• Journal of Forest and Environmental Science
• /
• 제31권1호
• /
• pp.1-6
• /
• 2015

Microwave assisted biodiesel production from crude Pongamia pinnata oil using homogeneous base catalyst (KOH) was unsuccessful because of considerable soap formation. Therefore, a two step process of biodiesel production from high free fatty acid (FFA) oil was investigated. In first step, crude P. pinnata oil was acid catalyzed using $H_2SO_4$ and acid value of oil was reduced to less than 4 mg KOH/g. Effect of sulfuric acid concentration, alcohol-oil molar ratio and microwave irradiation time on acid value of oil was studied. Result suggested that 1.5% $H_2SO_4$ (w/w), 6:1 methanol oil molar ratio and 3 min microwave irradiation time was sufficient to reduce the acid value of oil from 12 and 22 mg KOH/g to 2.9 and 3.9 mg/KOH/g, respectively. Oil obtained after pretreatment was subsequently used for microwave assisted alkali catalyzed transesterification. A higher biodiesel yield (99.0%) was achieved by adopting two step processes. Microwave energy efficiency during alkali catalyzed transesterification was also investigated. The results suggested a significant energy saving because of reduced reaction time under microwave heating.

• 한국응용과학기술학회지
• /
• 제20권2호
• /
• pp.141-147
• /
• 2003

Oxidized polyethylene wax is obtained by oxidation of polyethylene wax and it is composed of various chemicals, e.g., fatty acid, alcohol, ketone and ester. The application of oxidized polyethylene wax is determined by the composition of these chemical substances. In this basic study we observed the basic reaction parameters of time, temperature, oxygen concentration and catalysts on the oxidation reaction of low molecular weight polyethylene(PE wax) by analyzing the acid value, physical and chemical properties of oxidized PE wax to develop a new oxidation process. Acid values are increased with temperature increase in the rage of $150^{\circ}C^{\sim}180^{\circ}C$ but decreased beyond 190$^{\circ}C$. Acid values are also increased with oxygen concentration. As the oxidation reaction proceeds the molecular weight and softening points of oxidation products are decreased by cracking reaction, but the viscosities are increased. To observe the crystallinity of oxidation products SEM experiment was performed. To obtain a high acid-value product in a mild condition, we adopted free radical catalysts and the acid value of the product using catalyst was higher than the product obtained without catalyst in the same reaction condition. The effective initiators were dicumyl peroxide(DCPO), t-butylperoxy-2-ethyl hexanoate(HOPO) and benzoyl peroxide(BPO) having long half-life.

• 산업식품공학
• /
• 제21권1호
• /
• pp.49-56
• /
• 2017

Vegetable seed oils (VSOs) have been extracted and used not only as ingredients in food and as sources of dietary lipids, but also as sources of nutraceuticals used to overcome the various oxidative stresses that contribute to the development of diseases, including cancer and other chronic conditions. The chemical compositions and oxidative stabilities of various VSOs were therefore investigated; samples were stored for 35 d, with each oil having been tested under $O_2$ exposure, sealed from $O_2$ exposure and sealed from $O_2$ exposure while containing $O_2$ scavengers. Oxidative stability was evaluated by peroxide value (POV), p-anisidine value (p-AnV), iodine value (IV), and thiobarbituric acid (TBA) value. Perilla seed and flaxseed oil were mostly composed of linolenic acid (45.5% and 59.7%, respectively), whereas pine seed oil was mostly composed of linoleic acid (48.3%). Meanwhile, camellia seed and olive oils contained 80% oleic acid, which correlated strongly with oxidative stability. The POV, p-AnV, and TBA values were the highest under $O_2$ exposure, and the lowest in the presence of $O_2$ scavengers. These results indicate that VOS oxidative stability depends not only on storage conditions, but on unsaturated fatty acid profiles as well.

• Journal of Nutrition and Health
• /
• 제13권1호
• /
• pp.65-69
• /
• 1980

갈치를 직사광선(直射光線)에 건조(乾燥)시켰을 때의 산가(酸價), 과산화물가(過酸化物價), TBA 가(價) 및 지방산조성(脂肪酸組成)의 변화(變化)를 관찰한 바 아래와 같다. 1) 신선한 갈치의 지질함량(脂質含量)은 9.91%였으며 그중 포화지방산(包和脂肪酸)이 43.3%, 불포화지방산(不包和脂肪酸)이 56.7%로 산가(酸價), 과산화가(過酸化價) 및 TBA 가(價)는 4주일째까지 완만한 증가(增加)를 보였으며 5주일째는 다소 급진(急進)하는 경향(傾向)을 나타내었다. 2) 신선(新鮮)한 갈치 육지질(肉脂質)의 지방간조성(脂肪酸組成) GLC 법(法)으로 분석(分析)한 결과 oleic acid(44.3%)가 대부분이고 palmitic acid(29.22%), palmitoleic acid(11.3%), myristic acid(6.6%), stearic acid(5.4%), $C_{17},C_{17}\;:\;1$의 순으로 되고 linoleic acid는 흔적만 나타냈다. 3) 건조기간(乾燥期間) 따른 지방산조성(脂肪酸組成)의 변화(變化)는 불포화지방산(不包和脂肪酸)은 3주째 건조까지는 감소(減少)하는 경향이고 포화지방산(包和脂肪酸)은 증가(增加)하였다.

• 한국식품저장유통학회:학술대회논문집
• /
• 한국식품저장유통학회 2003년도 제23차 추계총회 및 국제학술심포지움
• /
• pp.164.2-165
• /
• 2003

Structured lipids (SLs) are defined as triacylglycerols to change the fatty acid composition in the glycerol backbone and lipases are known as a powerful tool for the syntheses of SLs. Structured lipid from corn oil, capric acid, and conjugated linoleic acid (CLA) by transesterification reaction and using several amounts of immobilized lipase RM IM (from Rhizomucor miehei) was studied, and 4% of lipase amount was selected for further study as the optimal amount. Comparison the chemical properties (free fatty acid value, iodine value, saponification value, tocopherols, and color analysis), solidification behavior, and volatile fractions (from headspace SPME GC-MS) between com oil and SL com oil was obtained.

• 한국식품조리과학회지
• /
• 제17권3호
• /
• pp.229-236
• /
• 2001

This study was conducted in order to set the shelf life of Rice Yoogwa, Sesame Yoogwa and Yackwa to marketed in department store. It was investigated acid value, peroxide value, microbiological test and sensory evaluation for 50 days. Acid value of Rice Yoogwa, Sesame Yoogwa and Yackwa were not significantly different during storage period. Peroxide values of Rice Yoogwa and Yackwa were significantly increased after 30 days of storage but there was no different in Sesame Yoogwa. Fungus were appeared Sesame Yoogwa of A company, Rice Yoogwa and Yackwa of B company after 40 days of storage. In sensory evaluation, odor, taste, texture and overall acceptability after 40 days were significantly lower than 10 days of storage and rancid odor was gradually increased with preservation period in all materials. Correlation of acid value and peroxide value were positive throughout whole preservation period and rancid odor was increased. Odor, taste, texture and overall acceptability of Yoogwa and Yackwa were negative correlation with preservation period. In view of the above results, it came to the conclusion that shelf life of Yoogwa and Yackwa was 40 days.

• 대한가정학회지
• /
• 제46권10호
• /
• pp.1-9
• /
• 2008

The purpose of this study was to increase uv-cut ability of cotton, ramie, and rayon fabrics dyed with safflower red colorants. For this purpose, samples treated with uv-cut agent and tannic acid were compared with the untreated samples after ultraviolet(uv)-light exposure in terms of K/S value, color changes(${\Delta}E$), SEM, and tensile strength retention. K/S value rapidly decreased with increasing exposure time, but K/S value of the samples treated with both uv-cut agent and tannic acid decreased less than that of untreated samples. As increasing exposure time, $L^*$ and $b^*$ increased, $a^*$ decreased, and so ${\Delta}E$ increased, indicating less red character and more yellow character in color. This leads to change hue, value and chroma value. But color change of samples treated with both uv-cut agent and tannic acid was less than that of untreated samples. SEM pictures showed a severe degradation by uv exposure in all samples. Tensile strength slowly decreased for 21 days. And after this point, the decreased proceeded more rapidly. Tensile strength retention of the samples treated with uv-cut agent and tannic acid was higher than that of untreated samples.

• 한국식품조리과학회지
• /
• 제25권5호
• /
• pp.600-605
• /
• 2009

본 연구는 시판되는 닭튀김류의 지방함량과 지방산 조성, 트랜스 지방산함량 및 산가를 조사하기 위해 총 20종을 대상으로 분석하였다. 그 결과는 다음과 같다. 20종의 닭튀김에서 추출된 지방함량은 $4.94{\sim}18.06%$의 다양한 범위를 나타내었다. 이러한 지방함량의 분포는 닭 자체의 지방함량이나 닭을 튀긴 기름의 종류, 튀김온도, 시간, 튀김옷의 성분차이 등 다양한 요인에 의한 차이라고 생각된다. 조사된 닭튀김의 주요 지방산 조성은 palmitic acid, stearic acid, oleic acid, linoleic acid 등이었다. 포화 지방산 중에서 palmitic acid($10.67{\sim}25.43%$)가 불포화지방산 중에서는 oleic acid($29.78{\sim}67.85%$)와 linoleic acid($8.42{\sim}39.54%$)가 가장 많았다. 식품 100 g당 함유되어 있는 트랜스 지방산 함량은 0.1 g 이하의 낮은 함량을 보여주었으며 닭튀김에 함유된 지방을 추출하여 산가를 측정한 결과 20종의 닭튀김의 결과치는 식품공전상 튀김식품의 산가 규격을 초과하지 않는 양호한 결과를 나타내었다.

• 한국응용과학기술학회지
• /
• 제10권2호
• /
• pp.49-56
• /
• 1993

The effect of frozen storage and cooking methods on lipid oxidation in chicken meat was studied. Chicken meats were stored 0, 30, 60, 90, 120 days at $-18^{\circ}C$ and were evaluated before and after cooking. 1. The crude fat content of chicken meat is the highest thigh meat with skin in microwaving. Fat content was increased duting 30 days of frozen storage, and then after. 2. Peroxide value, acid value and TBA value was increased during the days of storage because lipid autoxidation was processed cooking and during frozen storage time. The peoxide value and acid value were higher compared to sample cooked by other methods. 3. The fluoresence units were increased with frozen storage, and initial levels of fluoresent after processing. 4. The fatty acid composition of chicken meat fats is mainly palmitic acid and oleic acid, and the effect of frozen storage and meats part is not significantly change but fatty acid significantly change according to frying that linoleic acid was increased during frozen time. From all the results obtained in this study it can be conclude that lipid autoxidation of the chicken meat frozen storage at $18^{\circ}C$ was consistantly processed, and breast meat oxidation was increased than thigh meat because chicken breast meat include many polyunsaturated fatty acid. Frying was significantly increased highest than other cooking methods.

• 한국식품영양과학회지
• /
• 제30권1호
• /
• pp.6-13
• /
• 2001

The study was conducted to investigate the effect of the browning inhibitors such as PVPP(polyvinylpoly-pyrrolidone), A.A.(ascorbic acid) on nonezymatic browning factors [free sugar, total amino acid, organic acid, A.A., HMF (hydroxymethylfurfural)] and enzymatic browning factors [PRO (polyphenoloxidase) activity, polyphenol compounds] in concentrated apple juice during 90 days storage. Considering color value (L value, $\Delta$E), absorbance at 420 nm, concentrated apple juice during 90 days storage. Considering color the effect of browning inhibition. According to the storage period, the changes of nonenzymatic factors in concentrated apple juice added with browning inhibitors were similar to those in control (concentrated apple juice without browning inhibitors), which were the decreased of sucrose(0.24~0.35% at 90 days), the slight increase of glucose and fructose, the decrease of total amino acid (530.4~573.1 mg/10g at 90 days), same value of A.A. at 90 days (38.5~78.6 mg/100g), and the increase of HMF (27.8~30.6 mg/100g at 90 days). On the contrary, enzymatic browning factors were significantly inhibited in concentrated apple juice added with PVPP, judging from the slow increase of PRO activity and the significant decrease of initial value in polyphenol compounds (especially chlorogenic acid). These results suggest that PVPP plays an important role as enzymatic browning inhibitor, that is, a scavenger of polyphenol compounds by adsorption in concentrated apple juice.