• Korean Journal of Food Science and Technology
• /
• v.32 no.1
• /
• pp.62-68
• /
• 2000

Effects of conjugated linoleic acid (CLA) on physico-chemical properties of cooked ground pork patty were investigated for 11 days at $4^{\circ}C$. Pork patties containing 0, 1, 2, and 3% CLA were cooked at $90^{\circ}C$ for 30 min. The contents of crude protein and fat did not change whereas the content of ash and water decreased as the level of CLA enhanced. Lipid oxidation as measured by thiobarbituric reactive substances of patty was inhibited by addition of CLA. CLA treatment also reduced nitrite and cholesterol content and changed fatty acid composition. Consequently, given these positive effects of CLA, it may be assumed that CLA could be used as a fat additive for value-added pork patty.

• Korean Journal of Food Science and Technology
• /
• v.30 no.6
• /
• pp.1267-1272
• /
• 1998

The changes in physicochemical properties of gamma irradiated porks were investigated during storage at different temperature and periods. TBA values increased according to the increment of irradiation dose levels. TBA values of nonirradiated and irradiated samples drastically increased with storage period and temperatures at both $5^{\circ}C\;and\;-20^{\circ}C$. The acid value of porks stored at $5^{\circ}C$ was increased rapidly with the elapse of storage period in both nonirradiated and irradiated samples. However, the value decreased with increasing irradiation dose levels. VBN values increased more rapidly in nonirradiated samples than in irradiated samples with the storage period. Especially, VBN value of nonirradiated pork was four times higher than that of 3 kGy-irradiated one. No significant differences in the composition of fatty acids were observed in gamma irradiated samples. Free amino acids were changed with storage periods, but were not significantly affected by gamma irradiation.

• Journal of Dairy Science and Biotechnology
• /
• v.35 no.4
• /
• pp.270-285
• /
• 2017

Among milk proteins, caseins are not subjected to chemical changes during heat treatment of milk; however, whey proteins are partially denatured following heat treatment. The degree of whey protein denaturation by heat treatment is decreased in the order of high temperature short time (HTST) > low temperature long time (LTLT) > direct-ultra-high temperature (UHT) > indirect-UHT. As a result of heat treatment, several changes, including variations in milk nitrogen, interactions between beta-lactoglobulin and k-casein, variations in calcium sulfate and casein micelle size, and delay of milk coagulation by chymosin action, were observed. Lysine, an important essential amino acid found in milk, was partially inactivated during heat treatment. Therefore, the available amount of lysine decreased slightly (1~4% decrease) after heat treatment, However, the influence of heat treatment on the nutritional value of milk was negligible. Nutritional value and nitrogen balance did not differ significantly between UHT and LTLT in milk. In conclusion, our results showed that heat treatment of milk did not alter protein quality. Whey proteins denatured to a limited extent during the heat treatment process, and the nutritional value and protein quality were unaffected by heat treatment.

• Korean journal of food and cookery science
• /
• v.5 no.1
• /
• pp.69-74
• /
• 1989

Trans fatty acids are formed during refining process of vegetable oils (deodorization), hydrogenation, the high temperature treatment of oils and rancidity. Trans fatty acids contents were measured in vegetable oils added to tuna, oyster and mussel Can by Glass Capillary Gas Chromatography. Also Acid Values, Peroxide Values, iodine Values and Saponification Values of vegetable oils added to Can were determined. The results were as follows; 1. Among vegetable oils added to Can, trans fatty acids isomer of cotton seed oil were mostly t,c-18:2 and t,c,c-18:3. 2. Total average contents of trans fatty acids of soybean oil added to tuna Can (Ab) were shown the highest values among tuna (Aa, Ab), oyster, mussel (Cb) Cans. 3. All of oils added to Can had been keeping safe quality during 1 year or more with low Acid and Peroxide Values.

• Korean Journal of Food Science and Technology
• /
• v.28 no.1
• /
• pp.109-116
• /
• 1996

The relationship between antioxidant activities and physicochemical properties of several fractions obtained from freeze-dried (FD) coffee were investigated. The nine kinds of fraction were consecutively extracted from FD coffee with solvents in increasing order of polarity, and the higher polarity of the solvent the higher extraction yield of the fraction. The antioxidant activities of the fractions were determined by Rancimat and oven test on edible oils. The antioxidant activities of the fractions increased in the order of acetone>ethanol>methanol>50% methanol/water>water fraction, and the antioxidant activities of them were higher on lard than on soybean oil. The antioxidant activity of each fraction was strongly related to the contents of total phenol, total nitrogen content and acidity, whereas color intensity, reducing power, carboxylic acid content showed little contribution to the activity. All fractions had three peaks maxima at 208, 275 and 324 nm on UV-visible spectra, but the only one at 324 nm was linealy proportional to the antioxidant activities of the fractions.

• Korean Journal of Food Science and Technology
• /
• v.32 no.6
• /
• pp.1306-1312
• /
• 2000

This study was conducted to examine the effects of levels of flavoring materials on the sensory characteristics of chicken feet Jokpyun (Korean traditional gel type food) and to determine the optimum levels. Consumer desirability of Jokpyun flavored with different levels of black pepper and ginger was evaluated. Optimum levels of variables were obtained using response surface methodology. The levels were 0.33% and 0.1% for black pepper and ginger extract, respectively. The shelf-life of the optimized Jokpyun at $4^{\circ}C$ was determined as 6 days. Addition of powdered chicken broth in the Jokpyun preparation at the level of 1.5%(w/w) markedly increased boiled chicken flavor without resulting in undesirable properties.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.12 no.4
• /
• pp.387-394
• /
• 1983

The factor, which was capable of accelerating the yeast cell wall lysis of the zymolyase(${\beta}-1$, 3-glucanase), was purified to a homogeneous state from the protease fraction of the crude zymolyase by Sephadex G-75 gel filtration and preparative polyacrylamide gel disc electrophoresis. The molecular weight of the purified factor was estimated to be 40,500 by SDS-polylacrylamide gel disc electrophoresis and it's iso-electric point was pH 9.6. The factor was found to be a basic protease consisted of single polypeptide chain with 395 amino acid residues and it showed the $E_{280,cm}^{1%}$ of 11.9 and the molecular extinction coefficient of $4.83{\times}10^4$, respectively.

• Korean Journal of Soil Science and Fertilizer
• /
• v.6 no.4
• /
• pp.227-230
• /
• 1973

To elucidate the effect of the organic carbon compounds included in a separate from glutamic acid fermentation residue (G. A. F. R) on the improvement of the physico-chemical properties of soil, on a soil low in organic matter content, treated with G. A. F. R and compost, observations on the total organic matter, humic acid, fulvic acid, C. E. C. and the development of aggregates were made. From the results of the investigations it was concluded that, the organic carbon compound in the tested G. A. R. F. is more effective than compost in increasing the total organic matter, humic acid, fulvic acid and C. E. C. of soil and in enhancing the development of soil aggregates.

• Korean Journal of Soil Science and Fertilizer
• /
• v.19 no.2
• /
• pp.123-131
• /
• 1986

This study was conducted to evaluate the effect of annual application of silicate fertilizer on rice yield and soil physico-chemical properties. Field experiment was done on the condition of fertilization of silicate fert. 150 and 250kg/10a to the clay loam paddy field for ten years from 1975 to 1984. Data for rice growth and nutrient uptake was analyzed for ten years base. The results obtained are as follows. 1. Average unhulled rice yield for 10 years increased at 16% in the treat of silicate fert. 150kg/10a annually applied in comparison with the N.P.K treated plot, but silicate fert. 250kg/10a treated plot was decreasing tendency somewhat in yield. 2. Amount of potassium uptake of rice straw at the harvesting stage was positively significant recognized with unhulled rice yield and straw yield of rice plant. 3. The amounts of N, $P_2O_5$ and $K_2O$ uptake in the treat of silicate fert. 150kg/10a were much more than those of silicate fert. 250kg/10a treated plot. However the treat of silicate fert. 250kg/10a increased the amounts of CaO, MgO and Silica uptake than other treats markedly. Especially the treat of silicate fert. 150kg/10a was higher in nitrogen recovery rate than other nutrients recovery rate, but the recovery of silica was low. 4. The treat of silicate fert. 250kg/10a annually applied markedly decreased the translocation rate of nitrogen, potassium and silica from straw to the unhulled rice grain. 5. Ten years' average value of soil O.M. content was much more in the treat of silicate fert. 150kg/10a which show higher yield increase than other treats, but in the treat of silicate fert. 250kg/10a, soil O.M. content was lower, however silicate content in soil was the most among other treats.

• Korean journal of food and cookery science
• /
• v.9 no.4
• /
• pp.323-328
• /
• 1993

Benzo(a)pyrene [B(a)P], one of the polycyclic aromatic hydrocarbons (PAHs) is known as a potent carcinogen. As lipid consumption increases recently, the toxic effect of overheated lipid foods and fats ＆ oils were reported increasingly. In this study, the contents of B(a)p, other PAHs and rancidities of soybean oil were determined, and then the proper heating temperature, time and frequency were recommended, The work was carried out using soybean oil heated at $180\pm$5^{\circ}C$$, $200\pm$5^{\circ}C$$, and $300\pm$5^{\circ}C$$,for 50 hours. Acid Value(AV) and Conjugated Diene Value of samples were determined. The contents of B(a)P and other PAHs contents of all samples were masured by HPLC/UV method. The results obtained were as follows; Each content of PAHs in the fresh soybean oil was: Pyr 1.093, B(a)A 0.986, Ch 1.147, DMBA 1.082, B(e)P 0.664, Per 1.135, B(a)P 0.146, DBA 1.053, 3-MC 0.05 rg/kg. When the soybean oil was heated at $180\pm$5^{\circ}C$$, for 10, 20, 30, and 50 hours, B(a)P conterlts in heated soybean oils were 0.391, 0.692, 0.451, and 0.372 $\mu\textrm{g}$/kg respectively. Acid value of them were 0.26, 0.26, 0.29, and 0.33, and conjugated diene value was 0.67, 0.76, 0.99, and 1.04, respectively. When the soybean oil was heated at $200\pm$5^{\circ}C$$,and $300\pm$5^{\circ}C$$,for 10, 20, 30, and 50 hours, B(a)P coiltents in soybean oil heated at $200\pm$5^{\circ}C$$,were 0.844, 0.512, 0.479 and 0.247 Ig/kg respectively, Acid value 0.22, 0.21, 0.23 and 0.51 and CDNV 0.39, 0.49, 3.27, and 3.89. B(a)P contents in soybean oil heated at $300\pm$5^{\circ}C$$,were 0.466, 0.706, 0.607 and 0.247$\mu\textrm{g}$/kg respectively, Acid value 0.47, 1.57, 3.90, and 6.42 and CDNV 0.65, 2.15, 3.00, and 3.88.