Pretreatment of eliminating FFA is needed to make biodiesel from animal fat recovered from leather wastes because its acid value is high. This study was carried out to investigate the influence of 4 different pretreatment methods, which are heterogeneous catalyst method, ion exchange resin method, low pressure.high temperature method, and alkali method on the eliminating FFA and fatty acid composition. The results showed that the rate of eliminating FFA increased in the order of alkali method > catalyst method > low pressure high temperature method > ion exchange method. In the case of pretreatment of alkali method using NaOH, the rate of eliminating FFA appeared more than 86% regardless of acid value. Therefore, it was considered that alkali method using NaOH was the most effective in the view of economical and productive aspects, taking it into account that the acid value of animal fat recovered from fleshing scrap generated during leather making processes was 7 to 8.

Fleshing scrap is a kind of wastes produced during leather making process and used in the test of manufacturing biodiesel. The early step of manufacturing biodiesel is fat recovery from fleshing scrap. Hence, we investigated the influence of the way of fat recovery on the fatty acid composition. We used three different recovery ways, that is chemical method by protein decomposition with acid/fat recovering, physical method by protein denaturalization with heat and vacuum/fat pressing, and biodiesel method by protein decomposition/fat recovering. The biological method yielded the best results in terms of appearance transparency. It was most effective to lower acid value. Also the recovered fat by biological method would be favorable methyl-ester reaction raw material for biodiesel because it contains more than 5% of oleic acid among unsaturated fatty acid.

This study was conducted to investgate the effect of gamma irradiation on the lipid oxidation, olfactory properties, fatty acid isomer and volatile compound profiles of five different oil sources. Three plant oils, canola oil, corn oil and soy oil, and two animal fat, tallow and fish oil, were irradiated with 0, 5, 10, and 20 kGy level of dose by Co-60 as a radiation source. Lipid oxidation parameters, FFA, POV and TBARS, were determined according to the AACC and AOCS method. Olfactory property of irradiated oil sources was analyzed using electronic nose (FOX3000, AlphaMOS Co., France) with 12 metal oxide sensors and the result was interpreted using principle component analysis program. Fatty acid isomer profiles and volatile compound profiles of irradiated oils were also measured by GC and GC-MS, respectively. Although the free fatty acid level of oil were the highest by high dose level (20 kGy) of irradiation, changes of both TBARS and POV values by gamma irradiation were varied between oil sources and irradiation level of dose. Electronic nose analysis showed a distinct difference among dose levels of irradiation. Although there was no new volatile compound produced by gamma irradiation, amounts of each volatile compounds were increased by irradiation. Only cis isomer, 9c12c15c of linolenic acid was dose-dependently decreased as irradiation level increased but there was no difference among other isomer profiles of linoleic acid and linolenic acid by gamma irradiation. This study showed that changes in physico-chemical properties of both plant and animal oil were remarkable by gamma irradiation. Therefore, a further study should be needed to scrutinize the interaction among lipid oxidation, production of volatile compounds and off-flavor, and isomerization of fatty acid by gamma-irradiation.

The objective of this study was to determine the effect of dietary oils on the levels of the γ-linolenic acid in chicken meat lipids. Three hundred ten five, 1-d old, male, Ross strain, broiler chicks were fed for 35 d to compare diets containing evening primrose oil(EPO) and hemp seed oil(HO) to a control diet. Fatty acid composition of lipid from chicken skin, thigh and breast muscle were determined at the end of the trial. The level of γ-linolenic acid of lipids from chicken meat fed diets containing EPO or HO was significantly higher than that of the control group(p〈0.05). The level of γ-linolenic acid of lipids from chicken skin was highest in the group, which had been fed the EPO 0.85%, followed in order by EPO 0.7%, 0.5%, EPO mixed oil, HO and HO mixed oil. There was a significant difference in the level of γ-linolenic acid of chicken skin between the control and treatment groups(p〈0.05). The level of γ-linolenic acid of lipids from chicken thigh muscle was also similar to skin, and significantly higher than that of the control group(p〈0.05). The level of γ-linolenic acid of lipids from chicken breast muscle was highest in the group, which had been fed the EPO 0.5%, followed in order by EPO 0.7%, 0.85%, HO 0.5% and HO mixed oil. There was a significant difference in the level of γ-linolenic acid of chicken breast muscle between the control and treatment groups(p〈0.05).

Volatile fatty acids (VFAs) are malodor compounds which are produced from the decomposition of animal or plant species. It is very difficult to detect VFAs due to their strong adsorptive properties. In this study we develop an analytical method using headspace-GC/FID with an alkali-impregnated filter sampling. The addition of NaCl and H₂S0₄ makes the salt-out and pH-lowering effect, respectively. The high boiling points (141~185℃) and vapor pressures require a high temperature and long heating time for the standard sample in vials to reach an equilibrium. The analytical response was highest when the absolute quantity in the sample was 5 mL in a 22 mL vial. The addition of NaCl for the salt-out effect can give a higher sensitiviry by a factor of 1.1~4.2 than that of Na₂SO₄. The mass amount of 4.6 g of NaCl can result in a higher sensitivity, which is higher than the supersaturated solubility of 4.2 g. The concentration of H₂SO₄ is as low as 2% (v/v). When the concentration range is 8.3 -562.1 ppb, a coefficient of R²~0.99 can be obtained for the five VFAs samples. The analytical errors in a reproducibility test are less than 10% and the detection limit is estimated to be 0.05~0.1 ppb. Our headspace-GC/FID analytical method can be utilized to effectively detect the five kinds of VFAs which shall be restricted in Republic of Korea from the year of 2010.

We investigated the electrochemical properties for Langmuir-Blodgett (LB) films mixed with fatty acid (8A5H) and phospholipid (DLPE, DMPC, and DPPA). LB films of 8A5H monolayer and 8A5H-phospholipid mixture were deposited using the Langmuir-Blodgett method on the indium tin oxide(ITO) glass. The electrochemical properties measured using cyclic voltammetry with three-electrode system, an Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode at various concentrations(0.1, 0.5, and 1.0 mol/L) of NaClO4 solution. A measuring range was reduced from initial potential to -1350 mV, continuously oxidized to 1650 mV and measured to the initial point. The scan rate was 50, 100, 150 and 200 mV/s, respectively. As a result, LB films of fatty acid and phospholipid (8A5H/DLPE and DPPA) appeared irreversible process were caused by only the reduction current from the cyclic voltammogram and LB film of 8A5H-DMPC mixture was found to be caused by a reversible oxidation-reduction process.

In this study, alkali impregnated filter sampling method was considered for VFAs in ambient air. When KOH concentration was 0.5 N and sampling flow velocity was 5~10 L/min the sampling efficiency was higher than 90 percent. More than 3 minute shaking make the sampled filter to be suspended in the 22.3 mL Vial. Alkali impregnated filter sampling method showed more than 4 times higher response compared to alkali solution sampling method, when the sample was analysed by headspace-gas chromatography. Five kinds of volatile fatty acids (propionic acid, i-butyric acid, n-butyric acid, i-valeric acid, valeric acid) were detected within 1.0~9.8 ppbv in the cow shed by alkali impregnated filter method and headspace gas chromatography. The alkali impregnated filter method was the most suitable sampling method for ambient volatile fatty acids with headspace gas chromatography analysis.

대두유의 탈취과정에서 탈취온도, 진공도, cycle time 및 stripping steam 주입량의 4대 요소를 조정하여 탈취를 행한 후 탈취유의 산가, 과산화물가 및 trans 지방산 함량을 측정한 결과는 다음과 같았다. 즉, 탈취온도가 높을수록 AV, POV는 하락하였으나 trans 지방산 함량이 비례적으로 증가하였다. 진공도는 4torr 수준이 적정하였으며, CT는 길어질수록 효과가 우수하였다. SS주입량은 2.0%(w/w) 수준이 가장 적절한 조건이었다. 이러한 결과를 종합적으로 볼 때, 대두유에서 trans 지방산 함량을 상대적으로 낮게 할 수 있는 탈취조건은 최고 탈취온도 235℃, 진공도 4torr, CT 14~15분 및 SS주입량 2.0%(w/w)내외의 조건에서 trans 지방산 함량 0.31% 내외의 우수한 탈취유의 생산이 가능하였다. 결과적으로 탈취과정에서 trans 지방산 생성량을 극소화하기 위하여는 탈취온도가 가장 중요하였는데, AV, POV 등 다른 품질 요인들을 동시에 고려할 때, 더 이상의 탈취온도 하락은 어려운 것으로 판단된다.

We investigated the electrochemical properties for Langmuir-Blodgett (LB) films mixed with 4-octyl-4'-(5-carboxylpentamethyleneoxy)azobenzene (denoted as 8A5H) and phospholipid(L-α-dimyristoylphosphatidylcholine, denoted as DMPC). LB films of 8A5H monolayer and 8A5H-DMPC were deposited by using the Langmuir-Blodgett method on the indium tin oxide(ITO) glass. The electrochemical properties measured by using cyclic voltammetry with a threeelectrode system, an Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode at various concentrations(0.1, 0.5, and 1.0mol/L) of NaClO4 solution. A measuring range was reduced from initial potential to -1350mV, continuously oxidized to 1650mV and measured to the initial point. The scan rates were 50, 100, 150 and 200mV/s, respectively. As a result, LB films of 8A5H monolayer appeared irreversible process caused by only the oxidation current from the cyclic voltammogram and LB films of 8A5H-DMPC mixture were found to be caused by a reversible oxidation-reduction process.