Investigation of thermal-oxidative stability of esters by means of differential scanning calorimetry

1982 ◽  
Vol 18 (10) ◽  
pp. 517-519
Author(s):  
E. M. Nikonorov ◽  
N. S. Sazonova ◽  
L. N. Petrova ◽  
O. V. Ataeva
Keyword(s):  
Differential Scanning Calorimetry ◽  
Oxidative Stability ◽  
Scanning Calorimetry ◽  
Thermal Oxidative Stability

scholarly journals Thermal Oxidative Stability of Biodiesel/Petrodiesel Blends by Pressurized Differential Scanning Calorimetry and Its Calculated Cetane Index

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 174
Author(s):  
Jilliano B. Silva ◽  
Josue S. Almeida ◽  
Rodrigo V. Barbosa ◽  
Glauber J. T. Fernandes ◽  
Ana C. F. Coriolano ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Oxidative Stability ◽  
Scanning Calorimetry ◽  
Vehicle Performance ◽  
Thermal Oxidative Stability ◽  
Cetane Index ◽  
Diesel Cycle ◽  
High Concentrations ◽  
Fuel Mixtures ◽  
Calorific Power

Diesel fuel mixtures with high concentrations of biodiesel have been investigated to analyze the technical feasibility of their use in diesel cycle engines regarding thermal and oxidative properties. The results of combined techniques of oxidative stability, high Pressurized Differential Scanning Calorimetry (P-DSC), Calculated Cetane Index (CCI), and calorific power were used to verify the effect of the thermal-oxidative stability as a function of the percentage of biodiesel in the mixtures. The obtained results evidenced that the thermal and oxidative stability decreased with the addition of biodiesel from 50 to 5% v/v. Low stability fuels require rapid use as the oxidation compounds degrade the product and impair vehicle performance, as well as lead to corrosion and clogging problems in various mechanical systems.

Comparative analysis of polysaccharide properties and their effect on oxidative stability of food emulsions

2021 ◽  
pp. 50-53
Author(s):  
Варужан Амбарцумович Саркисян ◽  
Юлия Владимировна Фролова ◽  
Роман Владимирович Соболев ◽  
Алла Алексеевна Кочеткова
Keyword(s):  
Differential Scanning Calorimetry ◽  
Comparative Analysis ◽  
Oxidative Stability ◽  
Potato Starch ◽  
Locust Bean Gum ◽  
Scanning Calorimetry ◽  
Multivariate Statistical ◽  
Food Ingredients ◽  
Food Emulsions ◽  
Locust Bean

Полисахариды являются многофункциональными пищевыми ингредиентами, применяемыми в различных типах пищевых продуктов. Особый интерес вызывает изучение роли полисахаридов в качестве потенциальных про- или антиоксидантов в составе пищевых эмульсий. Основным недостатком традиционных способов оценки развития окислительных процессов в эмульсиях является необходимость предварительной экстракции жировой фазы, что может сопровождаться искажением реальных значений показателей окисления. В данной работе влияние полисахаридов на окислительную стабильность эмульсий изучено при помощи реактора окислительной устойчивости Oxitest, который позволяет проводить прямое измерение потребления кислорода в процессе окисления липидов, тем самым исключая необходимость экстракции и повышая достоверность полученных данных. Проведен сравнительный анализ 6 различных полисахаридов (альгинат натрия, i-каррагинан, камедь рожкового дерева, пектин амидированный, пектин высокоэтерифицированный, картофельный крахмал) в составе пищевых эмульсий. Методами ИК-Фурье спектроскопии и дифференциально-сканирующей калориметрии охарактеризованы состав и свойства исходных полисахаридов. Изучена вязкость 0,5%-ных растворов полисахаридов при помощи метода ротационной вискозиметрии. В результате проведенного анализа полисахаридов выявлены и охарактеризованы основные отличия в колебательных спектрах поглощения функциональных групп. Методом дифференциально-сканирующей калориметрии определены энтальпии теплового эффекта отделения влаги и начала термической деградации полисахаридов. Проведен многомерный статистический анализ полученных данных, выявивший основные закономерности между структурой и свойствами полисахаридов в составе эмульсий. Наибольшую окислительную стабильность проявили эмульсии на основе камеди рожкового дерева и амидированного пектина. Polysaccharides are multifunctional food ingredients used in various types of food products. The role of polysaccharides as potential pro- or antioxidants in food emulsions is of particular interest is. The main drawback of traditional methods for assessing the development of oxidative processes in emulsions is the need for preliminary extraction of the fat phase, which may be accompanied by a distortion of the real values of oxidation indices. In this work, the effect of polysaccharides on the oxidative stability of emulsions was studied using the Oxitest oxidative stability reactor, which allows the direct measurement of oxygen consumption during lipid oxidation, thereby eliminating the need for extraction and increasing the reliability of the obtained data. Comparative analysis of 6 different polysaccharides (sodium alginate, i-carrageenan, locust bean gum, amidated pectin, highly esterified pectin, potato starch) in food emulsions was performed. The composition and properties of the initial polysaccharides were characterized by FTIR spectroscopy and differential scanning calorimetry methods. The viscosity of 0.5% solutions of polysaccharides was studied using the rotary viscometry method. The analysis of polysaccharides revealed and characterized the main differences in the vibrational absorption spectra of functional groups. The enthalpies of the thermal effect of moisture separation and the beginning of thermal degradation of polysaccharides were determined by differential scanning calorimetry. A multivariate statistical analysis of the obtained data revealed the main relations between the structure and properties of polysaccharides in emulsions. Emulsions based on locust bean gum and amidized pectin exhibited the highest oxidative stability.

scholarly journals Application of Thermal Methods to Analyze the Properties of Coffee Silverskin and Oil Extracted from the Studied Roasting By-Product

2020 ◽  
Vol 10 (24) ◽  
pp. 8790
Author(s):  
Agata Górska ◽  
Rita Brzezińska ◽  
Magdalena Wirkowska-Wojdyła ◽  
Joanna Bryś ◽  
Ewa Domian ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Oxidative Stability ◽  
Reliable Data ◽  
Scanning Calorimetry ◽  
Thermal Methods ◽  
Modulated Differential Scanning Calorimetry ◽  
Coffee Silverskin ◽  
Derivative Thermogravimetry ◽  
Coffee Roasting

The aim of the study was to characterize the thermal properties of coffee silverskin and fat extracted from the material by using differential scanning calorimetry, modulated differential scanning calorimetry and thermogravimetry/derivative thermogravimetry. Additionally, the thermokinetic parameters, oxidative stability and fatty acid composition of the extracted oil were defined. Thermal decomposition of the studied coffee roasting by-product under oxygen occurred in three defined stages. The most significant changes in weight were observed in the region of 200–500 °C and correspond to polysaccharide decomposition. These results are in agreement with the data obtained from the differential scanning calorimetry curve. On the curve course of silverskin, two main exothermic peaks can be observed with a maximum at 265 and 340 °C. These exothermic events represent the transitions of hemicellulose and cellulose. Fat extracted from silverskin turned out to be a source of polyunsaturated fatty acids with the recommended n-6 to n-3 ratio reaching the value 4:1. The studied fat was characterized by low oxidative stability. Considering the obtained results, it can be stated that thermal analysis can provide fast and reliable data concerning the composition and properties of coffee silverskin and coffee silverskin oil.

The Study of Oxidative Stability of Castor Oil Based Biodiesel

2013 ◽  
Vol 724-725 ◽  
pp. 334-337 ◽  
Author(s):  
Yun Feng Yang ◽  
Guo Sheng Hu ◽  
Yin Jie Chen
Keyword(s):  
Differential Scanning Calorimetry ◽  
Oxidative Stability ◽  
Constant Temperature ◽  
Castor Oil ◽  
Acid Value ◽  
Scanning Calorimetry ◽  
Accelerated Oxidation ◽  
Temperature Method ◽  
Pressure Differential Scanning Calorimetry ◽  
Activity Energy

The oxidative stability of castor oil based biodiesel, added different antioxidant, was studied systematacially through pressure differential scanning calorimetry (PDSC), accelerated oxidation test, constant temperature method, programmed temperature method. The result shows after adding antioxidant in castor oil, the generation of hyperoxide and acid value were suffocated for the biodiesel. When the content of antioxidant 300 was 0.6 wt.%, the initiation oxide temperature raised to 197.7°C, the acid value reduced to 1.41, the solubility of oxide reduced to 1.40mg/100mL, and the activity energy of oxidation was 48.18kJ/mol.

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