Effect of crystallization of oil phase on the destabilization of O/W emulsions containing vegetable oils with low melting points

Control of emulsion crystal growth in low-temperature environments

Currently, various types of emulsions can be applied to a wide range of systems. Emulsions are thermodynamically unstable systems, and their crystallization can be affected by a variety of factors. The nucleation and growth processes of emulsion crystal networks are determined on the basis of reported theoretical and experimental methods. The issues addressed include changes in the apparent crystal morphology of samples, changes in thermal properties with respect to temperature, changes in boundary conditions, and changes in the various applications of emulsions as feedstocks or in processing and storage methods. Changes in a variety of common emulsions during constant-temperature storage and unavoidable temperature fluctuations (e.g., multiple freeze-thaw cycles) are considered. Different methods for controlling the crystalline stability of these colloidal systems are also discussed. This review outlines the crystallization mechanism of emulsions during their food processing and storage.

New Insight into Food-Grade Emulsions: Candelilla Wax-Based Oleogels as an Internal Phase of Novel Vegan Creams

Cream-type emulsions containing candelilla wax-based oleogels (EC) were analyzed for their physicochemical properties compared to palm oil-based creams (EP). The microstructure, rheological behavior, stability, and color of the creams were determined by means of non-invasive and invasive techniques. All the formulations exhibited similar color parameters in CIEL*a*b* space, unimodal-like size distribution of lipid particles, and shear-thinning properties. Oleogel-based formulations were characterized by higher viscosity (consistency index: 172-305 mPa·s, macroscopic viscosity index: 2.19-3.08 × 10-5 nm-2) and elasticity (elasticity index: 1.09-1.45 × 10-3 nm-2), as well as greater resistance to centrifugal force compared to EP. Creams with 3, 4, or 5% wax (EC3-5) showed the lowest polydispersity indexes (PDI: 0.80-0.85) 24 h after production and the lowest instability indexes after environmental temperature changes (heating at 90 °C, or freeze-thaw cycle). EC5 had particularly high microstructural stability. In turn, candelilla wax content ≥ 6% w/w accelerated the destabilization processes of the cream-type emulsions due to disintegration of the interfacial layer by larger lipid crystals. It was found that candelilla wax-based lipids had great potential for use as palm oil substitutes in the development of novel vegan cream analogues.

Recent advances in hydrophobic nanocellulose aerogels for oil spill applications: A review

In a rapidly growing world, petroleum is used extensively in various industries, and the extraction, processing, and transportation of petroleum generates large amounts of petroleum-containing wastewater. Conventional oil/water separation methodologies are often ineffective and costly. Nanocellulose-based aerogels (NA) have emerged as a possible solution to this problem. However, hydrophobic modification is required for effective use in oil/water separation. This review on materials commonly used in these processes and outlines the requirements for adsorbent materials and methods for creating unique lipophilic surfaces. New trends in hydrophobization methods for NA are also discussed. Additionally, it includes the development of composite nanocellulose aerogels (CNAs) and cellulose based membrane specially developed for oil/water (o/w) separation considering different separation requirements. This analysis also examines how CNAs have evolved by introducing special properties that facilitate oil collection or make the adsorbent recyclable. We also discuss the difficulties in creating effective NAs for these important applications in a changing society, as well as the difficulties in creating oil recovery equipment for oil spill cleanup.

Characterization of Lemon Pepper and Black Ginger Extracts and Macroemulsions as Natural Pain Relievers for Spice Stick Balsam Formulation

Lemon pepper or andaliman (Zanthoxylum acanthopodium) and black ginger (Kaempferia parviflora) are rich in bioactive compounds that possess antioxidant and anti-inflammatory activities. Our recent study demonstrated that andaliman ethanolic extract also exerted anti-arthritic and anti-inflammatory effects in arthritic mice in vivo. Therefore, natural anti-inflammatory and anti-arthritic compounds for alternative natural pain relievers in balsam formulation are needed. This study aimed to produce and characterize lemon pepper and black ginger extracts and their macroemulsion products, followed by formulation, characterization, and stability of spice stick balsam products containing lemon pepper and black ginger macroemulsions. The extraction yields obtained were 24% w/w for lemon pepper and 59% w/w for black ginger. GC/MS results showed that the lemon pepper extract contained limonene and geraniol compounds, and black ginger extract contained gingerol, shogaol, and tetramethoxyflavone compounds. Spice extracts were successfully made in the form of a stable emulsion. The antioxidant activity in both spice extracts and emulsions was relatively high (>50%). The five stick balsam formulas obtained had a pH of 5, 4.5–4.8 cm spread ability, and 30–50 s of adhesion. The stability of products showed no microbial contamination. Based on the organoleptic results, the stick balsam formula of black ginger and black ginger: lemon pepper (1:3) was the most preferred by the panelists. In conclusion, lemon pepper and black ginger extracts and macroemulsions could be used as natural pain relievers in stick balsam products to promote health protection.

Ultraviolet Radiation Protective and Anti-Inflammatory Effects of Kaempferia galanga L. Rhizome Oil and Microemulsion: Formulation, Characterization, and Hydrogel Preparation

Long-term UV radiation exposure can induce skin disorders such as cancer and photoallergic reactions. Natural products have been considered as non-irritate and potential sunscreen resources due to their UV absorption and anti-inflammatory activities. This study aimed to evaluate the in vitro ultraviolet radiation protective effect and anti-inflammatory activity of K. galanga rhizome oil and microemulsions. The chemical components of K. galanga rhizome oil was analyzed via gas chromatography coupled with mass spectrometry. Microemulsions containing K. galanga rhizome oil were formulated using a phase-titration method. The microemulsion was characterized for droplet size, polydispersity index, and zeta potential, using a dynamic light-scattering technique. The physical and chemical stability of the microemulsion were evaluated via a dynamic light scattering technique and UV-Vis spectrophotometry, respectively. The UV protection of K. galanga rhizome oil and its microemulsion were investigated using an ultraviolet transmittance analyzer. The protective effect of K. galanga rhizome oil against LPS-induced inflammation was investigated via MTT and nitric oxide inhibitory assays. In addition, a hydrogel containing K. galanga rhizome oil microemulsion was developed, stored for 90 days at 4, 30, and 45 °C, and characterized for viscosity, rheology, and pH. The chemical degradation of the main active compound in the microemulsion was analyzed via UV-Vis spectrophotometry. The formulated O/W microemulsion contained a high loading efficiency (101.24 ± 2.08%) of K. galanga rhizome oil, suggesting a successful delivery system of the oil. The size, polydispersity index, and zeta potential values of the microemulsion were optimized and found to be stable when stored at 4, 30, and 45 °C. K. galanga rhizome oil and microemulsion demonstrated moderate sun protective activity and reduced the nitric oxide production induced by LPS in macrophage cells, indicating that microemulsion containing K. galanga rhizome oil may help protect human skin from UV damage and inflammation. A hydrogel containing K. galanga rhizome oil microemulsion was developed as a topical preparation. The hydrogel showed good physical stability after heating and cooling cycles and long-term storage (3 months) at 4 °C. The use of K. galanga rhizome oil as a natural sun-protective substance may provide a protective effect against inflammation on the skin. K. galanga rhizome oil microemulsion was successfully incorporated into the hydrogel and has the potential to be used as a topical sunscreen preparation.

Assessment of Chemical, Physicochemical, and Lipid Stability Properties of Gelled Emulsions Elaborated with Different Oils Chia (Salvia hispanica L.) or Hemp (Cannabis sativa L.) and Pseudocereals

Gelled emulsion (GE) systems are one of the novel proposals for the reformulation of meat products with healthier profiles. The aims of this research were (i) to develop gelled emulsions using pseudocereal flours (amaranth, buckwheat, teff, and quinoa) and vegetable oils (chia oil, hemp oil, and their combination), (ii) to determine their chemical composition, physicochemical properties, and lipid stability, and (iii) to evaluate their stability during frozen storage. The results showed that GEs are technologically viable except for the sample elaborated with teff flour and a mix of oils. The lipid oxidation was not greater than 2.5 mg malonaldehyde/kg of sample for any of the samples analyzed. The physicochemical properties analyzed showed both the pH and color values of the GEs within the range of values obtained for the fat of animal origin. The texture properties were affected by the type of oil added; in general, the firmness and the work of shear increased with the addition of the mixture of both oils. The samples elaborated with buckwheat and chia oil and quinoa and chia oil had the highest emulsion stability values, which remained among the highest after freezing. The results showed that gelled emulsions, based on chia oil, hemp, and their mixture with pseudocereal flours, are a viable alternative as a possible substitute of saturated fat in the development of novel foods.

Fabrication of Concentrated Palm Olein-Based Diacylglycerol Oil-Soybean Oil Blend Oil-In-Water Emulsion: In-Depth Study of the Rheological Properties and Storage Stability

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.

Catalytic efficiency of the eggshell calcined and enriched with glycerin in the synthesis of biodiesel from frying residual oil

Currently, there are several studies using calcium oxide, calcium alkoxide, and calcium hydroxide for biodiesel production. However, there is still a lack of studies highlighting the use of calcium diglyceroxide (calcium oxide enriched with glycerin in the presence of methanol) as a catalyst in the transesterification process. Therefore, the present work aimed to investigate the catalytic efficiency and reutilization of the eggshell calcined and enriched with glycerin and methanol (ECEG), in the synthesis of methylic esters from frying residual oil. As a result, thermochemically modified eggshells showed catalytic efficiency during methylic transesterification of residual oils in mass concentrations of 15%, 5%, 3%, and 1% due to the presence of a high level of esters (97.39, 96.97, 97.75, and 92.96%, respectively). The initial concentration of the enriched eggshell used in methanolysis had a direct effect on the final ester mixture. A 15% increase in the water content of the frying oil contributed to an increase in the ester content. The ECEG was reactive and efficient for four reaction cycles (without reactivation of the catalytic sites) due to the evidence of a high ester content (97.85%, 98.67%, 98.89%, 98.46%), reaching the standard quality of worldwide biodiesel regulations. Graphical abstract.