• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.803-810
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• 1998

The mechanical and thermal properties of solutions of acorn starch were investigated, to determine the effect of sucrose on the retrogradation. The contents of moisture and amylose of purified acorn starch was 9.35, 27% respectively. From the moecular weight distribution, Mw and Mn of acorn starch were 1,220,432 and 137,201 relatively and the polydispersity of acorn starch was 8.8952. The creep compliance of acorn starch with and without sucrose were decreased with increasing sucrose concentration in the short term. The temperatures of DSC curve of 15% acorn starch solution containg sucrose shifted slightly to higher temperatures with increasing sucrose content. The enthalpy change associated with the gelatinization was increased with increasing sucrose content. After 7 days storage, the creep compliance of acorn starch gel with sucrose were shown higher than acorn starch gel. Regelatinization enthalpy of acorn starch/sucrose/water system was decreased with increasing sucrose content and increased with storage time. In addition, the characteristic temperatures such as onset temperature, peak temperature and conclusion temperature was increased by sucrose addition. Retrogradation ratio decreased with increasing sucrose content, thus sucrose inhibit retrogradation in the long term. Sucrose acts as an antistaling reagents and retatards the retrogradation.

• The Korean Journal of Food And Nutrition
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• v.35 no.4
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• pp.247-252
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• 2022

To improve the shelf-life of Centella asiatica, Centella asiatica was treated with gel packs containing slow-released chlorine dioxide (ClO₂) gas at 3-5 ppm for 20 days at 4℃. The weight loss rate, as well as the changes in pH, color, and texture of the treated samples, were investigated. The weight of the control and ClO₂ gas-treated samples was decreased during the storage period. The change in weight of the control was slightly faster than that of the samples treated with 3 and 4 ppm ClO₂ gas. The pH of the control and the ClO₂ gas treated samples were decreased during the storage period and there was no significant difference between the control and ClO₂ gas treated samples. Concerning color (lightness, redness, and yellowness) changes of Centella asiatica during the storage period, there was no significant difference between the control and ClO₂ gas treated samples. The change in shear force in the leaf and stem of Centella asiatica during the storage period was slightly lower in the 4 ppm ClO₂ gas treated samples (in the leaf) compared to the control and 3 and 4 ppm ClO₂ gas treated samples (in the stem) compared to the control and 5 ppm ClO₂ gas treated sample.

• Korean Journal of Food Science and Technology
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• v.25 no.6
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• pp.698-702
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• 1993

Effect of heating temperature on elution patterns of soluble carbohydrate of legume starches and the texture of starch gels was investigated. The elution profiles of soluble carbohydrate obtained by Sepharose 2B-CL showed that the larger molecules were leached as the heating temperature increased. The elution profiles of soluble carbohydrate of cow pea and mung bean starches were similar, but those of kidney bean starch were different. The gel structures of cow pea and mung bean were stable with showing high values in hardness and cohesiveness. But red bean and kidney bean gels were weak in hardness and cohesiveness. As the heating temperature rised, hardness and cohesiveness were increased in gels prepared by heating for 15 min. However, the gels made by heating for 1 hour showed that less hard and more cohesive gels from cow pea and mung bean, while harder and more cohesive gels from red bean and kidney bean were obtained as the heating temperature increased from $85^{\circ}C\;to\;95^{\circ}C$.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.6
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• pp.816-821
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• 2007

The physical properties and sensory characteristics of acorn starch gels (Dotori Mook), which were gamma-irradiated up to 3 kGy, were evaluated during storage at $4^{\circ}C$. Even at the dose of 2 kGy, the gamma irradiation decreased total bacteria in the Dotori Mook during 5 days of storage, to lower than the detection limit $(10^2CFU/g)$. The hardness of the control sample increased according to the days of storage, while the gamma irradiated samples had decreased hardness according to the irradiation dose. The sample irradiated at 3 kGy maintained the same hardness as the control at day 0 of storage. Irradiation did not affect the Hunter color values. No significant differences were observed in off-odor, color, springiness, and overall acceptability (p<0.05) at the irradiation dose of 2 kGy. It can be concluded that the irradiation of Dotori Mook, up to 2 kGy, does not affect the quality of the Mook during storage, with regard to texture and sensory characteristics. Moreover, the irradiated Mook was superior in maintaining hardness and had prolonged shelf-life time by sanitation.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.613-618
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• 2021

The quality characteristics of jelly-containing vinegar drinks were divided into three stages in this study. The jelly, which differs from the contents of the vinegar drink, sharply decreased the pH. After sterilization, hardness was significantly decreased, and the formulation was not maintained, which was considered the effect of low pH and high total acidity of vinegar drinks. Different experiments confirmed that pH and sterilization heating conditions were the major quality variables for gelation as both sodium citrate content and jelly hardness were correlated before and after sterilization. The hardness of the jelly, which differs in gel content, correlated with the increase in gelation content both before and after sterilization. Therefore, considering the spout jelly of a vinegar drink, pH of 3.5-3.7 and a content of glucomannan and caragenane mixed gel were considered appropriate to match the product's sensory properties.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.695-700
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• 2021

The purpose of this study was to prepare low-molecular weight collagen using a commercial proteolytic enzyme (Protamex) from collagen extracted from feet of Korean native chicken and to investigate the quality characteristics of this collagen. The collagen content of Korean native chicken feet was 13.9 g/100 g, which was higher than the 6.21 g/100 g of general broilers. It was found that the content of low molecular weight collagen increased as the concentration of proteolytic enzymes and reaction time increased. In particular, reaction with 1% Protamex for 7 h resulted in 55.6% of low molecular weight (1,000-5,000 Da) collagen content, and the average molecular weight was 5,390 Da. Regarding the texture of the enzyme-treated collagen, the collagen with high molecular weight peptides decomposed into low molecular weight peptides, and the gel type could not be formed, whereas the sol type was maintained.

• Fisheries and Aquatic Sciences
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• v.15 no.4
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• pp.265-273
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• 2012

The effects of processing and frozen storage conditions on the quality of anchovy Engraulis japonica fried surimi gels were investigated. Protein content decreased after surimi gel processing from 19.6% (raw meat) to 12.1% (kamaboko) due to the added ingredients and change in water content. Lipid content decreased from 2.8% (raw meat) to 1.3% in minced and 0.5% in surimi, but fried kamaboko showed a 6.9 % lipid level. Thiobarbituric acid values and thiobarbituric acid reactive substances levels were highest in kamaboko samples, 89.5 and 1.9 mg/g solid, and increased gradually with storage time to 101.8 and 4.6 mg/g solid, respectively. In vitro protein digestibility increased from 79.2% in raw anchovy to 88.5% in kamaboko samples. Levels of trypsin inhibitor decreased gradually with processing and during storage time from 2.43 in raw anchovy to 0.31 mg/g solid in the kamaboko sample after 60 days of frozen storage. No noticeable changes in total essential amino acid was observed during processing conditions. Computed protein efficiency ratio for kamaboko was highest (2.59) compared with whole anchovy (1.96), minced (1.94) and surimi (2.50). Fresh fried anchovy kamaboko showed similar values of hardness, springiness, gumminess and chewiness to commercial surimi gel, but a higher values were seen for fracturability and adhesiveness, and lower values for cohesiveness and resilience. The frozen and thawed anchovy kamaboko showed higher values for all of these rheological parameters compared with fresh and commercial kamaboko. Anchovy kamaboko showed the lowest lightness (62.9) and redness (0.16) and similar yellowness (11.9) compared with commercial kamaboko. Frozen storage and vacuum packaging were effective maintaining the shelf life of anchovy kamaboko within 30 days, but were not effective after 45 days due to fat oxidation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.44-51
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• 1985

The changes of the get forming ability of common carp (Cyprinus carpio) and conger eel (Astroconger myriaster) meat during ice and frozen storage were investigated in connection with the other quality indices, such as pH, K-value, VBN, viable cell count and sensory evaluation. The shelf-life of iced common carp and conger eel as the raw materials for fish jelly product was considered to be about 16 and 13 days, respectively. Little change in gel forming ability of two species was found during frozen storage at $-30^{\circ}C$ for 3 months. From the results obtained in the examination on the gel forming abilities of the two species stored at $-30^{\circ}C$ for 3 months were superior to those stored in ice for 3 to 4 and 4 to 6 days individually. Fish jelly from the common carp was much more elastic than that of conger eel meat. The overall qualities of two species held in frozen storage as the raw material for fish jelly product were excellent.

• Korean Journal of Food Science and Technology
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• v.9 no.2
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• pp.123-130
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• 1977

A laboratory study was made to develop a simple and economic model method for the systematic determination of functional properties of 'Soy Protein Isolates (SPI)' prepared from defatted soybean meal. These are required to evaluate and to predict how SPI may behave in specific systems and such proteins can be used to simulate or replace conventional proteins. Data concerning the effects of pH, salt concentration, temperature, and protein concentration on the functional properties which include solubility, heat denaturation, gel forming capacity, emulsifying capacity, and foaming capacity are presented. The results are as follows: 1) The yield of SPI from defatted soybean meal increased to 83.9 % as the soybean meal was extracted with 0.02 N NaOH. 2) The suitable viscocity of a dope solution for spinning fiber was found to be 60 Poises by using syringe needle (0.3 mm) with 15 % SPI in 0.6 % NaOH. 3) Heat caused thickening and gelation in concentration of 8 % with a temperature threshold of $70^{\circ}C$. At $8{\sim}12\;%$ protein concentration, gel was formed within $10{\sim}30\;min$ at $70{\sim}100\;^{\circ}C$. It was, however, disrupted rapidly at $125\;^{\circ}C$ of overheat treatment. The gel was firm, resilient and self-supporting at protein concentration of 14 % and less susceptible to disruption of overheating. 4) The emulsifying capacity (EC) of SPI was correlated positively to the solubility of protein at ${\mu}=0$. At pH of the isoelectric point of SPI (pH 4.6), EC increased as concentration of sodium chloride increased. Using model system$(mixing\;speed:\;12,000\;r.p.m.,\;oil\;addition\;rate:\;0.9\;ml/sec,\;and\;temperature\;:\;20{\pm}1\;^{\circ}C)$, the maximum EC of SPI was found to be 47.2 ml of oil/100 mg protein, at the condition of pH 8.7 and ${\mu}=0.6$. The milk casein had greater EC than SPI at lower ionic strength while the EC of SPI was the same as milk casein at higher ionic strength. 5) The shaking test was used in determining the foam-ability of proteins. Progressively increasing SPI concentration up to 5 % indicated that the maximum protein concentration for foaming capacity was 2 %. Sucrose reduced foam expansion slightly but enhanced foam stability. The results of comparing milk casein and egg albumin were that foaming properties of SPI were the same as egg albumin, and better than milk casein, particularly in foam stability.

• Korean journal of food and cookery science
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• v.13 no.1
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• pp.7-15
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• 1997

The composition and polymeric structure of starch are the most important factors to determine the functional properties of rice. In an effort to relate the structural characteristics and its functional properties of starch in rice, molecular structural properties of starch from 6 rice cultivars were analysed. To relate the structure and function of starch the texture of Jeung-pyun made of rice were analyzed during retrogradation. The polymeric structure of rice starch was analyzed by debranching with isoamylase after gelatinization and fractionated with Sephadex G-75 gel filteration. The size fractionated debranched starch was categorized into four groups such as Fraction I, II, III and Intermediate Fraction depending in their max, The fractions with the max higher than 620 nm were designated as Fraction I, while those in the range of 600-620 nm and 540-600 nm as the Intermediate Fraction and Fraction II, respectively. The Fractions with the max lower than 540 were described as Fraction III. The average degree of polymerization (DP) of the Fraction I was estimated to be higher than 200, and those of other fractions, i.e. the Intermediate Fraction I, Fraction II and III were 150,45 and 25, respectively. The levels of Fraction I were varied from II to 35％ of total sugar. The Fraction I showed the linear relationship with the amylse contents, and the Intermediate Fraction, which might contain the mixture of short chain of amylose and debranched long chain of amylopectin, were measured to be in the range of 2.7∼8.4%. The levels of fraction II and III, both to be considered as the branches of amylopectin, were ranged 14.5∼23.6% and 39.7∼73.0%, respectively. The ratio of Fraction III to Fraction II describing the degree of branch or compactness of amylopectin was estimated to be around 4.0 for waxy varieties and around 2.0 for high amylose cultivars. With these results, it can be suggested that the degree of branch of the amylopectin may effect on amylose contents of starch or rice versa, To invertigate processing aptitude of different rice cultivars for the preparation of Jeung-pyun, its texture was analyzed by Instron, hardness, cohesiveness, elasticity, gumminess and chewiness of Jeung-pyun made of rice showed the significant relationship with the amylose content. Hardness was increased during retrogradation of product, but the relationship between hardness and amylose content due to not only difference in amylose content but also difference in structural characteristics of starch. In analysis of relationship between structure of rice starch and mechanical properties of Jeung-pyun during retrogradation elasticity did not show any relationship before retrogradation bur during retrogradation showed significant correlation. With these result, it can be suggested that the degree of branch of the amylopectin may effect on elasticity during retrogradation. However hardness, cohesiveness, gumminess and chewiness which were significant different before retrogradation, showed some correlation with structure of rice starch during retrigradation.