Stabilisation of oleofoams by lauric acid and its glycerol esters

Effect of diacylglycerol on partial coalescence of aerated emulsions: Fat crystal-membrane interaction and air-liquid Interface interaction insights

Currently, the poor whipping capabilities of anhydrous milk fat (AMF) in aerated emulsion products are a major obstacle for their use in beverages like tea and coffee, as well as in cakes and desserts, presenting fresh hurdles for the food industry. In this study, the mechanism of action of diacylglycerols (DAGs) with different carbon chain lengths and degrees of saturation on the partial coalescence of aerated emulsions was systematically investigated from three fundamental perspectives: fat crystallization, air-liquid interface rheology, and fat globule interface properties. The optimized crystallization of long carbon chain length diacylglycerol (LCD) based on stearate enhances interactions between fat globules at the air-liquid interface (with an elastic modulus E' reaching 246.42 mN/m), leading to a significantly reduced interface membrane strength. This promotes fat crystal-membrane interactions during whipping, resulting in a thermally stable foam structure with excellent shaping capability due to enhanced partial coalescence of fat globules. Although Laurate based medium carbon chain length diacylglycerol (MCD) promoted fat crystallization and optimized interface properties, it showed weaker foam properties because it did not adequately encapsulate air bubbles during whipping. Conversely, oleate long carbon chain length diacylglycerol (OCD) proved to be ineffective in facilitating fat crystal-membrane interaction, causing foam to have a subpar appearance. Hence, drawing from the carefully examined fat crystal-membrane interaction findings, a proposed mechanism sheds light on how DAGs impact the whipping abilities of aerated emulsions. This mechanism serves as a blueprint for creating aerated emulsions with superior whipping capabilities and foam systems that are resistant to heat.

Study on the foam properties of peanut oil body (POB)-based oil-in-water-in-oil (O/W/O) foamed emulsion gel: The key role played by the interface between the water phase and the outer oil phase

A novel POB-based O/W/O foamed emulsion gel was constructed. The mechanism by which POB strengthens the foamed emulsion gel was preliminarily explored by studying the microstructure and rheological properties, and the applications of POB in decoration and 3D printing were analyzed. The adsorption of POBs and their fragments might strengthen the interface between the water and internal oil phases, thereby increasing the yield stress of the system, which protected the O/W/O structure from being damaged during whipping, and formed a special foam structure where air-in-oil (A/O) structures and O/W/O structure coexist. Besides, adding POB promoted the overrun of the emulsion gel, and the maximum overrun rate was 68.6 %. Finally, POB-based O/W/O foamed emulsion gel exhibited good decoration and 3D printing performance and is expected to become a healthy and higher-quality foamed food in the future.

The lipid-amylose complexes enhance resistant starch content in candelilla wax-based oleogels cookies

The substitution of margarine with candelilla wax (CW)-based oleogel is currently a prominent focus of research in the bakery industry. However, the use of CW-based oleogel in cookies increased starch digestibility, potentially posing a risk to human health. Thus, the anti-enzymatic mechanism of lipid-amylose complexes was used to evaluate the influence of olive diacylglycerol stearin (ODS) on starch digestibility in CW-based oleogel cookies. The in vitro digestibility analysis demonstrated that the DCW/ODS-35 cookie exhibited a increase of 27.72 % in slowly digestible starch (SDS) and resistant starch (RS) contents, compared to cookie formulated with margarine. The in-vivo glycemic index analysis revealed that the DCW/ODS-35 cookie had a medium glycemic index of 68. XRD pattern suggested that the presence of ODS in oleogels facilitated the formation of lipid-amylose complexes. The DSC analysis revealed that the addition of ODS resulted in the gelatinization enthalpy of DCW-based cookies increased from 389.9 to 3314.9 J/g. The FTIR spectra indicated that the combination of ODS could promote a short-range ordered structure in DCW-based cookies. Overall, these findings demonstrated that the utilization of DCW-based oleogel presented a viable alternative to commercial margarine in the development of CW-based cookies with reduced starch digestibility.

Pickering Foam Stabilized by Diacylglycerol-Based Solid Lipid Nanoparticles: Effect of Protein Modification

Pickering foams have great potential for applications in aerated foods, but their foaming ability and physical stability are still far from satisfactory. Herein, solid lipid particles (SLNs) were fabricated by using diacylglycerol of varying acyl chain lengths with modification by a protein. The SLNs showed different crystal polymorphisms and air-water interfacial activity. C14-DAG SLN with a contact angle ∼ 79° formed aqueous foam with supreme stability and high plasticity. Whey protein isolate and sodium caseinate (0.1 wt %) considerably enhanced the foamability and interfacial activity of SLNs and promoted the packing of particles at the bubble surface. However, high protein concentration caused foam destruction due to the competitive adsorption effect. β-sheet increased in protein after adsorption and changed the polymorphism and thermodynamic properties of SLN. The foam collapsing behaviors varied in the presence of protein. The results gave insights into fabricating ultrastable aqueous foams by using high-melting DAG particles. The obtained foams demonstrated good temperature sensitivity and plasticity, which showed promising application prospects in the food and cosmetic fields.

Impact of Air Bubbles on the Saltiness Perception of NaCl-Loaded Oleogel-Stabilized Water-in-Oil Emulsions

Reducing salt intake without affecting the saltiness perception remains a great challenge for the food industry. Herein, the demulsification of water droplets and air bubbles was controlled to modulate the release of sodium from oleogel-stabilized water-in-oil emulsions (OGEs) stabilized by monoglyceride crystals. The effect of monoglycerides with carbon chain length (glycerol monolaurate-GML, glyceryl monostearate-GMS, and glycerol monopalmitate-GMP) and homogenization methods (hand-shaking or high-speed blender) on sodium release and saltiness was investigated by in vitro and in vivo oral processing tests. Milky-white stable emulsions were formed with both water droplets and air bubbles dispersing in the oil phase, regardless of the selected homogenization methods. Air bubbles were more unstable than water droplets during oral digestion. GML OGEs with more and larger air bubbles and the lowest hardness exhibited the highest sodium release rate and the strongest saltiness, independent of homogenization methods. The balance between air bubbles and water droplets in the GMS and GMP OGEs caused slower sodium release and lower saltiness. Overall, the presence of air bubbles in NaCl-loaded W/O oleogel-based emulsions was shown to have important implications for tailoring their sodium release and saltiness.

A comprehensive review: Impact of oleogel application on food texture and sensory properties

Oleogels, characterized by their semisolid matrix formed from liquid oil structured by gelators, are emerging as a pivotal innovation in food formulation, primarily due to their capacity to enhance the nutritional profile of products by incorporating healthier fats. This review explored the integration of oleogels into diverse food matrices, examining their impact on texture, mouthfeel, and overall sensory characteristics. Through an extensive analysis of current research, this paper illustrates the versatility of oleogels created with a variety of structuring agents across different food applications. It also addresses the challenges inherent in the use of oleogels, including the preservation of their stability and consistency through varying storage and processing conditions, navigating the regulatory landscape concerning oleogelator safety and acceptability, and confronting higher production costs. Overall, this comprehensive review highlights the potential of oleogels as a promising tool for achieving desirable textural and sensory attributes in food products while also identifying areas for future research and development.

Enhancement of resistant starch content in ethyl cellulose-based oleogels cakes with the incorporation of glycerol monostearate

The objective of this work was to completely replace margarine with peanut diacylglycerol oil/ethyl cellulose-glycerol monostearate oleogel (DEC/GMS) oleogel, and evaluate its effect on starch digestibility of cakes. The in vitro digestibility analysis demonstrated that the DEC/GMS-6 cake exhibited a 26.36% increase in slowly digestible starch (SDS) and resistant starch (RS) contents, compared to cakes formulated with margarine. The increased SDS and RS contents might mainly be due to the hydrophobic nature of OSA-wheat flour, which could promote the formation of lipid-amylose complexes with GMS and peanut diacylglycerol oil. XRD pattern suggested that the presence of GMS in DEC-based oleogels facilitated the formation of lipid-amylose complexes. The DSC analysis revealed that the addition of GMS resulted in a significant increase in gelatinization enthalpy, rising from 249.7 to 551.9 J/g, which indicates an improved resistance to gelatinization. The FTIR spectra indicated that the combination of GMS could enhance the hydrogen bonding forces and short-range ordered structure in DEC-based cakes. The rheological analysis revealed that an increase in GMS concentration resulted in enhanced viscoelasticity of DEC-based cake compared to TEC-based cakes. The DEC-based cakes exhibited a more satisfactory texture profile and higher overall acceptability than those of TEC-based cakes. Overall, these findings demonstrated that the utilization of DEC-based oleogel presented a viable alternative to commercial margarine in the development of cakes with reduced starch digestibility.

An overview of edible foams in food and modern cuisine: Destabilization and stabilization mechanisms and applications

Foam, as a structured multi-scale colloidal system, is becoming increasingly popular in food because it gives a series of unique textures, structures, and appearances to foods while maintaining clean labels. Recently, developing green and healthy food-grade foaming agents, improving the stability of edible foams, and exploring the application of foam structures and new foaming agents have been the focus of foam systems. This review comprehensively introduces the destabilization mechanisms of foam and summarizes the main mechanisms controlling the foam stability and progress of different food-grade materials (small-molecular surfactants, biopolymers, and edible Pickering particles). Furthermore, the classic foam systems in food and modern cuisine, their applications, developments, and challenges are also underlined. Natural small-molecular surfactants, novel plant/microalgae proteins, and edible colloidal particles are the research hotspots of high-efficiency food-grade foam stabilizers. They have apparent differences in foam stability mechanisms, and each exerts its advantages. However, the development of foam stabilizers remains to be enriched compared with emulsions. Food foams are diverse and widely used, bringing unique enjoyment and benefit to consumers regarding sense, innovation, and health attributes. In addition to industrial inflatable foods, the foam foods in molecular gastronomy are also worthy of exploration. Moreover, edible foams may have greater potential in structured food design, 3D/4D printing, and controlled flavor release in the future. This review will provide a reference for the efficient development of functional inflatable foods and the advancement of foam technologies in modern cuisine.

Oleofoams stabilized by monoacylglycerides: Impact of chain length and concentration

Oleofoams are plant oil based whipped systems which have drawn academic and industry attention in recent years. The aim of this study was to determine the effect of fatty acid chain length and monoacylglyceride (MAG) concentration on the performance and structural properties of MAG-based oleofoams. Four different MAGs (monolaurin, monomyrystin, monopalmitin, and monostearin) were studied at three concentration levels (5, 10, and 15 wt%). The fatty acid chain length had a statistically significant impact on the size and shape of crystals formed, while higher MAG concentrations led to higher numbers of crystals in the continuous oil phase. These differences affected the performance and physical properties of the oleofoams: compared to other MAGs, monostearin based oleofoams were harder and exhibited higher values of G' and G″, had higher overrun and showed better stability. Lastly, through microscopy techniques it was successfully proved that monostearin-based oleofoams are stabilized by both bulk and Pickering stabilization.

Interfacial behavior, gelation and foaming properties of diacylglycerols with different acyl chain lengths and isomer ratios

Diacylglycerols (DAG) of varying chain lengths were synthesized and the acyl migrated samples with different 1,3-DAG/1,2-DAG ratios were obtained. The crystallization profile and surface adsorption differed depending on DAG structure. C12 and C14 DAGs formed small platelet- and needle-like crystals at the oil-air interface which can better reduce surface tension and pack in an ordered lamellar structure in oil. The acyl migrated DAGs with higher ratios of 1,2-DAG showed reduced crystal size and lower oil-air interfacial activity. C14 and C12 DAG oleogels exhibited higher elasticity and whipping ability with crystal shells surrounding bubbles, whereas C16 and C18 DAG oleogels had low elasticity and limited whipping ability due to the formation of aggregated needle-like crystals and loose gel network. Thus, acyl chain length dramatically influences the gelation and foaming behaviors of DAGs whereas the isomers exert little influence. This study provides basis for applying DAG of different structures in food products.

A novel approach for the development of edible oleofoams using double network oleogelation systems

Whipped oleogels (oleofoams) are commonly stabilized by crystalline particles. Still, external factors like temperature fluctuations could change the state of the crystals (phase transitions), leading to the destabilization and disruption of oleofoams. Herein, a double network oleogelation system comprised of a primary crystalline network (using glycerol monostearate) and a secondary colloidal network (stabilized by soy protein isolate-anionic polysaccharides Mailard conjugates) is proposed as a novel strategy to overcome these challenges. It was observed that the incorporation of the secondary network resulted in a lower over-run, but a higher melting point, elasticity, foam stability, and more uniform bubble size distribution. This was explained by the strong interfacial stabilization provided by the colloidal network that can protect the crystalline particle against coarsening and oil drainage. These double network oleofoams, which could retain 41-48 % air (oleogel-based), display great potential for utilization in low-calorie lipid-based products.

Crystallization Behavior and Physical Properties of Monoglycerides-Based Oleogels as Function of Oleogelator Concentration

Oleogels have been shown as a promising replacer of hydrogenated vegetable oil. Fatty acid glycerides, including some typical mono- and di-glycerides, were used to form oleogels. The concentration effects of fatty acid glycerides on the crystallization behavior and physical properties of oleogels were investigated by using different analysis techniques. The results showed that all the oleogels formed by saturated fatty acid glycerides (glyceryl monostearate (GMS), glyceryl monolaurate (GML), glycerol monocaprylate (GMC)) exhibited a solid-like behavior and were thermally reversible systems, while a higher amount of unsaturated fatty acid glycerides (monoolein (GMO), diolein (GDO)) were needed to form oleogels. The onset gelation concentration of GMS and GMC was found to be 2 wt% (w/w), while that of GML was 4 wt% by the inverted tube method. The crystallization results illustrated that the GMS and GMC formed small needle-like crystals with the presence of β and β' crystals, while GML formed large flake-like crystals with α crystals in oleogels, and faster cooling rates caused smaller crystals. GMS- and GMC-based oleogels had higher crystallinity, resulting in higher thermal stability and better mechanical properties than GML-based ones at the same monoglyceride (MAG) level. With the increasing MAG content, the oleogels showed a more compact three-dimensional network leading to higher mechanical properties and better thermal stability and resistance to deformations. Hence, MAG-based oleogels, especially GMC ones with medium chain fatty acid, could be a promising replacer for hydrogenation vegetable oils.

Effect of Glyceryl Monoolein Addition on the Foaming Properties and Stability of Whipped Oleogels

Medium Chain Triglyceride (MCT) oil was successfully combined with Glyceryl Monostearate (GMS) and Glyceryl Monoolein (GMO) to form oleogels that were subsequently whipped to form stable oleofoams. The co-crystallization of GMS and GMO at a ratio of 20:1, 20:2.5, and 20:5 within MCT oil was studied through Differential Scanning Calorimetry (DSC), X-ray Diffraction analysis (XRD), rheological analysis, Fluorescence Recovery after Photobleaching (FRAP), Fourier Transform Infrared Spectroscopy (FTIR), and polarized microscopy. The addition of 5% GMO resulted in the production of more stable oleogels in terms of crystal structure and higher peak melting point, rendering this formulation suitable for pharmaceutical applications that are intended to be used internally and those that require stability at temperatures close to 40 °C. All formulations were whipped to form oleofoams that were evaluated for their storage stability for prolonged period at different temperatures. The results show that oleofoams containing 5% MGO retained their foam characteristics even after 3 months of storage under different temperature conditions.