Examination of the correlation of butter spreadability and its fat conformation by DSC

Since the appearance of margarines and spreads on the market, they have been serious competitors with butter. One of the reasons for this was the false nutritional propaganda, but today butterfat has scientifically regained its actual nutritional evaluation. The main disadvantage of butter in comparison to other spreadable tallow is that it does not immediately spread as well when taken out of the refrigerator. One method of obtaining better cold-spreadability is appropriate cream ripening in which a different system known as the corpuscular colloid is created. Recent examinations were conducted during the winter, when the problem of spreadability of butter is the greatest. Simple cold ripening in accordance with the method used in our earlier EPR studies ripened the cream, and by heat-step ripening, then butter was produced from these materials. By deconvolutional analysis of the DSC curves it was established that butter made from the cream ripened by the heat-step method had three characteristic melting peaks as distinct from the two melting peaks of butter made from cold-ripened cream, and the temperature of the second melting peak for butter from heat-step cream was identical to the characteristic melting temperature for fat particles from earlier EPR spectroscope assays. In sum it can be stated that the DSC method clearly shows both the homogeneous and the particle structure characteristic of butter.     

DSC and EPR investigation of the effect of fat crystallization on the consistency of butter

It was possible to determine the liquid fat content and melting behaviour of butters unenriched and enriched in low melting point milk fat fraction (mp=10?C) made from traditionally (6-11-11?C) and heat step technology ripened (6-20-11?C) cream by using EPR spectroscopy and ultrasensitive DSC methods. It was determined that

butters made from heat step technology (H) ripened cream have smaller liquid fat content in the continuous fat phase than that of made from traditionally (K) ripened cream.

there were different fat melting behaviours: the K-butter in temperature range of 0–20?C had one melting peak while H-butter had two ones, and

the effect of enrichment is different in the fraction of low melting point: the melting temperature decreased in the case of K-butter, but the H-butter exhibited smaller enthalpy at the lower melting temperature having same melting temperatures.

Our experiments support the view that H-butter is much more structured than K-butter which is caused by fat fragments containing cubic crystals, developed during the ripening of heat step technology. With respect to the minimum liquid fat content of maximum fat fragments, and vice versa, the cream ripening temperature of solid and spreadable butter can be optimalized by determination of cream ripening temperature-liquid fat content function (min.-max. curve) The experiments have proved without any doubt that butter of cold spreadable, not softening at room temerature, can be only produced by the combination of heat step cream ripening and enrichment with a low melting point fraction.     

Detection of recombined butter by DSC

DSC can be used to quickly determine if a product labeled as butter is actually a recombined butter made without milk. Recombined butter is manufactured from anhydrous milk fat, skim milk powder, water, salt, and lecithin. Melting profiles of tempered samples of natural butter and recombined butter were alike, but DSC curves from 5 to 25°C of untempered refrigerated samples revealed that the enthalpy of the melting transition around 17–20°C was much higher for natural butter than for recombined butter. The procedure for differentiating the two products can be completed in less than 20 min.Mention of brand or firm names does not constitute an endorsement by the U.S. Department of Agriculture over others of a similar nature not mentioned.The authors thank Dr. Thomas Foglia for helpful discussions and Donna Lu for assisting in butter extractions.     

The Use Of Hplc To Separate Triglycerides In Confectionery Fats Using Ultra Violet Detection

Abstract

The triglycerides of confectionery fats have been separated by reverse phase HPLC using mixtures of either acetonitrile and tetrahydrofuran or acetonitrile and methyl tertiary butyl ether using UV detection at 237 nanometres. The method has been applied to samples of cocoa butter, cocoa butter equivalents, milk fat and other vegetable fats. The fat from a milk chocolate has been separated by the above system.     

Melting and crystallization DSC profiles of milk fat depending on selected factors

The aim of this study was to test selected factors, such as sample preparation and measurement procedure, potentially influencing repeatability of DSC analysis of milk fat melting and crystallization. The study investigated the effect of such factors as scanning rate, type of sample pans, method of butter dehydration, and final temperature in the cooling experiment. Based on recorded results, it was observed that cooling rate has a considerable effect on temperature, enthalpy, and height of peaks in the process of milk fat crystallization, as well as peak height and enthalpy in the melting process. By contrast, in the melting process no significant differences were observed in all measured temperatures in the range of heating rate of 2–20 °C min^?1 (p > 0.05). No statistically significant effect on thermodynamic parameters was found for sample pan type, the applied butter dehydration method and various final cooling temperatures (?60, ?50, and ?40 °C) either in the melting or crystallization processes. Only temperature of the second peak (T _c2) in the crystallization process constituted an exception in this respect, with significant differences (p ≤ 0.05) being recorded depending on the applied pan and dehydration method. With regard to the dehydration method, for the extraction and centrifugation methods the first peak forming during crystallization was characterized by high instability, manifested by various peak shape. Generally, it was found that the analysis of the melting and crystallization processes in milk fat, despite its complex composition, is characterized by high repeatability. Mean values of RSD calculated from all the experiments were very low, i.e., 1.8 % for the temperature in the melting process and 1.5 % in crystallization, 0.9 % for melting enthalpy, and 3.2 % for crystallization enthalpy, whereas for peak heights in melting it was 2.9 % and for crystallization it was 9.3 %, respectively.     

Investigating Isothermal DSC Method to Distinguish Between Cocoa Butter and Cocoa Butter Alternatives

In the article thermal behaviours of cocoa butter and representatives of the 3 classes of cocoa butter alternative fats were investigated using isothermal DSC-method. Besides traditional parameters, Avrami transformation and polar qualification system (adapted from NIR-technique) were used for data evaluations.Using a new parameter, t_max^*, the influence of the temperature change could be avoided. This parameter gave 100% success in classification of the investigated confectionery fats (p<0.05).In comparison with traditional Avrami parameters such as n and lgk measured at different temperatures, a new parameter (t^*) gave the best result in distinguishing confectionery fats (approx. 71% correctly classified). The classification improved using lgk and n together (79%).Better classification could be achieved using polar qualification system. The percentage of correctly classified cases was 87.5% using either the point or the surface method (p<0.05). In every case there was a clear borderline between cocoa butter-CBE fat and CBR-CBS fats.Comparing Avrami method and PQS, it can be concluded that the latter is a more successful method in classification of unknown fat samples (pure cocoa butter alternative fats only). However PQS does not give any information about thermal behaviour of the sample.This revised version was published online in November 2005 with corrections to the Cover Date.     

Detection of butter adulteration with water using differential scanning calorimetry

The study evaluated the applicability of differential scanning calorimetry (DSC) for the detection of water content in butter. High correlation coefficients were found between the water content and the enthalpies of the ice melting/water crystallization. The correlation equations were adopted to calculate the water content for seven tested kinds of butter, and the results were compared with the values, obtained by using the reference method. The difference between the water content determined by the reference method and by DSC ranged between 0.2 and 2.6% for the measured enthalpy of ice melting, and between 1 and 5.6% for the enthalpy of water crystallization. In relation to the data obtained, it can be concluded that the parameter of ice melting enthalpy can be used in the identification of adulterations or confirmation of butter authenticity.     

Programmable Temperature Vaporizer (PTV) Applied to the Triglyceride Analysis of Milk Fat

The PTV (Programmable Temperature Vaporizer) is a split/splitless injector which allows the sample to be introduced at a relatively low temperature, thus affording accurate and reproducible sampling. After injection the PTV is rapidly heated to transfer the vaporized components into the capillary column. This type of injector has proved to be an efficient tool for the evaluation of fatty acids, essential oils, and pesticides in food analysis. In this work the suitability of PTV for the analysis of milk fat purity by the Official EU method was evaluated. This method is based on the gas chromatographic determination of triglycerides only according to their total number of carbon atoms followed by the application of formulae deriving from multiple linear regressions. The analysis is currently carried out with a packed column or a short capillary column and an on-column injection system. Several samples of pure milk fat and mixtures of milk fat with foreign fat were analyzed with the same capillary column and by using both PTV and on-column injection systems. The results show that the gas chromatographic profile obtained by PTV is comparable with that obtained by the on-column injector, while repeatability and reproducibility data meet the requirements indicated in the Official Method. Therefore, this study demonstrates that it is possible to use the PTV instead of the on-column injector to determine the purity of milk fat with this method.     

Melting characteristics of fat present on the surface of industrial spray-dried dairy powders

The melting characteristics of the fat present on the surface (surface free-fat) of two industrial spray-dried dairy powders (cream powder and whole milk powder) were investigated in comparison with those of other milk fat fractions present in the powder, such as free-fat from the interior of the powder particle (inner free-fat) and encapsulated fat. The melting characteristics of the milk fat fractions were studied by fatty acid composition, melting profile and solid fat content profile. The results indicated that all milk fat fractions including surface free-fat contained various triglycerides with melting points ranging from -40 to +40 degrees C. However, some fractionation was observed among the different milk fat fractions. The free-fat fractions (surface free-fat and inner free-fat) had a greater proportion of high-melting triglyceride species than the encapsulated fat. Furthermore, the high-melting triglyceride species present in the free-fat fractions were slightly accumulated at the surface of powder. This phenomenon was observed in both cream powder and whole milk powder and its effect on wetting time was established. This indicates that manipulation of the surface fat content during drying operation may hold the key to functionality improvement.     

Preparation of Low-Diacylglycerol Cocoa Butter Equivalents by Hexane Fractionation of Palm Stearin and Shea Butter

Herein, we prepared 1,3-dipalmitoyl-2-oleoyl glycerol (POP)-rich fats with reduced levels of diacylglycerols (DAGs), adversely affecting the tempering of chocolate, via two-step hexane fractionation of palm stearin. DAG content in the as-prepared fats was lower than that in POP-rich fats obtained by previously reported conventional two-step acetone fractionation. Cocoa butter equivalents (CBEs) were fabricated by blending the as-prepared fats with 1,3-distearoyl-2-oleoyl glycerol (SOS)-rich fats obtained by hexane fractionation of degummed shea butter. POP-rich fats achieved under the best conditions for the fractionation of palm stearin had a significantly lower DAG content (1.6 w/w%) than that in the counterpart (4.6 w/w%) prepared by the previously reported method. The CBEs fabricated by blending the POP- and SOS-rich fats in a weight ratio of 40:60 contained 63.7 w/w% total symmetric monounsaturated triacylglycerols, including 22.0 w/w% POP, 8.6 w/w% palmitoyl-2-oleoyl-3-stearoyl-rac-glycerol, 33.1 w/w% SOS, and 1.3 w/w% DAGs, which was not substantially different from the DAG content in cocoa butter (1.1 w/w%). Based on the solid-fat content results, it was concluded that, when these CBEs were used for chocolate manufacture, they blended with cocoa butter at levels up to 40 w/w%, without distinctively altering the hardness and melting behavior of cocoa butter.     

The Effect of Fat Content and Fatty Acids Composition on Color and Textural Properties of Butter

The textural properties of butter are influenced by its fat content and implicitly by the fatty acids composition. The impact of butter’s chemical composition variation was studied in accordance with texture and color properties. From 37 fatty acids examined, only 18 were quantified in the analyzed butter fat samples, and approximately 69.120% were saturated, 25.482% were monounsaturated, and 5.301% were polyunsaturated. The butter samples’ viscosity ranged between 0.24 and 2.12 N, while the adhesiveness ranged between 0.286 to 18.19 N·mm. The principal component analysis (PCA) separated the butter samples based on texture parameters, fatty acids concentration, and fat content, which were in contrast with water content. Of the measured color parameters, the yellowness b* color parameter is a relevant indicator that differentiated the analyzed sample into seven statistical groups; the ANOVA statistics highlighted this difference at a level of p < 0.001.     

Characterization,thermal properties and phase transitions of amazonian vegetable oils

Thermal profiles of buriti pulp oil (Mauritia flexuosa Mart.), tucumã pulp and kernel oils (Astrocarium vulgare Mart.), rubber seed oil (Hevea brasiliensis), passion fruit oil (Passiflora edulis) and ucuúba butter (Virola surinamensis) were analyzed by thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC). Gas chromatography and calculated iodine values were performed to determine the fatty acid profile and to measure the degree of unsaturation in these oils, respectively. The TG curves showed three steps of mass loss, which can be attributed to the degradation of polyunsaturated, monounsaturated and saturated fatty acids. The DSC crystallization and melting curves are reported and depended on the fatty acid composition. Usually, oil samples with a high degree of saturation showed crystallization and melting profiles at higher temperatures than the oils with a high degree of unsaturation. The data obtained by physicochemical analysis of oil samples were analyzed by principal component analysis and hierarchical cluster analysis to increase understanding of the data set, examining the presence or absence of natural groupings between samples.     

Gas-liquid chromatographic determination of milk fat and cocoa butter equivalents in milk chocolate: interlaboratory study

A collaborative trial was conducted to validate an analytical approach comprising method procedures for determination of milk fat and the detection and quantification of cocoa butter equivalents (CBEs) in milk chocolate. The whole approach is based on (1) comprehensive databases covering the triacylglycerol composition of a wide range of authentic milk fat, cocoa butter, and CBE samples and 947 gravimetrically prepared mixtures thereof; (2) the availability of a certified cocoa butter reference material for calibration; (3) an evaluation algorithm, which allows reliable quantitation of the milk fat content in chocolate; (4) a subsequent correction to take account of the triacylglycerols derived from milk fat; (5) mathematical expressions to detect the presence of CBEs in milk chocolate; and (6) a multivariate statistical formula to quantitate the amount of CBEs in milk chocolate. Twelve laboratories participated in the validation study. CBE admixtures were detected down to a level of 0.5 g CBE/100 g milk chocolate, without false-positive or -negative results. The applied quantitation model performed well at the statutory limit of 5% CBE addition to milk chocolate, with a prediction error of 0.7%, and HorRat values ranging from 0.8 to 1.5. The relative standard deviation for reproducibility (RSDR) values for quantitation of CBEs in analyses of chocolate fat solutions ranged from 2.2 to 3.8% and for analyses of real chocolate samples, from 4.1 to 4.7%, demonstrating that the whole approach, based solely on chocolate fat blends, is applicable to real milk chocolate samples.     

Effect of ingredients on the mass loss,pasting properties and thermal profile of semi-sweet biscuit dough

The drive to utilise different lipids, both for health benefits and for commercial reasons, in bakery goods has been extensive. However, the roles of the lipid plays in many products, let alone the influence of the level of saturation, are uncertain. The objective of work carried out is to understand how the typical ingredients in biscuit would impact on the thermal profile of semi-sweet biscuit dough. Three different techniques have been used namely gravimetric analysis (TGA), rapid visco analyser and differential scanning calorimetry (DSC). Wheat flour, sugar and fat/oil were the main ingredients used to produce basic dough of semi-sweet biscuit for this study. Semi-sweet biscuit dough formulations with varying types of oils namely palm oil, palm olein, palm stearine, sunflower oil and butterfat were developed. The final mass (i.e. the total amount of moisture lost) for the samples showed significant differences between the doughs; with the control dough, dough contained palm stearine and butter falling into one group and the butter, palm oil, palm olein and sunflower oil forming the second group that showed less mass loss. Doughs containing low levels of saturated fatty acids (palm olein, palm oil and sunflower oil) showed significant difference on the drying properties of samples compared to doughs containing high saturated fatty acids (palm stearine and butter) as revealed by TGA. Pasting properties result showed that oil with different saturation influenced peak viscosity obtained. The DSC results showed that sugar and oil increased the gelatinisation peak temperature up to 2 and 6 °C, respectively. Oils with low saturated fatty acids have more capability to make contact with starch granules during the mixing processing as compared to oil with a high level of saturated fat. It is suggested that the oil presence in the system was delaying the drying process by coating the wheat flour particles hence slowing the drying process as compared to a sample without oil.     

Crystallization behavior of blends of cocoa butter and milk fat or melk fat fractions

Mixtures of milk fat or milk fat fractions, produced by melt crystallization, and cocoa butter were studied using isothermal calorimetry. Crystallization of cocoa butter (at 15, 20 and 25C) was observed, and induction time for nucleation, peak time and amount of heat produced were recorded. Melting profiles and X-ray spectra were also obtained, yielding information about extent of crystallization and type of polymorph obtained. Induction time for nucleation generally increased with increasing temperature. Peak time increased at 15C, but decreased at 20C. Amount of crystallized fat decreased with increasing level of milk fat.This work was supported by the National Dairy Promotion and Research Board and the Wisconsin Milk Marketing Board. Special thanks are extended to Jennifer Wood for valuable participation in this research and to Dr. George Zografi and his research group for their assistance with the DSC studies.     

Synthesis and properties of minor crypto-active triglycerides of cocoa butter

Summary 1. The crypto-active triglycerides sn-PPO, sn-SSO, and sn-OSS have been synthesized.2. It has been shown that the melting points of mixtures of the main racemic triglyceride components of cocoa butter are affected by more unsaturated triglycerides. Cryptoactive triglycerides scarcely affect the melting points of the mixtures.M. V. Lomonosov Moscow Institute of Fine Chemical Technology. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 8–11, January–February, 1975.     

Simple Procedures for Enrichment of Chlorinated Aromatic Pollutants from Fat,Water and Milk for Subsequent Analysis by High-Resolution Methods

Abstract

Procedures for enrichment of non-volatile chlorinated aromatic pollutants from fat, water and milk are described. ¹⁴C-DDT was used as a model compound in recovery experiments. A several thousand-fold enrichment of DDT added to butter was achieved by two consecutive straight-phase chromatographies on Lipidex 5000.

Trace amounts of DDT in liter volumes of water could be quantitatively extracted by rapid filtration through 2 ml beds of Lipidex 1000. A batch extraction procedure permitted enrichment of DDT from milk after addition of n-pentylamine, methanol and water. DDT could then be eluted from the gel with retention of more than 90% of the lipids.

A reversed-phase system with Lipidex 5000 could be used for separation of TCDD from DDT and PCBs. The liquid-gel chromatographic procedures are simple and suitable for clean-up of samples prior to application of high-resolution methods.     

超高分子量聚乙烯温等静压成型工艺及性能

利用全软模温等静压成型方法成功制备出直径达120mm,高105mm的超高分子量聚乙烯柱状制件,研究了成型压力对成型性能的影响。利用扫描电镜、X射线衍射及示差扫描量热法研究了不同成型压力下结晶度的差异。结果表明:提高压力更有利于结晶,160 MPa下成型样品的熔点为143.0℃,片晶厚度为123nm,结晶度达到69.39%,抗拉强度达到36.8 MPa,缺口冲击强度达到152.3kJ/m~2,断裂伸长率达到634%。     

Development and Physicochemical Properties of Low Saturation Alternative Fat for Whipping Cream

We developed an alternative whipping cream fat using shea butter but with low saturation. Enriched stearic-oleic-stearic (SOS) solid fat was obtained from shea butter via solvent fractionation. Acyl migration reactant, which mainly contains asymmetric SSO triacylglycerol (TAG), was prepared through enzymatic acyl migration to obtain the creaming quality derived from the β’-crystal form. Through enzymatic acyl migration, we obtained a 3.4-fold higher content of saturated-saturated-unsaturated (SSU) TAG than saturated-unsaturated-saturated (SUS) TAG. The acyl migration reactant was refined to obtain refined acyl migration reactant (RAMR). An alternative fat product was prepared by blending RAMR and hydrogenated palm kernel oil (HPKO) at a ratio of 4:6 (w/w). The melting points, solid fat index (SFI), and melting curves of the alternative products were similar to those of commercial whipping cream fat. The alternative fat had a content of total unsaturated fatty acids 20% higher than that of HPKO. The atherogenic index (AI) of alternative fat was 3.61, much lower than those of whipping cream fat (14.59) and HPKO (1220.3), because of its low atherogenic fatty acid content and high total unsaturated fatty acids. The polymorphic crystal form determined by X-ray diffraction spectroscopy showed that the β’-crystal form was predominant. Therefore, the alternative fat is comparable with whipping cream that requires creaming quality, and has a reduced saturated fat content.     

Impact of oil type on nanoemulsion formation and Ostwald ripening stability

The formation of stable transparent nanoemulsions poses two challenges: the ability to initially create an emulsion where the entire droplet size distribution is below 80 nm, and the subsequent stabilization of this emulsion against Ostwald ripening. The physical properties of the oil phase and the nature of the surfactant layer were found to have a considerable impact on nanoemulsion formation and stabilization. Nanoemulsions made with high viscosity oils, such as long chain triglycerides (LCT), were considerably larger ( D = 120 nm) than nanoemulsions prepared with low viscosity oils such as hexadecane ( D = 80 nm). The optimization of surfactant architecture, and differential viscosity eta D/eta C, has led to the formation of remarkably small nanoemulsions. With average sizes below 40 nm they are some of the smallest homogenized emulsions ever reported. What is more remarkable is that LCT nanoemulsions do not undergo Ostwald ripening and are physically stable for over 3 months. Ostwald ripening is prevented by the large molar volume of long chain triglyceride oils, which makes them insoluble in water thus providing a kinetic barrier to Ostwald ripening. Examination of the Ostwald ripening of mixed oil nanoemulsions found that the entropy gain associated with oil demixing provided a thermodynamic barrier to Ostwald ripening. Not only are the nanoemulsions created in this work some of the smallest reported, but they are also thermodynamically stable to Ostwald ripening when at least 50% of the oil phase is an insoluble triglyceride.