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

Abstract

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 c 2) in the crystallization process constituted an exception in this respect, with significant differences (p B 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.

Determination of Total Phenolic Compounds in Common Beverages Using CdTe Quantum Dots

“…; Covas et al . ; Stevenson and Hurst ; Tomaszewska‐Gras ). Rich sources of phenolic compounds are commonly consumed as beverages like coffee, tea, and herb infusions.…”

“…Polyphenols are compounds widespread in the plant kingdom that are widely studied due to their positive activity in humans. Benefits from the consumption of polyphenols include a reduced risk of cancer, cardiovascular disease, neurodegeneration, diabetes, and osteoporosis (Fortes et al 2003;Hao and He 2004;Arts and Hollman 2005;Graf et al 2005;Manach et al 2005;Scalbert et al 2005;Covas et al 2006;Stevenson and Hurst 2007;Tomaszewska-Gras 2013). Rich sources of phenolic compounds are commonly consumed as beverages like coffee, tea, and herb infusions.…”

DSC coupled with PCA as a tool for butter authenticity assessment

“…Lambelet and Ganguli [13] reported that measurements based on crystallization diagrams have the advantage of avoiding problems linked to polymorphism of fats, so that the results are independent of the thermal treatment of the samples prior to analysis. However, it was shown by the study on milk fat [16] that melting curves are characterized by better reproducibility than crystallization curves, only if the sample is initially heated to destroy any previous crystalline structure. There is also little research regarding the comparison of the feasibility of DSC crystallization and melting curves for monitoring the presence of nonmilk fats.…”

Multivariate analysis of seasonal variation in the composition and thermal properties of butterfat with an emphasis on authenticity assessment

“…For the evaluation of DSC applicability, it is crucial to identify the factors affecting measurement repeatability. The factors connected with sample preparation and conditions of DSC analysis (heating and cooling rates) were analyzed by Tomaszewska-Gras (2013). Heterogeneous organic substances with a complex composition such as food are characterized by the natural variability of raw material, which should also be considered.…”