Thermodynamic and kinetic aspects of fat crystallization

Impact of fatty acid chain length and content on hydrophobicity of starch films: Structure-property analysis

Fatty acids are often used as additives in starch films to modulate their interactions with water. However, there is currently a poor understanding of the relationship between the structure of fatty acids and their impact on film properties. For this reason, this study investigated the impact of fatty acid chain length (lauric, myristic, and palmitic acids) and concentration (5, 10, 15 and 20 % w/w) on the structural, physicochemical, and functional properties of starch films. Lauric acid formed starch-fatty acid complexes, which produced a continuous crystalline layer on the surface of the starch films, enhancing film hydrophobicity. In contrast, myristic and palmitic acids formed crystalline regions within the starch film matrix, which disrupted the structural integrity and reduced the hydrophobicity of the films. The addition of 20 % w/w lauric acid resulted in the highest contact angle (82.42°), lowest surface energy (36.65 mN/m), and lowest water vapor permeability (0.83 × 10-12 g m-1 s-1 Pa-1) among all the films. In contrast, the addition of 20 % w/w palmitic acid led to the highest water vapor permeability (1.79 × 10-12 g m-1 s-1 Pa-1) and opacity. These results demonstrated that the chain length of fatty acids plays a key role in modulating starch-moisture interactions, thereby affecting water affinity, migration, and adsorption by the films. This work provides guidance for optimizing starch-based films by selecting suitable fatty acids for specific applications.

On the relevance of inhomogeneity in saturated fatty acid compositions for the crystallization kinetics of fat blends

In this contribution, the crystallization kinetics of model fat blends containing trisaturated and mono-unsaturated TAGs of different saturated fatty acid composition are investigated via differential scanning calorimetry (DSC) and time-resolved small and wide angle X-ray scattering (SAXS/WAXS). The effect of inhomogeneity in saturated fatty acid composition was studied by varying between palmitic and stearic sources for trisaturated (POSt - palm stearin and FHRO - fully hydrogenated rapeseed oil) and using palm mid fraction (PMF) and shea stearin (ShSt) sources for mimicking the mono-unsaturated TAGs (PMF - palm mid fraction and ShSt - shea stearin). The kinetics were followed via SAXS/WAXS upon cooling at different rates (1 and 10 °C min-1) and during the isothermal hold at 0 °C (273 K) for 60 min. The blends revealed a multiple step crystallization with co-existing polymorphic forms and a slow restructuring process. Generally, mono-unsaturated triglycerides tended to impede the polymorphic transition of the trisaturated fraction. The trisaturated triglyceride fraction formed an α phase at the beginning of the crystallization. Quickly after, co-existing β' and β phases were recorded. In each case, the subsequent crystallization events were dictated by the mono-unsaturated fraction with ShSt affecting the crystallization more drastically than PMF. Differences were diminished when a low cooling rate was applied. Further, the low cooling rate allowed the formation of a β phase in FHRO-containing samples before an additional β' phase was recorded. The differences in explicit fatty acid composition, TAG diversity and minor components are discussed as primary potential sources of differences in crystallization behavior. Calorimetric experiments capturing the crystallization and melting behavior of the industrial grade binary blends were compared to that of blends based on pure TAGs diluted in rapeseed oil, namely the combinations PPP-POP, SSS-SOS, PPP-SOS, and SSS-POP.

Molar Ratio-Dependent Crystallization in Coamorphous Celecoxib-Carbamazepine Systems: The Interplay of Thermodynamics and Kinetics

Coamorphous drug delivery systems have emerged as a promising formulation strategy to enhance the solubility, oral bioavailability, and physical stability of poorly water-soluble drugs. The molar ratio of components in coamorphous systems plays a critical role in determining their physical stability. In this study, we investigated the crystallization behavior of coamorphous celecoxib-carbamazepine (CEL-CBZ) systems at different molar ratios. The growth rates of CEL crystals, CBZ crystals, and CEL-CBZ cocrystals were observed to exhibit distinct dependencies on the molar ratio of coamorphous systems, primarily due to their unique thermodynamic driving forces, despite sharing the same kinetic factor. The influence of the molar ratio on the crystallization of coamorphous systems arises from the interplay between its effects on molecular mobility and thermodynamic driving forces, leading to either cooperative or competing effects. Both the crystal growth and crystallization tendency results reveal that thermodynamics plays a more dominant role than kinetics in the crystallization of coamorphous CEL-CBZ systems across various molar ratios. This study provides fundamental insights into the mechanism by which the molar ratio influences the crystallization of coamorphous systems, highlighting the complex crystallization behavior of multicomponent amorphous systems as an interplay between kinetics and thermodynamics.

Crystallization Behavior of Plant-Based Fat Blends Formulated as an Alternative for Anhydrous Milk Fat in Milk Chocolate

Due to the increasing global demand for chocolate products and changes in consumer preferences, chocolate manufacturers have recently started to explore novel solutions to reformulate chocolate. Milk fat alternatives (MFA) are blends of triglycerides from different plant-based sources that resemble anhydrous milk fat in physical properties, particularly thermal behavior and solid fat content. However, in order to use MFA as potential ingredients for vegan milk chocolate formulations, it is necessary to understand their crystallization behavior, particularly in light of their chemical composition. Here, we applied synchrotron X-ray scattering, polarized light microscopy, and differential scanning calorimetry to investigate the crystallization behavior of four selected commercial MFAs (MF1, 2, 3, and 4), on their own and mixed with cocoa butter (CB). Chemical characterization revealed significant differences among samples and with both anhydrous milk fat (MF) and CB. POP-rich MF1 presented a specific polymorphic and thermal behavior, with the unstable β' form persisting for longer times than all other samples. Sample MF2 exhibited a polymorphic behavior more similar to CB in terms of number, type, and melting behavior due to the compositional similarities (e.g., prevalence of both SOS and POP). SOS-rich MF3 was characterized by metastable forms γ and β'(3L), whereas MF4 at ambient conditions showed only β(2L) forms due to its specific composition. Mixtures of CB and all MFAs behaved similarly to CB and MF mixtures, with good miscibility at ambient temperature and a lower melting point. Despite significant differences in chemical composition, MF4 presented similar solid fat content compared to MF; this is due to the high amount of relatively long chain, unsaturated fatty acids and the broad distribution of different TAGs, which all lower the melting point of this sample.

Precision Processing for Value-Added Fats and Oils

Lipids are key compounds in foods and provide energy and nutrients to the body. They are carriers of aroma and flavor compounds and contribute to structure and texture. Nutritional research has shown that positive effects on human health are derived from the intake of specific lipids. Similarly, food science research has shown that food matrix design benefits from having tailored lipid fractions with specific functions such as melting profiles, crystal structures, and oil-binding capacities. Minor constituents such as polar lipids or waxes also have valuable functional properties such as the ability to stabilize interfaces, facilitate spreadability, provide barriers, or act as organogelators. Coupled with the emergence of new feedstocks such as new plants, microbes, or insects, this has fueled a renewed interest in designing efficient, effective, and environmentally friendly processes to extract and fractionate lipids from feedstocks. Such precision-processing approaches are intended to yield not just bulk oils and fats but also specialty lipids with tailored properties. In this review article, we discuss the extraction and fractionation approaches used to obtain lipid fractions from plants, animals, or microbial fermentation, discuss their properties and functionalities, and highlight process design approaches, with a focus on sustainable extraction technologies. Recent advances in the three main steps in obtaining food lipids are highlighted: (a) crude oil manufacture; (b) refinement; and (c) fractionization. Finally, two case studies of specialty ingredients derived from such precision-processing approaches are presented.

Lipid Nanoparticles: Formulation, Production Methods and Characterization Protocols

Lipid nanoparticles (LNs) have emerged as advanced lipid-based delivery systems, offering an effective approach for encapsulating and protecting lipid-soluble bioactive compounds, increasing their bioavailability. Solid Lipid Nanoparticles (SLNs) and Nanostructured Lipid Carriers (NLCs) are particularly promising for bioactive compound entrapment. However, to fully exploit their potential, it is crucial to carefully select the appropriate lipid matrices and emulsifiers. This review offers a comprehensive, up-to-date examination, considering studies published in the last 15 years, of the chemical, physical, and structural characteristics of lipids employed in LN production, focusing on the key components of the formulations: lipid matrices, emulsifiers, and bioactive compounds. In addition, it provides an in-depth analysis of production methods, drawing on insights from the latest scientific literature, and emphasizes the most important characterization techniques for LNs. Key parameters, including particle size (PS), zeta potential (ZP), crystallinity, thermal behavior, morphology, entrapment efficiency (EE), load capacity (LC), and physical stability, are discussed. Ultimately, this review aims to identify critical factors for the successful production of stable LNs that efficiently encapsulate and deliver bioactive compounds, highlighting their significant potential for applications in food systems.

Effects of polyunsaturated fatty acid and diacylglycerol on the crystallization behaviors of palm-based oil

Diacylglycerol (DAG) is a novel functional structural lipid, but its application in base oils remains underexplored. This research investigated the effect of three liquid oils (groundnut oil, corn oil, and flaxseed oil), with varying polyunsaturated fatty acid (PUFA) (39.60, 69.50, and 77.65 %) and DAG content (0.00, 40.00, 80.00 %), on the crystallization behaviors of palm-based oil. DAG (40.00 %), obtained through enzymatic glycerolysis and molecular distillation, was found to stabilize the binary system with good compatibility and fine crystal structure. "Liquid" DAG played a dual role: diluting solid lipids, and promoting crystallization. Increasing DAG content led to larger crystalline domain size, while higher PUFA content accelerated crystallization and increased crystal orderliness, though decreasing crystal density. These results demonstrated the clear influence of PUFA and DAG content on palm-based oil crystallization. This knowledge can guide the utilization of different unsaturated DAGs for tailored fat crystallization in food application.

Solid Fat Content and Relaxation Time Measurement of Petrolatum Using Time-Domain NMR, and the Correlation with Viscosity and Crystallinity

This study aimed to clarify the relationship between the NMR parameters of petrolatum obtained using the time-domain NMR (TD-NMR) technique and the physical properties obtained using conventional methods. Six commercially available drug-free petrolatums were used. First, the physical properties of these samples were recorded by conventional methods: polarized light microscopy, viscometry, and X-ray diffraction (XRD). The XRD pattern showed a characteristic diffraction pattern corresponding to the crystallization of paraffin wax. Next, the TD-NMR technique estimated the solid fat content (SFC) and T2 and T1 relaxation times as NMR parameters. The free induction decay of petrolatum showed the characteristic biphasic decay, while the SFC value was estimated from signal intensities. Finally, a scatterplot matrix was drawn to clarify the relationship between the NMR parameters and the physical properties. Using the Spearman rank-order correlation, the SFC showed a strong and positive correlation with the crystallinity (ρ = 0.855), and the T2 relaxation time showed a moderate and negative correlation with the viscosity (ρ = -0.707). In conclusion, this study clarified which NMR parameters correspond to the conventional physical properties: the SFC corresponded to the crystallinity and the T2 relaxation corresponded to the viscosity. Utilization of the TD-NMR technique to evaluate molecular mobility may be useful in terms of complementing the conventional physical characterization of petrolatum.

Cellulose Acetate Butyrate-Based In Situ Gel Comprising Doxycycline Hyclate and Metronidazole

Cellulose acetate butyrate is a biodegradable cellulose ester bioplastic produced from plentiful natural plant-based resources. Solvent-exchange-induced in situ gels are particularly promising for periodontitis therapy, as this dosage form allows for the direct delivery of high concentrations of antimicrobial agents to the localized periodontal pocket. This study developed an in situ gel for periodontitis treatment, incorporating a combination of metronidazole and doxycycline hyclate, with cellulose acetate butyrate serving as the matrix-forming agent. Consequently, assessments were conducted on the physicochemical properties, gel formation, drug permeation, drug release, morphological topography, and antimicrobial activities of the formulation. The formulation demonstrated an increased slope characteristic of Newtonian flow at higher bioplastic concentrations. The adequate polymer concentration facilitated swift phase inversion, resulting in robust, solid-like matrices. The mechanical characteristics of the transformed in situ gel typically exhibit an upward trend as the polymer concentration increased. The utilization of sodium fluorescein and Nile red as fluorescent probes effectively tracked the interfacial solvent-aqueous movement during the phase inversion of in situ gels, confirming that the cellulose acetate butyrate matrix delayed the solvent exchange process. The initial burst release of metronidazole and doxycycline hyclate was minimized, achieving a sustained release profile over 7 days in in situ gels containing 25% and 40% cellulose acetate butyrate, primarily governed by a diffusion-controlled release mechanism. Metronidazole showed higher permeation through the porcine buccal membrane, while doxycycline hyclate exhibited greater tissue accumulation, both influenced by polymer concentration. The more highly concentrated polymeric in situ gel formed a uniformly porous structure. Metronidazole and doxycycline hyclate-loaded in situ gels showed synergistic antibacterial effects against S. aureus and P. gingivalis. Over time, the more highly concentrated polymeric in situ gel showed superior retention of antibacterial efficacy due to its denser cellulose acetate butyrate matrix, which modulated drug release and enhanced synergistic effects, making it a promising injectable treatment for periodontitis, particularly against P. gingivalis.

Moxifloxacin HCl -loaded Cellulose Acetate Butylate In Situ Forming Gel for Periodontitis Treatment

Periodontitis presents significant treatment challenges due to its complexity and potential complications. In response, an in situ forming gel (ISG) loaded with moxifloxacin HCl (Mx) and cellulose acetate butyrate (CAB) was developed for targeted periodontitis therapy. Mx-loaded 10-45% CAB-based ISGs were developed, and their physicochemical properties such as rheology, viscosity, contact angle, gel morphology and gel formation, interface interaction were investigated. Moreover, the formulation performance studies including drug release and kinetics, in vitro degradation, and antimicrobial activities were also evaluated. The Mx-loaded ISGs containing 25-45% CAB demonstrated rapid matrix formation in both macroscopic and microscopic examinations and presented plastic deformation matrix. Tracking with sodium fluorescein and Nile red fluorescence probes indicated delayed solvent movement owing to CAB matrix formation. Adequate CAB content sustained Mx release for one week, following Peppas-Sahlin model and indicating a predominantly Fickian diffusion mechanism. Higher CAB content likely contributed to a denser matrix structure, leading to a slower in vitro degradation rate. Synchrotron radiation X-ray tomographic and SEM imaging provided insights into the CAB matrix structure and porous network formation. These ISG formulations effectively inhibited Staphylococcus aureus, Escherichia coli, Candida albicans, and Porphyromonas gingivalis. The Mx-loaded 40% CAB-based ISG shows promise as a dosage form for treating periodontitis. Further clinical trials are necessary to ensure the safety of this new ISG formulation, despite existing safety data for other medicinal uses of CAB. HIGHLIGHTS: Moxifloxacin HCl-loaded 10-45% cellulose acetate butyrate (CAB)-based in situ forming gels (ISG) were developed. They were evaluated for physicochemical properties, drug release, in vitro degradation, and antimicrobial activities. ISGs with 25-45% CAB showed swift matrix formation and plastic deformation Adequate CAB content sustained Mx release with Fickian diffusion mechanism They promise for periodontitis treatment because of effective inhibition of related pathogens.

Bio-Based Phase Change Materials for Sustainable Development

The increasing global population has intensified the demand for energy and food, leading to significant greenhouse gas (GHG) emissions from both sectors. To mitigate these impacts and achieve Sustainable Development Goals (SDGs), passive thermal storage methods, particularly using phase change materials (PCMs), have become crucial for enhancing energy efficiency and reducing GHG emissions across various industries. This paper discusses the state of the art of bio-based phase change materials (bio-PCMs), derived from animal fats and plant oils as sustainable alternatives to traditional paraffin-based PCMs, while addressing the challenges of developing bio-PCMs with suitable phase change properties for practical applications. A comprehensive process is proposed to convert bacon fats to bio-PCMs, which offer advantages such as non-toxicity, availability, cost-effectiveness, and stability, aligning with multiple SDGs. The synthesis process involves hydrolysis to break down fat molecules obtained from the extracted lipid, followed by three additional independent processes to further tune the phase change properties of PCMs. The esterification significantly decreases the phase transition temperatures while slightly improving latent heat; the UV-crosslinking moderately raises both the phase transition temperature and latent heat; the crystallization remarkably increases the both. The future research and guidelines are discussed to develop the large scale manufacturing with cost effectiveness, to optimize synthesis process by multiscale modeling, and to improve thermal conductivity and latent heat capacities at the same time.

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.

Interfacial crystallized oleogel emulsion with improved freeze-thaw stability and tribological properties: Influence of cooling rate

In this study, the influence of cooling rate on the freeze-thaw stability, rheological and tribological properties of interfacial crystalized oleogel emulsion was investigated. Results showed that slower cooling rate could promote formation of larger crystals and stronger network in oleogels. Additionally, oleogel emulsions showed higher freeze-thaw stability than those stabilized solely by emulsifiers. The slower cooling rate resulted in larger crystals adsorbed at the droplet surface. This led to greater steric hindrance that prevented the migration of oil droplets with higher resistance to disruption by ice crystals. The rheological and tribological measurements suggested that with appropriate amount of crystals, the tribological properties were better maintained for emulsions prepared at slow cooling rate after freeze-thaw treatment. This strategy greatly enriched oleogel emulsion formulations and provided important clues for potential applications in food products involved with freeze-thaw treatment.

Dry fractionation efficiency of milk fats from different sources and the characteristics of their fractions in chemical composition, thermal property, and crystal morphology

The physicochemical properties of anhydrous milk fats (AMF) often change according to different regions and seasons, inevitably affecting dry fractionation. This study analyzed the differences in the fraction yields and physicochemical characteristics of four AMFs from different sources. The results showed that single-stage dry fractionation conducted at 25 °C easily separated AMFs into liquid fractions (L25) and solid fractions (S25) via pressure filtration, both producing satisfactory yields. Moreover, all L25s exhibited few crystals with good fluidity at 25 °C, while S25s presented as semi-solids supported by β crystal networks with a certain hardness and plasticity. However, four AMFs displayed fractionation efficiency variation, while the thermal differences among them showed no obvious correlation with those among their fractions. Generally, more trisaturated triglycerides with 48 to 54 carbon atoms in the AMF increased the S25 yield and decreased the slip melting points (SMP) of both fractions.

Determination of Triacylglycerol Composition in Mealworm Oil (Tenebrio molitor) via Electrospray Ionization Tandem Mass Spectrometry with Multiple Neutral Loss Scans

Mealworms (Tenebrio molitor) have been used as an alternative source of proteins and lipids. Triacylglycerols (TAGs) are major sources of energy and have been used to provide essential fatty acids. They are also the main components of mealworm oil, and their composition and content are extensively linked to its physical and chemical properties. However, because of the complexity of TAG molecules, their identification and quantitation are challenging. This study employed electrospray ionization tandem mass spectrometry (ESI-MS/MS) with multiple neutral loss scans (NLS) to analyze the TAG composition and content in mealworm oil. Identifying and quantifying TAGs using ESI-MS/MS in combination with multiple NLS was an efficient way to improve accuracy and timeliness. For the accurate quantification of TAGs, isotopic deconvolution and correlation factors were applied. A total of 57 TAGs were identified and quantified: C52:2 (16:0/18:1/18:1) (1549.4 nmol/g, 18.20%), C52:3 (16:0/18:1/18:2) (1488.1 nmol/g, 17.48%), C54:4 (18:1/18:1/18:2) (870.1 nmol/g, 10.23%), C54:6 (18:1/18:2/18:2) (659.8 nmol/g, 7.76%) and C52:4 (16:0/18:2/18:2) (600.5 nmol/g, 7.06%), which were the most abundant TAGs present in the mealworm oil. The fundamental properties of mealworm oil, including its degree of oxidation, nutritional effect and physical properties, were elucidated.

Fluconazole-Loaded Ibuprofen In Situ Gel-Based Oral Spray for Oropharyngeal Candidiasis Treatment

Oral candidiasis is a fungal infection affecting the oral mucous membrane, and this research specifically addresses on a localized treatment through fluconazole-loaded ibuprofen in situ gel-based oral spray. The low solubility of ibuprofen is advantageous for forming a gel when exposed to an aqueous phase. The 1% w/w fluconazole-loaded in situ gel oral sprays were developed utilizing various concentrations of ibuprofen in N-methyl pyrrolidone. The prepared solutions underwent evaluation for viscosity, surface tension, contact angle, water tolerance, gel formation, interface interaction, drug permeation, and antimicrobial studies. The higher amount of ibuprofen reduced the surface tension and retarded solvent exchange. The use of 50% ibuprofen as a gelling agent demonstrated prolonged drug permeation for up to 24 h. The incorporation of Cremophor EL in the formulations resulted in increased drug permeation and exhibited effective inhibition against Candida albicans, Candida krusei, Candida lusitaniae, and Candida tropicalis. While the Cremophor EL-loaded formulation did not exhibit enhanced antifungal effects on agar media, its ability to facilitate the permeation of fluconazole and ibuprofen suggested potential efficacy in countering Candida invasion in the oral mucosa. Moreover, these formulations demonstrated significant thermal inhibition of protein denaturation in egg albumin, indicating anti-inflammatory properties. Consequently, the fluconazole-loaded ibuprofen in situ gel-based oral spray presents itself as a promising dosage form for oropharyngeal candidiasis treatment.

Internal Factors Affecting the Crystallization of the Lipid System: Triacylglycerol Structure, Composition, and Minor Components

The process of lipid crystallization influences the characteristics of lipid. By changing the chemical composition of the lipid system, the crystallization behavior could be controlled. This review elucidates the internal factors affecting lipid crystallization, including triacylglycerol (TAG) structure, TAG composition, and minor components. The influence of these factors on the TAG crystal polymorphic form, nanostructure, microstructure, and physical properties is discussed. The interplay of these factors collectively influences crystallization across various scales. Variations in fatty acid chain length, double bonds, and branching, along with their arrangement on the glycerol backbone, dictate molecular interactions within and between TAG molecules. High-melting-point TAG dominates crystallization, while liquid oil hinders the process but facilitates polymorphic transitions. Unique molecular interactions arise from specific TAG combinations, yielding molecular compounds with distinctive properties. Nanoscale crystallization is significantly impacted by liquid oil and minor components. The interaction between the TAG and minor components determines the influence of minor components on the crystallization process. In addition, future perspectives on better design and control of lipid crystallization are also presented.

Nitrocellulose for Prolonged Permeation of Levofloxacin HCl-Salicylic Acid In Situ Gel

Currently, the application of solvent exchange-induced in situ gel is underway for drug delivery to the body target site. Nitrocellulose was attempted in this research as the matrix-forming agent in solvent exchange-induced in situ gel for acne and periodontitis treatments. The gel incorporated a combination of 1% w/w levofloxacin HCl and 2% w/w salicylic acid as the active compounds. In order to facilitate formulation development, the study explored the matrix-forming behavior of different concentrations of nitrocellulose in N-methyl pyrrolidone (NMP). Consequently, their physicochemical properties and matrix-forming behavior, as well as antimicrobial and anti-inflammatory activities, were evaluated using the agar cup diffusion method and thermal inhibition of protein denaturation in the egg albumin technique, respectively. All prepared formulations presented as clear solutions with Newtonian flow. Their contact angles on agarose gel were higher than on a glass slide due to matrix formation upon exposure to the aqueous phase of agarose, with an angle of less than 60° indicating good spreadability. Nitrocellulose concentrations exceeding 20% initiated stable opaque matrix formation upon contact with phosphate buffer pH 6.8. The high hardness and remaining force of the transformed gel indicated their robustness after solvent exchange. Fluorescence tracking using sodium fluorescein and Nile red confirmed the retardation of NMP and water diffusion by the nitrocellulose matrix. From the Franz cell permeation study, these drugs could permeate through neonate porcine skin and tissue of porcine buccal from the nitrocellulose in situ forming gel. Their accumulation in these tissues might enable the inhibition of the invading bacterial pathogens. The developed in situ gels effectively inhibited Staphylococcus aureus, Staphylococcus epidermidis, Propionibacterium acnes, and Porphyromonas gingivalis. Furthermore, the formulations demonstrated an anti-inflammatory effect. The low viscosity of LvSa25Nc makes it appropriate for injectable treatments targeting periodontitis, while the higher viscosity of LvSa40Nc renders it appropriate for topical applications in acne treatment. Therefore, the nitrocellulose in situ gel loaded with combined levofloxacin HCl and salicylic acid emerges as a promising dosage form for treating acne and periodontitis.

Producing superior oleofoams: Unraveling the impact of oil type, surfactant concentration, and production temperature on foam stability and functional characteristics

This study explores the impact of oil type, surfactant concentration, and production temperature on oleofoam properties. Oleofoams were prepared using different concentrations (5, 8, and 10 % w/w) of monoglyceride (MG) in olive, soybean, and sunflower oils at temperatures of 25 °C and 5 °C. The results indicate that higher surfactant concentrations and lower production temperatures enhance the stability, foamability, melting behavior, and hardness of the oleofoams, while minimizing oil drainage. Microscopic analysis reveals that lower production temperatures result in smaller bubble sizes in all oil blends which reduces oil loss and increases the hardness of the oleofoam. Also, oleofoams derived from different oils exhibit solid-like behavior. Among the oils studied, the oleofoam prepared with sunflower oil, at a concentration of 10 % MG and a production temperature of 5 °C, demonstrates superior properties. These findings provide valuable insights into optimizing oleofoam properties by controlling the oil type, surfactant concentration, and production temperature.

Mathematical and computational modeling of fats and triacylglycerides

Fats and oils are found in many food products; however, their macroscopic properties are difficult to predict, especially when blending different fats or oils together. With difficulties in sourcing specific fats or oils, whether due to availability or pricing, food companies may be required to find alternative sources for these ingredients, with possible differences in ingredient performance. Mathematical and computational modeling of these ingredients can provide a quick way to predict their properties, avoiding costly trials or manufacturing problems, while, most importantly, keeping the consumers happy. This review covers a range of mathematical models for triacylglycerides (TAGs) and fats, namely, models for the prediction of melting point, solid fat content, and crystallization temperature and composition. There are a number of models that have been designed for both TAGs and fats and which have been shown to agree very well with empirical measurements, using both kinetic and thermodynamic approaches, with models for TAGs being used to, in turn, predict fat properties. The last section describes computational models to simulate the behavior of TAGs using molecular dynamics (MD). Simulation of TAGs using MD, however, is still at an early stage, although the most recent papers on this topic are bringing this area up to speed.

Physical, textural and crystallization properties of ground nut oil-based diacylglycerols in W/O margarine system

Enzymatic glycerolysis produced ground nut oil-based diacylglycerols (GNO-DAG) with a purity of 43.28 ± 0.89% (GNO-DAG40). GNO-DAG80 (with a DAG purity of 87.33 ± 0.61%) was obtained after purification using molecular distillation. Traditional palm oil was mixed with the "liquid" DAG as margarine base oils. Subsequent evaluations of palm oil-DAG-based fats (PO-GNO DAG) as a margarine replacement in a W/O model system showed that the material was an ideal functional base oil with improved aeration properties and plasticity during application. The binary system physical, textural and crystallization property were determined, and the compatibility of the binary mixed system was analyzed by constructing a phase diagrams. The PO-GNO DAG showed decent compatibility between the two phases and had better texture and rheological properties. In addition, PO-GNO DAG40 showed better apparent viscosity and aeration characteristics than PO-GNO DAG80, with potential application in the food specialty fats industry.

Characterization and stability of solid lipid nanoparticles produced from different fully hydrogenated oils

The use of lipids from conventional oils and fats to produce solid lipid nanoparticles (SLN) attracting interest from the food industry, since due their varying compositions directly affects crystallization behavior, stability, and particle sizes (PS) of SLN. Thus, this study aimed evaluate the potential of fully hydrogenated oils (hardfats) with different hydrocarbon chain lengths to produce SLN using different emulsifiers. For that, fully hydrogenated palm kern (FHPkO), palm (FHPO), soybean (FHSO), microalgae (FHMO) and crambe (FHCO) oils were used. Span 60 (S60), soybean lecithin (SL), and whey protein isolate (WPI) were used as emulsifiers. The physicochemical characteristics and crystallization properties of SLN were evaluated during 60 days. Results indicates that the crystallization properties were more influenced by the hardfat used. SLN formulated with FHPkO was more unstable than the others, and hardfats FHPO, FHSO, FHMO, and FHCO exhibited the appropriate characteristics for use to produce SLN. Concerning emulsifiers, S60- based SLN showed high instability, despite the hardfat used. SL-based and WPI-based SLN formulations, showed a great stability, with crystallinity properties suitable for food incorporation.

Ways to Assess and Regulate the Performance of a Bi-Mechanism-Induced Borneol-Based In Situ Forming Matrix

As an alternative to the traditional polymeric-based system, it is now possible to use an in situ forming system that is based on small molecules. Borneol was used as matrix formation in this study. While triacetin was incorporated into the formulation for prolonging the drug release. The objective of this study is to understand the initial period of the solvent exchange mechanism at the molecular level, which would provide a basis for explaining the matrix formation and drug release phenomena. The evaluation of basic physical properties, matrix formation, in vitro drug release, and molecular dynamics (MD) simulation of borneol-based in situ forming matrixes (ISM) was conducted in this study. The proportion of triacetin was found to determine the increase in density and viscosity. The density value was found to be related to viscosity which could be used for the purpose of prediction. Slow self-assembly of ISM upon the addition of triacetin was associated with higher viscosity and lower surface tension. This phenomenon enabled the regulation of solvent exchange and led to sustaining the drug release. In MD simulation using AMBER Tools, the free movement of the drug and the rapid approach to equilibrium of both solvent and water molecule in a solvent exchange mechanism in borneol-free ISM was observed, supporting that sustained release would not occur. Water infiltration was slowed down and NMP movement was restricted by the addition of borneol and triacetin. In addition, the increased proportion of triacetin promoted the diminished down of all substances' movement because of the viscosity. The diffusion constant of relevant molecules decreased with the addition of borneol and/or triacetin. Although the addition of triacetin tended to slow down the solvent exchange and molecular movement from computation modelling results, it may not guarantee to imply the best drug release control. The Low triacetin-incorporated (5%) borneol-based ISM showed the highest ability to sustain the drug release due to its self-assembly and has proper solvent exchange. MD simulation addressed the details of the mechanism at the beginning of the process. Therefore, both MD and classical methods contribute to a clearer understanding of solvent exchange from the molecular to macroscopic level and from the first nanosecond of the formulation contact with water to the 10-day of drug release. These would be beneficial for subsequent research and development efforts in small molecule-based in situ forming systems.

Clotrimazole-Loaded Borneol-Based In Situ Forming Gel as Oral Sprays for Oropharyngeal Candidiasis Therapy

Oral candidiasis encompasses fungal infections of the tongue and other oral mucosal sites with fungal overgrowth and its invasion of superficial oral tissues. Borneol was assessed in this research as the matrix-forming agent of clotrimazole-loaded in situ forming gel (ISG) comprising clove oil as the co-active agent and N-methyl pyrrolidone (NMP) as a solvent. Their physicochemical properties, including pH, density, viscosity, surface tension, contact angle, water tolerance, gel formation, and drug release/permeation, were determined. Their antimicrobial activities were tested using agar cup diffusion. The pH values of clotrimazole-loaded borneol-based ISGs were in the range of 5.59-6.61, which are close to the pH of 6.8 of saliva. Increasing the borneol content in the formulation slightly decreased the density, surface tension, water tolerance, and spray angle but increased the viscosity and gel formation. The borneol matrix formation from NMP removal promoted a significantly (p < 0.05) higher contact angle of the borneol-loaded ISGs on agarose gel and porcine buccal mucosa than those of all borneol-free solutions. Clotrimazole-loaded ISG containing 40% borneol demonstrated appropriate physicochemical properties and rapid gel formation at microscopic and macroscopic levels. In addition, it prolonged drug release with a maximum flux of 370 µg·cm^-2 at 2 days. The borneol matrix generated from this ISG obsentively controlled the drug penetration through the porcine buccal membrane. Most clotrimazole amounts still remained in formulation at the donor part and then the buccal membrane and receiving medium, repectively. Therefore, the borneol matrix extended the drug release and penetration through the buccal membrane efficiently. Some accumulated clotrimazole in tissue should exhibit its potential antifugal activity against microbes invading the host tissue. The other predominant drug release into the saliva of the oral cavity should influence the pathogen of oropharyngeal candidiasis. Clotrimazole-loaded ISG demonstrated efficacious inhibition of growth against S. aureus, E. coli, C. albicans, C. krusei, C. Lusitaniae, and C. tropicalis. Consequently, the clotrimazole-loaded ISG exhibited great potential as a drug delivery system for oropharyngeal candidiasis treatment by localized spraying.

Control of API release with matrix polymorphism in tristearin microspheres

Glycerides are widely employed as solid matrices in a range of pharmaceutical intermediates and dosage forms. Diffusion-based mechanisms are responsible for drug release, with both chemical and crystal polymorph differences in the solid lipid matrix cited as controlling factors in drug release rates. This work uses model formulations composed of crystalline caffeine embedded in tristearin to study the impacts to drug release from the two primary polymorphic states of tristearin and dependencies on the conversion routes between them. Using contact angles and NMR diffusometry, this work finds that drug release from the meta-stable α-polymorph is rate limited by a diffusive mechanism relating to its porosity and tortuosity, but initial burst release occurs due to ease of initial wetting. Poor wettability resulting from surface blooming can be rate limiting for the β-polymorph, resulting in slower initial drug release relative to the α-polymorph. The route to achieve the β-polymorph strongly impacts the bulk release profile due to differences in crystallite size and packing efficiency. API loading enhances the effective porosity, leading to enhanced drug release at high loadings. These findings offer generalizable principles to guide formulators on the types of impacts to drug release rates that one may expect due to triglyceride polymorphism.

Nanostructured Lipid Carriers for Enhanced Transscleral Delivery of Dexamethasone Acetate: Development, Ex Vivo Characterization and Multiphoton Microscopy Studies

Corticosteroids, although highly effective for the treatment of both anterior and posterior ocular segment inflammation, still nowadays struggle for effective drug delivery due to their poor solubilization capabilities in water. This research work aims to develop nanostructured lipid carriers (NLC) intended for periocular administration of dexamethasone acetate to the posterior segment of the eye. Pre-formulation studies were initially performed to find solid and liquid lipid mixtures for dexamethasone acetate solubilization. Pseudoternary diagrams at 65 °C were constructed to select the best surfactant based on the macroscopic transparency and microscopic isotropy of the systems. The resulting NLC, obtained following an organic solvent-free methodology, was composed of triacetin, Imwitor® 491 (glycerol monostearate >90%) and tyloxapol with Z-average = 106.9 ± 1.2 nm, PDI = 0.104 ± 0.019 and zeta potential = -6.51 ± 0.575 mV. Ex vivo porcine sclera and choroid permeation studies revealed a considerable metabolism in the sclera of dexamethasone acetate into free dexamethasone, which demonstrated higher permeation capabilities across both tissues. In addition, the NLC behavior once applied onto the sclera was further studied by means of multiphoton microscopy by loading the NLC with the fluorescent probe Nile red.

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.

Investigating the Effect of Temperature History on Crystal Morphology of Thermoplastic Composites Using In Situ Polarized Light Microscopy and Probabilistic Machine Learning

Processing parameters including temperature history affect the morphology of semicrystalline thermoplastic composites, and in turn their performance. In addition, the competition between spherulite growth in resin-rich areas, and transcrystallinity growth from fiber surfaces, determines the final morphology. In this study, growth of crystals in low volume fraction PEEK-carbon fiber composites was studied in situ, using a polarized microscope equipped with a heating and cooling controlled stage and a probabilistic machine learning approach, Gaussian Process Regression (GPR). GPR showed that for spherulites, growth kinetics follows the established Lauritzen-Hoffman equation, while transcrystallinity growth deviates from the theory. Combined GPR model and Lauritzen-Hoffman equation were used to deconvolute the underlying competition between diffusion and secondary nucleation at growth front of spherulites and transcrystalline regions.

Stabilization of solid lipid nanoparticles with glycyrrhizin

This study investigated the influence of saponin glycyrrhizin on the formation and stability of solid lipid nanoparticles. The hypothesis was that glycyrrhizin facilitates the formation of stable crystalline lipid particles due to its molecular characteristics and slows down polymorphic transition. Tristearin solid lipid nanoparticles emulsified with glycyrrhizin at varying concentrations at pH 7 and 3 were generated by hot high-pressure homogenization. The influence of glycyrrhizin on the physical stability and crystallization behavior of solid lipid nanoparticles was evaluated by dynamic and static lights scattering, electrophoretic light scattering, optical microscopy, visual observations, and differential scanning calorimetry. The results showed that glycyrrhizin formed nanosized solid lipid nanoparticles at both pH 7 and 3. The glycyrrhizin concentration and the pH applied governed the crystallization behavior and the polymorphic stability as well as the physical appearance. Overall, glycyrrhizin showed remarkable ability to stabilize solid lipid nanoparticles against polymorphic transition over time. These results are relevant for food, pharmaceutical, and cosmetic industries to form stable carrier systems by using natural plant-based saponins as surfactants.

The Role of Starch in Shaping the Rheo-Mechanical Properties of Fat-in-Water Emulsions

The DMA technique was used to conduct experiments on the rheo-mechanical properties of emulsified bovine fat meat products stabilised with potato starch. Starch gels with starch concentrations corresponding to the concentration of starch in water in the emulsions under analysis were used as control systems. The research showed that the rheo-mechanical properties of starch gels and starch–fat gels result from the conformational changes occurring within the structural elements of their spatial network. In starch gels, segments formed by complex associations of amylose chains are structural elements, whereas in starch–fat gels (emulsions) these are additionally amylose–fat complexes. Changes occurring during progressive retrogradation increase the degree of cross-linking in them. In starch gels, they are conditioned by the starch concentration, whereas in emulsions they are conditioned by the concentration of starch and the presence of fat. The parameters obtained by adjusting the Avrami equation to the data obtained with the DMA method enabled the determination of three forms of organisation of the dispersion structure of starch–fat systems. Each of these forms of structure organisation is conditioned by the concentration of starch in the emulsion system.

Improving the crystallization and melting characteristics of cocoa butter substitute by blending with krabok seed fat

This work investigated the crystallization and melting behavior of a commercial cocoa butter substitute (CBS) blended with 10-80% (by weight) of a hard lauric fat called krabok seed fat (KSF). The aim was to find CBS-KSF blends with improved crystallization and melting characteristics from that of the CBS. It was found that the addition of 10-80% KSF to CBS improved the melting properties of the CBS. However, 10-20% KSF resulted in too high solid fat content (SFC) values at the body temperature (37 °C) which would lead to waxy mouth feel. Adding 30-40% KSF resulted in better melting profiles than 10-20% KSF with SFC values < 3% at 37 °C and SFC curves most similar to cocoa butter. However, 40% KSF led to a significant decrease in the crystallization rate from that of CBS and a significant increase in the average crystal size. With 60-80% KSF, although the blends melted completely at the body temperature, their crystallization rates were significantly reduced. All CBS-KSF blends crystallized into β' structure. Therefore, the addition of 30% KSF to the CBS is recommended for industrial use to obtain compound chocolate with improved quality.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05513-1.

Characteristics and feasibility of olive oil-based diacylglycerol plastic fat for use in compound chocolate

With an aim to prepare the healthier functional chocolate, olive oil-based diacylglycerol plastic fat (ODAGP) was prepared by mixing olive oil-based diacylglycerol stearin (O-DAGS) and olive oil-based diacylglycerol olein (O-DAGO) as confectionery fat in compound chocolate. We reported the physicochemical properties of ODAGP and ODAGP-CB blends, and then evaluated their application potential in compound chocolate based on sensory, blooming property and polymorphic transition. ODAGP (40% O-DAGS) showed a wide plastic range (7.1-45.2%) and high component compatibility. The crystal properties results indicated that ODAGP mainly existed in stable β-forms (β₁ and β₂). On the other hand, the ODAGP-CB binary system containing 10-40% ODAGP displayed similar melt-in-mouth property and crystal polymorphism (Form V) to natural CB. Compound chocolate prepared with ODAGP-CB blends obtained satisfactory overall acceptability (score > 7.8) and showed stronger fat bloom resistance.

Thermal Properties, Microstructure and Crystallization of Blends of Leaf Lard and Cottonseed Oil Stearin

Blend oils composed by leaf lard (LL) and cottonseed oil stearin (COS) were prepared and the thermal property, microstructure and crystallization of these blends were investigated in the present study. Solid fat content (SFC), thermal behaviors, triacylglycerols composition, crystal structure and morphology of the LL and COS blends were determined by pulsed nuclear magnetic resonance (pNMR), differential scanning calorimetry (DSC), high-performance liquid chromatography (HPLC), X-ray diffractometer (XRD) and polarized light microscope (PLM), respectively. SFC profiles and iso-solid diagrams indicated that SFCs of all blends were almost close to the weighted averages of the fat components at temperatures beyond 20°C; however, below 20°C, SFCs of blends exhibited higher than those of the weighted averages of the fat components. With the content of COS increasing, palmitic acid and linoleic acid in the blends increased, while stearic acid and oleic acid decreased; monounsaturated-disaturated (USS) and triunsaturated (UUU) glycerides in the blends enhanced, while monosaturated-diunsaturated (UUS) glycerides declined. The melting temperature of the blends decreased with the increase of COS content. The crystal forms in LL were β' and β, and the packing pattern was double and triple chain length (2L and 3L). With COS in blends increasing, β' form crystals and 3L pattern reduced. Polarized light micrographs showed that the number of crystal particles in the blends raised with the increase of COS content, meanwhile, the grainsize of the sample gradually decreased. Visual appearances of the blends indicated that blending LL with COS could efficiently reduce the graininess of LL. The addition of COS had a significant effect on the crystallization behavior of LL. LL presented one-step crystallization at 10°C and 20°C, while COS showed two-step crystallization at 10°C and one-step crystallization at 20°C. However, the blends exhibited obvious two-step crystallization at 10°C, one-step or slight two-step crystallization at 20°C.

An Attempt to Relate Oleogel Properties to Wax Ester Chemical Structures

Wax esters are considered to have a dominant contribution in the gelling properties of wax-based oleogels. To understand their gelling behavior, oleogels of seven different wax esters (total carbon number from 30 to 46; c = 10% [m/m]) in medium-chain triglycerides oil were characterized. Scanning electron microscopy revealed that wax esters crystallize in rhombic platelets with a thickness of 80 to 115 monomolecular layers. Bright field microscopy showed that the regularity and face length of the crystals increased with the total carbon number and molecular symmetry of the respective wax ester. Oscillatory rheology was used to characterize the gel rigidity (Gmax*). Here, wax ester oleogels with smaller total carbon numbers yielded higher Gmax* values than those of wax esters with higher total carbon numbers. The gel rigidity (Gmax*) inversely correlated with the crystal face length. Smaller and optically less well-defined platelets promoted higher gel rigidities. In the case of the microstructure of a specific oleogel composition being manipulated by a variation in the cooling rates (0.8; 5; 10 K/min), this relationship persisted. The information compiled in this manuscript further elucidates the crystallization behavior of wax esters in oleogels. This contributes to the understanding of the composition–structure–functionality relationship of wax-based oleogels supporting future food applications.

Lipid-based solubilization technology via hot melt extrusion: promises and challenges

INTRODUCTION

Self-emulsifying drug delivery systems (SEDDS) are a promising strategy to improve the oral bioavailability of poorly water-soluble drugs (PWSD). The excipients of SEDDS enable permeation through the mucus and gastro-intestinal barrier, inhibiting efflux transporters (e.g. P-glycoprotein) of drugs. Poor drug loading capacity and formulation instability are the main setbacks of traditional SEDDS. The use of polymeric precipitation inhibitors was shown to create supersaturable SEDDS with increased drug payload, and their solidification can help to overcome the instability challenge. As an alternative to several existing SEDDS solidification technologies, hot melt extrusion (HME) holds the potential for lean and continuous manufacturing of supersaturable solid-SEDDS. Despite being ubiquitously applied in solid lipid and polymeric processing, HME has not yet been widely considered for the preparation of SEDDS.

AREAS COVERED

The review begins with the rationale why SEDDS as the preferred lipid-based delivery systems (LBDS) is suitable for the oral delivery of PWSD and discusses the common barriers to oral administration. The potential of LBDS to surmount them is discussed. SEDDS as the flagship of LBDS for PWSD is proposed with a special emphasis on solid-SEDDS. Finally, the opportunities and challenges of HME from the lipid-based excipient (LBE) processing and product performance standpoint are highlighted.

EXPERT OPINION

HME can be a continuous, solvent-free, cost-effective, and scalable technology for manufacturing solid supersaturable SEDDS. Several critical formulations and process parameters in successfully preparing SEDDS via HME are identified.

Lipid-Based Nanocarriers for Neurological Disorders: A Review of the State-of-the-Art and Therapeutic Success to Date

Neurodegenerative disorders including Alzheimer's, Parkinson's, and dementia are chronic and advanced diseases that are associated with loss of neurons and other related pathologies. Furthermore, these disorders involve structural and functional defections of the blood-brain barrier (BBB). Consequently, advances in medicines and therapeutics have led to a better appreciation of various pathways associated with the development of neurodegenerative disorders, thus focusing on drug discovery and research for targeted drug therapy to the central nervous system (CNS). Although the BBB functions as a shield to prevent toxins in the blood from reaching the brain, drug delivery to the CNS is hindered by its presence. Owing to this, various formulation approaches, including the use of lipid-based nanocarriers, have been proposed to address shortcomings related to BBB permeation in CNS-targeted therapy, thus showing the potential of these carriers for translation into clinical use. Nevertheless, to date, none of these nanocarriers has been granted market authorization following the successful completion of all stages of clinical trials. While the aforementioned benefits of using lipid-based carriers underscores the need to fast-track their translational development into clinical practice, technological advances need to be initiated to achieve appropriate capacity for scale-up and the production of affordable dosage forms.