Influence of Fatty Acid Moieties of Sorbitan Esters on Polymorphic Occurrence of the Palm Mid‐Fraction

The influence of chain length and subcell packing of fatty‐acid moieties in sorbitan esters (SE) on the polymorphism of the palm midfraction (PMF) was examined. SE with different fatty‐acid moieties (sorbitan tripalmitate; sorbitan tristearate [STS]; and sorbitan tribehenate [STB]) were blended with PMF and PMF polymorph formation was examined using synchrotron radiation X‐ray diffraction and differential interference contrast microscopy. PMF without additives was crystallized in the β′ form under the isothermal condition at 22 °C; however, the addition of STS, which forms an α subcell structure, promoted the crystallization of PMF in the α form. In contrast, crystallization of PMF in the β′ form was accelerated by the addition of STB. These results showed that when the chain length of the fatty‐acid moiety between fat and emulsifiers was similar, the crystallization of PMF in the α form was promoted by the α subcell packing in STS crystals that were nucleated prior to PMF crystallization. In contrast, STB crystals, which have an α subcell packing, accelerated the crystallization of PMF in the β′ form because of the large difference between the chain lengths of STB and PMF. Therefore, structural similarities in both the chain length and the subcell packing are essential features that regulate the template effect, and the promotion of the crystallization of PMF in the β′ form by the addition of STB was caused by heterogeneous nucleation.     

Effect of food emulsifiers on polymorphic transitions of cocoa butter

The polymorphic behavior of cocoa butter in the presence of several food emulsifiers serving as crystal structure modifiers was investigated. Emphasis was placed on transitions among the relatively stable forms IV, V and VI, which are significant for a confectionery industry. As known from industry work, within the series of sorbitan esters and ethoxylated sorbitan esters, the solid emulsifiers were the most efficient in retarding transition of V form into VI modification. Blends of sorbitan monostearate (Span 60), ethoxylated sorbitan monostearate (Tween 60) and Span 60-Tween 65 used in the present study were particularly effective. Surprisingly, it was found that some combinations of emulsifiers accelerate the transition of form IV into form V. Transition of form V into form VI occurs via the solid state, and other transitions are known to take place via the liquid phase. Emulsifier was found to increase liquid fraction of the fat prior to its transition. Mechanistic considerations concerning these transitions are suggested.     

Emulsifiers derived from linseed oil and their potential use in coatings

In the development of a stable linseed oil emulsion paint, a series of emulsifiers were prepared from linseed, oil and its fatty acids and alcohols: (a) linseed monoglycerides, (b) mono-and dilinseed fatty sorbitan esters and a mixed ester obtained by the transesterification of linseed oil with sorbitol, (c) polyoxyethylene ether adducts formed by reacting, ethylene oxide with these sorbitan esters, and (d) linseed polyoxyethylene ether made by ethoxylation of linseed alcohols. Another series of surfactants was prepared by esterifying a polyoxyethylene ether of sorbitol with various amounts of linseed fatty acids. Conditions of preparation and pertinent physical, and chemical properties of the emulsifiers are given. Some of these emulsifiers demonstrated filmforming properties. Combinations were formulated into linseed oil emulsion paints with and without zinc oxide. Paints containing zinc oxide have been relatively stable in viscosity for about 2 yr.     

Pharmaceutical and cosmetic uses of palm and lauric products

The pharmaceutical and cosmetic industries are large and still growing. New products, astute marketing and sophisticated advertising have been very effective in these industries. They are more and more exacting and highly complex in their requirements. They require specification products with specific performance characteristics. The cosmetic industry and drug or pharmaceutical industries are defined. Information is given about the unique composition of palm and lauric oils which make them suitable raw materials for use in these applications. These two base oils are used in the form of triglycerides, whole fatty acids, fractionated fatty acids or fatty chemical derivatives. Information is given about these various ingredients, their use in specific cosmetic and pharmaceutical products and reasons for their use. Particular use is made of palmitic, stearic, myristic and short-chain fatty acids. The derivatives would include glycerine esters, monostearates, other monoglycerides, propylene glycol esters, polyglycerol esters, sorbitans and sorbitan ethylene oxide products, isopropyl palmitic and myristate. Specific powdered stearins and cocoa butter substitutes are used in various formulations. The production and marketing of ingredients for this industry are natural growths of the developing fatty acid industry in Malaysia and nearby countries of southeast Asia.     

Herstellung,Analyse und DC-Trennung von Fettsäurepartialestern mehrwertiger Alkohole

Preparation, Analysis and TLC-Separation of Partial Esters of Fatty Acids with Polybasic Alcohols Direct esterification of 99% capric acid, lauric acid, myristic acid, palmitic acid and stearic acid with ethyleneglycol, diethyleneglycol, thiodiethyleneglycol, triethyleneglycol, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,5-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, 1,2,4-butanetriol, glycerol, 1,2,6-hexanetriol, trimethylolpropane and pentaerythritol in a molar ratio of 1 :1.25 yields 100 different partial esters of fatty acids. These partial esters are extensively freed from the polyhydric alcohols by washing with sodium sulfate solution and recrystallization in ethanol. Chemical constants and TLC-separation into classes and into polyhydric alcohols permit the evaluation of these compounds as emulsifiers, stabilizers and solubilization acids. All the partial esters of the fatty acids are mixtures, which can be separated by TLC according to the polyhydric alcohol moiety into monoester, diester, triester and tetraester; furthermore, the separation of positional isomers of monoesters and diesters is possible. Several observations made during the synthesis and analysis of partial esters of fatty acids are reported.     

Preparation and surfactant properties of diglycerol esters of fatty acids

Fatty acid mono- and diesters of diglycerol constitute the major portion of commercial polyglycerol esters; hence, their composition influences the performance of the latter as emulsifiers. The correlation of structure of the fatty acids in the mono- and diesters with surfactant properties is of interest. Linear diglycerol was isolated from polymerized glycerol by acetonation, fractional distillation and regeneration. Diglycerol mono- and diesters of undecenoic, lauric, stearic, oleic and ricinoleic acids were prepared by reacting diglycerol and fatty acids in a refluxing mixture of acetonitrile-tetrahydrofuran (75:25) in the presence of p-toluenesulfonic acid and molecular sieves. Mono- and diesters were separated by silica gel column chromatography, and their purities were ascertained by thin layer chromatography and determination of saponification value. The structures were confirmed by periodic acid oxidation, chemical-ionization mass spectrometry and 13 C-NMR spectroscopy. Surfactant properties of the esters were determined. Monoesters showed higher ability in surface tension reduction, emulsification and foaming than the diesters. Short-chain fatty acid esters showed better surfactant properties than the long-chain fatty acid esters. The presence of a central double bond in the lipophilic part of the monoesters reduced emulsion stability. The presence of a hydroxy group in acyl chain retarded foaming and surface tension reducing power.     

Fatty acid polymorph identification by infrared

IR spectra in the 7.5–25.0 μm region are shown to be unique for polymorphic modifications of long chain saturated fatty acids of even carbon number and also for the individual fatty acids. IR spectra are presented for the A-, B-, C- and E-forms of stearic acid and for the C-form of myristic, palmitic, arachidic and behenic acid and the differences discussed. X-ray determined crystal long spacings for the A-, B-, C- and E-forms of a series of homologous even carbon-numbered acids are presented and compared with literature values. The formation of the different polymorphic forms are found to be temperature-concentration related and affected little by polarity of the solvent. Wideline nuclear magnetic resonance second moment values are given for the polymorphic forms of stearic acid. Presented in part at the AOCS Meeting, Houston, May 1971. S. Market. Nutr. Res. Div., ARS, USDA.     

Chemoenzymatic Synthesis of Fragrance Compounds from Stearic Acid

Fatty acids are versatile precursors for fuels, fine chemicals, polymers, perfumes, etc. The properties and applications of fatty acid derivatives depend on chain length and on functional groups and their positions. To tailor fatty acids for desired properties, an engineered P450 monooxygenase has been employed here for enhanced selective hydroxylation of fatty acids. After oxidation of the hydroxy groups to the corresponding ketones, Baeyer–Villiger oxidation could be applied to introduce an oxygen atom into the hydrocarbon chains to form esters, which were finally hydrolyzed to afford either hydroxylated fatty acids or dicarboxylic fatty acids. Using this strategy, we have demonstrated that the high-value-added flavors exaltolide and silvanone supra can be synthesized from stearic acid through a hydroxylation/carbonylation/esterification/hydrolysis/lactonization reaction sequence with isolated yields of about 36 % (for ω−1 hydroxylated stearic acid; 100, 60, 80, 75 % yields for the individual reactions, respectively) or 24 % (for ω−2 hydroxylated stearic acid). Ultimately, we obtained 7.91 mg of exaltolide and 13.71 mg of silvanone supra from 284.48 mg stearic acid.     

Two‐stage synthesis of sorbitan esters,and physical properties of the products

A series of sorbitan‐fatty acid esters with various fatty acid/sorbitol ratios was prepared using a 2‐stage process. In the first stage, sorbitol was dehydrated to sorbitan at 180 °C (using phosphoric acid as catalyst), and in the second stage, the sorbitan was esterified with the fatty acid at 220 °C (sodium hydroxide as catalyst). The course of the reaction was monitored and the composition of final products was determined by thin‐layer chromatography using a flame‐ionisation detector (TLC‐FID). The properties (surface tension, melting points, viscosity) of prepared sorbitan esters depend on the molecular ratio of fatty acid and sorbitol. The described method is suitable for the preparation of sorbitan esters at industrial scale.     

Sugar-based surfactants for consumer products and technical applications

Sugar-based surfactants, such as sorbitan esters, sucrose esters, alkyl polyglycosides, and fatty acid glucamides gain increasing attention due to advantages with regard to performance, health of consumers, and environmental compatibility compared to some standard products. Sorbitan esters are well established products, which are mainly used as leather and textile auxiliaries or as emulsifiers for food at a volume of approx. 20,000 t/a. Sucrose esters are relatively hydrophobic products. The actual market size is estimated to be < 4,000 t/a – the main application being emulsifiers for food and cosmetics. Their use is still limited. Alkyl polyglycosides and fatty acid glucamides represent a perfect amphiphilic structure with excellent surface activity as well as solubility due to highly selective syntheses. For alkyl polyglycosides industrial processes have been developed in the past couple of years and a total capacity of ca. 80,000 t/a has been established. They are mainly used for cosmetic, manual dishwashing, and detergent applications. Fatty acid glucamides to date are exclusively used by one company in liquid and powdered detergents. The estimated production capacity is approx. 40,000 t/a. Comparable in their performance profile as co-surfactants, both products differ in their raw material base: whereas in the case of the fatty acid glucamides methylamine is incorporated in the product, alkyl polyglycosides are completely based on renewable resources. This, combined with very good performance and mildness, could be one reason why alkyl polyglycosides are the most successful sugar-based surfactants nowadays. Research to develop derivatives on this basis is still ongoing.     

Polyglycerine und Fettsäure-Polyglycerinpartialester (Herstellung,Kennzahlen, DC-Trennung)

Polyglycerols and Partial Fatty Esters of Polyglycerols (Preparation, Chemical Constants, TLC-Separation) Polyglycerols of varying degree of condensation were synthesized by condensation of 99% glycerol and these products were analyzed by TLC. The polyglycerols were directly esterified with 99% capric acid, lauric acid, myristic acid, palmitic acid and stearic acid to the corresponding fatty partial esters of polyglycerols, which were analyzed, together with commercial products, by chemical constants and TLC. Thin-layer chromatography, especially the two-dimensional technique, on boric acid impregnated silicagel 60 precoated plates enabled the separation of fatty partial esters of polyglycerols into a large number of substance classes, which were partly identified by comparison with known synthetic compounds, such as partial esters of palmitic acid with diglycerols and triglycerols. This simple TLC method provides characteristic chromatograms, gives an insight into the complex character of such fatty partial esters of polyglycerols, and enables the identification of these substances which are used as emulsifiers.     

Chemical Characterization of Sorbitan Tri-Stearate Commercial Samples and Their Determination in Confectionery Fats by HPLC High-Resolution Mass Spectrometry

Nominal sorbitan tristearate (E492) commercial samples are widely used generally as emulsifiers and particularly as anti-bloom agents in confectionery products. In spite of this generalized use, their qualitative and quantitative evaluation is poorly documented in literature and the relative works go back to the last decades of last century. In the present work, a deep study by HPLC-High Resolution Mass Spectrometry of qualitative composition of five E492 commercial samples was made up showing a very complex pattern of stearic and palmitic acid esters with the sorbitol anhydrides, sorbitan, and isosorbide. A clear distinction of sorbitan mono-, di-, tri-, and tetra-esters, of sorbitol penta- and hexa-esters and isosorbide mono- and di-esters was achieved. Contemporarily, difference in the qualitative pattern between E492 commercial samples coming from different suppliers was established. As a consequence, quantitative evaluation can be reliably obtained by using as calibration standard the same E492 present in real samples. The accuracy and recovery of the method were determined allowing in this way a reliable application to commercial confectionery products. The detailed knowledge of STS composition may be of great help to orient the synthesis conditions in order to modulate its properties as a function of various experimental necessities.     

The lipids of the common house cricket,Acheta domesticus L. I. Lipid classes and fatty acid distribution

The lipids of the common house cricket,Acheta domesticus L., have been examined with the following results. The fatty acids associated with the lipid extracts do not change significantly from the third through the eleventh week of the crickets' postembryonic life. The major fatty acids are linoleic (30–40%), oleic (23–27%), palmitic (24–30%), and stearic acids (7–11%). There are smaller amounts of palmitoleic (3–4%), myristic (∼1%), and linolenic acids (<1%). The fatty acid composition of the cricket lipids reflects but is not identical to the fatty acids of the dietary lipids: linoleic (53%), oleic (24%), palmitic (15%), stearic (3%), myristic (2%), and linolenic acid (2%). The amount of triglycerides present in the crickets increases steadily from the second through the seventh or eighth week of postembryonic life, then drops sharply. Other lipid classes, such as hydrocarbons, simple esters, diglycerides, monoglycerides, sterols, and free fatty acids remain about constant. The composition of the fatty acids associated with the tri-, di-, and monoglycerides and the free fatty acid fraction are all about the same. The fatty acids associated with the simple esters are high in stearic acid. Postdoctoral Research Associate, Department of Chemistry, University of Michigan, 1965–1967.     

Fatty acid monoesters of 1-ascorbic acid and d-isoascorbic acid

Summary Fat-soluble fatty acid monoesters of 1-ascorbic acid (vitamin C) and d-isoascorbic acid have been prepared from lauric, myristic, palmitic, and stearic acids in 40–50 per cent yields. Evidence has been presented to show that only the primary hydroxyl group of each of the ascorbic acids has been esterified. Antioxidant properties of these esters are being studied. Preliminary tests on the esters have indicated that they may have useful properties as interfacial modifiers.     

Analyses of Monoglycerides and Other Emulsifiers by Gaschromatography

GLC-analysis has become a still more important tool for the analysis of many emulsifiers and is a powerful supplement to the chemical method for describing an emulsifier. The autosampling technique has made GLC more reproducible which is necessary for quantitative analysis. The new generation of gas chromatographs with computer connection is a good and almost necessary help for calculation of the sample composition and has opened up possibilities for more information. Methods and examples are described for the analysis of monoglyceride, lactic acid esters of monoglyceride, acetic acid esters of monoglyceride, and propylene glycol esters of fatty acids. For more complicated separations of components in emulsifiers capillary columns can be used with good results.     

Impact of Fatty Acid Structure on CALB‐Catalyzed Esterification of Glucose

Enzymatic synthesis of fatty acid glucose esters from different fatty acyl donors are performed via enzymatic catalysis in the presence of Candida antarctica lipase B (CALB), using acetonitrile as the solvent. The acyl donor nature (fatty acid or fatty acid vinyl ester) and structure are varied. Lower reaction rates and lower conversions are obtained with fatty acids in comparison to their corresponding vinyl esters. Moreover, the acyl donor with the longest chain length gives the highest conversions. The presence of unsaturation on the acyl donor chain is also shown to be detrimental to the conversion. Practical Applications: The practical applications of the present work are related to the production of gluco‐esters that could be used as nonionic surfactants as detergents, cosmetics and food emulsifiers, emollients or conservatives, respectively. In this study, it is shown that in order to get high production yields, each reaction parameter has to be tuned properly.     

Effects of hydrophobic emulsifier additives on crystallization behavior of palm mid fraction in oil-in-water emulsion

Ultrasonic velocity measurements and X-ray diffraction were employed to monitor the crystallization behavior of palm mid fraction (PMF) in oil-in-water emulsions (20 vol%). Three hydrophobic emulsifiers—sucrose oligoesters (SOE) containing palmitic acid (P-170) and stearic acid (S-170) moieties and a polyglycerine ester (DAS-750) containing a stearic acid moiety—were added to PMF in an attempt to increase the rate and extent of crystallization of PMF, which are otherwise suppressed owing to emulsification of the oil phase into many droplets. The results revealed that the hydrophobic emulsifiers accelerate the nucleation of PMF in the emulsion system, while retarding the rate of crystal growth. As a results, the crystallization temperature (T _c) of PMF increased with increasing concentrations of the hydrophobic emulsifiers. The effects of the three additives were different; in particular the addition of DAS-750 remarkably enhanced crystallization at low concentrations. By adding the emulsifiers at higher concentrations, the polymorphic behavior of PMF crystallization was also modified to different degrees, depending on the type of emulsifier. With addition of SOE, PMF crystallized predominantly in the β′ form; with addition of DAS-750, the extent of β′ nucleation was reduced by comparison with that observed with SOE. The results were explained in terms of adsorption of the hydrophobic emulsifier additives at the oil-water interface, which provides a template for acceleration of surface heterogeneous nucleation of PMF in the emulsion system.     

Qualitative DC-Trennung einiger Polyalkohol-Fettsäurepartialester und Identifizierung der Polyalkohol-Komponente

Qualitative TLC-Separation of a Few Polyalcohol-Fatty Acid Partial Esters and Identification of the Polyalcohol Component Using thin-layer chromatography, a few emulsifiers, such as partial esters of fatty acids with ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 1,6-hexanediol, diethylene glycol, triethylene glycol, glycerol, trimethylolpropane, pentaerythritol and sorbitol were separated into classes of compounds. The number of TLC-fractions reveal the nature of the fatty acid ester of the polyol. In another procedure the polyols are isolated and separated by TLC. Partial esters of fatty acids with polyols can be unequivocally identified by the two TLC-separations.     

Organic reactions in emulsions—Preparation of glycerol and polyglycerol esters of fatty acids by transesterification reaction

Monoglycerol and polyglycerol esters of fatty acids have been prepared in an emulsion medium of polyglycerol in esters of fatty acids. Transesterification between glycerol or polyglycerols and methyl esters of fatty acids is made at relatively low temperatures (95–150 C) in the presence of alkaline catalyst and anionic or nonionic emulsifiers. The reaction system consists of two immiscible phases transformed into a “milky” (macro) or transparent (micro) emulsion throughout the heating process. The product obtained using this technology is not a highly substituted ester since the transesterification reaction is selective. The type and the amount of emulsifier have to be carefully selected. Unsuitable emulsifiers which will not stabilize the emulsion are ineffective in enlarging the contact between the reactants; therefore, the conversion of the reactants is very poor. With suitable emulsifiers, the conversions and the yields improved due to a better contact between reactants.     

Emulsion polymerisation of vinyl chloride in relation to the chemical structure of the emulsifier

The influence of the chemical structure of the emulsifier on the rate of polymerisation, the yield and the properties of the polymer in the emulsion polymerisation of vinyl chloride was studied. The highest molecular weights were obtained with the sodium salts of the sulphuric acid esters of fatty alcohols with a chain length of 10 and 18 C atoms. In the group of aliphatic sulphonates, sulphates and salts of fatty acids there was no great difference. In general the effect of emulsifiers increases with the chain length. Unsaturated emulsifiers decrease the rate of polymerisation. Non-ionic emulsifiers are less active than ionic ones.