Sweet potato β-amylase is a tetrameric enzyme consisting of four identical polypeptide chains with a molecular weight of 5.6×10 exp (4), though most of the other β-amylases are monomeric enzymes. But, the relationship between subunit structure and catalytic function of the enzyme is not known. This study was done to know what the function of the subunit structure of the enzyme is. We obtained the monomer from the enzyme by the treatment of SDS, alkali pH buffer and urea. But the monomer had not activity. We tried to prepare the active monomer from the enzyme by the modification with periodate-oxidized soluble starch. In the result, we succeeded in isolating an active monomer as an oxidized soluble starch-conjugated form. The active monomer had 57% of the original activity, 13.2% of the sugar and the molecular weight was estimated to be 6.4×10 exp (4). This results suggest that the tetrameric form of the enzyme is a most stable one and exists in nature, and the subunit structure of the enzyme plays an important role in stabilization but not catalytic function.
Toxohormone-L is a lipolytic factor, found in ascites fluid of sarcoma 180-bearing mice and of patients with hepatoma. A substance that inhibited the lipolytic action of Toxohormone-L was isolated and purified from Korean red ginseng powder. This substance had a pectin-like a 1, 4-polygalacturonan backbone with some acetoxyl groups, and so was an acidic polysaccharide. It inhibited Toxohormone-L induced liploysis in a dose dependent manner at concentrations higher than 10㎍/㎖. Purified acidic polysaccharide yield(PG_4-3 and PG_4-4 fraction) was about 0.03%. And also pectic acid that inhibited the lipolytic action of Toxohormone -L.
This studies were carried out to investigate the effects of non-volatile organic acids in the KimChi by lactic acid bacteria. The organism isolated from KimChi, Pediococcus dextrinicus, Leuconostoc mesenteroides, Lactobacillus plantarum and Lactobacillus brevis, were inoculated for preparation of KimChi. pH of all on the KimChi sample dropped sharply according as fermentation continued. pH of on optimum ripening period KimChi(4.4 and 4.2) reached 1.3 and 1.9 day at all on sample, respectively. Optimum acidity(0.6%) of KimChi were reached within 2 day all on sample. The total number of lactic acid bacteria reached 10×10 ex (7)cells/㎖ in 1 day and decreased slowly after 4 day. Main non-volatile organic acids were identified lactic, malic and succinic acid. The sensory score of mixed lactic acid bacteria inoculated KimChi was better than that of another KimChi.
The soybean β-amylase [α-1, 4-glucan maltohydrolase, EC. 3. 2. 1. 2] is composed of seven isozymes( Ⅰ`, Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴ and Ⅵ), and isozyme Ⅱ and Ⅳ are the main components among these. The purification of β-amylase isozymes from soybean whey were performed by ammonium sulfate fractionation, CM-Sephadex C-50 column chromatography, DEAE-Sephadex chromatography and Gel filtration. The resulted purity of β-amylase was throughly confirmed by electrophoresis, and then determined its isoelectric point and molecular weight. The results obtained were as follows ; 1. Five active fractions of soybean β-amylase were derived on CM-Sephadex C-50 column chromatography . 2. Seven active bands of β-amylase isozymes were detected by isoelectric focusing gel electrophoresis, and their isoelectric points ( Ⅰ` to Ⅵ) were 5.07, 5.15, 5.25, 5.40, 5.55, 5.70 and 5.93, respectively. 3. Isozyme Ⅱ and Ⅳ were main components of soybean β-amylase. 4. The molecular weights of both isozyme Ⅱ and Ⅳ were determined to be 56, 000 daltons by the result of SDS polyacrylamide gel electrophoresis. 5. Km values of main isozyme Ⅱ & Ⅳ for amylopectin were determined to be 2.25㎎/㎖, which suggest the same function of each isozyme.
The survey was conducted for the period from 25th to 29th July, 1990. The survey area were selected the mountain area in Kang Won Province. Intake of foods and nutrients of all members in the households surveyed by means of questionnaire was computed based on number of meals a day. On the other hand, daily intake of nutrients by an individual was calculated by sex, age and type of work based on the conversion rate of RDA (Korean Recommended Dietary Allowances for Adult) . 1. Status of food intake. The average food intake per person per day in surveyed area was 1103.49g. The total intake of food was consisted of 44.17% grains, 23.31% vegetables, 10.66% fruits, respectively. These findings led us to the conclusion that people in the surveyed area depended heavily on plant foods. 2. Status of nutrient intake. 1) The average intake of Calorie was 2567.54㎈ per day, which was slightly higher than 2500㎈ of RDA. 2) The average intake of protein was 82.92g per day, which was higher than 70 g of RDA. Though the quantity was above the RDA, it was largely from plant foods. 3) The average intake of calcium was 383.93㎎ per day, which was much lower than 600㎎ of RDA. 4) The average intake of iron was 11.88㎎ per day, which was nearly the same quantity as 10㎎ of RDA . 5) Intake of vitamin group were high among the inhabitants than recommended by RDA 3. The Kinds of food intake. The kinds of food intake in surveyed area were totally 66 different kinds. 4. Economic status. As for the education level, almost of the food handlers finished the primary school and the average monthly income was ￦364, 600 in surveyed area. Households used gas(100%) for fuel.
Effects of metal chelating agents and metal ions on the volatile substance of cooked oil with chicken and pork mixture meat were examined by chemical analysis and sensory test. The addition of Na-tripolyphosphate(Na-TPP) to chicken and pork mixture meat increased the amount of H_2S among volatiles evolved during cooking but decreased that of volatile carbonyl compounds(VCC). This treatment enhanced meat flavor in cooked oil with chicken and pork mixture. It was recognized that the increase in H_2S evolution was caused by the rise of pH value. On the contrary cupric ion produced a negative effect on the production of chicken and pork mixture meat flavor and this addition increased VCC and TBA value. Other metal chelating agents such as citric acid, phytic acid and EDTA, provided the same results as Na-TPP. It was supposed that these phenomena were attributable to the chelating action to metal prooxidant in mixture meat. It could be concluded that a proper evolution of H_2S and protection against lipid oxidation during cooking were important to produce an excellent chichen and pork mixture meat flavor.
General components, amino acids and minerals contained in 7 kind of edible wild grasses were estimated. Samples were collected from the field of Kapyong area, Kyung-ki, Korea. Results of the estimation were summarized as follows ; 1) A relatively large amounts of protein and fat were contained in the edible parts of each sample. 2) The most abundant amino acids in the edible parts of each sample were glutamic acid (26.6%), serine (18.7%), valine (22.4%), respectively. 3) A high level of calcium and iron was found in the edible parts of each samples. Especially calcium was abundant in the leaves of Rumex coreanus Nakai and iron was abundant in the Commelina communis L. Both copper and zinc were abundant in the Sanguisorba officinalis L.
Bok Sik Bang, a book of cooking, was written in Korea in the 17th century. Various cooking methods of traditional foods were described in this book. 1. The kinds of cooking foods were Wine(69), Side dish(39), Seasoning(12), and Dessert (5). 2. The materials used in the cooking foods were cereals, vegetables, fishes, meats and etc. 3. The cooking methods were different and complicated. 4. The way of heating were also different such as to stew, to boil, to pan-boil, to frying, etc. 5. Utensils and table wares used for processing and cooking were poor and specific. 6. The measuring units were not accurate and unscientific. 7. Many of special words and expressions which are not used today in cooking and processing were reviewed.
This investigation on the composition of fatty acids of hempseed through gas -chromatography analysis found the follwing results. Myristic acid and other ten materials were detected. And there was mainly composed of myristic acid 29.4%, palmitoleic acid 16.2%, linoleic acid 14.9%, oleic acid 12.4%. It also showed that heptadecanoic acid 10.8%, erucic acid 0.5%, docosahexaenoic acid 0.3% and essential fatty acid were contained 17.9% between them. As stearic acid, docosahexaenoic acid, linoleic acid and arachidonic acid made lower cholesterol level in body, they will help prevention of senile disease with the oil of hemp seed.
Paper chromatography and (NH_4)_2SO_4 precipitation method were used for refinement and separation of proteins. Color reaction was tested by Biuret test, Million test, Xanthoprotein test, and Ninhydrin test. Precipitation reaction and coagulation of proteins were tested by heating method(Ethanol, HNO_3).