Viscosity change in oil/water food emulsions prepared using a membrane emulsification system

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

This study aimed to investigate the physicochemical properties of beverage emulsions containing crocetin as a functional ingredient. The effect of different concentrations of gum Arabic (GA; 1-4%), various types of oils (10% sunflower or sesame oil containing 0.1% of crocetin) in the presence of xanthan gum (XG; 0.1%) were studied using a general full factorial design. The dependent variables were pH, opacity, size index, stability index (determined in accelerated and storage conditions), particle size, and steady shear rheological measurements. The main effects of GA concentration were significant (p < 0.001) on all of the physicochemical characteristics. However main effects of oil types were only significant (p < 0.001) on the mean diameter size, size index, and consistency coefficient (k) of prepared crocetin beverage emulsions. Results suggested sunflower oil may be more suitable for formulating a beverage emulsion containing crocetin because of the smaller mean particle size and lower size index.

Ultrasonic assisted water-in-oil emulsions encapsulating macro-molecular polysaccharide chitosan: Influence of molecular properties, emulsion viscosity and their stability

An ultrasonic technique was applied to formulation of two-phase water-in-paraffin oil emulsions loading a high-molecular polysaccharide chitosan (CS) and stabilized by an oil-soluble surfactant (Span80) at different operational conditions. The influence of chitosan molecular properties, phase volume ratio (φ_w), Span80 volume fraction (φ_s) and ultrasonic processing parameters were systemically investigated on the basis of mean droplet diameter (MDD) and polydispersity index (PDI) of emulsions. It was observed that the molecular weight (M_w) of CS was an important influential factor to MDD due to the non-Newtonian properties of CS solution varying with M_w. The minimum MDD of 198.5 nm with PDI of 0.326 was obtained with ultrasonic amplitude of 32% for 15 min at an optimum φ_w of 35%, φ_s of 8%, probe position of 2.2 cm to the top of emulsion, while CS with M_w of 400 kDa and deacetylation degree of 84.6% was used. The rise of emulsion viscosity and the reduction of negative zeta potential at φ_w increasing from 5% to 35% were beneficial to obtain finer droplets and more uniform distribution of emulsions, and emulsion viscosity could be represented as a monotonically-decreasing power function of MDD at the same φ_w. FTIR analysis indicated that the molecular structure of paraffin oil was unaffected during ultrasonication. Moreover, the emulsions exhibited a good stability at 4 °C with a slight phase separation at 25 °C after 24 h of storage. By analyzing the evolution of MDD, PDI and sedimentation index (SI) with time, coalescence model showed better fitting results as comparison to Ostwald ripening model, which demonstrated that the coalescence or flocculation was the dominant destabilizing mechanism for such W/O emulsions encapsulating CS. This study may provide a valuable contribution for the application of a non-Newtonian macromolecule solution as dispersed phase to generate nano-size W/O emulsions via ultrasound, and widen knowledge and interest of such emulsions in the functional biomaterial field.

Optimization of ultrasound induced emulsification on the formulation of palm-olein based nanoemulsions for the incorporation of antioxidant β-D-glucan polysaccharides

Polysaccharides of β-D-glucan configuration have well-known antioxidant activity against reactive free radicals generated from the oxidation of metabolic processes. In this study, β-D-glucan-polysaccharides extracted from Ganoderma lucidum were incorporated in palm olein based nanoemulsions which act as carrier systems to enhance the delivery and bioactivity of these polysaccharides and could be potentially useful for skin care applications. Initially response surface statistical design (Central Composite Design--CCD) was subjected to optimize the formulation variables of oil-in-water (O/W) nanoemulsions induced by ultrasound. The optimal formulation variables as predicted by CCD resulted in considerably improving the physical characteristics of ultrasonically formulated nanoemulsions by minimizing their droplet size, polydispersity index and viscosity. Moreover, the β-D-glucan-loaded nanoemulsions exhibited good stability over 90 days under different storage conditions (4 °C and 25 °C). The studies using palm olein based β-D-glucan-loaded nanoemulsion generated using ultrasound confirm higher antioxidant activity as compared to free β-D-glucan.

Quality of Opuntia robusta and its use in development of mayonnaise-like product

The aim of this study was to characterize Opuntia robusta parenchyma and mucilage as foodstuffs. Solute absorption of Opuntia robusta parenchyma was studied, mucilage was used to develop a mayonnaise-like product as substitute emulsifier alternative to egg yolk and oil substitute. Shelf life of mayonnaise-like product was evaluated. Scanning electron microscopy demonstrated that oxalate calcium crystal were present in the Opuntia robusta parenchyma and mucilage with druses morphology; whereas that in the mayonnaise-like product were not observed calcium oxalate crystals, due probably to the product pH is acidic. The heat treatment of parenchyma at 50 °C, 65°Brix, had highest influence on the solute absorption (about 35 %). Results revealed that best mixture was the formulated with 26.79 % oil, 62.50 % mucilage and 10.71 % whey protein. Mucilage was the component showing the highest effect on all textural characteristics of mayonnaise-like product. The storage temperature had highest effect on the textural characteristics of mayonnaise-like product than storage time. With the right combination of mucilage of Opuntia, oil and whey protein, it is possible to develop a low-fat mayonnaise with functional properties similar to those of commercial mayonnaise.