cytellin and gamma-oryzanol

Mixtures of β-sitosterol and γ-oryzanol form gels in a range of organic solvents. Despite being widely studied, particularly as potential oleogels for food application, details of the intrinsic gel-forming building blocks remain unclear. Small-angle neutron scattering (SANS) combined with solvent contrast variation has been used to evaluate potential structural models. While evidence exists that the building blocks are hollow cylinders (tubules), the simultaneous fitting of twelve contrast-varied SANS data sets indicates that the previously proposed model of double walled tubules is incorrect. Predicted scattering based on real space models provides compelling evidence that the origin of the gelling behaviour is the limited assembly of adjacent tubules to form a space-filling network of fibrils.

Topics: Gels; Phenylpropionates; Scattering, Small Angle; Sitosterols; Solvents

Structured fat phases are the basis of many consumer relevant properties of fat-containing foods. To realise a nutritional improvement - less saturated, more unsaturated fatty acids - edible oleogels could be remedy. The feasibility of traditional fat phases structured by oleogel in culinary products has been evaluated in this study. In this contribution the oleogel application in bouillon cubes as model system for culinary products is discussed. Three different gelators (sunflower wax (SFW), a mixture of β-Sitosterol and γ-Oryzanol (SO) and ethylcellulose (EC)), at two concentration levels (5% and 10% (w/w)) each, were evaluated with respect to their physical properties, in the food matrix and application. The application of pure and structured canola oil (CO) was benchmarked against the reference, palm fat (PO). The assessment of the prototypes covered attempts to correlate the physicochemical analyses and sensory data. Organoleptic and analytical studies covered storage stability (up to 6 months) monitoring texture, color and fat oxidation. The results indicate that the substitution of palm fat by oleogel is essentially possible. The characteristics of the bouillon cubes are tuneable by gelator choice and inclusion level. Most importantly, the data show that the anticipated risk of intolerable effects of oxidation during shelf life is limited if antioxidants are used.

Topics: Cellulose; Chemical Phenomena; Fat Substitutes; Food Handling; Food Quality; Helianthus; Humans; Nutritive Value; Organic Chemicals; Phenylpropionates; Rapeseed Oil; Sitosterols; Taste; Waxes

Sunflower oil enriched with curcuminoid compounds (CUs) was gelled by adding 5% (w/w) saturated monoglycerides (MG), rice bran waxes (RW) or a mixture of β-sitosterol and γ-oryzanol (PS). The resulting oleogels differed for rheological properties and firmness due to the difference in gel network structure. PS oleogel was the firmest sample followed by RW and MG ones. Upon in vitro digestion, fatty acid release as a function of digestion time was greatly affected by oleogel structure: the extent of lipolysis decreased as oleogel strength increased (PS < RW < MG). On the other hand, the nature of the oleogelator affected CUs bioaccessibility, which was lower in oleogels containing crystalline particles (MG and RW). These findings appear interesting in the attempt to develop oleogels able to control lipid digestion as well as to deliver bioactive molecules in food systems.

Topics: Biological Availability; Diarylheptanoids; Digestion; Fatty Acids; Humans; Lipolysis; Monoglycerides; Organic Chemicals; Particle Size; Phenylpropionates; Rheology; Sitosterols; Sunflower Oil

The objective of this study was to investigate the influence of self-assembled microstructure on lipid digestibility in phytosterol (γ-oryzanol and β-sitosterol) oleogels. Different molar ratios of γ-oryzanol and β-sitosterol yielded a variety of crystal morphologies; the resulting gels were tested for their lipid emulsification efficiency, release rate of free fatty acids (FFAs) during lipolysis, and their effect on lipase behavior. Results indicated that oleogels were harder to emulsify when compared to oil samples. The emulsification efficiencly was affected by both the gel strength and crystal morphology of the self-assembled structures within phytosterol oleogels. In oil emulsions, intestinal digestion resulted in more extensive lipid droplet coalescence with increased particle size when compared to oleogel emulsions. The FFA release rate suggested that the extent of lipid digestion was correlated to the emulsification efficiency. The interfacial binding of lipase indicated that the amount of lipase adsorption was positively correlated to the interface area created during the emulsification process. Finally, isothermal titration calorimetry results indicated that self-assembled structures within these oleogels physically obstructed the interaction between lipase and lipid. Ultimately, this led to lower reaction rate during gastrointestinal digestion. Collectively, these results may have important implications in designing oleogel systems with controlled lipid digestibility as well as controlling the bioavailability of delivered lipid-soluble bioactive compounds.

Topics: Digestion; Emulsions; Humans; Lipase; Organic Chemicals; Phenylpropionates; Phytosterols; Sitosterols; Structure-Activity Relationship

Coconut oil rich in medium-chain saturated fatty acids was enzymatically modified at the sn-2 position with polyunsaturated fatty acids from fish oil by trans-esterification reaction. The modified coconut oil was combined with gelators (γ-oryzanol and β-sitosterol) to prepare organogels. The effects of different modified coconut oil contents and γ-oryzanol:β-sitosterol ratios on thermodynamic and rheological properties, and microstructures of organogels, as well as their relationships, were studied. The results showed that the addition of gelators increased the hardness, solid fat content, and oil binding capacity of organogels. In addition to its highest melting point and enthalpy change, the organogel containing γ-oryzanol:β-sitosterol (6:4) had the best texture properties that closely resemble the crystalline structure properties. Moreover, the developed organogels had the properties of a pseudoplastic fluid, as described by the power law equation. G' of organogel was found to be significantly higher than G'', which indicates that the organogel remains in solid state. The analysis of crystal morphology showed that the crystal of organogels were clusters, consisting of dense three-dimensional network of gel.

Topics: Chemical Phenomena; Coconut Oil; Crystallization; Esterification; Fatty Acids; Fatty Acids, Unsaturated; Fish Oils; Gels; Phenylpropionates; Rheology; Sitosterols; Thermodynamics

Oleogels were produced using a phytosterol blend of β-sitosterol/γ-oryzanol or a blend of sucrose stearate/ascorbyl palmitate (SSAP) as oleogelators. Four lipid phases were compared in oleogel formation for each oleogelator blend: menhaden oil, structured lipid (SL) of menhaden oil and 30 mol% caprylic acid (SL-C), SL of menhaden oil and 20 mol% stearic acid (SL-S), and SL of menhaden oil and 14 mol% each of caprylic and stearic acid (SL-CS). All SLs were produced enzymatically using a recombinant lipase from Candida antarctica as the biocatalyst. Menhaden oil, SL, phytosterol, or SSAP oleogels were evaluated as alternatives to shortening in the preparation of yellow cake in terms of batter and cake physicochemical properties. The shortening, phytosterol, and SSAP oleogel batters exhibited statistically similar specific gravities (0.85). The shortening, and menhaden oil phytosterol and SSAP oleogel batters, exhibited similar Power-Law values (n: 0.78, k: 31 Pa s

Topics: Ascorbic Acid; Caprylates; Fat Substitutes; Fatty Acids; Fish Oils; Food Analysis; Food Handling; Gels; Organic Chemicals; Phenylpropionates; Phytosterols; Sitosterols; Stearic Acids; Sucrose

γ-Oryzanol is a naturally occurring component of rice bran and consists of various steryl ferulates. The antioxidant activities of γ-oryzanol have mostly been demonstrated in cell-free systems. Therefore, we determined whether steryl ferulate of γ-oryzanol suppress spontaneous intracellular reactive oxygen species (ROS) in cell-based systems. We found that cycloartenyl ferulate and β-sitosteryl ferulate suppressed spontaneous intracellular ROS in a similar way to N-acetylcysteine and α-tocopherol.

Topics: Antioxidants; Bridged-Ring Compounds; Coumaric Acids; HT29 Cells; Humans; Phenylpropionates; Reactive Oxygen Species; Sitosterols

In this study the effect of lecithin (L) addition and solvent quality in a well-established oleogel system formed by β-sitosterol and γ-oryzanol (BG) was investigated. Medium chain triglycerides (MCT) and sunflower oil (SFO) were used as triglycerides and hexadecane (HEX) as a model of linear hydrocarbon. Lecithin was proposed due to its natural and versatile properties, showing different functionalities such as emulsifier and co-oleogelator. A study based on hierarchical organization of structured oil was performed applying techniques for bulk, meso and nanoscale. Self-sustained structures could no longer be observed after 40 wt% of BG replacement by lecithin. Small-angle X-ray scattering showed that the formed nanostructures (building blocks) were dependent on type of solvent and BG:L ratio in the mixture of oleogelators. Differential scanning calorimetry showed that stability against temperature was improved decreasing the polarity of the oil, and a time-dependent self-assembly of hybrid systems was observed from thermal and rheological measurements. Microscopy images exhibited changes on typical fibril aggregation of BG as lecithin was added, which promoted to a certain extent the suppression of ribbons. Oscillatory shear and uniaxial compression measurements were influenced by BG:L ratio and solvent mainly at higher lecithin amount. The combination of BG and MCT appeared to be the most affected by lecithin incorporation whereas SFO rendered harder oleogels. These results could contribute to understand the role of both lecithin and solvent type influencing the host oleogelator structure. It was hypothesized that intermolecular BG complex formation is hindered by lecithin, besides this phospholipid also might coexist as a different phase, causing structural changes in the gel network. Addressing the role of co-oleogelator it can provide the opportunity to tune soft materials with adjusted properties.

Topics: Calorimetry, Differential Scanning; Crystallization; Lecithins; Organic Chemicals; Phenylpropionates; Phytosterols; Sitosterols; Sunflower Oil; Triglycerides

Rheology and atomic force microscopy (AFM) were employed to examine the microstructure of β-sitosterol:γ-oryzanol organogels in sunflower oil. Using time-resolved rheology, we followed gel formation, paying specific attention to the fibril aggregation process, which had not been studied in detail previously for this system. Using AFM, we observed gel structures directly and obtained detailed information on the gel structure, far exceeding previous studies. Our analysis suggests that though gels are formed by the self-assembly and aggregation of one-dimensional fibrils, the manner in which these fibrils aggregate into ribbons results in complex structures of higher dimensionality. We emphasize that it is a surprise to find ribbons and not twisted strands. Comparing AFM images of 10% w/w and 20% w/w gelator systems, we observed differences in the degree of branching which are consistent with the rheology. We also observed the individual self-assembled fibrils which make up these gels with much greater clarity than in previous microscopy studies, and the fibril diameters of ∼9.8 nm we measured agree excellently with those obtained from existing small-angle neutron scattering data. These results provide new insight into the structure and formation kinetics of this important organogel system.

Topics: Gels; Phenylpropionates; Scattering, Small Angle; Sitosterols

A current challenge in the area of food emulsion is the design of microstructure that provides controlled release of volatile compounds during storage and consumption. Here, a new strategy addressed this problem at the fundamental level by describing the design of organogel-based emulsion from the self-assembly of β-sitosterol and γ-oryzanol that are capable of tuning volatile release. The results showed that the release rate (v

Topics: Emulsions; Phenylpropionates; Phytosterols; Sitosterols

HPLC fingerprint analysis combined with chemometrics was developed to discriminate between the red and the white rice bran grown in Indonesia. The major component in rice bran is γ-oryzanol which consisted of 4 main compounds, namely cycloartenol ferulate, cyclobranol ferulate, campesterol ferulate and β-sitosterol ferulate. Separation of these four compounds along with other compounds was performed using C18 and methanol-acetonitrile with gradient elution system. By using these intensity variations, principal component and discriminant analysis were performed to discriminate the two samples. Discriminant analysis was successfully discriminated the red from the white rice bran with predictive ability of the model showed a satisfactory classification for the test samples. The results of this study indicated that the developed method was suitable as quality control method for rice bran in terms of identification and discrimination of the red and the white rice bran.

Topics: Cholesterol; Chromatography, High Pressure Liquid; Indonesia; Oryza; Phenylpropionates; Phytosterols; Sitosterols; Triterpenes

Algae oil, enriched with omega-3 long-chain polyunsaturated fatty acids (ω-3 LC-PUFA), is known for its health benefits. However, protection against lipid oxidation as well as masking of unpleasant fishy malodors in algae oil enriched foods is a big challenge to achieve. In this study, we firstly achieved a one-pot ultrasound emulsification strategy (alternative heating-homogenization) to prepare phytosterol structured thermosensitive algae oil-in-water nanoemulsion stabilized by quillaja saponin. After spray drying, the resulting algae oil powders from the structured nanoemulsion templates exhibit an excellent reconstructed behavior, even after 30 d of storage. Furthermore, an enhanced oxidative stability was obtained by reducing both the primary and secondary oxidation products through formulation with β-sitosterol and γ-oryzanol, which are natural antioxidants. Following the results of headspace volatiles using dynamic headspace-gas chromatography-mass spectrometry (DHS-GC-MS), it was clear that the structured algae oil-loaded nanoemulsion and powder had lower levels of fishy off-flavour (e.g., (Z)-heptenal, decanal, ethanone, and hexadecenoic acid), whereas the control emulsion and oil powder without structure performed worse. This study demonstrated that the structure from phytosterols is an effective strategy to minimize the fishy off-flavour and maximize oxidative stability of both algae oil nanoemulsions and spray-dried powders, and opens up the possibility of formulation design in polyunsaturated oil encapsulates as novel delivery systems to apply in functional foods and beverages.

Topics: Antioxidants; Drug Stability; Emulsions; Fatty Acids, Omega-3; Food, Fortified; Odorants; Oils; Phenylpropionates; Phytosterols; Powders; Quillaja Saponins; Sitosterols; Taste

In this study, water-in-oil emulsions were prepared from water containing different salt concentrations dispersed in an oil phase containing a mixture of β-sitosterol and γ-oryzanol. In pure oil, the β-sitosterol and γ-oryzanol molecules self-assemble into tubular microstructures to produce a firm organogel. However, in the emulsion, the water molecules bind to the β-sitosterol molecules, forming monohydrate crystals that hinder the formation of the tubules and resulting in a weaker emulsion-gel. Addition of salt to the water phase decreases the water activity, thereby suppressing the formation of sitosterol monohydrate crystals even after prolonged storage times (∼1 year). When the emulsions were prepared with less polar oils, the tubular microstructure was promoted, which significantly increased the firmness of the emulsion-gel. The main conclusion of this study is that the formation of oryzanol and sitosterol tubular microstructure in the emulsion can be promoted by reducing the water activity and/or by using oils of low polarity.

Topics: Emulsions; Phenylpropionates; Plant Oils; Sitosterols; Sunflower Oil; Water

Small-angle neutron scattering (SANS) experiments have been performed on self-assembled tubules of sitosterol and oryzanol in triglyceride oils to investigate details of their structure. Alternative organic phases (deuterated and non-deuterated decane, limonene, castor oil and eugenol) were used to both vary the contrast with respect to the tubules and investigate the influence of solvent chemistry. The tubules were found to be composed of an inner and an outer shell containing the androsterol group of sitosterol or oryzanol and the ferulic acid moieties in the oryzanol molecule, respectively. While the inner shell has previously been detected in SAXS experiments, the outer shell was not discernible due to similar scattering length density with respect to the surrounding solvent for X-rays. By performing contrast variation SANS experiments, both for the solvent and structurant, a far more detailed description of the self-assembled system is obtainable. A model is introduced to fit the SANS data; we find that the dimensions of the inner shell agree quantitatively with the analysis performed in earlier SAXS data (radius of 39.4 +/- 5.6 angstroms for core and inner shell together, wall thickness of 15.1 +/- 5.5 angstroms). However, the newly revealed outer shell was found to be thinner than the inner shell (wall thickness 8.0 +/- 6.5 angstroms). The changes in the scattering patterns may be explained in terms of the contrast between the structurant and the organic phase and does not require any subtle indirect effects caused by the presence of water, other than water promoting the formation of sitosterol monohydrate in emulsions with aqueous phases with high water activity.

Topics: Alkanes; Castor Oil; Cyclohexenes; Deuterium; Eugenol; Limonene; Neutron Diffraction; Phenylpropionates; Scattering, Small Angle; Sitosterols; Terpenes; Triglycerides; X-Ray Diffraction