The Role of Oil Phase in the Stability and Physicochemical Properties of Oil-in-Water Emulsions in the Presence of Gum Tragacanth

Different emulsions based on six types of vegetable oils (sunflower, canola, sesame, olive, coconut, and palm olein) were studied to investigate the role of the oil phase in the stability and physicochemical characteristics of oil-in-water emulsions prepared with gum tragacanth. The results indicated that the stability, rheological parameters, and size distribution of emulsions were dependent on the oil type. Based on the interfacial tension value, the type of oil did not have a significant effect on the gum tragacanth-emulsifying properties. The formulation based on sunflower and coconut oil led to producing more stable emulsion and a sample containing palm olein resulted in an unstable emulsion. Rheological analysis revealed that the sample based on palm olein showed the lowest consistency coefficient (2.10 ± 0.05 Pas ⁿ), elastic modulus (3.90 ± 0.21 Pa), and energy of cohesion (80.87 ± 1.1 J m⁻³). This study revealed that using oils with lower viscosity and higher density led to the higher stability of the emulsion samples.     

Optimization of Headspace Single-Drop Microextraction Coupled with Gas Chromatography–Mass Spectrometry for Determining Volatile Oxidation Compounds in Mayonnaise by Response Surface Methodology

In this assay, headspace single-drop microextraction (HS-SDME) coupled with gas chromatography–mass spectrometry (GC–MS) as a simple, low-cost and rapid method has been developed and validated for determining volatile oxidation compounds including hexanal and heptanal in mayonnaise. The main microextraction variables affecting the HS-SDME procedure such as extraction temperature and time, stirring rate, and amount of NaCl were optimized by response surface methodology employing a central composite design. Obtained results demonstrated that higher yield of extracted analytes could be achieved under the following optimal conditions: extraction temperature of 45 °C, extraction time of 16 min, stirring rate at 700 rpm, and addition of 2 g NaCl. The optimized HS-SDME/GC–MS method was validated for oxidized mayonnaise samples (50 °C/48 h) by calculating analytical parameters (linearity, precision, accuracy, and sensitivity). Good linearity (R ²?>?0.99) was observed by plotting calibration curves of extracted hexanal and heptanal over the concentration range of 0.025–10 μg g^?1, and the repeatability of the method, expressed as relative standard deviation, were found to be 4.04 % for hexanal and 3.68 % for heptanal (n?=?7). After the microextraction process of spiked mayonnaise sample, high levels of relative recovery were obtained for hexanal (107.33 %) and heptanal (91.43 %). The detection limits were 0.008 ng g^?1 and 0.021 ng g^?1 for hexanal and heptanal, respectively, while quantification limits of hexanal and heptanal were calculated to be 0.027 ng g^?1 and 0.071 ng g^?1, respectively. The possibility of the HS-SDME followed GC–MS to determine and quantify volatile oxidation compounds such as hexanal and heptanal was confirmed by analyzing commercial fresh mayonnaise stored at 4 and 25 °C during 3 months.     

Oleogel Fabrication Based on Sodium Caseinate,Hydroxypropyl Methylcellulose,and Beeswax: Effect of Concentration,Oleogelation Method,and Their Optimization

In the present study, the oleogel preparation with hydroxypropyl methylcellulose (HPMC) (0–2 g/100 g), sodium caseinate (CN) (0–4 g/100 g), beeswax (0–5 g/100 g), and oleogelation method (foam and emulsion template) was optimized using response surface methodology (RSM) to attain the desirable oil retaining ability, rheological, and textural characteristics. For all the chosen responses, the quadratic model was the best-fitting model with a determination coefficient of R² > 0.91. Results exhibited that the HPMC and CN concentrations were the most influential tested factors on the oil binding capacity, textural, and rheological characteristics of the oleogels due to the formation of more complex and strong network. There was a significant improvement in oil binding capacity and structure recovery of samples by beeswax addition. To produce oleogel similar to industrial shortening, the optimization method was done based on maximum oil binding capacity and thixotropic recovery and other responses were chosen equal to those of shortening values (ɳ_a = 330 Pa.s, G′ = 276,543 Pa, A value = 164,308 Pa s rad⁻¹, and firmness = 44.99 g). As regards the optimized level of structuring agents and responses (ɳ_a = 317 and 329 Pa.s, G′ = 249,782 and 260,997 Pa, A value = 180,022 and 180,373 Pa s rad⁻¹, and firmness = 44.37 and 36.98 g corresponding to Optimization 1 and Optimization 2, respectively), fabrication of oleogels with at least 90 g/100 g trans-free and low saturated oil and attributes close to industrial shortening is possible.     

Risk of respiratory exposure of dental personnel to amalgam alternatives

Although the use of alternatives to dental amalgam is increasing, the possible hazard associated with their occupational exposure has received inadequate attention. The purpose of this study is to use available toxicological and environmental information in a qualitative risk assessment to address potential health hazards associated with exposure to these materials by dental personnel. The members of dental profession should be aware of risk due to long-term exposure to dental materials.     

Physicochemical characteristics of beverage emulsions containing crocetin as a functional ingredient of saffron

Food Science and Biotechnology - This study aimed to investigate the physicochemical properties of beverage emulsions containing crocetin as a functional ingredient. The effect of different...     

Concentrated O/W emulsions formulated by binary and ternary mixtures of sodium caseinate,xanthan and guar gums: rheological properties,microstructure, and stability

Food Science and Biotechnology - The effects of xanthan gum (XG) (0, 0.3, 0.6 wt%), guar gum (GG) (0, 0.3, 0.6 wt%) and XG:GG mixtures (0.3–0.3, 0.3–0.6, 0.6–0.3 and 0.6–0.6...     

Modelling and optimization of main independent parameters for biodiesel production over a Cu0.4Zn0.6Al2O4 catalyst using an RSM method

In this research, the modeling of Cu0.4Zn0.6Al2O4 catalysts performance and optimizing of esterification reactions were considered by the central composite design (RSM) response method. The main independent parameters of temperature, the ratio of alcohol to oil, the amount of catalyst and time duration have been considered for setting the esterification process. To access the maximum activity in the esterification process, the optimum conditions are estimated at 10.42 the molar ratio of alcohol to oil, 2.98 wt.% for the amount of catalyst at the temperature of 163.37 °C and within 4.15 hrs. Under these conditions, the conversion will be above 97.94%. These conditions have been applied to adjust the process of transesterification of waste cooking oil. The reusability of the Cu0.4Zn0.6Al2O4 nanocatalyst in the esterification reaction was investigated in this study. Employed statistical techniques and developed models can be employed as a useful tool for design, prediction, and optimization of the biodiesel production process with effective performance for various industrial applications. © 2021 Society of Chemical Industry (SCI).     

Application of Microwave Irradiation for Preparation of a KOH/Calcium Aluminate Nanocatalyst and Biodiesel

Microwave combustion was applied for the fabrication of KOH/calcium aluminate for microwave‐enhanced biodiesel production. The effect of calcium nitrate and potassium hydroxide dosages on the properties and activities of samples was assessed. When the Ca/Al ratio was increased, the activity was enhanced probably due to the transformation of the sample to an active mayenite structure. The activity of the sample was reduced by a higher KOH loading as a result of covering the surface and porosity of the support by potassium components. The optimum sample was utilized in the transesterification reaction by two heating systems where the microwave irradiation reduced the reaction time drastically as compared to the conventional heating system. The sample converted canola oil to methyl ester nearly completely and showed high stability via calcination after each usage.     

Oleogel production based on binary and ternary mixtures of sodium caseinate,xanthan gum,and guar gum: Optimization of hydrocolloids concentration and drying method

We report the optimization of oleogel formulation based on sodium caseinate (CN, 0–4 g/100 g), xanthan gum (XG, 0–1 g/100 g), guar gum (GG, 0–1 g/100 g), and drying method (freeze and oven drier) using response surface methodology to achieve the desired oil binding capacity, textural, and rheological attributes. All the selected responses were successfully fitted by a quadratic model with determination coefficient values higher than .95 with the exception of firmness values which was fitted by linear model. There were considerable increases in all the responses for the samples containing ternary mixtures of protein-gum (CN:XG:GG) as well as binary mixtures (CN:GG and CN:XG) compared to samples containing protein or gums alone due to the synergistic effect of CN and gums on formation of highly ordered and strong gel network. Regression modeling demonstrated that freeze drying method led to significantly greater structure recovery values than those of oven drying method. The best formulation was the freeze dried oleogel containing 4 g/100 g CN, 0.43 g/100 g XG, and 0.98 g/100 g GG. Results showed that fabrication of oleogels with at least 94.5 g/100 g sunflower oil and characteristics similar to industrial shortening is feasible.