non-Newtonian Pseudoplastic Flow Research Articles

Ultrasound-Assisted Extraction of Okra Mucilage: Rheological Properties of its Aqueous Solutions

Using chemical and physicochemical techniques, we extracted the mucilaginous component of okra (Abelmoschus esculentus L.) by the ultrasound-assisted extraction method, then evaluated the resulting polysaccharide extract's rheological properties. Our investigation encompassed examining the flow behavior of polysaccharides extracted under different okra to distilled water ratios (1:10 and 1:30) and various polysaccharide concentrations (1, 2, 3 and 4%, w/v) over a temperature range of 10°C to 80°C. Employing the power law model, we derived parameters and found that okra polysaccharides displayed non-Newtonian pseudoplastic flow characteristics. The flow behavior index ranged from 0.234 to 0.947, with the consistency coefficient ranging from 4.37 to 244.50 mPa.s. Increasing temperature resulted in a decrease in both the consistency coefficient (K) and flow behavior index (n), while concentration elevation led to higher consistency coefficient values. However, the flow behavior index did not exhibit consistent trends with concentration variations. Three statistical parameters; correlation coefficient (R2), root mean square error (RMSE) and chi-square (χ2) were used to evaluate the fit of the power law model to the experimental data. Our study further explored temperature’s impact on the apparent viscosities of okra polysaccharide samples and modeled the influence of temperature on the consistency index using the Arrhenius equation. Samples with solid-to-solvent ratios of 1:10 and 1:30 showed increasing activation energy with concentration rise, with the highest value recorded at 275.84 kJ/mol for the 1:10 ratio sample with a 4% concentration. In SEM images, okra polymers exhibit irregular, wavy, rough textured surface, and amorphous appearance. These findings hold promise for optimizing ultrasound extraction protocols and enhancing the industrial utilization of mucilages through their rheological properties.

Multi-scale ultrasound induced composite coacervates of whey protein and pullulan polysaccharide on emulsion forming and stabilizing mechanisms

A non-destructive technique known as multi-scale ultrasound (MSU) was employed to modify the emulsion consisting of glycosylated bovine whey protein (WP) and pullulan (Pu). To assess the effect on the structural and emulsifying properties of the WP-Pu, the formulated emulsion, was treated with divergent MSU at (single: 20 kHz, 40 kHz, and 60 kHz; dual: 20–40 kHz, 40–60 kHz, and 20–60 kHz; and tri: 20–40-60 kHz) frequency for a duration of 30 min. The tri-frequency, treated emulsion showed improved emulsifying stability compared to the control and MSU-treated single, and dual-frequency samples, as indicated by the particle size, structural morphology, and adsorbed protein. The molecular docking and numerous spectral analysis provided evidence that WP can undergo successful phenolation. This modified form of WP then interacts with Pu through various forces, including H-bonding and other mechanisms, resulting in the formation of a composite emulsion. The rheological properties revealed that both the control emulsion and the MSU-treated emulsion exhibited non-Newtonian pseudoplastic flow behavior. This behavior is characterized by shear thinning, where the viscosity decreases with increasing shear rate. The shear rates tested ranged from 1 to 300 1/s, additionally, the degree of crystallinity increased from 18.2° to 19.4°. Overall, the tri-frequency effect was most pronounced compared to single and dual-frequency. Ultrasonication, an emerging non-thermal technology, proves to be an efficient approach for the formulation of WP-Pu composites. These composites have significant potential for use in drug delivery systems and functional foods.

Synergistic approach for acne vulgaris treatment using glycerosomes loaded with lincomycin and lauric acid: Formulation, in silico, in vitro, LC-MS/MS skin deposition assay and in vivo evaluation

This study aims to develop a pharmaceutical formulation that combines the potent antibacterial effect of lincomycin and lauric acid against Cutibacterium acnes (C. acnes), a bacterium implicated in acne. The selection of lauric acid was based on an in silico study, which suggested that its interaction with specific protein targets of C. acnes may contribute to its synergistic antibacterial and anti-inflammatory effects. To achieve our aim, glycerosomes were fabricated with the incorporation of lauric acid as a main constituent of glycerosomes vesicular membrane along with cholesterol and phospholipon 90H, while lincomycin was entrapped within the aqueous cavities. Glycerol is expected to enhance the cutaneous absorption of the active moieties via hydrating the skin. Optimization of lincomycin-loaded glycerosomes (LM-GSs) was conducted using a mixed factorial experimental design. The optimized formulation; LM-GS4 composed of equal ratios of cholesterol:phospholipon90H:Lauric acid, demonstrated a size of 490 ± 17.5 nm, entrapment efficiency-values of 90 ± 1.4 % for lincomycin, and97 ± 0.2 % for lauric acid, and a surface charge of −30.2 ± 0.5mV. To facilitate its application on the skin, the optimized formulation was incorporated into a carbopol hydrogel. The formed hydrogel exhibited a pH value of 5.95 ± 0.03 characteristic of pH-balanced skincare and a shear-thinning non-Newtonian pseudoplastic flow. Skin deposition of lincomycin was assessed using an in-house developed and validated LC-MS/MS method employing gradient elution and electrospray ionization detection. Results revealed that LM-GS4 hydrogel exhibited a two-fold increase in skin deposition of lincomycin compared to lincomycin hydrogel, indicating improved skin penetration and sustained release. The synergistic healing effect of LM-GS4 was evidenced by a reduction in inflammation, bacterial load, and improved histopathological changes in an acne mouse model. In conclusion, the proposed formulation demonstrated promising potential as a topical treatment for acne. It effectively enhanced the cutaneous absorption of lincomycin, exhibited favorable physical properties, and synergistic antibacterial and healing effects. This study provides valuable insights for the development of an effective therapeutic approach for acne management.

Hydrogel Containing Silibinin-Loaded Pomegranate Oil-Based Nanocapsules for Cutaneous Application: In Vitro Safety Investigation and Human Skin Biometry and Permeation Studies.

In previous studies, we developed a hydrogel formulation containing silibinin-loaded pomegranate oil nanocapsules (HG-NCSB) that had improved in vivo anti-inflammatory action in comparison to non-encapsulated silibinin. To determine skin safety and whether the nanoencapsulation influences silibinin skin permeation, NCSB skin cytotoxicity, HG-NCSB permeation in human skin, and a biometric study with healthy volunteers were conducted. The formulation of nanocapsules was prepared by the preformed polymer method while the HG-NCSB was obtained by thickening the suspension of nanocarriers with gellan gum. The cytotoxicity and phototoxicity of nanocapsules were assessed in Keratinocytes (HaCaT) and fibroblast (HFF-1) using the MTT assay. The hydrogels were characterized regarding the rheological, occlusive, and bioadhesive properties, and silibinin permeation profile in human skin. The clinical safety of HG-NCSB was determined by cutaneous biometry in healthy human volunteers. NCSB yielded better cytotoxicity results than the blank nanocapsules (NCPO). NCSB did not cause photocytotoxicity, while NCPO and the non-encapsulated substances (SB and pomegranate oil) were phototoxic. The semisolids presented non-Newtonian pseudoplastic flow, adequate bioadhesiveness, and low occlusive potential. The skin permeation demonstrated that HG-NCSB retained a higher SB amount in the outermost layers than HG-SB. In addition, HG-SB reached the receptor medium and had a superior concentration of SB in the dermis layer. In the biometry assay, there was no significant cutaneous alteration after the administration of any of the HGs. Nanoencapsulation promoted greater SB retention in the skin, averted percutaneous absorption, and made the topical use of SB and pomegranate oil safer.

Improvement of dissolution profile of eplerenone with solidified self-emulsifying drug delivery systems (S-SEDDS)

Context Eplerenone is a member of antihypertensives used individually or in combination with other medicines. Eplerenone exhibits poor solubility and is considered a class II drug. Objective Increasing the solubility of eplerenone by using both liquid and solid self-emulsifying drug delivery systems as an alternative to its marketed tablet product. Methods Solubility studies of eplerenone were done with different oils, surfactants, and co-surfactants to determine which one has the highest solubility for eplerenone and determine the preference in the formulations of liquid self-emulsifying drug delivery system. The solidification process was carried out with the adsorption to solid carrier method. Optimal ratios of components were specified with the pseudo-ternary phase diagram technique. Self-emulsifying drug delivery system formulations were characterized in terms of chemical interaction, droplet size/distribution, crystallization behaviors, and rheological evaluation. In vitro drug release studies were conducted and compared to pure drugs and marketed products. Results The solubility screening results showed high solubility of EPL in triacetin (11.99 mg/mL) as oil, Kolliphor®EL (≈ 2.65 mg/mL), and Tween80 (≈ 1.91 mg/mL) as surfactant and polyethylene glycol 200 (PEG200) (≈ 8.50 mg/mL), dimethyl sulfoxide (≈ 7.57 mg/mL), TranscutolP (≈ 6.03 mg/mL) as co-surfactant, respectively. Rheology studies revealed that liquid self-emulsifying drug delivery formulations exhibited non-Newtonian pseudoplastic flow. Conclusion Solid self-emulsifying drug delivery systems prepared with Aerosil and Neusilin have shown tremendous improvement in terms of eplerenone dissolution by releasing the entire dose with boosted effect within 5 and 30 min respectively compared to the marketed product and pure eplerenone (p < 0.05).

Effect of powders on aluminum nitride components fabricated by PIM

Powder selection is essential to the success of powder injection molding (PIM). In this study, aluminum nitride (AlN) powder synthesized through carbon-thermal (C-R) reduction and direct nitridation (DN) were used as the raw material. These two kinds of powder were mixed with wax-based binder and the rheological properties of AlN feedstocks were examined. Then the green parts were fabricated by powder injection molding and sintered after solvent and thermal debinding. Finally, the appearance, microstructure and thermal conductivity of sintered AlN were inspected. It was found that the C-R powder has higher critical solid loading (60 vol%) than DN powder (58 vol%). Feedstocks viscosity decreased when the shear rate increased, indicating the presence of non-Newtonian pseudoplastic flow. The C-R powder also has better rheology properties with lower viscosity, higher melt flow rate, higher shear thinning, and higher activation energy. As for the performance after short-time sintering, the thermal conductivity of C-R AlN is 183 W·m−1·k−1 while the value of DN AlN is 130 W·m−1·k−1, and the bending strength of C-R AlN is 363 MPa while that of DN AlN is only 320 MPa.

Production and evaluation of microbiological & rheological characteristics of kefir beverages made from nuts

Herein we report the preparation of nut milks followed by kefir production from Almond, peanut, hazelnut, walnut, and cashew. Nut-based milks were used to make kefir from 100% vegetable milk without food additives or sugar. During 30 days of storage at 4 °C, the microbiological (total aerobic mesophilic bacteria, lactobacilli, lactococci, acetic acid bacteria, yeast) and rheological (apparent viscosity, consistency constant, flow behavior index, thixotropy) parameters of kefir samples made from cow's milk and nut-based milk were monitored and compared to examine the effects of different milk types and storage time. The titratable acidity value of nut kefirs was lower than cow kefir. Kefir from walnut milk had the lowest titratable acidity value (0.15%), lowest apparent viscosity (3.3 mPa s) and consistency coefficient (682.1 mPa.sn). Titratable acidity values of the samples increased while apparent viscosity, thixotropy, flow behavior index and consistency coefficient decreased during storage. According to the power-law model, the kefir samples exhibited non-Newtonian pseudoplastic flow behavior. The apparent viscosity values of peanut and almond kefirs were higher among the prepared samples (p < 0.05). The total number of aerobic mesophilic, lactic acid and acetic acid bacteria of kefir samples decreased during storage, while the number of yeasts increased. Kefir made from cow's milk had the highest average total aerobic mesophilic bacteria, lactococci, lactobacilli, and acetic acid bacteria counts, whereas kefir made from peanut milk had the highest yeast count (p < 0.05). During storage the lowest decrease (%) in the counts of microorganism was determined in almond kefir (4.06%), followed by cow (5.16%), walnut (5.73%), peanut (6.72%), cashew (7.78%), and hazelnut kefirs (9.53%).

Locust bean gum hydrogels are bioadhesive and improve indole-3-carbinol cutaneous permeation: influence of the polysaccharide concentration

The locust bean gum (LBG) is a polysaccharide with thickening, stabilizing and gelling properties and it has been used in the preparation of pharmaceutical formulations. Hydrogels (HGs) are obtained from natural or synthetic materials that present interesting properties for skin application. This study aimed to develop HGs from LBG using indole-3-carbinol (I3C) as an asset model for cutaneous application. HGs were prepared by dispersing LBG (2%, 3% and 4% w/v) directly in cold water. The formulations showed content close to 0.5 mg/g (HPLC) and pH ranging from 7.25 to 7.41 (potentiometry). The spreadability factor (parallel plate method) was inversely proportional to LBG concentration. The rheological evaluation (rotational viscometer) demonstrated a non-Newtonian pseudoplastic flow behavior (Ostwald De Weale model), which is interesting for cutaneous application. The HET-CAM evaluation showed the non-irritating characteristic of the formulations. The bioadhesive potential demonstrated bioadhesion in a concentration-dependent manner. Permeation in human skin using Franz cells showed that the highest LBG concentration improved the skin distribution profile with greater I3C amounts in the viable skin layers. The present study demonstrated the feasibility of preparing HGs with LBG and the formulation with the highest polymer concentration was the most promising to transport active ingredients through the skin.

An analysis of the rheological properties of carob molasses and carob powder-added peanut bu

This study aimed to analyse the effects of using carob molasses (2.5%, 5%, 10%, and 20%) and carob powder (2.5%, 5%, 10%, and 20%) at different ratios on rheological of peanut butter. The examined peanut butter samples showed non-Newtonian pseudoplastic flow behaviour. The rheological properties of the peanut butter samples were found to fit the HerschelBulkley model, and R2 values appeared to range between 0.9753 an 0.9988. The viscosity, yield stress (0), and flow index (n) turned out to decrease along with the addition of carob molasses or carob powder to the peanut butter samples to increase the concentration, improving its viscosity and spreadability.

Formulation and in vitro and in vivo evaluation of surfactant-stabilized mucoadhesive nanogels for vaginal delivery of fluconazole

Surfactant-stabilized mucoadhesive nanogels (NGs) for vaginal delivery of fluconazole (FLZ) were studied and evaluated in this work. FLZ-NG formulations were prepared using two different types of mucoadhesive polymers, Carbopol 934 (Ca934) and Pluronic F-127 (PF127). A rheology study revealed a non-Newtonian pseudoplastic flow behavior (shear thinning) in the prepared NGs. The viscosity of Ca934 NG (0.47 Pa s) was much lower compared to the PF127 NG (6.10 Pa s). The rheology study results correlated well with the in vitro FLZ release profile from the NG formulations. A pH study (pH = 3.90–4.90) revealed that the formulations were physiologically suitable for vaginal application, to avoid the irritation of the vaginal mucosa. Finally, in vitro and in vivo antimicrobial tests were performed. FLZ incorporated into the Ca934 gel had the strongest antimicrobial effect, with a mean inhibition zone of 24 ± 1.6 mm. Based on these results, it was concluded that the mucoadhesive NG incorporating FLZ resulted in a sustained release and enhanced antimicrobial effect, which would enhance and prolong the therapeutic effects of vaginally delivered FLZ.

ВЛИЯНИЕ ОЛИВКОВОГО МАСЛА НА РЕОЛОГИЧЕСКИЕ ХАРАКТЕРИСТИКИ МАЙОНЕЗА

Rheological properties are an important parameter for the quality of mayonnaise. This article in-vestigated the effect of adding olive oil on the rheological properties and color change of mayon-naise. The influence of the storage time of mayonnaise in the refrigerator on the change in rheo-logical properties was also investigated. Mayonnaise was prepared on a laboratory rotary disperser of the Turrex type with a rotor / stator system with a rotor speed range (10000-30000 rpm) at room temperature. Mayonnaise contains 75% oil with varying proportions of sunflower oil and ol-ive oil. Rheological measurements were carried out on a Brookfield rotary viscometer with con-centric cylinders at temperatures of 10 ° C and 25 ° C. Based on the data obtained, the consistency coefficient of the rheological parameters, the flow index and the apparent viscosity were calculat-ed. The color of the test samples of mayonnaise was measured using a three-color colorimeter. All mayonnaise samples exhibit non-Newtonian pseudoplastic flow with a defined thixotropic loop area. Research results have shown that the addition of olive oil affects the rheological properties and color of mayonnaise. The addition of olive oil to the oil phase of mayonnaise reduces shear stress, apparent viscosity, consistency factor and color change at 25 ° C and 10 ° C. When storing mayonnaise in the refrigerator for 15 days, the rheological parameters change. Sunflower oil may-onnaise (75%) has the highest value (L), which means it is measured instrumentally as the bright-est.

Complex High-Internal Phase Emulsions that can Form Interfacial Films with Tunable Morphologies.

High-internal phase emulsions (HIPEs) were considered as an important functional material and have been the focus of intense development effort, but their fundamental attributes have hardly been altered at either the microcosmic or macroscopic level, which severely limits their practical applications in various areas. In this work, we report a general strategy for creating complex HIPEs that can form interfacial films at liquid interfaces. Double HIPEs and Janus HIPEs are both realized for the first time. They feature complex microscopic patterns with short-range anisotropy and exhibit non-Newtonian pseudoplastic flow behavior. By taking advantage of their response to a high-pH subphase, interfacial films can be successfully obtained, which are tunable in thickness and morphologies under compression. Complex HIPEs can greatly expand the applications of liquid materials, and the interfacial films of droplets represent an important step toward producing 2D soft materials with a unique functionality that can be broadly applied to biological processes.

Isolation of an exopolysaccharide from a novel marine bacterium Neorhizobium urealyticum sp. nov. and its utilization in nanoemulsion formation for encapsulation and stabilization of astaxanthin

The increasing health awareness among population has resulted in demand for foods with minimum side effects. In recent times, natural biomolecules are more preferred as compared to their synthetic counterparts. Microbial polysaccharides have shown potential to replace synthetic food additives. The present study aims to explore marine exopolysaccharide (EPS) as a replacement for synthetic emulsifiers such as sorbates and polysorbates. In the process, an EPS designated as K1T-9 was isolated from the marine bacterium Neorhizobium urealyticum K1T sp. nov. that showed pH stable emulsification activity. This EPS K1T-9 was utilized as an emulsifier for nanoemulsion formation through ultrasonication to encapsulate and enhance the bioavailability of astaxanthin. Partial characterization of the EPS suggested that it is a heteropolysaccharide consisted of glucose and galacturonic acid with a molecular weight of 207 kDa. Interestingly, the functional properties of K1T-9 have revealed that the molecule exhibited non-Newtonian pseudoplastic and shear-thinning flow behavior along with high water (356 ± 0.8%), oil holding (697 ± 1% for coconut oil, and 317 ± 1.3% for olive oil), and swelling capacity (200 ± 1.1%). Thus, the EPS K1T-9 obtained from Neorhizobium urealyticum sp. nov. holds plausible applications in food and related industries.

Rheological, structural and physicochemical characteristics of heat-induced egg albumin/sesbania gum mixed gels

The effects of sesbania gum (SG) on the rheological and physicochemical properties of heat-induced egg albumin gels were investigated. The formation of the gels of egg albumin (4%, w/v)/SG (0, 0.1, 0.2 and 0.3%, w/v) mixtures were induced by heating. It was evident from the appearance of gels' microstructure that phase separation occurred in egg albumin/SG systems. Non-Newtonian pseudoplastic flow behavior was observed in all the gels and it was further evident that 0.1% of SG could significantly (p < 0.05) improve the apparent viscosity of the egg albumin gels. The rheological characteristics of the gels demonstrated a more stable and plastic character gel formed at 0.1% SG. The temperature stability test showed that the structures of egg albumin/SG gels maintain their stability when reheated. The hardness of the egg albumin gels was improved with the addition of 0.1% SG, and their water holding capacity (WHC) was also improved. For egg albumin gel with 0.1% SG, a three-dimensional stranded network was observed, indicating the formation of a more stable and tight gel. The FTIR results confirmed that egg albumin and SG are thermodynamically incompatible, which suggested that there is no covalent bonding between egg albumin and SG.

Gellan gum-based hydrogel containing nanocapsules for vaginal indole-3-carbinol delivery in trichomoniasis treatment

Trichomonas vaginalis infection is the STI most common worldwide. Indole-3-carbinol (I3C) is a phytochemical presenting promising biological activities. In this study, design, formulation, and evaluation of a vaginal hydrogel containing I3C-loaded nanocapsules for the treatment of trichomoniasis have been investigated. Nanocapsules of Eudragit® RS100 and rosehip oil containing I3C (NC-I3C) were prepared by interfacial deposition of preformed polymer method. In vitro evaluations showed that free I3C (IC50 = 3.36 µg/mL) was able to reduce the trophozoites viability at higher concentrations (3.13 and 6.25 µg/mL), while nanoencapsulation (IC50 = 2.09 µg/mL) reduced the viability at all concentrations evaluated. Comparing free and nanoencapsulated I3C, we observe that nanoencapsulation improved anti-T. vaginalis activity. In order to obtain a formulation for vaginal administration, hydrogels (HG-NC-I3C) were prepared by thickening the NC-I3C with gellan gum. HG-NC-I3C presented particle size below 195 nm, low polydispersity index (<0.2), I3C content = 0.50 ± 0.01 mg/g, pH = 7.05, non-Newtonian pseudoplastic flow behavior and exhibited mucoadhesion to cow's vaginal mucosa. Evaluation of irritation potential by chorioallantoic membrane method indicated that the formulations are considered non-irritating. Besides that, permeation through the cow's vaginal mucosa showed that nanoencapsulation promoted I3C controlled release. This way, the developed HG-NC-I3C can be considered a promising approach for trichomoniasis treatment through vaginal administration.

Potential applications of Abelmoschus moschatus polysaccharide as colon release tablets-Rheology and gamma scintigraphic study

In the present scenario of pharmaceutical development, researchers are focusing on the herbal excipients for different delivery systems. This work describes diverse characteristics of novel polysaccharide extracted from the stem of Abelmoschus moschatus (AM). Further, polysaccharide was explored for its potential role as polymer in controlling colon-specific release of metronidazole (MNZ). Cell toxicity study confirmed its safety aspects in biological applications. The aqueous solution of polysaccharide exhibited non-Newtonian pseudoplastic flow property. The consistency coefficient (k) was found to increase with increase in concentration and particle size of AM polysaccharide. Viscosity was found to increase by increasing pH of the aqueous solution of AM. In-vivo gamma scintigraphy study of radiolabeled MNZ tablet in human volunteers confirmed small intestinal transit time of 300–480 min and colon arrival time of 360–480 min. The present study revealed that AM polysaccharide may be a choice of pharmaceutical excipients as an alternative to synthetic polymers.

A biological active artificial saliva formulation containing flower mucilage from Ceylon Spinach (Basella alba Linn.).

Ceylon Spinach (Basella albe) is an edible perennial vine found in tropical Asia and Africa, known as vegetables containing mucilage. Its mucilage from flowers was extracted by microwaving and precipitated with 95% ethanol. Five artificial saliva formulations composing of mucilage from Ceylon Spinach, calcium chloride (CaCl2), potassium chloride (KCl) and sodium fluoride (NF) were developed. The best formulation No.5 containing 0.61% of the mucilage with the non-Newtonian pseudoplastic flow (8.9 ± 0.2 cP) and the wetting time (12.50 ± 2.24 min) similar to the normal human saliva was selected. This artificial saliva formulation exhibited biological activities including an antioxidative activity by DPPH free radical scavenging with the SC50 of 14.26 ± 2.00 mg/ml (0.05 folds of ascorbic acid), and the adhesion inhibition of S. mutans on hydroxyapatite beads at 17.01 ± 7.75%, while the natural human saliva exhibited an increase bacterial adhesion of 33.10 ± 9.70%. The safety of this formulation which gave no cytotoxicity on normal human gingival fibroblasts at 99.20 ± 21.09% cell viability was also demonstrated. The results from this study have indicated high biological activity and safety of the developed formulation containing mucilage from Ceylon Spinach which is potential to be used as artificial saliva for xerostomia patients.

Formulation and Evaluation of Polyherbal Antioxidant Face Cream Containing Ethanol Extracts of Psidium Guajava and Ocimum Gratissimum

Background: Aging is a natural progressive process that leads to aesthetic and functional changes in the skin. The aim of this research work is to formulate and evaluate a polyherbal antioxidant face cream using the ethanol extracts of psidium guajava and ocimum gratissimum.Method: The ethanol extract of the herbs was incorporated at varying concentrations into six different emulsion bases. Antioxidant activity of the formulations was assessed using 2, 2-Diphenyl-1-picrylhydrazyl method. The formulations were evaluated for pH, viscosity, spreadability and microbial content. Accelerated stability tests were performed on all the formulations to assess stability at varying storage conditions.Results: All the formulations showed good spread ability, good consistency, homogeneity, appearance, pH without phase separation occurring. Rheological tests showed that the all formulations exhibited non-Newtonian pseudo plastic flow. All six formulations also showed concentration dependent antioxidant activity. Ascorbic acid a potent antioxidant served as the standard for these tests. Formulation AFCR6 showed the highest antioxidant activity with IC50 value of 80.1 μg/mL.Conclusion: The polyherbal antioxidant cream containing extracts of Psidium guajava and Ocimum gratissimum have been shown to have excellent antioxidants properties. It can serve to protect the skin from reactive oxygen species created by UV radiation and environmental toxin, thus protecting the skin from photo aging.Keywords: Anti-oxidant, Face cream, Psidium guajava, Ocimum gratissimum

Effects of mastic gum ( Pistacia lentiscus ) on chemical, rheological, and microbiological properties of yogurt ice cream

The aim of this study was to determine the effects of mastic gum (0.02 and 0.04%) in yogurt ice cream. The physicochemical, textural, rheological, and sensory properties, and the vitality of yogurt bacteria were investigated. The melting rate and overrun of samples were detected to be 12.14–17.82/g/min and 22.45–27.93% on the first day of storage, respectively. The mix showed non-Newtonian pseudoplastic flow (n < 1) in all the samples. At the end of the storage period, the Streptococcus salivarius ssp. thermophilus counts were determined to be 3.44, 2.94, and 2.82 log CFU/g in the control and yogurt ice cream samples with 0.2 and 0.4% mastic gum, respectively. The sensory properties of ice cream were appraised using principal component analysis. When the sensory characteristics of the yogurt ice cream were evaluated, it was found that yogurt ice cream containing 0.02% mastic gum was preferable. Practical applications In the Mediterranean region, mastic gum is widely used in ice cream. Mastic gum is a natural aromatic substance, which is also useful for health supplements. This ingredient is of low cost and readily available cheaply and easily, and enhances the functional properties of yoghurt ice cream. In addition, positive effects on the sensory properties of ice cream can also been introduced.

Numerical Solution of Natural Convective Heat Transfer Under Magnetic Field Effect

Abstract In this study, non-Newtonian pseudoplastic fluid flow equations for 2-D steady, incompressible, the natural convective heat transfer are solved numerically by pseudo time derivative. The stability properties of natural convective heat transfer in an enclosed cavity region heated from below under magnetic field effect are investigated depending on the Rayleigh and Chandrasekhar numbers. Stability properties are studied, in particular, for the Rayleigh number from 104 to 106 and for the Chandrasekhar number 3, 5 and 10. As a result, when Rayleigh number is bigger than 106 and Chandrasekhar number is bigger than 10, the instability occurs in the flow domain. The results obtained for natural convective heat transfer problem are shown in the figures for Newtonian and pseudoplastic fluids. Finally, the local Nusselt number is evaluated along the bottom wall.