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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Korean Journal of Food Science and Technology
Journal Basic Information
Journal DOI :
Korean Society of Food Science and Technology
Editor in Chief :
Volume & Issues
Volume 26, Issue 6 - Dec 1994
Volume 26, Issue 5 - Oct 1994
Volume 26, Issue 4 - Aug 1994
Volume 26, Issue 3 - Jun 1994
Volume 26, Issue 2 - Apr 1994
Volume 26, Issue 1 - Feb 1994
Selecting the target year
Quality Evaluation of Thermal Oxidized Fats and Oils by Spectrophotometer
Chang, Young-Sang ; Yi, Young-Soo ; Cho, Kyung-Ryun ; Lee, Chul-Won ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 655~658
This study was designed to investigate the suitability of oxidation matters and physico-chemical characteristics as a quality evaluation for the extent of rancidity development in fats and oils undergoing thermal oxidation. The results showed that acid value rapidly increased during heating time. Soybean oil, especially revealed a faster increase than palm oil and palm olein. Anisidine value and conjugated diene value also increased. Especially, soybean oil increased more rapidly than palm oil and palm olein. Active oxygen method stability was good in the ranks of palm oil, palm olein and soybean oil. Primary oxidation matter (POM) and secondary oxidation matter (SOM) were surveyed as an evaluation method for the extent of rancidity development in fats and oils. POM and SOM showed a sharp increase during the thermal oxidation period.
Optimal Conditions of Saccharification for a Traditional Malt Syrup in Cheju
Kim, Hyo-Sun ; Kang, Yeung-Joo ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 659~664
Waxy rice, Oryza sativa, and foxtail millet, Setaria italitica, and mixture (1 : 1, w/w) of the cereals were saccharified by barley malt. The optimum conditions of saccharification were at
for 3 hrs on waxy rice and
for 3 hrs on foxtail millet, respectively. The equilibrium of saccharification were reached at
on waxy rice and mixture, and
in foxtail millet. The free sugars in saccharifying liquids were found maltose, glucose and fructose with the contents of ca. 13%, 1% and trace, respectively, by HPLC analysis. The close relationships (r=0.954) between
and reducing sugar of saccharifying liquids were observed. The result may be useful for the estimation of the end point of the saccharification.
Rapid Gas Chromatographic Screening of Dairy Products for Volatile and Nonvolatile Organic Acids
Kim, Jung-Han ; Kim, Kyoung-Rae ; Chai, Jeong-Young ; Oh, Chang-Hwan ; Park, Hyung-Kook ; Choi, Kyoung-Sook ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 665~669
A rapid gas chromatographic (GC) profiling method was applied to dairy products (milk and cheeses) for the simultaneous analysis of volatile and nonvolatile organic acids. Cheese samples were first made into aqueous samples by dissolving in water. The aqueous samples were then extracted with organic solvents after the acidification and NaCI saturation. The organic layers (diethyl ether : hexane= 1 : 1) were extracted with
saturated solution with subsequent solid-phase extraction of the aqueous phases using Chromosorb P column/diethyl ether followed by triethylamine treatment. The resulting triethylammonium salts of acids were directly converted into volatile tert.-butyldimethylsilyl derivatives, which were analyzed by dual-capillary column GC, and GC-mass spectrometry. From milk and four cheese samples studied, 31 organic acids including 21 fatty acids and other hydroxy and dioic acids were tentatively identified. The amounts of the fatty acids were different among the kinds of cheese and thus the simplified retention index (RI) spectra of organic acids were useful for the visual pattern recognition of each sample, when the Direct Comparision method between cheese and a blind sample were attempted, it was quickly recognized to be a gouda cheese with the 999 ppt match quality value.
Studies on the Effects of Amylase Addition to Rice Extrusion on the Rheological Properties of the Extrudate for Weaning Food Base
Lee, Gang-Gweon ; Kim, Ji-Yong ; Lee, Cherl-Ho ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 670~678
The effects of amylase addition during extrusion cooking of rice on the physico-chemical properties of the extrudates were investigated in order to develop rice-based Korean style weaning food products. A laboratory-built single screw extruder was used, the enzymes used were Termamyl 120LS(amylase from Bacillus licheniformis, NOVO Co.), BAN 240L(amylase from Bacillus amylolichuefaciens, NOVO Co.) and malt powder. By the addition of enzymes, the water soluble index of the extrudates increased by 3 times compared to that of the extrudates without enzyme and the concentration of reducing sugar in the extrudates increased drastically at 28 feed moisture. The gel permeation chromatographic pattern showed that the large molecular starch fractions diminished by the addition of enzyme during extrusion and the low molecular fraction increased. The residual enzyme activity in the extrudate were 27% for the most thermo-resistance enzyme by treating at
in the metering section of the extruder. The sediment volume of the extrudate dispersion increased as the metering section temperature increased to
. By the addition of enzymes the viscosity of extrudate dispersion was redused
of that of the extrudates without enzyme. It allowed to use 1.8 times of solid material to the weaning food formulation to attain the same level of consistency as the commercial products. It proves that the addition of amylase during rice extrusion is effective to increase the energy density of weaning food by starch degradation, which results in the increases of water solubility, reducing sugar content, dispersibility and fluidability.
Changes in Volatile Sulfur Compounds of Garlic (Allium sativum L.) under Various Drying Temperatures
Chung, Shin-Kyo ; Seog, Ho-Moon ; Choi, Jong-Uck ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 679~682
The volatile sulfur compounds in raw and dried garlic (Allium sativum L.) under various temperatures (50, 60, 70 and
) were separated, identified by GC and GC/MS. In hexane extracts of raw garlic, 8 volatile sulfur compounds were identified and 11 compounds were identified in steam distillation extracts. The volatile sulfur compounds of raw and dried garlic were mostly composed of diallyl disulfide, diallyl trisulfide, allyl methyl trisulfide. According to the increase of drying temperature total amounts of volatile sulfur compounds in the hexane extracts decreased to
, and in the steam distillation extracts decreased to
. The amounts of diallyl disulfide, allyl methyl trisulfide decreased more than other volatile sulfur compounds, but diallyl trisulfide comparatively decreased lower.
Improvement on the Functional Properties of Gelatin Prepared from the Yellowfin Sole Skin by Precipitation with Ethanol
Kim, Jin-Soo ; Lee, Eung-Ho ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 683~689
With a view to utilizing effectively fish skin wastes from marine manufactory, a gelatin solution extracted from yellowfin sole skin was fractionated by precipitation with ethanol, and then the functional and physico-chemical properties for the fractionated gelatin were determined. Ethanol was added up to 50% of ethanol content to a gelatin solution extracted from yellowfin sole skin, then the mixture was left to stand at
for 12 hours. Finally, the precipitates were dried by hot-air (
). The gel strength and melting point of a 10% gel of gelatin prepared from yellowfin sole skin by precipitation with ethanol has 322.4g and
, respectively. The physico-chemical properties of the ethanol treated fish skin gelatin were superior to those of fish skin gelatin prepared without ethanol treatment. Besides, the functional properties of the ethanol treated gelatin were lower in solubility and higher in water holding capacity, oil binding capacity, emulsifying activity, emulsifying stability, foam expansion and foam stability than those of pork skin gelatin sold on market as well as gelatin prepared without ethanol treatment. It may be concluded, from these results, that the fish skin gelatin prepared by precipitation with ethanol can be effectively utilized as a human food by improving the functional properties.
Studies on the Isolation of Antioxidative Components of Perilla Oil
Kim, Choong-Ki ; Song, Geun-Seoup ; Kwon, Yong-Ju ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 690~695
The perilla seed and the germinated perilla seed
were extracted by n-hexane, and from the extracted oil the antioxidative components were separated, and then the effect of the change in the contents of antioxidative components by germination on the oxidative stability of the perilla oil was studied. The perilla oils were solved acetone and methanol, and kept at
overnight and separated into the frozen oil fraction and unfrozen solvent soluble fraction. By comparing the antioxidative stability of the frozen oil fraction the antioxidative components in the perilla oil were found to be methanol soluble. The methanol soluble fraction of perilla oil was applied to silica gel column chromatography and the separated fractions were compared in terms of antioxidative activity. The fraction of n-hexane : ethyl acetate (7 : 3, v/v) showing the highest antioxidative activity was further separated by TLC. The components included in the band
showing the highest antioxidative activity was separated by HPLC. Four peaks were observed on the HPLC chromatogram and the peak areas were changed by germination (perilla seed : peak 1; 46.5%, peak 2; 25.6%, peak 3; 22.6%, germinated perilla seed : peak 1; 43.8%, peak 2; 20.6%, peak 3; 29.8%). The comparative change in the contents of these components was considered to be one factor affecting the antioxidative stability of perilla oil by germination.
Changes in Gelatinization Properties of Potato Starch by Microwave Heating Methods
Choi, Ock-Ja ; Koh, Moo-Seok ; Shin, Mal-Shick ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 696~703
The purpose of this study was to investigate the gelatinization properties of potato starch heated with microwave. Two types of potato starches were prepared; In group A raw potato starch was heated with microwave and in group B potato starch was isolated from potato heated with microwave. Both groups were exposed to the microwave energy in a 560W, 2,450 MHz oven for 60, 120, 180 and 300 seconds. Gelatinization behaviour by DSC made a few differences according to the ratio of starch to water. As the microwave heating time took longer, gelatinization temperature and gelatinization
were decreased in and melting
was increased in group A. Whereas they were increased in group B. In both groups, maximum viscosity in gelatinization by Brabender amylogram was decreased by microwave heating. Then the peak of the maximum viscosity was shifted to higher temperature and cold viscosity was slightly increased. In group A, viscosity in gelatinization and light transmittance by NaOH was increased in initial stage and gel volume in gelatinization by KSCN was decreased. On the other hand, in group B, viscosity by alkali was slightly decreased, but light transmittance by NaOH was almost never changed. Gel volume is decreased like group A.
Influence of the Extraction Method on Quality of Citron Juice
Jeong, Jin-Woong ; Kwon, Dong-Jin ; Hwang, Jin-Bong ; Jo, Yong-Jin ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 704~708
This study was performed to compare quality of citron juice as affected by the extraction method. The yield of citron juice was 24.49% by method I (rotary-crushing and screening), 18.09% by method II (pressing) and 12.60% by method III (belt-pressing), respectively. Juices by methods I and II had more soluble solid contents and essential oil and pulp volume than that by method III. Method III was higher in titratable acidity than methods I and II. The contents of fructose, glucose and sucrose in method III were 0.54%, 0.37% and 1.11%, respectively, which were lower values than those in other methods. But there was no siginificant difference in the contents of total sugar by the extraction method. For fatty acids composition, the contents of oleic acid in method I, palmitic acid, linoleic acid and linolenic acid in method II, and stearic acid in method III, respectively, were highest when compared with other methods. The contents of free amino acids detected in method III were smaller than those in methods I and II. Threonin was detected only in method I, methionine and cystine were not detected in methods I. II and III. But the contents of the total amino acids in method III were
times as large as those in methods I and II.
Flavor Components of Citron Juice as Affected by the Extraction Method
Jeong, Jin-Woong ; Lee, Young-Chul ; Jung, Sung-Woon ; Lee, Kyung-Mee ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 709~712
The volatile components of citron juice juice extracted by three methods, which were Rotary-crushing and screening method (method I), Pressing method (method II) and Belt pressing method (method III), were analyzed with GC and GC/MS. Juice extracted by method III had more components of flavor than those by methods I and II. Also, the contents of total volatile components in method III were about 1.36 and 1.59 times than those in methods I and II, respectively. Limonene in juice extracted by method III was predominantly occupied, amount of which was 76.87%. Other important components were terpene hydrocarbons, such as
and so on.
Changes of Gas Composition in Package of Fresh Peeled Garlic by Packing Materials
Hong, Seok-In ; Kim, Yun-Ji ; Park, Noh-Hyun ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 713~717
Effects of packing materials on the gas compositions in package of fresh peeled garlic (Allium sativum L.) were investigated. The fresh peeled garlics packed in
HDPE pouches were stored at
, 76% RH. The variables including respiration characteristics, gas compositions, general appearance, and film permeabilities to
vapor were measured. A model was evaluated for the prediction of
equilibrium concentrations inside packages and for the optimization of packaging parameters. Experimental and simulated gas composition results were found to be in good agreement. The
HDPE pouch with 4%
equilibrium concentrations conferred the best appearance of peeled garlic, giving 6 days of storage life. As a result, MA seemed to have a beneficial effect on appearance of fresh peeled garlic, possibly due to reduced microbial activity.
Application of Near Infrared Reflectance Spectroscopy in Quality Evaluation of Domestic Rice
Moon, Sung-Sik ; Lee, Kyung-Hee ; Cho, Rae-Kwang ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 718~725
The applicability of near infrared reflectance spectroscopy (NIRS) to determine moisture, protein, fat and amylose content of domestic rice was studied. The standard error of prediction (SEP) of moisture, protein, fat and amylose in polished rice was 0.014, 0.196, 0.098 and 1.427%, and those SEP of brown rice was 0.12, 1.226, 0.153 and 1.923%, respectively. It is concluded that the NIRS method allowed to detect the content of moisture and protein in rice samples with fair precision comparing conventional analysis, but the accuracy for determining amylose and fat was not acceptable.
Reduction of Fermentation Time for Preparation of Dongchimi Juice
Kim, Dong-Hee ; Chun, Yun-Kee ; Kim, Woo-Jung ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 726~732
Development of an effective method for the preparation of dongchimi juice was investigated by addition of NaCl, sucrose and hydrolytic enzymes before fermentation and addition of dongchimi juice during fermentation. The Chinese radish was ground and suspended in water (1:1, w/v) with addition of spices of garlic, green onion and ginger followed by fermentation at
. Increase in NaCl concentration of brinning solution from 1.0 to 5.0% resulted in a significant decrease in the rates of pH decrease and acidity increase. The sugar addition resulted in a faster changes of them, particulary after 24 hours at
. The fermentation rate was also greatly improved by enzymatic hydrolysis with using viscozyme, a commercial polysaccharides hydrolyzing enzyme, before fermentation. When the fermented juices of two stage (pH 5.4 and pH 4.4) were added up to 15% before (pH 5.4 juice) and during (pH 4.4 juice) fermentation, the initial and second stage of fermentation were significantly improved. Therefore a method of addition of sugar, hydrolytic enzymes and dongchimi juice before or during fermentation was suggested for dongchimi juice preparation.
Screening of Natural Antimicrobial Edible Plant Extract for Dooboo, Fish paste, Makkoli Spoilage Microorganism
Ahn, Eun-Sook ; Kim, Moon-Suk ; Shin, Dong-Hwa ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 733~739
To extend the self-life of Dooboo (tofu), fish paste and Makkoli (Korean traditional rice wine) for which severe heat treatment are not expectable, main putrefactive microorganisms were isolated from each product and tested their growth inhibition by ethanol and water extracts of several edible plants. The ethanol extract of Phellodandron amurense Ruprs had the strong effect of growth inhibiting to all three isolates from Dooboo and Makkoli, and Eugenia caryophyllus, Pinus rigia Mill, Bletilla striata (Thunb) Reichb. Fill and Paeonia albiflora Pall were also same effect to isolates from fish paste. The ethanol extract was more effective inhibiting than water extract in all test microorganisms. The evident inhibition level of each extract was 2000 ppm of Pa ethanol for fish paste and 1000 ppm for Makkoli.
Effect of Green Tea Beverage on the Removal of Cadmium and Lead by Membrane Filtration
Choi, Sung-Inn ; Lee, Jung-Hi ; Lee, Su-Rae ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 740~744
This study was undertaken to prove the suppressing effect of green tea on the intestinal absorption of heavy metals using in vitro membrane filtration system. From drinking water contaminated with 10 and 100 times level of water quality standard for heavy metals, the removal ratio of lead (Pb) was
by green and black teas, and
by roasted barley tea. The removal ratio of cadmium (Cd) was
by green tea and black teas, and
by roasted barley tea. The removal effect from drinking water contaminated with both lead and cadmium was lower than that from water contaminated singly with lead or cadmium. It appears that tea components and filter membrane compete toward the adsorption of two heavy metals. Among the extraction conditions of raw tea materials at
, 2 minutes and
, 10 minutes, the removal ratios of heavy metals were similar.
Effect of Green Tea Beverage for the Removal of Cadmium and Lead by Animal Experiments
Choi, Sung-Inn ; Lee, Jung-Hi ; Lee, Su-Rae ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 745~749
Animal experiments were conducted to confirm the suppressive effect of green tea on the intestinal absorption and tissue accumulation of toxic heavy metals in rats. When drinking water contaminated with 500 and 5000 times level of water quality standard for lead or cadmium was administrated to rats for 3 weeks, feed intake and body weight gain were not significantly differrent among all groups except for high cadmium group. In the relative weights of target organs, kidney and femur showed a significant difference by heavy metal administration and green tea did not influence on the weights. Green tea showed a suppressing effect on the accumulation of heavy metals in target organs, in which the reducing effect in femur was
for lead, and 42% for cadmium. As calcium content of femur decreased by heavy metal administration was increased in green tea group, it was concluded that heavy metal accumulation in femur was interrupted by tea beverage.
Determination and Multivariate Analysis of Flavour Components in the Korean Folk Sojues Using GC-MS
Lee, Dong-Sun ; Park, Hye-Seong ; Kim, Kun ; Lee, Taik-Soo ; Noh, Bong-Soo ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 750~758
Flavour components of seven Korean folk sojues, five Chinese kaoliangchiews and Japanese shochu were determined by GC and GC-MS after solid phase extraction with polydivinyl benzene. Less volatile ethyl succinate and ethyl pelargonate were present in Korean folk sojues while volatile ethyl acetate and ethyl butyrate in Chinese kaoliangchiews. In the case of alcohols, the amount of isopentyl alcohol was relatively higher than that of isobutyl alcohol or n-propyl alcohol in Korean folk sojues. On the contrary, less volatile n-propyl alcohol was present more than isopentyl alcohol in Chinese kaoliangchiews. Multivariate statistical analyses involving principal components analysis (PCA) and discriminant analysis (DA) were applied to the GC data. The results of PCA clearly demonstrate that the first principal scores of Korean folk sojues were similar but the second principal scores were different from each other. Classification of Korean sojues and Chinese kaoliangchiews into two groups could be conducted by DA. These results suggested that the common charateristics and identities as a distilled liquors was found in Korean folk sojues.
Rutin and Mineral Contents on Improved Kinds of Korean Buckwheat at Growing Stage
Kim, Young-Soon ; Chung, Soo-Hyun ; Suh, Hyung-Joo ; Chung, Seung-Tai ; Cho, Jung-Soon ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 759~763
For utilization of buckwheat as vegetable, rutin and minerals of the leaves at growing stages were investigated. The contents of crude protein and crude fat in seed of nine improved kinds of Korean buckwheat were
respectively. Ash content
in the improved kinds were higher than those in the native kinds. Content of crude fiber in the improved kinds were lower than those in the native kinds. Suwon 11 (0.12%) and Suwon 5 (0.11%) had high contents of rutin among the improved kinds. The composition of K, Ca, Mg and Fe in the improved kinds were better than that in the native kinds. Vegetable of the improved kinds had higher content of crude protein than the native kinds. Suwon 10 and 11 among vegetables of the improved kinds contained high amount of crude protein. Swon 5 had the highest content of rutin (0.40%) in the improved kinds. Suwon 5 was tested for the changes of rutin content in growing. Rutin content was 0.40% in the first growing stage, whereas 1.32% in the final growing stage. Insoluble materials in 10% HCl was also 69.8% in the first growing stage, whereas 4.68% in the final growing stage. Iron and calcium contents were increased with growing of vegetable.
The Conductance Determination of Total, Coliform and Psychrotrophic bacteria Counts in Raw Milk by Using Malthus
Nam, Eun-Sook ; Chung, Choong-Il ; Kang, Kook-Hee ; Jeong, Dong-Kwan ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 764~769
This study was performed to obtain fast, consistant and reliable estimation system of bacterial counts of raw milk, which effectively related to the quality of sanitaion and the condition of production at the farm. This study compared regression equation and correlation coefficient relationship between standard plate counts and data of Malthus conductance method for the detection time of total, psychrotrophs, coliform bacterial counts in raw milk. Regression equation (RE) between conductance detection time (Y) and total bacterial log counts (X) was Y=18.27651 - 2.07550X, with correlation coefficient -0.95(n=201). In coliform, RE was Y=9.320848 - 1.15598X with correlation coefficient -0.90 (n=207). Psychrotrophs had the RE of Y=29.96008-3.02487 with correlation coeffecient -0.9 (n=201). This conductance method gave results more quickly and was less labor-intensive than traditional standard plate count method.
Relationships Between Fermentative Gas Pressure and Quality Changes of Packaged Kimchi at Different Temperatures
Hong, Seok-In ; Park, Jin-Sook ; Park, Noh-Hyun ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 770~775
Kimchi packed in polypropylene(PP) tray was stored at different temperatures (0, 10,
) to investigate the relationships between fermentative gas pressure and quality changes. The quality of Kimchi during storage was evaluated in terms of pH, titratable acidity, color, and sensory properties. The fermentative gas pressure changes due to
evolution showed typical sigmoidal curves at each temperature. Accordingly, inflation of Kimchi packages caused by increasing gas pressure occurred in 40 hours, 5 and 30 days at 20, 10,
, respectively, at which gas pressure inside the packages ranged
. Following inflation, Kimchi packages stored at 20 and
were burst out on 3 and 8 days, but those at
were not. As the fermentative gas pressure increased, pH decreased (r > 0.968) and titratable acidity increased (r > 0.973) proportionally. Regarding to the color change of crushed Kimchi juice, L and b values were decreased exponentially, but a value remained constant during storage. Among sensory properties, the sourness and texture scores showed good accordance with pH changes. In conclusion, although Kimchi kept optimal tastes during storage, the inflation of package restricted shelf-life of Kimchi.
Sensory Evaluation of Cooked Rice with Fuzzy Reasoning
Lee, Seung-Ju ; Noh, Wan-Seob ; Choi, Yoo-Chul ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 776~780
Fuzzy reasoning was applied to sensory evaluation of cooked rice. A sensory attribute diagnostics was done in terms of tour kinds of attributes-texture, taste, odor and appearance which determine overall palatability. First, rating for the contribution level of each attribute to the overall palatability was asked as one of five scales-very important, important, moderate, slight and very slight. Secondly, the preference level of each attribute for a cooked rice sample was asked as one of five hedonic scales-excellent, good, fair, poor and very poor. Thirdly, the results of the scales were converted into fuzzy values and operated by fuzzy reasoning. Finally, the contribution and preference levels of the attributes were composed to infer the overall palatability of cooked rice sample.
Formation of Meatlike Flavors by Maillard Reaction Using Hydrolyzed Vegetable Protein (HVP)
Yoon, Suk-Hwan ; Lee, Jung-Keun ; Nam, Hee-Sop ; Lee, Hyung-Jae ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 781~786
Meatlike flavors were manufactured using hydrolyzed vegetable protein (HVP) with several reactive precursors at different reaction conditions. Both pH and temperature affected significantly on brown colority of reaction product, whose velocity became fast with increasing pH and temperature. Drastic decrease in residual reducing sugars and free amino acids appeared until 1 hour, being little affected by reaction temperature. Glutamic acid and cysteine were decreased with reaction time, whereas glycine and methionine remained constant. Forty nine aroma compounds formed through Maillard reaction were isolated and identified with GC/MSD, including 3-methyl butanal, 2-methyl tetrahydrothiophen-3-one, 3,4-dimethylthiophene and 2,4-dimethyl thiazole previously known as natural meat flavors. The sensory evaluation showed that one-hour reaction product was the highest in savory taste and the lowest in nasty taste on the level of 5% significant difference among all reaction products tested in this experiment. From the results above, it could be speculated that the initial stage of Maillard reaction in this experimental system occured until one hour, thereafter, savory taste decreased accompanied by increasing nasty taste with elapsed reaction time.
Decolorization of Shrimp Chitin Using Sodium Hypochlorite
Ahn, Chang-Won ; Nam, Hee-Sop ; Lee, Hyung-Jae ; Shin, Yong-Choul ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 787~790
An effective process manufacturing the decolorized chitin with high quality was established using shrimp shell powder. Ash and protein in shrimp shell powder were efficiently removed by 1.66% HCl and 3% NaOH treatments, respectively. A bleached chitin could be also obtained by 0.16% NaClO for 30 minutes, the treatment of which was much better than previously reported decolorization methods such as ethanol, acetone and
treatments. Since the pattern of IR spectrum of sample chitin was closely similar to those of commercially available chitins and the degree of deacetylation showed low value of 22.8%, it could be concluded that the bleached chitin obtained had highly-purified character as well as high quality of appearance.
Ohmic Heating Characteristics of Fermented Soybean Paste and Kochujang
Cho, Won-Il ; Kim, Do-Un ; Kim, Young-Suk ; Pyun, Yu-Ryang ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 791~798
Ohmic heating is a food processing operation in which heat is internally generated within foods by the passage of alternating electric current. The process enables highly viscous paste foods such as Kochujang, and fermented soybean paste to be heated very fast. In order to develope the novel pasteurization process of paste foods, static Ohmic heating system was built, and heating characteristic during Ohmic heating under various conditions were studied. Electric conductivities of Kochujang and fermented soybean paste at room temperature were 1.865 S/m and 2.510 S/m, respectively and increased linearly with increasing temperature. Specific heating rate was highly dependent on the frequency. The highest heating rate was achieved at 5 KHz for Kochujang and 20 KHz for fermented soybean paste. Uniform heating throughout the sample was achieved during Ohmic heating with low frequency electrical currents, however above 5 KHz frequency, surface temperature was several degrees higher than the bulk.
Physicochemical Properties of Konjac Glucomannan
Kim, Nam-Soo ; Ji, Soo-Kyung ; Mok, Chul-Kyoon ; Kim, Seung-Ho ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 799~804
A 0.625% dispersion of the pretreated konjac (Amorphophallus konjac) flour was treated with 3 volumes of ethanol and the precipitate was dried at room temperature to produce purified glucomannan in 67.2% yield. Konjac glucomannan was analyzed for proximate composition and the contents of total dietary fiber and minerals. TLC analysis with a mobile phase of isopropanol :
(4 : 1, v/v) revealed the presence of mannose and glucose as component sugars. The molecular mass of konjac glucomannan was in the range between 240 and 370 kDa as determined by HPLC with a Protein Pak 300SW column. Water holding capacity of konjac glucomannan was greater than those of most other gums except guar and xanthan gums. Konjac glucomannan accelerated foam formation of bovine serum albumin. As the concentration of konjac glucomannan increased up to 2%, maximum viscosity increased drastically, whereas the swelling time at maximum viscosity decreased. When swelling temperature increased, maximum viscosity and the swelling time at maximum viscosity decreased simultaneously.
Effect of Various Pretreatments and Drying Methods on the Quality of Dried Vegetables
Hwang, Keum-Taek ; Rhim, Jong-Whan ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 805~813
Zucchini slices, sweet potato stems, taro stems, and platycodon treated with various methods such as dipping in citric acid solution, sulfite solution, or sulfur fumigation were dried by the natural sun drying method or the forced air drying method at 50, 70, 90, or
. Mold growth of the dried vegetables and sensory quality of the dried and rehydrated vegetables were investigated. Limiting moisture contents to prevent mold growth over 3 month storage under room temperature were 15, 20, 25, and 15% for zucchini slices, sweet potato stems, taro stems, and platycodon, respectively. The chlorophyll containing vegetables dehydrated by the forced hot air showed better sensory quality than those by the natural sun. Among the pretreatments, dipping in the sulfite solution provided the best sensory quality to the dried vegetables. The sensory quality of dried platycodon was improved to a small extent by sulfur fumigation and sulfite solution treatment. The sensory quality of the dried platycodon was not found to be affected by the drying methods. All the tested vegetables dried at
had the worst sensory quality. Except drying temperature of
, the lower the drying temperature, the better the sensory quality and the rehydration rates were obtained for the tested vegetables except platycodon. The sensory quality of the platycodon was little affected by the drying temperature tested in the range of
Effect on Fermentation and Storage of Yogurt Using Control System of Refrigerator
Ko, Yong-Duck ; Chung, Hee-Yeop ; Kim, Kyeong-Sook ; Lee, Kwang-Hoon ; Kim, Yang-Woo ; Chun, Sung-Sik ; Sung, Nack-Kie ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 814~818
Control system for both rapid fermentation and storage of yogurt in refrigerator was developed and its performance was investigated. Fermentation temperature for normal and Bifidus containing yogurt was maintained at maximum
for about 7 and 11 hours, respectively. The pH, acidity, total viable cell number of lactic acid bacteria and viscosity of both yogurts after completing the fermentation were
, respectively. The rate of fermentation for normal yogurt was faster than that of Bifidus yogurt. The changes of pH, acidity, viable cell number and viscosity during storage time were
, respectively. Yeast and fungi were not nearly detected during storage time for both yogurts.
Preparation and Characterization of Rice Starch Maltodextrin
Kim, Jong-Wook ; Shin, Hae-Hun ; Kim, Jung-Min ; Kim, Young-Sook ; Pyun, Yu-Ryang ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 819~823
For the development of rice-derived fat replacing ingredient, low dextrose equivalent (D.E.) malto dextrin was prepared by enzyme hydrolysis, and its physical and rheological properties were studied. The molecular sizes of rice maltodextrin were measured by gel permeation chromatography on Sephadex G-50. Gel permeation column chromatograms showed a large single peak, suggesting a limited hydrolysis, and the average degree of polymerization decreased from 72.8 for 3 D.E. maltodextrin to 48.7 for 6 D.E. maltodextrin. Cold water solubility of maltodextrin was increased with increasing D.E. value and its values ranged from 47.3% to 71.3%. 8% solution of rice maltodextrin showed pseudoplastic behavior. Flow behavior index was decreased as D.E. value was increased.
Effects of Steam Sources and Glycerol on the Storage Stability of Fish Oil
Yi, Ock-Sook ; Han, Dae-Seok ; Cho, Dong-Wuk ;
Korean Journal of Food Science and Technology, volume 26, issue 6, 1994, Pages 824~827
Sardine oil was vacuum-steam deodorized at
with acid (acetic and citric acid) and ethanol solution as steam sources. Glycerol was added to fish oil to remove volatile odorous constituents. The storage stability of deodorized fish oil was determined by totox value, secondary parameter obtained from peroxide and anisidine values. Both deodorization with acetic acid solution and addition of glycerol to the oil resulted in improved storage stability. The totox values of fish oil deodorized with water, glycerol+water and glycerol+acetic acid solution were 936, 611, and 443, respectively after 10 days at
. The result showed that acetic acid seemed to destroy the odorous constituents and glycerol accelerated the removal of odorous constituents, such as amines in fish oil.