• Food Science and Biotechnology
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• 제16권3호
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• pp.415-420
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• 2007

The aim of this study was to determine the various bioactive components of five olive oil varieties, as well as to assess their contribution to the oxidative stability of the oils. Fatty acids, ${\alpha}$-tocopherol, ${\beta}$-carotene, total flavonoids, total phenols, and certain phenolic compounds of extra virgin olive oils (EVOO; blended, arbequina, hojiblanca, and picual) and pure olive oil (POO) were examined. Oxidation stability was evaluated by the peroxide value (POV). The total content of all the studied antioxidant compounds was significantly higher in the EVOOs than the POO (p<0.05). Among the EVOOs, picual had the highest levels of ${\alpha}$-tocopherol ($10.18{\pm}0.40\;mg/100\;g$), ${\beta}$-carotene ($557{\pm}8\;{\mu}g/100\;g$), and total phenols ($110.7{\pm}1.3\;mg/g$), which correlated strongly with antioxidative capacity. Furthermore, the lowest POV occurred in picual EVOO and correlated with the highest monounsaturated fatty acid (MUFA, C16:1 and C18:1) and lowest polyunsaturated fatty acid (PUFA, C18:2 and C18:3) compositions, suggesting the ratio of MUFA to PUFA is a critical parameter for the oxidative stability of olive oil. Our results indicate that the oxidative stability and antioxidant potential of EVOO depends not only on the antioxidant vitamins, but also on the amount of phenolic compounds and fatty acid profile of the oil.

• 한국식품과학회지
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• 제20권6호
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• pp.868-872
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• 1988

잣을 저장조건을 달리하여 산화양상을 살펴보고 이어 정제단계별로 산화양상에 따른 변화를 살펴보았다. 잣을 $35^{\circ}C$에서 10주간 저장하면서 함유지방질의 산화양상을 살펴본 결과 잣 알갱이 상태는 조직을 마쇄하더라도 지방질로 추출한 상태보다 대단히 높은 산화안정성을 나타내었다. 또한 조지방질은 정제단계를 거칠수록 그 산화안정성이 감소되었으며 정제지방질, 탈검 및 탈산된 지방질, 탈검 탈산 및 탈색된 지방질, 탈검된 지방질, 조지방질 순으로 산화 안정성이 높아졌다. 이것은 정제단계에서 제거된 물질들이 산화 안정성을 증가시키는 요인으로 작용하는 것으로 여겨진다.

• Fisheries and Aquatic Sciences
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• 제18권1호
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• pp.21-26
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• 2015

Seasoned laver Pyropia spp. is a traditional Korean seafood that has gained popularity worldwide because of its unique taste, texture, and health benefits. It is prepared by roasting a sheet of dried laver, to which vegetable oils have been applied, at an ultra-high temperature (UHT) of $300^{\circ}C$. Therefore, the oxidative stability of the oils is the most important factor in determining the shelf life of seasoned laver products. In this study, we investigated changes in the thermal oxidative stability of six major vegetable oils (sesame, perilla, sunflower, rice bran, canola, and olive) during the seasoned laver processing. The oxidation induction time of each oil from the seasoned laver products was decreased compared with the fresh oil. These results indicate that the UHT treatment ($300^{\circ}C$, 10 s) induced thermal oxidation of the oils. Among the six seasoned laver oils, the induction times of olive (OL, 8.02 h) and sesame (SE, 5.31 h) oils were significantly higher than the other oils. The acid values (AVs) of OL and SE oils from the seasoned laver were 0.49 and 0.79, respectively. On the other hand, perilla oil had the overall worst thermal oxidative properties (induction time: 0.35 h, AV: 2.82). Our results provide useful information about seasoned laver products for researchers or manufactures.

• 한국식품과학회지
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• 제23권4호
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• pp.465-470
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• 1991

대두유, 팜유, 쇼트닝 그리고 대두유에 팜유를 각각 50%, 70% 배합한 혼합유로 French fry용 감자를 반복 튀김 했을 때 튀김기름의 열분해 및 산화에 대한 안정성을 알아보기 위하여 10회의 반복튀김에 사용된 기름을 매회 취하여 산값, 과산화물값, TBA값, 색도, 굴절율, 비중 등의 이화학적 특성을 측정하였다. 열분해 및 산화에 대한 대두유의 불안정성은 대두유에 팜유를 배합함으로써 감소시킬 수 있었는 바, 대두유에 대한 팜유의 비율이 커질수록 그 안정성이 증가하였다. 팜유가 50% 배합된 혼합유의 경우에는 대두유를 단독 사용했을 때 보다 그 안정성이 현저히 증가하였고 팜유가 70% 배합된 혼합유의 경우에는 팜유를 단독 사용했을 경우와 거의 같았다.

• Asian-Australasian Journal of Animal Sciences
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• 제22권3호
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• pp.421-427
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• 2009

A mixture of three dietary medicinal herb extracts (MHE, mulberry leaf:Japanese honeysuckle:goldthread = 48.5: 48.5:3.0) was prepared as an additive of hen's feed. One hundred-eight, 28-wk-old Lohmann Brown hens were assigned randomly with three levels of MHE in the diet (0, 0.3, and 1%). Hens were fed for 6 wks and eggs were collected in the 6th week, and stored at $4^{\circ}C$ for 14 days to investigate the effect of MHE on the quality and oxidative stability of eggs. Internal quality of the egg including weight, shell color, albumen height, yolk color, shell weight, shell thickness, and Haugh units was not different among the dietary treatments. The oxidation stability of raw and cooked egg was determined by 2-thiobarbituric acid reactive substances (TBARS) value, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and 2,2'-azinobis(3-ethylbenzonthianoline-6-sulfonic acid) ($ABTS^{+}$) radical reducing ability. Results indicated that TBARS value at day 0 and $ABTS^{+}$ radical reducing ability of eggs from hens fed MHE were higher than from the control group. However, DPPH radical scavenging activity showed no difference in both raw and cooked samples. Results of the present study indicate that dietary MHE may slightly enhance the oxidative stability of eggs.

• 멤브레인
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• 제17권4호
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• pp.294-301
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• 2007

비불소계 스티렌 고분자 전해질 막의 산화안정성을 개선하기 위해 p-methyl styrene, t-butyl styrene, ${\alpha}-methyl$ styrene과 같은 스티렌 유도체를 단독 또는 복합으로 도입하고 모노머 흡수법을 이용하여 막을 제조하였다. 제조된 막의 특성분석으로 중합무게비, 함수율, 이온교환용량, 수소이온 전도도 및 가속조건에서의 산화안정성을 조사하였다. 사용된 스티렌 유도체의 구조 및 특성에 따라 모노머 흡수, 중합 및 술폰화 단계가 영향을 받는 것으로 나타났다. 산화적으로 안정한 고분자를 형성하는 ${\alpha}-methyl$ styrene은 중합 단계가 어렵기 때문에 스티렌 또는p-methyl styrene과 공중합하여 제조하였고 p-methyl styrene과 공중합된 ${\alpha}-methyl$ styrene 막은 스티렌과 공중합한 막보다 높은 전도도 및 안정성을 나타내었으나 낮은 분자량으로 인해 안정성의 개선을 크게 보이지 못하였다. 벤젠 고리에 큰 치환기를 갖는 t-butyl styrene은 모노머 흡수 및 술폰화과정이 용이하지 않기 때문에 제조된 막의 성능이 감소하였으며 이를 p-methyl styrene과 공중합할 때 우수한 성능과 스티렌막보다 크게 개선된 안정성을 보였다.

• 한국자동차공학회논문집
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• 제15권6호
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• pp.81-86
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• 2007

Biodiesel fuel that consists of saturated and unsaturated long-chain fatty acid alkyl esters is an alternative diesel fuel produced from vegetable oils or animal fats. However, air causes autoxidation of biodiesel fuel during storage, which can reduce fuel quality by adversely affecting its properties, such as the kinematic viscosity and acid value. One approach for improving the resistance of fatty derivatives to autoxidation is to mix them with antioxidants. This study investigated the effectiveness of five such antioxidants in mixtures with biodiesel fuels produced by three biodiesel manufacturers : tert-butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate (PrG) and $\alpha$-tocopherol. Oxidation stability was determined using Rancimat equipment. The results show that TBHQ, BHA, and BHT were the most effective and $\alpha$-tocopherol was the least effective at increasing the oxidation stability of biodiesel. This study recommends that TBHQ and PrG be used for safeguarding biodiesel fuel from the effects of autoxidation during storage.

• Tribology and Lubricants
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• 제29권6호
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• pp.392-396
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• 2013

Biodiesel fuels contain unsaturated fatty acid ester, which can easily oxidize, especially when exposed to ultraviolet light. The products formed by this oxidation give rise to sediment or gum formation. As a result, the fuel can contribute to the corrosion and plugging of the filter pump. Antioxidants have been used in an effort to stabilize biodiesels, but there is still a need for a biodiesel composition with improved oxidation stability. In general, good fuel compositions should provide synergistic combinations of a biodiesel and antioxidants. Our work involved the synthesis of antioxidants to improve the oxidative stability of biodiesel fuel.

• Elastomers and Composites
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• 제57권4호
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• pp.165-174
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• 2022

The effect of fumed silica loading on the thermal stability and mechanical properties of fluorosilicone (FVMQ) rubber was investigated. The distribution of fumed silica inside FVMQ was characterized using scanning electron microscopy, and the thermal stability of composites was evaluated using thermogravimetric analysis and by the changes in mechanical performance during thermo-oxidative aging. The function mechanism of fumed silica was studied by Fourier transform infrared spectroscopy. The results show that with increasing silica content, the crosslink density of composites, the modulus at 100%, and tensile strength also increased, whereas the elongation at break decreased. Furthermore, increasing the silica content of composites increased the initial decomposition temperature (T_d) and residual weight of the composite after exposure to nitrogen. In addition, the thermal oxidative aging experiment demonstrated improved aging resistance of the FVMQ composites, including lower change in tensile strength, elongation at break, and modulus at 100%.

• Journal of Animal Science and Technology
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• 제62권5호
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• pp.730-740
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• 2020

This feeding trial was conducted to investigate the effects of Mentha arvensis (MA) and Geranium thunbergii (GT) in drinking water on physicochemical attributes, sensory qualities, proximate analysis and oxidative stability of broiler leg meat. One hundred and twenty broiler chicks were assigned to 1 of 4 dietary treatments for 5 weeks. The dietary treatments were 1) control, 2) T1 (0.1% 1 MA:1 GT), 3) T2 (0.1% 1 MA:4 GT), 4) T3 (0.1% 4 MA: 1 GT). The water holding capacity and cooking loss were improved (p < 0.05) in T2 and T3. The flavor, texture and acceptability of leg meat by consumers were significantly increased in T2 relative to the control (p < 0.05). The crude protein content was increased in T3 while the crude fat decreased in T2 (p < 0.05). Moreover, broilers supplemented with plant extracts had the lowest leg meat TBARS (thiobarbituric acid reactive substances) values after 2 weeks of storage as compared with the control. Total phenolic contents and 1-1-diphenyl 2 picrylhydrazyl (DPPH) activity were also better in the T2 group (p < 0.05) compared with the control, whereas 2,2-Azinobis-3 ethytlbenzothiazoline-6-sulfonic acid (ABTS⁺) remained unaffected. Overall, these results demonstrate that broiler drinking water with the inclusion of plant extract combination can be used to enhance the oxidative stability, shelf life and quality characteristics of broiler leg meat without compromising the growth performance.