan concentrations (0.1% - 0.5%, w/w). The addition of chitosan improved the emulsion stability and decreased the extent of creaming and turbidity loss rate, which improved the oxidative stability of the emulsion significantly (p < 0.05). Moreover, chitosancoated emulsion conferred higher heat stability under thermal treatments (63 °C and 100 °C) as indicated by the consistent droplet sizes. In the third stage, the fish oil emulsion stabilized with thiol-modified β-LG fibrilchitosan complexes was microencapsulated via spray drying using different inlet temperatures (160 °C, 170 °C and 180 °C). The results showed that the fish oil emulsion microencapsulated at 160 °C exhibited significantly higher microencapsulation efficiency (p < 0.05) with enhanced reconstitution properties. Fish oil microcapsules stabilized by thiol-modified β-LG fibril/0.5% chitosan complexes exhibited slightly higher glass transition temperature with a smooth-surfaced as observed via scanning electron microscopy. In the fourth stage, the storage stability and in-vitro digestibility of the microencapsulated fish oil emulsion stabilized with thiolmodified β-LG fibril-chitosan complexes was studied, revealing minimal changes in terms of surface colour and peroxide and p-anisidine values coupled with higher oil retention over 4-weeks of storage period. It was also stable against different ionic strengths. This is related to the thicker wall materials formed by thiol-modified β-LG fibril/0.5% chitosan complexes. It was found that chitosan coating slightly hinder the enzymatic digestion process. The findings of this study suggest that thiol-modification improved the functionalities of β-LG fibrils, including greater tolerance to pH and environmental changes. In addition, the complexation of thiol-modified β-LG fibrils with chitosan contributed to the stability and improved microencapsulation efficiency (> 89%) of a fish oil emulsion

Eukaryotic translation initiation factor 4-γ, 1 gene mutations are rare in Parkinson's disease among Taiwanese

Parkinson's disease (PD) is the second most common neurodegenerative disorder worldwide. Although idiopathic PD accounts for most of the cases, several genetic mutations have been found to cause PD. Mutations in the eukaryotic translation initiation factor 4-γ, 1 (EIF4G1) gene have been identified since 2011, which were reported to be associated with PD among Caucasians in subsequent research. However, this observation was not consistent. The contribution to other ethnic groups remains limited, with < 1% of sporadic cases. We conducted a case–control study to analyze if EIF4G1 is a risk factor for PD patients in Taiwan. Methods: There were 595 PD patients and 600 controls without neurological diseases enrolled in this study. Four reported mutations—A502V (c.1505C>T), G686C (c.2056 G>T), R1197W (c.3589C>T), and R1205H (c.3614G>A)—were analyzed. Results: There were no mutations found in either PD patients or controls. Conclusion: This study indicates that the EIF4G1 mutation is rare in Taiwan, which is consistent with other reports from Asia. Ethnicity could have a great influence on EIF4G1 in PD. Further large scale studies are warranted to evaluate the association of PD and EIF4G1 gene

Microencapsulation of fish oil-in-water emulsion using thiol-modified β-lactoglobulin fibrils-chitosan complex

Fish oil was encapsulated via spray-drying using different β-lactoglobulin (β-LG) fibril variants, chitosan and maltodextrin. The effects of different wall materials and inlet temperatures on the physicochemical properties of fish oil microcapsules were investigated. A lower polydispersity index (0.29–0.37) coupled with larger mean droplet size (0.96–1.25  μm) and higher zeta potential (41.3–41.6  mV) were achieved in the reconstituted fish oil microcapsules formed using thiol-modified β-LG fibril/0.5% chitosan complex. Lower angle of repose (<30°) displayed by the same sample suggested good flow properties, and this finding correlated well with its smooth surface, as observed using scanning electron microscopy. Microcapsules stabilized using the complex exhibited comparable encapsulation efficiency and slightly higher glass transition temperature than that of using unmodified β-LG fibrils, indicating the former's greater heat stability. This study provided valuable insight into the application of protein fibrils-polysaccharide complexes as an effective encapsulation agent