scholarly journals Oxidation of Olive Oils during Microwave and Conventional Heating for Fast Food Preparation

2009 ◽  
Vol 27 (Special Issue 1) ◽  
pp. S173-S177 ◽  
Author(s):  
E. Abd El-Moneim Mahmoud ◽  
J. Dostálová ◽  
J. Pokorný ◽  
D. Lukešová ◽  
M. Doležal
Keyword(s):  
Fast Food ◽  
Oxidation Stability ◽  
Microwave Treatment ◽  
Conjugated Dienes ◽  
Microwave Oven ◽  
Oxidation Products ◽  
Conventional Heating ◽  
Olive Oils ◽  
Peroxide Values ◽  
Conjugated Trienes

The oxidation stability of extra virgin and refined olive oils produced in different countries were studied under different conditions of microwave heating (microwave oven Electrolux, 2450 MHz, 500 W) and conventional heating (200°C). Oils were heated in a microwave oven and in a conventional oven for 0, 3, 6, 9, 12, 15, 20, 25, and 30 minutes. The evaluated parameters were peroxide value, content of conjugated dienes, conjugated trienes (determined by absorbance at 233 nm and 274 nm, respectively), and fatty acid composition by GC. During microwave and conventional heating peroxide values and contents of dienoic compounds differed significantly between control and the heated samples. The microwave treatment did not produce significantly greater amount of oxidation products than traditional heating.

scholarly journals Effects of microwave and conventional heating on the oxidative stability of corn oil enriched with different antioxidants

2019 ◽  
Vol 70 (4) ◽  
pp. 326
Author(s):  
A. Baştürk
Keyword(s):  
Antioxidant Activity ◽  
Fatty Acid ◽  
Reaction Rate ◽  
Corn Oil ◽  
Ascorbyl Palmitate ◽  
Conjugated Dienes ◽  
Conventional Heating ◽  
Rosemary Extract ◽  
Conjugated Trienes ◽  
Severe Deterioration

Four different corn oil samples including stripped (SCO, Control), refined (RCO), stripped corn oil enriched with rosemary extract (SCO+ROS) and ascorbyl palmitate (SCO+AP) were exposed to microwave (MWH) and conventional heating (CVH). For both heating methods, peroxide value (PV) and conjugated dienes increased at up to 230 °C, at which temperature hexanal (HEX) and conjugated trienes started to increase instead. Kinetic analysis revealed that PV and HEX formation were first ordered and the reaction rate among the samples was as follows: Control > SCO+ROS > RCO > SCO + AP for PV and SCO + ROS > RCO > SCO+AP > Control for HEX. The unsaturated fatty acid contents of CVH and MWH treated samples showed 9.5 and 12.9% reduction in SCO, while they were 2.9 and 7.7% in RCO, 3.6 and 6.1% in SCO + ROS, and finally 4.0 and 4.8% in SCO + AP. It was concluded that MWH led to a more severe deterioration and that the antioxidant activity of ROS was superior to that of AP for both heating methods.

Comparative Study on the Deterioration of Oils by Microwave and Conventional Heating

1992 ◽  
Vol 55 (9) ◽  
pp. 722-727 ◽  
Author(s):  
R. S. FARAG ◽  
F. M. HEWEDI ◽  
S. H. ABU-RAIIA ◽  
G. S. EL-BAROTY
Keyword(s):  
Fatty Acids ◽  
Palm Oil ◽  
Fatty Acid Content ◽  
Oxidative Degradation ◽  
Acid Value ◽  
Cottonseed Oil ◽  
Degree Of Polymerization ◽  
Microwave Oven ◽  
Oxidation Products ◽  
Conventional Heating

Refined cottonseed oil and hydrogenated palm oil were heated by two methods, conventionally by gas-cooker (deep fat frying) and by microwave energy. Quality assurance methods such as refractive index, color, diene content, acid value, peroxide value, thiobarbituric acid value, iodine value, petroleum ether insoluble oxidized fatty acid content, and degree of polymerization were determined. Exposing the oil samples to various heating times and microwave oven power levels caused some hydrolysis to free fatty acids and accelerated the formation of hydroperoxides and secondary oxidation products. The value from each test increased with both the power settings of the microwave oven and the time of heating. In general, the development of rancidity for refined cottonseed oil heated by microwaves was twice as fast as that produced by conventional heating. Also, the chemical values indicating deterioration for refined cottonseed oil were much higher for refined cottonseed oil than for hydrogenated palm oil in all cases. Gas-liquid chromatographic analysis of fatty acids obtained from the heated oils indicates the occurrence of oxidative degradation and production of short-chain acids.

Vitamin B1 and B6 Retention in Milk after Continuous-Flow Microwave and Conventional Heating at High Temperatures

2001 ◽  
Vol 64 (6) ◽  
pp. 890-894 ◽  
Author(s):  
ISABEL SIERRA ◽  
CONCEPCIÓN VIDAL-VALVERDE
Keyword(s):  
High Temperatures ◽  
Continuous Flow ◽  
Vitamin B6 ◽  
Vitamin B1 ◽  
Raw Milk ◽  
Microwave Treatment ◽  
Conventional Heating ◽  
Conventional System ◽  
Tubular Heat Exchanger ◽  
Heating And Cooling

The effect of continuous-flow microwave treatment at high temperatures on the retention of vitamins B1 and B6 in raw milk with different fat content was evaluated. Results were compared with those obtained using a conventional system (tubular heat exchanger) with the same heating and cooling phases. Heat treatment of whole (3.4% fat) and skim (0.5% fat) milk at 90°C produced no losses of vitamin B1 or vitamin B6 (pyridoxamine and pyridoxal). However, at 110 and 120°C, while vitamin B1 content of milk remained constant, pyridoxamine increased (4 to 5% and 9 to 11%, respectively) and pyridoxal decreased (5 to 6% and 9 to 12%, respectively). Under the assayed conditions, no differences were observed between the content of these vitamins in conventionally and continuous-flow microwave-treated milk.

Assessment of the Thermal Treatment of Milk during Continuous Microwave and Conventional Heating

1996 ◽  
Vol 59 (8) ◽  
pp. 889-892 ◽  
Author(s):  
ROSINA LOPEZ-FANDIÑO ◽  
MAR VILLAMIEL ◽  
NIEVES CORZO ◽  
AGUSTIN OLANO
Keyword(s):  
Heat Treatment ◽  
Continuous Flow ◽  
Thermal Denaturation ◽  
Microwave Treatment ◽  
Conventional Heating ◽  
Treatment Intensity ◽  
Heat Distribution ◽  
Conventional System ◽  
Effective System ◽  
Β Lactoglobulin

The effect of continuous-flow microwave treatment of milk was estimated by using indicators of the heat treatment intensity (β-lactoglobulin denaturation, inactivation of alkaline phosphatase and lactoperoxidase). Results were compared with those obtained using a conventional process having the same heating, holding, and cooling phases. Continuous microwave treatment proved to be an effective system for pasteurizing milk, with the inclusion of a holding phase to maintain the time and temperature conditions required. At high pasteurization temperatures, the extent of thermal denaturation observed with the microwave treatment was lower than that obtained with the conventional system. This result could be attributed to a better heat distribution and the lack of hot surfaces contacting the milk in the case of the microwave unit.

Spectral study on the oxidation products of conjugated dienes of high molecular weight

1965 ◽  
Vol 6 (1) ◽  
pp. 38-42
Author(s):  
R. M. Aseeva ◽  
Yu. G. Aseev ◽  
A. A. Berlin ◽  
V. I. Kasatochkin
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Spectral Study ◽  
Conjugated Dienes ◽  
Oxidation Products

Oxidation Stability of Diesel/Biodiesel Fuels Measured by a PetroOxy Device and Characterization of Oxidation Products

2015 ◽  
Vol 29 (7) ◽  
pp. 4345-4355 ◽  
Author(s):  
Kenza Bacha ◽  
Arij Ben-Amara ◽  
Axel Vannier ◽  
Maira Alves-Fortunato ◽  
Michel Nardin
Keyword(s):  
Oxidation Stability ◽  
Oxidation Products ◽  
Biodiesel Fuels

scholarly journals 5α,6α-Epoxyphytosterols and 5α,6α-Epoxycholesterol Increase Oxidative Stress in Rats on Low-Cholesterol Diet

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Tomasz Wielkoszyński ◽  
Jolanta Zalejska-Fiolka ◽  
Joanna K. Strzelczyk ◽  
Aleksander J. Owczarek ◽  
Armand Cholewka ◽  
...  
Keyword(s):  
Redox State ◽  
Glutathione Transferase ◽  
Conjugated Dienes ◽  
Oxidation Products ◽  
Paraoxonase 1 ◽  
Cholesterol Oxidation ◽  
Cholesterol Diet ◽  
Phytosterol Oxidation Products ◽  
Reduced Activity ◽  
Low Cholesterol

Objective. Cholesterol oxidation products have an established proatherogenic and cytotoxic effect. An increased exposure to these substances may be associated with the development of atherosclerosis and cancers. Relatively little, though, is known about the effect of phytosterol oxidation products, although phytosterols are present in commonly available and industrial food products. Thus, the aim of the research was to assess the effect of 5α,6α-epoxyphytosterols, which are important phytosterol oxidation products, on redox state in rats. Material and Methods. The animals were divided into 3 groups and exposed to nutritional sterols by receiving feed containing 5α,6α-epoxyphytosterols (ES group) and 5α,6α-epoxycholesterol (Ech group) or sterol-free feed (C group). The levels of malondialdehyde (MDA), conjugated dienes (CD), and ferric reducing antioxidant potential (FRAP) were assayed in the plasma; anti-7-ketocholesterol antibodies and activity of paraoxonase-1 (PON1) were determined in serum, whereas the activity of catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), S-glutathione transferase (GST), and superoxide dismutase (SOD) were assayed in RBCs. Results. During the experiment, the levels of lipid peroxidation products increased, such as CD and anti-7-ketocholesterol antibodies. At the same time, the plasma levels of FRAP and serum activity of PON1 decreased alongside the reduced activity of GPx, GR, and SOD in RBCs. There was no effect of the studied compounds on the plasma MDA levels or on the activity of CAT and GST in RBCs. Conclusions. Both 5α,6α-epoxyphytosterols and 5α,6α-epoxycholesterols similarly dysregulate the redox state in experimental animal model and may significantly impact atherogenesis.

scholarly journals Thermal-Oxidation Stability of Soybean Germ Phytosterols in Different Lipid Matrixes

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4079 ◽  
Author(s):  
Jingnan Chen ◽  
Dami Li ◽  
Guiyun Tang ◽  
Jinfen Zhou ◽  
Wei Liu ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Olive Oil ◽  
Thermal Oxidation ◽  
Loss Rate ◽  
Unsaturated Fatty Acids ◽  
Oxidation Stability ◽  
Oxidation Products ◽  
Higher Temperature ◽  
The Stability ◽  
Thermal Oxidation Stability

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.

scholarly journals Effect of Omega-3 Microcapsules Addition on the Profile of Volatile Compounds in Enriched Dry-Cured and Cooked Sausages

Foods ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1683
Author(s):  
Juan Carlos Solomando ◽  
Teresa Antequera ◽  
Alberto Martín ◽  
Trinidad Perez-Palacios
Keyword(s):  
Lipid Oxidation ◽  
Volatile Compounds ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Oxidation Stability ◽  
Meat Products ◽  
Oxidation Products ◽  
Gas Chromatography Mass Spectrometry ◽  
Omega 3 ◽  
Meat Samples

The main goal of the present study was evaluating the effect of enriching meat products (cooked (C-SAU) and dry-cured sausages (D-SAU)) with monolayered (Mo) and multilayered (Mu) fish oil microcapsules on the profile of volatile compounds, with special interest in lipid oxidation markers. For that, Solid-Phase Microextraction (SPME) and Gas Chromatography-Mass Spectrometry (GC-MS) were used. Significant differences were found in the volatile compound profile between Mo and Mu, which was been reflected in the meat samples. Thus, in general, volatile compounds from lipid oxidation have shown higher abundance in Mo and C-SAU and D-SAU enriched with this type of microcapsule, indicating that the wall of Mu (chitosan-maltodextrine) might protect the encapsulated bioactive compounds more effectively than that of Mo (maltodextrine). However, this finding is not reflected in the results of previous studies evaluating the sensory perception and oxidation stability of C-SAU and D-SAU, but it should be considered since unhealthy oxidation products can be formed in the enriched meat products with Mo. Thus, the addition of Mu as an omega-3 vehicle for enriching meat products may be indicated.

Synthesis of Conjugated Trienes and Related Oxidation Products of α-Farnesene

1994 ◽  
Vol 47 (11) ◽  
pp. 1979 ◽  
Author(s):  
MA Brimble ◽  
DD Rowan ◽  
JA Spicer
Keyword(s):  
Ring Opening ◽  
Room Temperature ◽  
Oxidation Products ◽  
Epoxide Ring ◽  
Epoxide Ring Opening ◽  
Superficial Scald ◽  
Conjugated Trienes ◽  
Conjugated Triene ◽  
Cyclic Peroxide

The synthesis of conjugated trienes and related oxidation products of α- farnesene (1), principally from the epoxides of α- farnesene (1), is reported. Base-promoted ring opening of 6,7-epoxide (4) by KOBut/LiNPri2 affords the conjugated triene (2), whilst the 3,4-epoxide (5) affords trienol (7). In contrast, 10,11-epoxide (6) fails to undergo epoxide ring opening; it rearranges to the conjugated triene epoxide (8). Base-promoted ring opening of bisepoxide (9) afforded trienol epoxide (11) at -30°C, whilst cyclization to tetrahydrofurans (10a,b) occurred at room temperature. Photosensitized oxidation of 10,11-epoxide (6) followed by in situ treatment with acid gave the cyclic peroxide (3) and on reduction triol (12). Bisallylic alcohol (13) was prepared by alkylation of 3-methylsulfolene with geranial. Trienes (2) and (3) have been isolated previously as autoxidation products of α- farnesene (1) and are implicated as the causal agents of superficial scald of stored apples.

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