• Journal of Nutrition and Health
• /
• v.13 no.3
• /
• pp.145-149
• /
• 1980

To study the rancidity of dried yellow carlbina oil by oxidation during the storage period general properties of the oil and composition of its fatty acid were analysed quantitatively with gas chromatography The results indicated that I) The dried yellow carbina oil was involved in drying oil of high degree of unsaturation with IV 138 and consisted of higher-fatty acid with SV 194. 2) The composition of the fatty acids were composed of 18 fatty acids involving 6 unknown fatty acids and comprised poly-unsaturated fatty acid with $C_{18}^{:3}\:and\:C_{22}^{:5}$ 3) After three morths storage of dried yellow carbina the content of malonaldehyde was about 12mg/kg in its exterior part, but 6mg/kg in interior part, which indicateing that the degree of rancidity of poly unsaturated glycerides in exterior part of carbina were two times as much as that of interior part.

• Journal of Marine Bioscience and Biotechnology
• /
• v.2 no.4
• /
• pp.257-262
• /
• 2007

Squid viscera oil was investigated by pretreatment method for enhancing the commercial value. Transeterification was performed to reduce rancidity of the oil, off-flavor was removed by using activated carbon adsorption. Analysis using ATD (Automatic Thermal Desorber) and GC/MG shows the efficacy of off-flavor removement. The rates of Transesterification employing inorganic catalyst and biocatalyst were tested, respectively. With stepwise addition of ethanol, the most efficiency of the reaction was achieved by inorganic catalyst. The efficiency of the reaction was estimated by acid value corresponding to rancidity of reaction product.

• Journal of the Korean Applied Science and Technology
• /
• v.7 no.2
• /
• pp.91-100
• /
• 1990

• Korean journal of food and cookery science
• /
• v.28 no.3
• /
• pp.265-273
• /
• 2012

The purpose of this study was to determine the effects of the duration of frying and storage periods on physicochemical characteristics of various oils using at home. The materials used for the study consisted of four kinds of vegetable oils: soybean, canola, extra virgin olive and pure olive oils, and shortening. Chicken breasts were fried in oils heated at $180^{\circ}C$. The oils were stored with or without filtering and reused 3 times, during the 10 day period. The extra virgin and pure olive oils showed higher acid, peroxide value and yellowness than the other oils (p<0.05), but soybean oil showed the highest increase in acid, peroxide value and yellowness with reusing and storage. In sensory evaluation, the chicken breast fried with soybean oils remarkably decreased the overall acceptance. These results suggested that all frying oils are available because acid and peroxide values of the oils are lower than the standard level. However, reusing soybean oil should be noted with caution in that it is very easy to reduce rancidity, and extra virgin olive oil is not appropriate for frying.

• Applied Biological Chemistry
• /
• v.34 no.2
• /
• pp.154-161
• /
• 1991

An objective method for measuring rancidity in soybean oil was developed based on the volatile contents obtained by headspace gas chromatographic analysis. Apparatus for headspace volatile cold trapping-thermal desorption was described, designed to collect and analyze volatiles of soybean oil. Samples of commercially processed soybean oil were stored under controlled condition and then evaluated for flavor by a eight member trained panel and for volatile contents by headspace gas chromatographic analysis. Twenty-three GC peaks were identified on the basis of relative retention time of reference compounds and gas chromatography-mass spectrometry. The volatile compounds identified were autoxidation products of principal unsaturated fatty acids of soybean oil. The simple linear regressions of flavor score with the pentanal or hexanal contents in aged soybean oil gave correlation coefficient of 0.990 and 0.994. respectively. Pentanal and hexanal contents could be used as a potentially useful index for predicting flavor scores of soybean oil.

• Journal of the Korean Society of Food Culture
• /
• v.23 no.1
• /
• pp.26-32
• /
• 2008

: In this experiment, three samples of oils were used. These oils were hydrated soybean oil, pure soybean oil and regular soybean oil. Oil was used after heating at $235-240^{\circ}C$ every four hours term and total heating hours was 16 hours. The physio-chemical analysis and sensory evaluation were performed on these oils. The hydrated soybean oil showed lower acid, peroxide and carbonyl value than the other two oils (p<0.05 or p<0.001). The other two oils were more affected in rancidity than the hydrated soybean oil. In color test, whereas L value lowed during the heating time, a and b value increased during the heating time. The tendency of high L value and low b value in a long-time heating was more apparant on the pure soybean oil and the regular soybean oil than on the hydrated soybean oil (p<0.05). In sensory evaluation, color and rancidity order increased during the heating time. The hydrated soybean oil showed color and rancidity order than the other two oils. In overall quality test, the pure and regular soybean oil that had been used for 12 and 16 hour were not preferable. The hydrated soybean oil that had been used for 16 hour were not preferable. In sensory evaluation, the hydrated soybean oil, the pure and regular soybean oil did not show a apparent difference, although the hydrated soybean oil had a little better scores on the overall quality.

• Food Science and Preservation
• /
• v.25 no.1
• /
• pp.36-43
• /
• 2018

In this study, we investigated the inhibition effect of various herbs on the rancidity of soybean oil. The antioxidant activity of herb-infused oils was evaluated by examining their total phenolic contents and DPPH radical scavenging abilities. The total phenolic contents were found to increase with addition of herbs to the soybean oil. Rosemary-infused oil (RO) exhibited the highest total phenolic contents ($77.28{\mu}g\;GE/mL$), followed by the lemon-balm-infused oil (LO), green-tea-infused oil (GO), and soybean oil (SO) alone (36.82, 36.66, and $21.24{\mu}g\;GE/mL$, respectively). Similary, the DPPH radical scavenging activity of the herb infused oil also increased. Moreover, measurements on the total polar compound (TPC) contents, acid value, and p-anisidine value were carried out in order to confirm the changes in the rancidity of the oils during frying. The time for the TPC content to reach 25% was confirmed to be delayed from 62 h for SO to 68 h, 74 h, and 80 h for GO, RO, LO, respectively. Even though there were some differences between the p-anisidine and acid values, it was confirmed that the addition of herbs inhibited the rancidity of soybean oil. Therefore, the results in this study show that adding herbs to soybean oil could positively contribute to the inhibition of oxidation and rancidity.

• Korean Journal of Food Science and Technology
• /
• v.1 no.1
• /
• pp.51-61
• /
• 1969

In order to eliminate the considerable loss of rice by insects, to protect the human body from toxin excreted by some microbes, and to promote the storage efficiency of rice by employing the irradiation, the following experiments were carried out. Two varieties of rice, Paldal and Nongkwang polished and unpolished by the conventional methods and were packaged in polyethylene bags. After irradiating to the doses of 6-400 Krad of gamma-radiation from a $Co-^{60}$ source the samples were stored at the room temperature $20^{\circ}C$ for 8 months. The effects of radiation in terms of the removal of insects and microbes and the changes of chemical components (such as moisture, amylose, free sugar, and rancidity) were determined monthly from march to October during the storage. 1) Infestation of insects was greatly influeneed by the packaging materials used. There was no infestation in rice being packaged in a polyethylene bag, while as the rice packaged in a straw sack was infested in two months of the storage. 2) Some yeast and molds survived 400 K rad of radiation. Sterilizing dose to inhibit reproduction and growth of microbes was presumed to be higher than 400 K rad. Yeast mainly were found on the surface of rice, but mold were embeded into rice kernels by mycelium. 3) Changes of moisture contents during storage was not affected by radiation but was by humidity of the storage room. 4) Amylose content in starch increased with increasing dose of radiation and with the length of storage time, indicating possible depolymerization of starch molecules. 5) Free reducing sugar content was not affected by radiation and decreased with storage time. 6) Rancidity also increased with does and storage time.

• Applied Biological Chemistry
• /
• v.34 no.2
• /
• pp.149-153
• /
• 1991

Several commercial soybean oils were stored at $20^{\circ}C,\;40^{\circ}C$ and $60^{\circ}C$ with daily exposure of fluorescent light for 12 hours and evaluated their rancidity by headspace gas chromatographic analysis of pentanal and hexanal. The data of gas chromatographic analysis was compared with organoleptic flavor evaluation. For headspace gas chromatographic analysis, the volatile compounds were recovered by porous polymer trap and flushed into a fused silica capillary column at $250^{\circ}C$, The pentanal and hexanal separated were identified by gas chromatography and gas chromatography-mass spectrometric method. The results showed that the contents of pentanal and hexanal were linearly increased during storage for 100 days. A very simple linear relationship was found between organoleptic flavor scores and amounts of two volatile compounds with very high correlation coefficient. A similar linear relationship was also obtained for acid and peroxide value with sensory data. This results suggested the possible implication of pentanal and hexanal as an quality index for rancidity evaluation of soybean oil.

• Korean Journal of Human Ecology
• /
• v.7 no.1
• /
• pp.33-41
• /
• 2004

The purpose of the study was to analyze in process of circulation market boiled whale meat's rancidity. oxidative rancidity is oil or fat food depend on oxygen in air oxidative change in quality. boiled whale meat faty come to oxidative rancidity food stability and hygiene reasons for people health poisonous point out, however it is not indication study of support. Accordingly confirm lead into circulation process boiled whale meat's rancidity examination and microorganism examination boiled whale meat's stability whether or not. The result obtained were summarized as follows: 1. Proximate percentage of boiled whale meat(pectoral, pelvic, fin, flank) of moisture and crude lipid and crude protein from samples shown to be : moisture was pectoral 16.4%, pelvic 36.2%, fin 46.2%, flank 19.2%, crude lipid was pectoral 54.1%, pelvic 42.8%, fin 15.8%, flank 40.6%,crude protein was pectoral 29.4%, pelvic 20.5%, fin 29.5%, flank 28.6%. 2. The fatty acid composition of total lipid were composed of pectoral 27.2%, pelvic 28.9%, fin 33.3%, flank 23.4% of oleic acid and pectoral 12.7%, pelvic 11.1%, fin 11.3%, flank 14.0% of palmitic acid pectoral 10.8%, pelvic 7.9%, fin 7.6%, flank 2.1% of docosahexaenoic acid, pectoral 14.2%, pelvic 7.5%, fin 1.9%, flank 7.2% of eicosenoic acid, pectoral 5.1%, pelvic 5.7%, fin 4.4%, flank 5.7% of myristic acid, 16: 0 11∼14 % of high saturated fatty acid. generally most of 18: 1ω9 of boiled whale meat's each portion, 22:6 7∼12%, 20:5 1∼14% of polyenoic fatty acid. 18:3 showen to be 1% make an expection of pectoral and fin portion the total lipid were most of netural lipid's about 90%, monoenic fatty acid were most of 19∼22% of saturated fatty acid, 77∼80% of monoenic fatty acid level of 47∼56% of 18:1 16:1 was markelly high to those of total lipid. 3. The storage number days variation of oxidation were shown to be by stages process favorably the past days of boiled whale meat's acid value for 5days. pectoral the day 0.1, five days 1.3, pelvic the day 0.1, five days 1.6, fin the day 0.3, five days 0.7, flank the day 0.2, five days 0.4. 4. The sealer and wrapper the storage number days variation of boiled whale meat oxidation for 7days were shown to be a stage of sealing, the temperature of a room, pectoral the day 0.1 seven days 0.6, pelvic the day 0.1, seven days 1.3, fin.