• Food Science and Preservation
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• v.13 no.1
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• pp.66-70
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• 2006

The effects of commercially available antioxidants in fish oil were studied. Induction period of fish oil was determined from the oxidation curve by rancin\mat. The longest Induction period was observed with catechin (1,000 ppm). Among the rosemary extracts (Antox1, Antox2, Antox3), the most effective antioxidant effect was observed with Antox3 even though higher amount (5,000 ppm) was needed compared to catechin. Compared to oder of control, catechin rather than Antox3 did not affect much the odor changes. When ascorbic palmitate, vitamin C, gallic acid, EDTA, citric acid, or propyl gallate as a synergist were added with catechin (500 ppm), vitamin C and ascorbic palmitate prolonged the induction period significantly. This effect was also observed with Antox3 (1,000 ppm). Among all combinations of catechin (500 ppm) and Antox3 (1,000 ppm) with synergists, the longest Induction period was obtained from Antox3 with vitamin C (200 ppm), suggesting that this combination is most effective combination for retarding the oxidation in fish oil.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.4
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• pp.336-341
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• 1983

A study on the oxidation effect of some amino acids(glutamic acid, phenylalanine, alanine) addition to the linoleic acid emulsion was conducted. Amino acid solutions in concentrations of $10^{-2}$, $10^{-3}$ and $10^{-4}M$ were mixed with equal volume of linoleic acid emulsions. The prepared samples were incubated at $60{\pm}1^{\circ}C$ and the extent of diene conjugation and TBA values were measured by using the UV visible spectrophotometer. The results were as follows: 1) From the extent of diene conjugation, we found that the addition of phenylalanine and alanine prolonged the induction period and the addition of glutamic acid shortened. There was an optimum concentration for each amino acid to act as an antioxidant during the induction period. The optimum concentration of alanine was $10^{-3}M$ and that of phenylalanine was $10^{-2}M$. 2) The results of TBA values showed that three amino acids possesed antioxidant activity after the induction period. There was also an optimum concentration to act as antioxidant after the induction period. The optimum concentrations of glutamic acid, phenylalanine, and alanine were $10^{-2}$, $10^{-3}$, and $10^{-3}M$, respectively.

• Tribology and Lubricants
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• v.16 no.1
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• pp.22-26
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• 2000

In this paper, the fuction of Zinc-dialkyldithiophosphate (ZnDTP) as an oxidation ingibitor of mineral oils was investigated and compared with 2,6-Di-tert-Butyl-4-Methylphenol (DBMP). Oxidation tests were conducted using an oxygen absorption apparatus. ZnDTP showedanti-oxidation property, and length of induction period prolonged by increasing ZnDTP concentration. The anti-oxidation property of ZnDTP was simmilar to that with DBMP. The amount of hydroperoxide decomposition ability with ZnDTP was much greater than that with DBMP, But the rate constant of radical scavenging with ZnDTP was less than that with DBMP. The anti-oxidation property of ZnDTP seems to by both synergy effect of hydroperoxide decomposition ability and radical scavenging ability.

• Tribology and Lubricants
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• v.12 no.1
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• pp.36-41
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• 1996

The suitability of a pressure differential scanning calorimetry (PDSC) in monitoring the quality of synthetic base fluids has been investigated using polyalphaolefin (PAO) oils as an example. Induction period meassured at 170, 180 and 19$0^{\circ}C$, and 3.53 MPa oxygen pressure was applied to characterize their oxidation stability. The PDSC method has proven to be simple and repeatable and requires only small sample size for testing. More importantly, it can be applied in differentiating the oxidation performance quality of PAO oils and is versatile enough for use in studying kinetic aspects of PAO oil oxidation which include the effect of temperature and antioxidant concentration. Additionally, the method appears to correlate well with a rotary bomb oxidation test (RBOT).

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.433-436
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• 1991

Natural compounds which could improve the oxidative stability of fish oil was screened from spices, herbs and naturally occurring antioxidants. Induction period of fish oil determined from oxidation curve by Rancimat ($80^{\circ}C$) was hardly affected with the addition of water-soluble and lipid-soluble fractions of garlic, leek, sesame leave and orange peel, and of organic acids such as citric acid, EDTA and selenium. Caffeic acid, catechin, quercetin and gallic acid laurylester, however, could extend the induction periods by $2.2{\sim}3.8$ times with the addition level of 0.1%(w/w). Rosemary extract and sesamol have a marked effect in retarding oxidation of fish oil. For example, induction periods of the oil samples stabilized with 0.1 rosemary extract and 0.1 sesamol were 16.4 hr and 11.6 hr, respectively, as compared to 4.0 hr of a control. When rosemary extract was used in combination with ascorbic acid (0.02%) or 8-tocopherol (0.2%), induction period could be extended to ca. 28 hr due to the synergism.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.486-492
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• 2009

Wet oxidations (WO) of quinoline in aqueous solution were carried out at $225^{\circ}C$ and $250^{\circ}C$. In the WO at $250^{\circ}C$, quinoline was degraded completely within 30 min and the reduction in total organic carbon (TOC) of 63% was achieved during 120 min. However, the rate of the reduction in TOC was only 13% within 240 min during the WO at $225^{\circ}C$. Nicotinic and acetic acid were found to be main intermediates formed during the oxidation of quinoline. With the addition of the homogeneous catalyst $CuSO_4$ or more easily oxidizable phenol, WOs of quinoline were also carried out under moderate conditions at $200^{\circ}C$. The catalytic WO with $CuSO_4$ of 0.20 g/L showed the destruction rates of quinoline and TOC comparable to those in the WO at $250^{\circ}C$. The WOs of quinoline-phenol mixture exhibited induction periods to degrade quinoline and phenol during which free radicals were produced to initiate WOs. With increasing initial concentrations of phenol at a given initial concentration of quinoline, the induction periods in the destructions of quinoline and phenol became shorter and the reduction in TOC increased from 60% to 75% during 180 min of the WOs. The reduction rate of an induction period decreased as increasing the initial concentration ratio of phenol to quinoline. On the other hand, phenol degradation in the WOs of quinoline-phenol mixtures required a longer induction period and proceeded slower compared to the case of the WO of phenol.

• Preventive Nutrition and Food Science
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• v.7 no.2
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• pp.151-156
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• 2002

Antioxidant activity or green tea extracts (GTE) was evaluated in soybean oil (SBO), rice bran oil (RBO) and winterized rice bran oil (WRBO) stored at 63$^{\circ}C$ for 36 days. Lipid oxidation of the oils was determined using the active oxygen method (AOM), peroxide value (POV), change in unsaturated free fatty acid concentrations and by sensory evaluation. SBO had a higher concentration of the polyunsaturated fatty acids, linoleic and linolenic acid than RBO and WRBO. WRBO and RBO were more stable against lipid oxidation than SBO. Addition of GTE (200 ppm) to the stored oils, increased the induction period (IP) in AOM, reduced the increase in POV, and lessened the change in unsaturated fatty acids. Furthermore, GTE prevented the development of rancid flavors resulting from storage, all of which demonstrate the protective antioxidative activity of GTE. However, oil color became darker in the GTE treated oils. The antioxidant protection of GTE was most effective in RBO.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.2
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• pp.155-165
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• 1994

To evaluate the antioxidant effect of flavonoids and a-tocopherol on purified fish oil(up to $40\%$ of n-3 polyunsaturated fatty acids), lipid peroxidation, and fatty acids content during storage and upon heating were determined. The potential of these compounds for inhibiting and delaying both oxidation and lipoxygenase processes was also evaluated. The oxidation of fish oil was effectively inhibited by flavonoids and a-tocopherol. The antioxidizing effect of these compounds increased in proportion to their concentration. The addition of a-tocopherol and catechin-a-tocopherol mixture were prolonged induction period of lipid oxidation by 3.5 to 4 times. All other flavonoids also shown more than twice the prolonging effect. Lipoxygenase activity was decreased by catechin and a-tocopherol effectively.

• Korean journal of food and cookery science
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• v.9 no.4
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• pp.317-322
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• 1993

Two kinds of simple and interesterfying mixed rapeseed oil were prepared according to add 30%, 50% and 70% of coconut and palm oil, then the physicochemical propecties such as the tedency of oxidation, foaming activity were Investigated. The initial AV and POV of interesterifyung mixed rape-seed oils were higher than those of simple mixed oils, but the tendencies of oxidation were similar. The intial value of IV interesterfied rapeseed oils was added in simple mixed rapeseed oil, Induction period were increased about 2.4~4 times. Induction period of intereterifyng mixed oils added palm ell increased about 2~3.2 times. While the foaming Buantity of interesterifing mixed rapeseed oils with palm oil were lower about 28~40% than those of the simple mixed rapeseed oils.

• Food Science and Preservation
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• v.9 no.1
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• pp.67-73
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• 2002

In order to obtain the basal data far quality and sanitary stability of sesame oil extracted from imported sesame flours oil of whole sesame and flour sesame were investigated the proximate composition, chemical properties, fatty acid composition, sesamol, sesamolin, sesamin contents and oxidation induction period by AOM test. Moisture contents of sesame flours were less remarkably than whole sesame. There were no differences in proteins. Acid value and saponiflcation value were higher sesame flour oil than whole sesame oil. iodine value of sesame flour oil were lower than whole sesame oils. In fatty acid composition of sesame oil, contents of linolenic acid and linoleic acid were 222.44 ∼144.14 and 2713.00 ∼ 1776.46 mg/mL, respectively. And the contents of linoleic acid and γ-linoleic acid were lower sesame flour oil than whole sesame oil. The sesamol contents of sesame oil were higher whole sesame oil than sesame flour oil, sesamol content of India whole sesame oil was highest of them. The sesaminl sesamolin contents of Korean whole sesame oil were the Highest Oxidation induction periods of sesame oil by AOM were 6.76 and 13.35 In on north Korea and Chinese sesame flour oil, respectively. Therefore, it appears that oxidative stability was lower in north Korea and China sesame flour oil than in whole sesame oil group.