• Journal of the Korean Society of Food Science and Nutrition
• /
• v.25 no.5
• /
• pp.791-795
• /
• 1996

Toha-jeot(salt-fermented Toha shrimp) is a traditional fermented food in Korea. Toha-jeot is fermented for 90 days at $4\pm1^{\circ}C$ with 20%(w/w) salt per live Toha shrimp. We expect that the high polymer chitin of Toha shell will be hydrolyzed by chitinase during the fermentation of Toha-jeot and that the low molecular weight of chitin oligosaccharides will be produced. We experimented 7 samples which were taken at the interval of 15 days during the total 90 days of fermentation. We also measured molecular weight of Toha-chitin, viscosity and molecular weight distribution of chitin during fermentation of Toha-jeot, The decrease of viscosity and average molecular weight of chitin were observed as fermentation proceeds. Chitin oligosaccharide with $10^3molecular$ weight was low until 60 days fer-mentation. However, chitin oligosaccharide with $10^3molecular$ weight was high after 75 days fer-mentation. And chitin oligosaccharide with $10^2molecular$ weight were observed after fermenting Toha for 75 days and 90 days, but chitin oligosaccharide with 10'molecular weight did not appear up to 60 days of fermentation.ation.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.30 no.3
• /
• pp.426-431
• /
• 2001

We made the Toha-jeot added cabbage kimchi with Toha-jeot, which is salt-fermented Toha shrimp in Korean traditional fermented food. The physicochemical characteristics of cabbage kimchi for 5 week fermentation at 4$^{\circ}C$ were observed. The salt content was 2.10~1.50% during the fermentation period. The salt content decreased rapidly during the first week, stayed the same level until the 4 week and then decreased after the 4 week. The pH of control kimchi and Toha-jeot added cabbage kimchi were 5.69, 5,64, respectively on preparation day. The rate of decrease of pH of Toha-jeot added cabbage kimchi was slow as the fermentation processed. The total acidity of the two kinds of kimchi was increased. The total acidity was higher from Toha-jeot added cabbage kimchi than control cabbage kimchi at the later stage of fermentation. The contents of total sugar and reducing sugar were higher from Toha-jeot added cabbage kimchi than control cabbage kimchi at the early stage of fermentation. The total sugar and reducing sugar contents of the two kinds of cabbage kimchi were decreased gradually as the fermentation processed. The ascorbic acid contents of the two kinds of kimchi were decreased slightly at the early stage of fermentation and then increased from 2 to 4 week, while there was no further change at 5 week.

• Preventive Nutrition and Food Science
• /
• v.3 no.3
• /
• pp.221-224
• /
• 1998

Toha-jeot, salt-fermented Toha shirmp(caridina denticulata denticulata DeHAAN) is a traditional fermented food in Korea. Samples of Toha-jeot used in the present study were a low-salt group of 15% sodium chloride(L), a high-salt group of 23% sodium chloride(H), a 50% conventional soybean sauce group(S), a low-salt group contraining 2% wheat bran (W2%-L) , a high -salt group containing 2% wheat bran(W2%-H), a low-salt group containing 4% wheat bran(W4%-L)and a high-salt group containing 4% wheat bran (W4%-H). These seven groups were refrigerated at 4 $\pm$1$^{\circ}C$ and then taken out for analysis at theree month intervals. We investigated the functional components of Toha-jeot during fermentation . Long fermentation of Toha-jeot lowered the viscosity of chitin and tended to reduce the distribution of molecular weight. THe formation of chitin oligosaccharides on the other hand, increased significantly. After nine months of fermenttion, chitin oligosaccharides(M.W. 823~1789) constituting 24.75% of Toha chitin were produced in the sample of W2%-H. During the same period, chitin oligosaccharides(M.W.1436-1879) constituting 66.30% of Toha chitin were produced in the samples of S. However, chitin oligosaccharides were not produced in Jeotsaeu-jeot made of sea-water shrimp when fermented for six months.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.25 no.4
• /
• pp.665-671
• /
• 1996

Changes in the nutritional components of Toha-jeot, salt-fermented Toha shrimp(Caridina denticulata denticulata $D_{E} H_{AAN}$), which was salted with 20%(w/w) sodium chloride and fermented during 60 days at $4\pm1^{\circ}C$ were investigated. The free amino acid contents in Toha-jeot, of which glutamic acid, leucine, Iysine, arginine, glycine and alanine occupy the majority, in order of abundance, increased gradually up to 50 days of fermentation. Most of the nucleotides were decomposed to hypoxanthine; thus ATP and ADP were not detected. Fermentation decreased inosine, IMP and unsaturated fatty acid contents and increased saturated fatty acid contents of Toha-jeot. Palmitic acid was the most abundant fatty acid, followed by palmitoleic acid, linoleic acid, EPA and stearic acid. Among the mineral constituents of Toha-jeot, Na and Ca were dominantly occupying. The Hunter "L" and "b" values of Toha-jeot increased during fermentation while "a" value remained unchanged.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.30 no.3
• /
• pp.432-438
• /
• 2001

The purpose of this study is to investigate the sensory characteristics of Toha-jeot added cabbage kimchi by Koreans and Japanese. The sensory evaluation was conducted for the following 9 items such as color, savory taste, carbonated taste, sour taste, hot taste, salty taste, off flavor, texture and overall preference. Sensory evaluation of kimchi was tested by Koreans or Japanese whose ages vary from 30 to 50 years old and each group had 25~30 evaluators. Kimchi at different stages of fermentation day 0, 10 and 18th was evaluated. Saltiness of kimchi was 1.5~2.1% through the fermentation period and pH of kimchis was decreased from pH 5.4~5.6 to 4.3~4.4 during the fermentation. The sensory evaluation of Toha-jeot added cabbage kimchi by Koran and Japanese showed the differences in evaluation as the fermentation proceeded. The color, texture and overall preference of Toha-jeot added cabbage kimchi fermentation for 10th days was scored significantly high by Korean group while the score for the savory taste was increased as the fermentation proceeded. The hot taste preference of Toha-jeot added cabbage kimchi fermented 18th days scored significantly high and also increased as the fermentation proceeded by Japanese group. The overall preference of Toha-jeot added cabbage kimchi by Japanese group was higher than that of control cabbage kimchi tested at 10 and 18th days fermentation.

• Korean Journal of Rural Living Science
• /
• v.10 no.2
• /
• pp.60-70
• /
• 1999

Changes in the nutritional components of Toha-jeot, salt-fermented Toha shrimp (Caridina denticulata denticulata $D_EH_{AAN}$), which was salted with a low-salt group of 15% sodium chloride (L), a high-salt group of 23% sodium chloride (H), a 50% conventional soybean sauce group (S) during long fermentation were investigated. These three groups were refrigerated at ${4\pm}1^{\circ}C$ and then taken out for analysis at three month intervals during 9 month. Even in the process of a long fermentation, the moisture containment of Toha-jeot in group L and S is 76.0~73.6% and in group H it is 70.0%, which are similar in all three groups. In case of the salinity, there was no change in groups L, H but it was lowered in group S during the fermentation. In all groups there was no change of pH. The free amino acid contents in Toha-jeot, of which ornitine, glutamic acid, leucine, alanine, lysine and valine occupy the majority, in order of abundance, increased gradually up to six months of fermentation and decreased by nine months. But free amino acid contents of S group increased continuously during the fermentation process. Hypoxanthine was altered almost among other nucleotides. ATP was not detected, IMP and inosine had disappeared after the six months for mentation. ADP was not detected after the nine months fermentation. Monoene, polyene and n-3 fatty acids were increased and saturated fatty acids were decreased in L and H groups. However, no changes of fatty acid contents in S group during fermentation were showed. The fatty acid contents of three groups, of which $C_{18:1},\;C_{16:0},\;C_{16:1}$ and $C_{20:5}$ occupy the majority, Mineral content of Toha-jeot is mainly consisted of Na, Ca, K and Mg. In the Hunter values, the redness of L group was superior to that of other groups.

• Korean Journal of Food Science and Technology
• /
• v.28 no.6
• /
• pp.1111-1118
• /
• 1996

The extracts of toha, a kind of freshwater shrimp (Caridina denticulata denticulata) being cultivated in Naju district, Chonnam of Korea and jeotsaeu, a kind of seawater shrimp (Acetes japonicus) being caught in Shinan district, Chonnam of Korea, were analyzed for the taste constituents-extractive nitrogen, free amino acids, oligopeptides, nucleotides and related compounds, quaternary ammonium bases, and guanidino compounds-using specimens collected from December in 1994 to November in 1995. The content of extractive nitrogen. free amino acids, oligopeptides, nucleotides and related compounds in toha extract was higher than that in jeotsaeu extract. On the contrary, the amount of homarine, trimethylamine oxide and trimethlamine in toha extract was lower than that in jeotsaeu extract. But in case of creatine and creatine both species showed almost the same level. Arginine, lysine, glutamine, glutamic acid, phenylalanine, leucine, alanine, asparagine and glycine were the major amino acids in toha extract, while arginine, glutamic acid, proline, glutamine, lysine, leucine, glycine, alanine and taurine were the major amino acids in jeotsaeu extract. Methionine, glutamine, valine were almost the same level between the two species. As for nucleotides and related compound, AMP was the principal constituent in toha extract, and inosine was the principal constituent in jeotsaeu extract. In conclusion, the content of major nitrogenous constituents in toha extract was more abundant than that in jeotsaeu extract. So toha was more excellent raw material than jeotsaeu.

• The Korean Journal of Community Living Science
• /
• v.13 no.2
• /
• pp.25-36
• /
• 2002

The purpose of this study is to investigate the sensory characteristics of Toha-jeot added mustard leaf kimchi by Koreans and Japanese in Jeonnam Province. The sensory evaluation was conducted for the following 9 items such as color, savory taste, carbonated taste, sour taste, hot taste, salty taste, off flavor, texture and overall preference. The test was done by the group of kimchi was tested by Koreans or Japanese with the age from 30 to 50 years, and each group contained 20~25 evaluators. Kimchi at different stages of fermentation day 0, 10 and 18th during fermentation at $4^{\circ}C$ for 4weeks was evaluated. During the fermentation period saltiness of kimchi was 2.25~1.77% and pH of kimchis was decreased from pH 5.6~5.8 to 4.2~4.6. The score for the sour taste, texture and overall preference of Toha-jeot added mustard leaf kimch increased as the fermentation proceeded in Japanese group. The overall preference of Korean and Japanese groups for Toha-jeot added mustard leaf kimchi was higher than that of control mustard leaf kimchi tested at 10th and 18th days fermentation.

• Korean Journal of Human Ecology
• /
• v.3 no.2
• /
• pp.77-89
• /
• 2000

In this study, to activate the industrialization and to improve the quality of Toha-jeot by shortening the fermentation period, we investigated the changes in the nutritional components of Toha-jeot. salt-fermented Toha shrimp( Caridina denticulata denticulata $D_{E}$ $H_{AAN}$) which was salted with a low-salt group and high-salt group during fermentation. In this experiment. there are four groups of Toha-jeot which were manufactured with 15% ratio of common salt: the first group containing 2% wheat bran (w2%-L). the second high-salt group containing 2% wheat bran( w2%-H) , the third low-salt group containing 4% wheat bran (w4%-L) and the last high-salt group containing 4% wheat bran(w4%-H). These four groups were refrigerated at 4${\pm}$1$^{\circ}C$ and then taken out for analysis at three month intervals during 9 month. Among the free amino acid contents in Toha-jeot, 22 kinds were detected. 6 month after the fermentation when the quantity of the amino acid contents in Toha-jeot is highest, ornitine, glutamic acid, leucine. alanine. lysine and valine occupy the majority, in the order of abundance. In cases of nucleotides. 6 month after the fermentation. from the groups w2%-L, w2%-H and w4%-L, inosine and IMP were not detected. and hypoxanthine, AMP, ADP were detected but 9 month after the fermentation ADP was not detected. The main constituents of fatty acid were as follows : (a) from w2%-L, w2%-H, 6 month after the fermentation. $C16:0$, $C12:0$, $C18:1$, $C18:3$, and $C16:1$. (b) from w4%-L. 6 month after the fermentation, $C18:3$, $C16:0$, $C12:0$ and $C18:1$. (c) from W4%-H, $C16:0$, $C12:0$, $C18:3$ and $C18:1$. In case of mineral contents. Na, Ca. K. Mg, Fe. Zn, Mn and Cu were detected according to the magnitude of the quantity. From the group w4%-H, high quantity of Na was detected during the total fermentation period. In case of color value, from the groups w2%. the values of L. a. b were highest after 6 month fermentation and were decreased after 9 month fermentation, while from groups w4%, the values of L, a, b were gradually decreased after 3 month fermentation.ion.

• Food Science and Preservation
• /
• v.8 no.4
• /
• pp.419-426
• /
• 2001

This study was carried out to develope a convenient instant spiced Toha-jeot. Toha-jeot was manufactured by five samples; 8%, 10%, 13% 23% sodium chloride and a conventional type soy sauce. The Toha-jeot was refrigerated at 4$\pm$1$\^{C}$ for 3 months and then boiled glutinous rice, red pepper powder, chopped garlic and ginger were added, and the spiced Toha-jeot was fermented at 4$\pm$1$\^{C}$ for 2 months, was freeze-dried at a condition of 40$\^{C}$, vacuum 100∼200 millitor millitorr and then packed in vacuum. It is called freeze-dried instant spiced Toha-jeot (FIST). Changes in the components and quality of refrigerated spiced Toha-jeot (RST) and FIST were investigated for 30day. The moisture content of RST was 53.79∼58.91%. Among the mineral constituents of RST, Na and Ca were dominantly occupying. Water activity of FIST was 0.28-0.39 while that of RST was 0.87-0.92. TBA value of FIST was lower than that of RST. Acidity, VBN (volatile basic nitrogen) and TBA(thiobarbituric acid) of the FIST and RST increased slightly, whereas pH decreased. The major components of fatty acids in FIST and RST were analysed into a feater amount of linoleic acid (Cl8:2), palmitic acid (Cl6:1), oleic acid (Cl8:1), linolenic acid (Cl8:3), EPA (C2O:5) and stearic acid(Cl8:0). In sensory evaluation, the RST had higher scores in color and taste and the FIST in chewiness and flavor. The qualitative characteristics and sensory evaluation of FIST and RST were similar.