• 대한가정학회지
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• 제11권4호
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• pp.374-387
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• 1973

This work was carried out to investigate the changes of chemical and physical properties of frying oil, when it was used many times continuously without adding new oil. Four kinds of frying oil (soybean oil, rapeseed oil, shortening and crude lard) and slices of potato and Aji (kind of fish) were used in the experiment under the condition of home cooking. Obtained results were as in the followings. 1. Acid values and peroxide values of each frying oil were under the safety level (A. V = 1.5, Po. V = 50) except crude lard, when frying works were continuously repeated five times for 50 days. 2. Changes of saponification values of each frying oil showed a decreasing tendency except the crude lard. But in cases, stickiness or clothing of oil were not seen in frying even at the five times frying. 3. Changes of optical density of each frying oil showed a decreasing tendency in all cases, according to the times of frying, especially at the first time frying. 4. Maximum heights of the shamp of each frying oil and their shampholding activites when heated, were slowly increased according to the times of frying. 5. Without concerning the cooking condition (kinds of oil, cooking material and repeating times of frying) decrement of oil in once frying was almost exactly 20g per 150g. 6. Decrements of cooking material in all cases of frying showed almost constant values, potato to be 40% and Aji 20%. 7. Differences of smoke point between new and old oil (frying repeated 5 times) showed also almost constant values. Liquid oil (soybean oil and rapeseed oil) showed number (6-$10^{\circ}C$), on the contrally solid oil (shortening and crude lard) a high number (10-$25^{\circ}C$). 8. Results of public tastic for the frying products were almost good even in that of a low five times frying, but the products, of third time frying with crude lard were expressed as disagreeable.

• 대한영양사협회학술지
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• 제4권1호
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• pp.99-108
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• 1998

The purpose of this study was to investigate the effect of frying methods of chickens ; deep-fat frying with raw chickens(A), with pre-cooked chickens(B) on the physicochemical properties of frying oil and fried chickens in the school foodservice. Acid, peroxide and TBA value of frying oil were significantly increased by increasing the number of frying times and those of method A were higher than those of method B. On the contrary, Iodine value was decreased significantly with increasing the number of frying times but there is no significant difference between method A and B. In fatty acids, the content of saturated fatty acid increased while that of unsaturated fatty acid decreased as the frying times increased. Also viscosity, yellowness and redness increased significantly by increasing the number of frying times. The content of vitamin $B_1 $, of fried chicken by the frying methods was not significantly different, but vitamin $B_2 $the method A was higher than by the method B. Ca, P, Na, K and Fe contents of fried chickens by the method A were higher than those by the method B.

• 한국축산식품학회지
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• 제36권5호
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• pp.612-616
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• 2016

This study was conducted to investigate the condition of frying oil used for frying chicken nuggets in a deep fryer. The acidification of the frying oils used, soybean oil (SB), canola oil (CA), palm oil (PA), and lard (LA), were determined as peroxide value, acid value, and fatty acid composition, after chicken nuggets were fried in them for 101 times. The acid value and peroxide value obtained were 5.14 mg KOH/g and 66.03 meq/kg in SB, 4.47 mg KOH/g and 71.04 meq/kg in CA, 2.66 mg KOH/g and 15.48 meq/kg in PA, and 5.37 mg KOH/g and 62.92 meq/kg in LA, respectively. The ranges of the major fatty acid contents were palmitic acid, 8.91-45.84%; oleic acid, 34.74-58.68%; linoleic acid, 10.32-18.65%; and stearic acid, 2.28-10.86%.Used frying oils for food except animal products have a legal limit for the freshness standard, set by the Food Codex regulations (AV<2.5, POV<50). Therefore, this study could help develop a freshness standard for frying oils used for animal products such as chicken nuggets. Based on the quality limits associated with food regulations stated, we suggested that the estimated frying times before acceptable freshness was exceeded were 41 for SB, 38 for LA, 53 for CA, and 109 for PA. This data may be useful in determining food quality regulations for frying oil used for animal products.

• 동아시아식생활학회지
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• 제16권6호
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• pp.717-723
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• 2006

Chemical characteristics of soybean oil after deep-frying with potato sticks (200 g, 10% w/w of soybean oil) were studied according to the 34 deep-frying times. After consecutive 34 deep-frying, total polyunsaturated FA contents was gradually decreased while the total saturated FA and trans FA were increased. Acid value and peroxide value were increased while iodine value decreased, respectively. The Hunter $L^{\ast}$ value decreased while each $a^{\ast}\;and \;b^{\ast}b$ value were gradually increased. Electronic nose equipped with 12 metal oxide sensors was used for the discrimination of odor pattern of frying oils against the times of deep-trying. The proportions of 1st and 2nd principal component analysis showed 75.97% and 21.23%, respectively. While 6 among total 12 sensors well responded to discrimination of odor in the repented frying oils, suggesting that the odor pattern of each oil after deep-frying would be discriminated against fresh soybean oil, especially after 14 times. From the results, electronic nose could differentiate the degree of quality deterioration of the repeated deep-frying oils.

• 한국식품영양과학회지
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• 제39권7호
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• pp.1011-1017
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• 2010

본 연구에서는 감자튀김 횟수에 따른 각종 식용유지의 화학적 특성 변화를 측정하였다. 식용유지로서는 sunflower oil(SO), canola oil(CO) 및 frying oil(FO)을 사용하였으며, 튀긴 감자에서 추출한 기름의 지방산 조성 변화와 산화 안정성에 대하여 실험하였다. 튀긴 감자에서 추출한 기름의 산화정도는 산가와 과산화물가를 측정하였다. CO 및 FO를 사용하여 튀긴 감자에서 추출한 기름에 대한 산가는 튀김 횟수가 30회의 경우 초기보다 각각 0.20, 0.17 증가한 결과를 나타내었다. SO의 산가는 CO와 FO에 비하여 그 값이 낮게 나타났다. 과산화물가 측정 결과는 일률적으로 증가하지는 않았다. 지방산 조성 변화에 대하여 측정한 결과 SO 및 FO를 사용하여 감자를 튀긴 경우 튀김 반복횟수가 증가할수록 oleic acid 함량은 감소하고 linoleic acid 함량은 증가하였다. 벤조피렌 생성 유무 측정 결과는 SO, CO 및 FO에서 튀김 초기와 반복횟수에 따라서 큰 변화는 나타나지 않았다. 이러한 결과 튀김에 사용한 식용유지 종류 및 튀김 반복 횟수에 따라서 지방산 조성에 변화가 나타나며 그로 인하여 유지의 산화 안정성에 영향을 미침을 알 수 있었다.

• 한국식품조리과학회지
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• 제16권4호
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• pp.328-335
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• 2000

학교급식에서 대량튀김시 많이 이용되는 냉동식품중 선호도가 가장 높은 돈까스를 튀길 때 튀김유 사용방법과 한 번 사용한 튀김유의 저장기간에 따른 이화학적 특성을 조사한 결과는 다음과 같았다. 1. 산가는 방법 A의 강우 신선한 기름의 0.14에서 튀기는 횟수가 증가할수록 점차증가하여 5회 튀긴 후에는 0.24로 증가하였으며, 방빈 B, C도 모두 같은 경향이었다. 이 때 방법 B에서 신선한 기름을 첨가하여 다시 튀기기 시작할 때의 산가는 감소하다가 튀김횟수가 증가함에 따라 방법 C보다 오히려 큰 폭으로 증가하였다. 과산화물가는 신선한 기름에서 0.7이었고 A, B, C세 가지 방법 모두 튀기는 횟수와 한 번 사용 후 저장기간이 증가할수록 증가하였다. 방법 B의 과산화물가도 산가와 같은 경향이었다. 한편 요드가와 검화가는 세 가지 방법에서 모두 튀기는 횟수와 한 번 사용 후 저장기간이 증가할수록 감소하였다. 지방산 조성의 변화를 보면 가열함에 따라 한 번 사용하는 튀김유의 저장기간이 증가할수록 포화지방산은 약간 증가한 반면 불포화지방산 중 특히 linoleic acid는 감소하였다. 2. 점도는 튀김횟수가 증가함에 따라 세 가지 방법에서 모두 약간 증가하는 경향을 보였는데, 한 번 사용한 튀김유의 저장기간이 길어짐에 따라 증가하였다. 색도도 튀김유의 사용횟수와 한 번 사용한 튀김유의 저장기간이 증가할수록 적색도와 황색도가 현저하게 증가하였다. 본 실험의 조건하에서는 학교급식에서 대량튀김시 주로 사용되는 튀김유의 사용방법과 한 번 사용한 튀김유의 저장기간은 튀김유의 이화학적 특성에 영향을 미치는 것으로 나타났다. 이상의 결과로 볼 때 물론 튀김유를 한번 쓰고 버리는 방법 A의 경우가 가장 바람직하겠지만 보관 후 한 번 더 사용하는 방법인 B와 C의 경우도 보건복지부에서 규정한 튀김유의 사용가능한 산가와 과산화물가의 기준보다는 훨씬 낮아 안전함을 알 수 있었다.

• 한국식품조리과학회지
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• 제10권3호
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• pp.301-307
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• 1994

Benzo(a)pyrene [B(a)P], one of the polycyclic aromatic hydrocarbons(PAHs) is know as a potent careinogen. As consumption of lipid food and fried food increases recently, the toxic effect of overheated lipid foods has report increasingly. This study was undertaken to measure the contents of B(a)P and other PAHs of fried chicken and frying oil. At the same time, the rancidities of frying oil and descarded oil were determined. B(a)P and other PAHs contents of all samples were measured by HPLC/UV method. The results obtained were as follows; B(a)P contents of fresh chicken and soybean oil were 0.073 and 0.146 ${\mu}$g/kg, respectively. During fried chicken at 180${\pm}$5$^{\circ}C$ and 200${\pm}$5$^{\circ}C$, B(a)P and PAHs contens decreased or increased In 20 times fried chicken, PAHs contents except Pyr and DMBA increased at 180${\pm}$5$^{\circ}C$ and PAHs contents except DMBA, DBA, and 3-MC increased at 200${\pm}$5$^{\circ}C$. In frying oils fried chicken, PAHs contents increased in 10 and 15 times frying oil at 180${\pm}$5$^{\circ}C$ and grew more increase and more increase during frying at 200${\pm}$5$^{\circ}C$. The changing pattern of PAHs contents of frying oils was remotely related that of rancidities of frying oils. In fried chicken, frying oils, and discarded oils obtained from fried chicken house at market, PAHs contents of fried chickens were lower than those of fried chicken cooked at laboratory but those of frying oils and discarded oils were higher than those of frying oils cooked at laboratory.

• 한국축산식품학회지
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• 제40권5호
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• pp.785-794
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• 2020

Food Codex regulations have set freshness limits for oils used to fry food, such as potato and fish products, and fried food itself; however, no such freshness limits have been set for meat products, such as sweet and sour pork. The freshness standard suggest that acid values (AVs) and peroxide values (POVs) for frying oil should be less than 2.5 and 50, respectively, whereas AVs and POVs for common fried food should be less than 5.0 and 60, respectively. Therefore, in this study, we investigate the effect of the number of frying cycles on oxidation-promoted changes in the oils used to fry sweet and sour pork and fried food itself during repeated frying over 10 d by determining their AVs and POVs, which were found to be highly correlated. Soybean, canola, palm, and pork lard oils could be reused approximately 37, 32, 58, and 87 times, respectively, to fry sweet and sour pork based on oil freshness, and 78, 78, 81, and 286 times, respectively, based on the freshness of fried food. Our data may help establish food-quality regulations for oils used to fry animal-based foods.

• 동아시아식생활학회지
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• 제18권2호
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• pp.181-189
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• 2008

In this study, changes in total trans fatty acid (tFA) and fat contents were determined in soybean oil, shortening, and olive oil after potato sticks were fried 30 consecutive times, respectively. Prior to frying, the potato sticks contained 3.8% fat, with 43.2% tFAs, After the first frying in soybean oil, the total tFA content of the potato sticks sharply decreased to 3.2%, and then it gradually increased to 8.1 % after 30 consecutive times of frying. However, the total fat content of the potato sticks, fried in soybean oil increased to 15.2% after the first frying and thereafter it decreased to 9.75% with 30 repeated episodes of frying. When the potato sticks were fried in olive oil, similar changes in tFA and fat contents were shown; while such changes were not observed when shortening was used. After 30 consecutive frying events, the tFA contents in the soybean oil and olive oil increased to 4.15 and 5.75%, respectively; however, such an increase was not observed in the shortening. One can assume that most of the tFAs in the fried oils were from the potato sticks, which contained relatively high tFA content during the repeated deep-frying process.

• 농업과학연구
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• 제42권4호
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• pp.439-446
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• 2015

Kimbugak is one of Korea's traditional snacks made of laver. This study was conducted to investigate the physical drying and frying characteristics of kimbugaks made by a pasting & garnishing machine. The drying and frying characteristics should be analyzed to develop a continuous operation system for manufacturing kimbugak because kimbugak has a high moisture content after pasting process. Materials for pasting and garnishing on laver were rice gruel and sesame. The aluminum shelf with square hole was selected as a drying shelf. The recommended size of the square hole type was $1.5mm{\times}1.5mm$ because characteristics of deformation and easy separation from the shelf were excellent at the hole size. The drying time of 2 hours was also recommended with the drying temperature of $70^{\circ}C$ based on the test results such as dried condition (good), moisture conten t (3.7%), deformation (12.1 mm), and shrinkage rate (19.8%). As the frying conditions for dried kimbugaks, recommended oil temperature and frying time were $170^{\circ}C$, 15 seconds, respectively when corn oil was used. In the case of frying for undried kimbugaks, recommended oil temperature and frying time were $210^{\circ}C$, 2 - 3 minutes, respectively for improvement of work efficiency.