INFLUENCE OF PRODUCT TO BE FRIED TYPE ON THE RATE OF THERMAL OXIDATION OF OILS

Author(s):  
А.В. БОРИСЕВИЧ ◽  
Т.И. ЧАЛЫХ

Проведено исследование процесса термического окисления подсолнечного и кокосового масел при 175°С в условиях поточного обжаривания в них картофеля и куриных наггетсов с отбором проб растительного масла через каждый час работы. Для определения количества продуктов окисления был использован метод спектрофотометрии. Установлено, что после 10 ч проведения обжарки исследованные фритюрные масла были пригодны для дальнейшего использования (Е < 15). Показатель оптической плотности кокосового масла независимо от вида обжариваемого в нем продукта в течение всего эксперимента был ниже аналогичного показателя подсолнечного масла. Предложена оптимальная температура нагрева кокосового масла для обжаривания во фритюре – не более 0,9 от температуры точки дымления. Показано более активное накопление вторичных продуктов окисления во фритюрном масле при обжаривании продукта животного происхождения по сравнению с обжариванием продукта растительного происхождения, что можно объяснить наличием в составе картофеля ингибиторов окисления (пероксидаза, каталаза, витамин С). The study of the process of thermal oxidation of sunflower and coconut oils at 175°C under conditions of in-line frying of potatoes and chicken nuggets in them with the sampling of vegetable oil every hour of operation was carried out. To determine the amount of oxidation products the method of spectrophotometry was used. It was found that after 10 hours of roasting, the studied fryer oils were suitable for further use (E < 15). The optical density index of coconut oil, regardless of the type of product fried in it, was lower than that of sunflower oil throughout the experiment. The optimal heating temperature of coconut oil for deep frying is proposed-no more than 0,9 of the temperature of the smoking point. A more active accumulation of secondary oxidation products in deep-frying oil is shown when frying an animal product compared to frying a vegetable product, which can be explained by the presence of oxidation inhibitors (peroxidase, catalase, vitamin C) in the composition of potatoes.

Author(s):  
Donatella Chionna ◽  
Concetto Puglisi ◽  
Filippo Samperi ◽  
Giorgio Montaudo ◽  
Antonio Turturro

2020 ◽  
Vol 14 (3) ◽  
pp. 85-89
Author(s):  
Ryosuke Tomio ◽  
Tsuyoshi Uesugi ◽  
Kazunori Akaji

2020 ◽  
Vol 56 (5) ◽  
pp. 3675-3691
Author(s):  
Sujith S. Nair ◽  
Tuhin Saha ◽  
Pranab Dey ◽  
Sambhu Bhadra

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 765
Author(s):  
Peng Tian ◽  
Wen Liang ◽  
Zhennan Cui ◽  
Guoming Zhu ◽  
Yonglin Kang ◽  
...  

The warm stamping technology is a promising technology to meet the needs of car weight reduction and energy conservation. In order to compare with the mechanical properties of the traditional hot-stamped boron-alloyed steel 22MnB5, a new warm-stamped niobium-alloyed steel 22Mn3SiNb was designed and tested. The optimal heating parameters for warm forming process were explored through mechanical tests, and the process of their microstructure evolution was investigated by scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD), etc. The experimental results indicate that the optimal heating parameters for the niobium-alloyed steel 22Mn3SiNb are a heating temperature of 800 °C and a soaking time of 5 min. Compared to the hot-stamped boron-alloyed steel 22MnB5 under their respective optimal heating parameters, the properties and microstructure characteristics of 22Mn3SiNb are greatly improved, and nearly no decarburized layer is found on the surface of the niobium-alloyed steel 22Mn3SiNb. In addition, the addition of Nb produces the effects of grain refinement and precipitation strengthening due to the introduction of plenty of nano-precipitated particles and dislocations. In the end, it can be predicted that the new warm-stamped niobium-alloyed steel will replace the conventional hot-stamped boron-alloyed steel.


2008 ◽  
Vol 55-57 ◽  
pp. 293-296 ◽  
Author(s):  
E. Wongrat ◽  
P. Pimpang ◽  
N. Mangkorntong ◽  
Supab Choopun

ZnO nanostructures were synthesized by thermal oxidation reaction from zinc powder and then impregnated by gold colloid. The gold colloid was prepared by chemical reduction technique and had red color. The heating temperature and sintering time of thermal oxidation were 700 °C and 24 hours, respectively under oxygen atmosphere. The morphology of ZnO nanostructures and ZnO impregnated gold colloid were studied by field emission scanning electron microscope (FE-SEM). The diameter and length of pure ZnO and ZnO impregnated gold colloid were about the same value and were in the range of 100-500 nm and 2.0-7.0 µm, respectively. The ethanol sensing properties of ZnO impregnated by gold colloid were tested in ethanol atmosphere at ethanol concentrations of 1000 ppm and at an operating temperature of 260-360 °C. It was found that the sensitivity and response time were improved for gold impregnated sensor with an optimum operating temperature of 300°C due to the enhanced reaction between the ethanol and the adsorbed oxygen at an optimum temperature.


Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4079 ◽  
Author(s):  
Jingnan Chen ◽  
Dami Li ◽  
Guiyun Tang ◽  
Jinfen Zhou ◽  
Wei Liu ◽  
...  

The stability of soybean germ phytosterols (SGPs) in different lipid matrixes, including soybean germ oil, olive oil, and lard, was studied at 120, 150, and 180 °C. Results on the loss rate demonstrated that SGPs were most stable in olive oil, followed by soybean germ oil, and lard in a decreasing order. It is most likely that unsaturated fatty acids could oxidize first, compete with consumption of oxygen, and then spare phytosterols from oxidation. The oxidation products of SGPS in non-oil and oil systems were also quantified. The results demonstrated that at relatively lower temperatures (120 and 150 °C), SGPs’ oxidation products were produced the most in the non-oil system, followed by lard, soybean germ oil, and olive oil. This was consistent with the loss rate pattern of SGPs. At a relatively higher temperature of 180 °C, the formation of SGPs’ oxidation products in soybean germ oil was quantitatively the same as that in lard, implying that the temperature became a dominative factor rather than the content of unsaturated fatty acids of lipid matrixes in the oxidation of SGPs.


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