Microemulsions based on five-component mixts. for food applications and improved oil solubilization have been studied. The compns. included water, oil phase [such as R(+)-limonene and medium-chain triglycerides (MCT)], short-chain alcs. (such as ethanol), polyols (propylene glycol and glycerol), and several surfactants and their corresponding mixts. (nonionic, such as ethoxylated sorbitan esters, polyglycerol esters, sugar ester, and anionic, such as phosphatidylcholine). The phase behavior of these systems is discussed with respect to the influence of polyols and short-chain alcs. on the degree of solubilization of oils in the aq. phase. The alc. and polyols modify the interfacial spontaneous curvature and the flexibility of the surfactant film, enhancing the oil solubilization capacity of the microemulsions. The solubilization of R(+)-limonene was dramatically improved in the presence of the alc. and polyols, whereas the improvement of solubilization for triglycerides contg. MCT was less pronounced. In some systems high oil solubilization was achieved, and some of them can be easily dild. to infinity both with the aq. phase and with the oil phase. Viscosity measurements along selected diln. lines [characterized by a single continuous microemulsion region starting from a pseudo binary soln. (surfactant/oil phase) to the microemulsion (water/polyol corner)] indicate that at a certain compn. the system inverts from a W/O to an O/W microemulsion. [on SciFinder(R)]

Surfactants contg. sugar components and fatty acids satisfy the quality stds. for food application. The food grade sugar ester in this study is a com. sucrose monoester of stearic acid (abbreviated SES), the oil phase consists of a 1:1 mixt. of n-tetradecane and l-butanol. The originally planned food grade oil, a medium chain triglyceride, is substituted by tetradecane because tetradecane is available as a fully deuterated product, which is necessary for some structural investigations. The investigated system is solid at room temp., but liquefies and structures into a homogeneous microemulsion when heated to above 37°C. The structural characterization of the microemulsions was studied. The established methods for this purpose are scattering methods, such as small-angle scattering of X-rays and neutrons and dynamic light scattering. These scattering techniques can be used to obtain valuable information on the size, shape, and internal structure of colloids and complex fluids. The authors started the investigation with the pseudobinary system SES, tetradecane and l-butanol, varying the SES content. The scattering results show that the sugar ester forms inverse globular micelles in the oil phase. The size of these micelles is about 6 nm. While the size is nearly const. in a wide SES concn. regime (5 up to 40% surfactant), the vol. or aggregation no. increases significantly with SES. This is explained by an increasing replacement of l-butanol mols. by sugar-ester mols. in the micelles formed. Moreover, it can be shown that these micelles strongly overlap. Their center-to-center distance is about 3.8 nm at 40% SES at a micellar diam. of 6 nm. The micellar overlap leads to a highly reduced diffusion of the micelles as was found with dynamic light scattering. When incorporating water in the micellar core, the micelles swell up to about 10 nm and the shape of the aggregates becomes more and more elongated with higher water content. (c) 2001 Academic Press. [on SciFinder(R)]

A review discusses the recent advances on the underlying principles of fractionation technologies and the applications of milk fat fractions as value-added ingredients in the food industry. The chem. compn. of milk fat is considered. Fractionation processes could be improved significantly with increasing knowledge of the mechanisms and kinetics of milk fat crystn. The application of milk fat fractions in food product requires an understanding of how milk component interacts with the other components in the product. [on SciFinder(R)]

A review with refs. on the crystal structure, polymorphism and phase transition mechanisms of fatty acids and acylglycerols. [on SciFinder(R)]

A review discusses the crystn. properties of mixed fatty acid monoglycerides and their org. acid esters. The phase behavior of com. food emulsifiers, primarily monoglycerides and their derivs., is also discussed. The formation of liq. cryst. structures in aq. systems is essential for interactions with carbohydrates or proteins, and it facilitates foam formation in aerated foods. Knowledge of the phys. properties of polar lipids is a major consideration in selecting the optimal emulsifier, or combinations, for a given application in the food industry as well as other tech. applications. [on SciFinder(R)]

A review on the mechanisms of sweating and blooming with respect to the sepn. of oils from wax and the crystn. of fatty acids. By understanding these mechanisms, the solid-liq. sepn. phenomena caused by sweating and blooming may be avoided during the storage of oleaginous solid cosmetic pencils such as lipsticks, eyeliners, and eyebrow pencils. Studies show that sweating is due to the expansion of oils in the wax matrix and/or shriveling of the wax matrix due to increased temp. and humidity. In contrast, blooming involves the soly. of higher fatty acids, a modulator the consistency and hardness of oleaginous cosmetics in oils, and is assocd. with a series of processes such as dissoln.-sepn.-transformation of crystals of higher fatty acids. [on SciFinder(R)]

A review focuses on crystal nucleation and growth in oil-in-water emulsions. The theory of crystn. is discussed considering that crystn. is initiated in the dispersed liq. phase and that the continuous phase of the emulsion cannot crystallize. Various exptl. methods in detg. the presence of cryst. materials and the measurements of crystn. in an oil-in-water emulsion are underlined. [on SciFinder(R)]

A review discusses the mol. mechanisms of the solid-solid phase transitions, such as the "rotator phase transition," of n-alkanes. Such mechanisms have important relevance to various complicated phys. and chem. properties of biol., food, and industrial materials. The rotator phase transitions of n-alkanes are mainly controlled by the primary nucleation and growth processes and a precursor called "wrinkle" plays an essential role in the onset of nucleation. Significant hysteresis in transition temp. between the heating and cooling processes is due to accumulation of strain within crystals on heating process which accelerates nucleation. Tilting and side chain packing are important independent factors in phase transitions. [on SciFinder(R)]

A review discusses the fundamental and application aspects of crystn. behavior of cocoa butter (CB). The polymeric nature of CB and its crystn. behavior under various external influences are discussed, including the mechanisms of fat bloom. [on SciFinder(R)]

A review on the mol. interactions and dynamic phase behavior of the polymorphic forms of the mixed acid triacylglycerols (I). A description of the kinetic properties of the monoacid I is provided for ref. Other topics discussed include: basic concepts of fat polymorphism; polymorphism in mixed-acid I; dynamic aspects in polymorphic transformations of principal I; and thermodn. and kinetic phase properties in binary mixts. of I. [on SciFinder(R)]

A review focuses on the major processes in the fractionation of palm oil including dry, detergent and wet fractionation. Oil fractionation generates a liq. oil with improved properties or produce a fraction with a narrower compn. and melting behavior. Factors affecting palm oil crystn. including phase behavior and polymorphism, minor components, additives, post crystn. processes and modeling are discussed. [on SciFinder(R)]

A review with refs. on the many factors affecting the formation and properties of fat crystal networks. [on SciFinder(R)]

Argan (Argania spinosa L.) oil has a high dietetic and culinary value because it consists of high percentage of unsatd. fatty acids, and it is rich in aroma and flavor. The main objectives of this study were to det. the stability of argan oil (55.4% oleic acid and 24.4% linoleic acid) and to compare it to high-oleic olive oil (78.2% oleic acid and 7.9% linoleic acid) and cottonseed oil (19.8% oleic acid and 52.0% linoleic acid) at high temps. in heating and deep-fat frying conditions. Several quality parameters were tested and compared in time-temp. conditions simulating abuse by heating and deep-fat frying. After frying no change in the contact angle of argan, olive and cottonseed oils was obsd., while in other tests (color index, viscosity, peroxide value, induction period, conjugated dienes content, total polar compds.) the stability of argan and olive oil was better than that of cottonseed oil. Oil uptake of deep-fried potatoes in argan oil was slightly lower than that in olive or cottonseed oil. It was concluded that argan oil can substitute olive or cottonseed oils in deep-fat frying. The aroma, flavor, oxidative stability and the health benefits might "compensate" for the high cost of the oil. Sensory evaluation of fried french potatoes and their storage stability were not studied, and addn. work is needed to evaluate the quality and storage stability of french potatoes fried in argan, olive and cottonseed oils. (c) 2001 Academic Press. [on SciFinder(R)]

A study was made of the characteristics of microemulsions composed of sucrose monostearate (SMS), medium-chain triglycerides (MCT), or R-(+)-limonene, alcs., and water. The systems are homogeneous, soft, and waxy solids at room temp. but liquefy and structure into homogeneous microemulsions when heated to \textgreater40 °C. The amt. of solubilized water is enhanced as a function of the alc./oil ratio and is inversely proportional to the alc. chain length. Over 60 wt% water can be solubilized in systems consisting of propanol/MCT/SMS at a wt. ratio of 3:1:4 (initial wt. ratio). These microemulsions are unique and differ from nonionic ethoxylated-based microemulsions in that their viscosity is very low and is reduced with increasing amts. of solubilized water. The elec. cond. increases only slightly as a function of the water content and does not show typical bicontinuous or percolated behavior. The water in the core of the microemulsion strongly binds to the headgroups of the surfactant. Only at \textgreater15 wt% solubilization of water was free or bulk water detected in the core of the microemulsions. Such unique behavior of the core water might have a possible application in systems requiring monitoring of enzymic (lipase) reactions carried out in the microemulsions as microreactors. [on SciFinder(R)]

Factors affecting water solubilization in four-component nonionic microemulsion systems stabilized by polyol nonionic surfactants (sucrose esters) have been investigated. The effect of changing the chain length of alcohol (used as cosurfactant) and the lipophilic moiety of surfactant have been explored. The maximum water solubilization in the isotropic region (at oil/n-butanol ratio of 1) was 47, 23 and 55 wt.% for sucrose stearate (S-1570), sucrose laurate (L-1695) and sucrose palmitate (P-1570), respectively. Replacing the triglyceride oil (MCT) by dodecane caused a decrease in the water solubilization (40 wt.%) for sucrose stearate with an oil/n-butanol ratio of 1. The empirical BSO (Bansal, Shah, O'Connell) \[\1] equation which was derived as an empirical condition for maximum water solubilization in microemulsions stabilized by anionic surfactants, in relation to the cosurfactant (alcohol) and oil chain lengths, i.e. N-S = N-O + N-A, where N-S, N-O, N-A are the surfactant chain lengths, oil and alcohol, respectively, was re-examined for this type of surfactants. This study demonstrates that a maximum water solubilization is obtained when the N-S = (N-O +/- 3) + N-A for N-S is greater than 14; when N-S is less than 14, this equation cannot predict the maximum water solubilization. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.