Mixtures Of Milk Fat Research Articles

Validation of the Methods for Detection the Non-Milk Fat in a Mixture of Milk Fat and Palm Oil

Milk fat contains a variety of nutritive and health-promoting compounds that guard against some disease. In the current system of global competition, when the quality of milk and milk products is not an option but rather a requirement, therefore, determining the purity of milk fat is critical. This study aims to validate analytical methods for detecting palm oil in a mixture of milk fat and palm oil. Methods of this study was involved detection of non-milk fat in fat blinders by determining the saponification value, iodine number, refractive index, butyro refractometer reading, Gas chromatography, Reverse Phase High-performance liquid chromatography, and Fourier transforms Infrared. The results of this study revealed that the saponification value, Iodine number, refractive index, and Butyro Reading could be used to detect the addition of palm oil by a level of 10% - 20% or more to the milk. The level of some fatty acids in the milk as determined by GC, such as myristic acid (C14:0), palmitic acid (C16:0), and stearic acid (C18:0), is correlated well with the level of adding palm oil to milk fat. The determination of cholesterol and β-sito-sterol content by RP-HPLC could be used for the detection of the addition of palm oil to milk fat. The spectrum behavior produced by FTIR spectroscopy in this adulterated sample is almost the same, so this technique could not be used to detect the palm oil in milk fat.

Development of fermentation parameters of milk-fat mixtures in the production of sour cream product with phytosterols

The object of research is a sour cream product with the addition of phytosterols in terms of the finished product from 0.141 to 1.710 g/100 g of product. One of the most problematic places when using phytosterols is their extremely low solubility in water and fats. There are several ways to add phytosterols to foods. Direct application is represented by suspensions of phytosterol nanoparticles. To improve the solubility in water, phytosterols are converted into the form of glycosides. To improve the solubility in fats and oils, phytosterols are converted into fatty acid ethers. An important issue in the development of fermented milk products is the effect of phytosterols on the homogeneity of the system, the fermentation process, the final properties of the product. During the study, the introduction of pre-esterified phytosterols as a substitute for milk fat with a melting point of 32–34 °C to milk-fat mixtures. Milk-fat mixtures of various compositions were fermented with the study of acidity during fermentation. To study the properties of the system, milk fat was replaced by vegetable fat by 25, 50, and 75 %. The content of lactic acid bacteria was determined for the final product and the organoleptic parameters of the product were compared. The results show that when fermenting for 14 hours, the required acidity parameters of pH 4.2 to 4.6, titratable acidity of 76 to 79 °T were achieved at 12 hours. Phytosterols did not harm the fermentation rate, and after the process did not worsen the taste and appearance of the product. This provides the opportunity to obtain a high-quality sour cream product with additional properties. The process of fermentation of sour cream products with phytosterols corresponds to the parameters of the standard sour cream product and sour cream. This provides advantages such as the ability to integrate a new product into the sour cream and sour cream production system without significant changes in technology and equipment.

Oxidation kinetics and melting profiles of the structured lipids used in infant cookies

In this study, fats extracted from cookies for infant and structured lipids of milkfat (MF), rapeseed oil (RSO), and concentrate of fish (ROPUFA) oil used to bake these cookies were oxidized. The experiments were done at five different heating rates with the use of differential scanning calorimeter (DSC). The onset oxidation temperature (Ton, °C) was determined as the intersection of the extrapolated baseline and the tangent line (leading edge) of the recorded exotherm. The kinetic parameters of the oxidation process (activation energy, pre‐exponential factor, and reaction rate constants) were calculated using the Ozawa–Flynn–Wall method and the Arrhenius equation. The activation energy for analyzed lipids ranged from 91.97 to 199.71 kJ/mol and the pre‐exponential factors ranged from 1.82 × 1011 to 4.11 × 1022 min−1. Fat extracted from cookies was characterized by a better oxidative parameters than fat used to bake them. In the experiment, the melting characteristic of structured lipids in comparison to the starting mixture was also done. The melting curves were recorded by DSC. The results indicate that structured lipids are complex mixtures of various TAGs with wide‐ranging melting points.Practical applications: The kinetic parameters obtained in this paper are thermodynamically and kinetically consistent and can help to predict oxidative stability of interesterified fats‐based products. The use of DSC method seems to be suitable for predicting the shelf life of the cookies intended for infants and children. It also saves a lot of time, which is very precious in quality control.Lipase‐catalyzed interesterification of milk fat, rapeseed oil, and concentrate of fish oil at weight ratio 4:5:1 was performed for producing structured lipids intended as fat to bake cookies for infant and young children. The melting characteristics of TAGs fractions for starting mixture and structured lipids was done using DSC. The mixture of MF, RSO, and ROPUFA before interesterification exhibited a four peaks. Interesterification produced noteworthy changes in the melting profile, whereas blending alone resulted in a dilution effect. All exhibited a wide melting range, with four distinct peaks. The kinetic parameters of the oxidation process (activation energy, pre‐exponential factor, and reaction rate constants) were calculated using the Ozawa–Flynn–Wall method and the Arrhenius equation. Fat extracted from cookies was characterized by a better oxidative parameters than fat used to bake them.

Effect of mechanical treatments applied to milk fat on fat retention and lipolysis in minicurds

The aim of this work was to identify a treatment on milk fat, applicable to pretreat cheese milk, which could enhance lipolysis. Three factors were studied in milk fat mixtures: physical treatment (pumping and mechanical agitation), temperature (5, 15, and 45°C) and fat content (5%, 15%, and 30%). Damage to fat globule was estimated by assessing free fat and by phase contrast microscopy. Moderate damage was achieved in a mixture of 30% of fat, treated with mechanical agitation at 2800 rpm/2 min at 5°C. Applying this procedure to prepare minicurds did not modify values of fat content, moisture and lipolysis.

DETECTION OF MILK FAT ADULTERATION USING DIELECTRIC PROPERTIES

Nowadays, milk adulteration and, in particular, milk fat adulteration represents a big problem. Because of its high price, ghee and butter has always been the object of adulteration by adding less expensive vegetable oils or animal fat. The determination of fatty acids by gas chromatography (GC) followed by calculation of suitable ratios is commonly used to detect extraneous vegetable oils or animal fats, but with the introduction of some lipids sources in cow's and buffalo's diets, the detection of extraneous fat become difficult. The dielectric properties (Breakdown voltage (KV) test) of oils are electrochemical and thermo-physical property widely used to determine the shelf life of mineral oils used in transformers. This property was determined in some vegetable oils, some animal fats, milk fats and margarine oil to see whether there is a big variation between them easy to be used to distinguish between these oils and fats or not. Also, this property was determined in mixture of milk fat with different edible oils and animal fat in different ratios. The obtained results indicated that it could be possible to depend on the dielectric breakdown voltage as a rapid and easy method to detect milk fat adulteration with other vegetable oils and animal fats.

Directly resistively heated‐column gas chromatography for the evaluation of cow milk fat purity

AbstractCow milk fat purity is currently evaluated by triacylglycerol (TAG) analysis. The method is based on the gas chromatographic analysis of TAG according to their total number of carbon atoms, followed by the application of formulae deriving from multiple linear regressions. The original procedure was set up by using a packed column, but different successive works showed its suitability also with the adoption of more modern adjustments. Recently, the use of high‐speed gas chromatography has been spreading. In this work, the suitability of the directly resistively heated‐column gas chromatography [Ultrafast module (UFM)‐GC] for the evaluation of milk fat purity by the Official EU method was tested. Pure milk fat, together with mixtures of milk fat containing two levels of four foreign fats (coconut fat, sunflower oil, lard and beef tallow), were analyzed by both the conventional capillary GC method and UFM‐GC. Sheep, goat and buffalo milk fats were also analyzed. The reference material CRM‐519 was used for calibration. Repeatability and reproducibility values were always below the limits reported in the Official method, demonstrating the suitability of UFM‐GC for the evaluation of milk fat purity. The investigation on sheep, goat and buffalo milk fat confirmed that the S ranges, calculated for cow milk fat, are not applicable to the evaluation of genuineness of non‐bovine milk fats.

Detección de adulteraciones en grasa láctea a través del tratamiento por regresión lineal múltiple de perfiles de ácidos grasos totales

The total fatty acids profile of a genuine milk fat from an important milk producing area of Argentina was determined together with the total fatty acids profiles of sunflower, soybean and coconut oils and bovine and porcine fats. These results were used for characterization of the fatty acid profile of genuine milk fat and for detection of the adulteration of milk fat with those oils and fats. Triglycerides were transesterified in an acid medium with ethanol – sulfuric acid. Ethyl esters were quantified by gas chromatography using two internal standards (C 7:0 and C 17:0 ) added to the anhydrous fat. The most characteristic fatty acids were determined. The fatty acids profiles of mixtures of milk fat with vegetable and animal fats were mathematically calculated. Vegetable oils were added from 2 to 10 %, while animal fats were added up to 15 %. In this way different data matrices were obtained. Stepwise multiple regression analysis was applied to these matrices with the aim of obtaining a relation between adulteration percentage and the total fatty acids profile for each fat selected as adulterant. Good correlation coefficients were obtained for analyzed matrices. Equations were validated by employing the cross validation method, and were applied to genuine samples of milk fat and to mixtures by mass balances of these milk fats with the different adulterant fats. A good prediction of adulterations was obtained with the application of equations.

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.

Study on the Performance of Three Different Capillary Gas Chromatographic Analyses in the Evaluation of Milk Fat Purity

The adulteration of milk fat with foreign fat has been and still is a major concern in the dairy industry. Milk fat purity is currently evaluated by triglyceride analysis by using the Official EU method. The detection limit of the various vegetable and animal fats ranges between 4 and 6%. This research was carried out to verify whether it is possible to decrease the detection limits of beef tallow, which is the most widely used adulterating animal fat. For this purpose, determinations of diglycerides and 3,5-cholestadiene, together with the Official EU method, were applied both to several samples of pure milk fat and to mixtures of milk fat with different percentages of beef tallow. The best results were obtained combining the data deriving from the three determinations by multivariate statistical techniques; in particular, the statistical model obtained by the UNEQ technique seems to be able to decrease the detection limit of beef tallow from 5.2 to 2%. The diglyceride and 3,5-cholestadiene evaluation, combined with the Official EU method for triglycerides, can be usefully applied both to detect small additions of beef tallow and to demonstrate the adulteration of milk fat samples showing results close to the detection limit of the official method.

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 25‡C) 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 15‡C, but decreased at 20‡C. Amount of crystallized fat decreased with increasing level of milk fat.

Detection of Milk Fat Adulteration by Molecular Distillation

Summary An apparatus and a method are described for the molecular distillation at 250C for 1 hr of food fats and oils without decomposition or polymerization. Seasonal variations in milk fat composition were shown to influence the distillate yield. Distillate yields from mixtures of milk fat, produced in different seasons of the year, and domestic food fats or oils, indicated that molecular distillation can detect additions of these fats or oils but not of coconut oil. If the production season of the milk fat were unknown, a minimum addition of 18-20% domestic food fat or oil could be detected; the detectable amount could well be less than 5% with milk fat produced at certain seasons of the year. Deviations in the refractive indices of the distillates, obtained from milk fat-edible fat and oil mixtures, from those considered normal for milk fat, indicated a possibility of detecting additions of coconut oil but not of domestic food fats or oils. If the production season of the milk fat were unknown, a minimum addition of 30% coconut oil could be detected; the detectable amount could be less than 5% with milk fat produced at certain seasons of the year.