• Korean journal of food and cookery science
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• v.8 no.2
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• pp.83-93
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• 1992

This dissertation was aimed to study the stability of egg foams and the quality of rice yackwa added with egg foams. Because of the difference of protein composion between rice flour and wheat flour, yackwa made from rice powder turned out to be harder and less raised. Egg foams were added to the rice flour to help raise the dough to a great extent and make it softer when frying. The smaples were prepared differently: in the finess of rice flour (100, 140 mesh), the kinds of egg foams (whole egg, egg white), and the content of egg foams (40 g, 60 g), respectively. The stability of egg foams was determined by an Optical microscope, the hardness of rice yackwa was examined by Instron, the structure by Scanning Electron Microscope, the color by Hunter's Colorimeter, and the sensory evaluation was also made. The resluts are as knows: The most stable egg white foam and whole egg foam were the 2 and 3 min. whipped ones, respectively. In the case of rice yackwa, which was made from 140 mesh rice flour and 60 g of whole egg, the hardness and the structure were similar to those of wheat yackm. It was very tasty and most preferred. As a whole, the color of rice yackwa was lighter man mat of wheat yackwa.

• Korean journal of food and cookery science
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• v.15 no.3
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• pp.264-271
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• 1999

This study was conducted to know the storage stability of Yackwa, a traditional Korean fried cookie, prepared by two different cooking methods; deep fat frying at 160$^{\circ}C$ for 8 min (DFF), and preheating Yackwa dough and then deep fat frying at 180$^{\circ}C$ for 2 min (MW/DFF). Soybean oil (SBO), hydrogenated soybean oil (HSBO) or hydrogenated palm oil (HPO) were used for frying Yackwa. Compared to Yackwa prepared by DFF, all MW/DFF Yackwa samples had low fat content and high moisture content. MW/DFF saved frying time 6 min compared with DFF. Non-hydrogenated soybean oil for frying fats was replaced with hydrogenated types of soybean oil and palm oil to improve the storage stability of Yackwa. To investigate the oxidation stability of Yackwa during the accelerated storage for 15 days at 60$^{\circ}C$, acid value, anisidine value, peroxide value and oxidation value of Yackwas were measured. Acid values of Yackwa made by MW/DFF were higher than those made by DFF through the whole storage periods, regardless of frying fats. Peroxide and anisidine values of Yackwa coated with syrup were much lower than those without syrup. MW/DFF cooking method, using hydrogenated soybean oil or hydrogenated palm oil for frying, showed lowering effects on peroxide value as well as anisidine value, resulting in improved oxidation stability of Yackwa during the storage. In sensory evaluation, the acceptability of MW/DFF Yackwa was higher than those of the commerical products. Yackwa prepared by MW/DFF cooking method using hydrogenated palm oil, showed the highest acceptability in color, taste and texture among the samples.

• Korean journal of food and cookery science
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• v.17 no.1
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• pp.7-12
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• 2001

Yackwa was prepared by different amounts of egg yolk and then instrumental characteristics and sensory evaluation were investigated during storage periods. In texture profile analysis, hardness, gumminess and chewiness of Yackwa were increased during storage and texture parameters were increased by increasing egg yolk level. In Hunter's color value, lightness and redness were increased by increment of egg yolk level, whereas. yellowness was increased in negative region. During storage all values were increased. In the results of sensory evaluation, crispiness and overall acceptance were significantly different during storage and other parameters didn't showed significant difference among samples. The results showed that Yackwa prepared with 20g of egg yolk had good sensory quality and nutritious improvement.

• Journal of the Korean Society of Food Culture
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• v.20 no.1
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• pp.103-112
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• 2005

The objective of this study was to clarify the effect of addition of green tea powder(0%, 2%, 4%, 6%, 8%) to Yackwa on quality and preservation. Addition of 4% green tea powder turned out to give positive effect on expansion. In test of physical characters, addition of green tea powder had a tendency to lower hardness, cohesiveness, springness and gumminess but to enhance brittleness. Considering the rancidity of oil within Yackwa, addition of green tea powder tended to show lower acid value and peroxide value than non-added treatment but its difference was slight. At the sensory test, surface color, bitterness and green tea flavor were strong but sweet and savory taste weak when green team powder was added(p<0.05). Overall quality appeared to have improved to 5.55 points which is compared to non-addition when the powder was added 4%(p<0.05). In conclusion, 4% addition of green tea powder would be the usefull method to enhance preference and quality of Yackwa.

• Korean journal of food and cookery science
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• v.18 no.6
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• pp.613-618
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• 2002

Yackwa was prepared with various amounts of egg and the texture profile analysis, Hunter's color measurement and sensory evaluation were performed during storage for 7 days. In the texture profile analysis, hardness, cohesiveness, springiness, gumminess and chewiness of Yackwa were increased in all samples during storage and the textural parameters were increased by increasing egg level. No significant difference was observed in the lightness, redness and yellowness (p＞0.05). During storage, L and a values in all samples were increased while b value was decreased. In the results of sensory evaluation, Yackwa prepared with 10g of egg had an acceptable sensory quality.

• Korean journal of food and cookery science
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• v.8 no.3
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• pp.297-307
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• 1992

This study has investigated a scientific approach to the manufacture of Yackwa, made by different frying conditions and has assessed texture characteristics through sensory evaluation and instrumental test. A standard Yackwa was made by frying at 150$^{\circ}C$ for 8 minutes and then soaking for 10 minutes in the newly developed syrup whose viscosity and sweetness were similar to expensive honey. The mixing ratio of the developed syrup was corn syrup: sugar: dextrose=32 : 1.5 : 1 (by weight), and me syrup was double-boned in a water bath for 20 minutes and men cooled to 25 C. As me results of sensory evaluation and instrumental test for Yackwa made by various frying conditions, the lower the frying temperature or me longer the frying time was the higher values of hardness and fracturability, while adhesiveness was the lower in almost all conditions. In the sensory evaluation of Yackwa with the similar outer color, mere were significant differences in me inner color, Crispiness and levels of rising and cracking.

• Korean journal of food and cookery science
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• v.30 no.6
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• pp.800-805
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• 2014

The purpose of this research was to prepare Yackwa by addition of red ginseng marc powder to enhance its functional properties. For this purpose, ginsenosides composition of red ginseng marc powder was analyzed and red ginseng marc powder was added at different levels (1 to 15%) for Yackwa preparation. Also, their quality characteristics such as texture and color were measured and sensory evaluation was performed. Four ginsenosides including Rg3, Rc, Rb2, and Rd were the most abundant forms in red ginseng marc powder. With the increase of red ginseng marc powder, the properties of hardness, cohesiveness, and gumminess of samples decreased. The $a^*$ value of sample was highest when 10% of red ginseng marc powder was added. With the addition of red ginseng marc powder, the $L^*$-and $b^*$-values of samples decreased significantly (p<0.05). Based on the results of sensory evaluation, we recommended 10% addition to prepare Yackwa with red ginseng marc powder.

• Korean journal of food and cookery science
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• v.11 no.2
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• pp.93-97
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• 1995

Effects of added ginger juice in Yackwa on the sensory quality and the lipid oxidation were studied. Also effects of soaking on the lipid oxidation were examined. There were no significant differences between Yackwa without adding ginger juice and ones with adding ginger juice on texture, shape, color. However, Yackwa, with ginger juice more than 1 tea spoon(1.5) of ginger juice per 1 cup of flour, was better than one without ginger juice on taste, flavor and overall acceptibility. Added ginger juice showed the antioxidant effect during frying in oil and storage at room temperature. The higher the amount of ginger juice was added, the slower of lipid oxidation was resulted in Yackwa. Yackwa soaked in syrup or in honey showed lower lipid oxidation than one without soaking during storage at room temperature. The antioxidant effect of soaking in honey was higher than one of soaking In syrup.

• Food Science and Preservation
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• v.21 no.4
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• pp.483-490
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• 2014

This study was conducted to evaluate the quality and to inhibit the lipid oxidation of Yackwa with 0, 1, 2, or 3% mulberry concentrate added. We stored Yackwa at $60^{\circ}C$ for three weeks. After the three-week storage, the acid value of the Yackwa with mulberry concentrate was lower than that of the control Yackwa. The hydroperoxide value (22.39 meq/kg) of the Yackwa with 3% mulberry concentrate at two weeks of storage was 50% lower than that of the control Yackwa (47.03 meq/kg). Also, after three-week storage, the TBA value of the Yackwa with 3% mulberry concentrate was about two times lower than that of the control group. The L and b values in the Hunter color system of the Yackwa with mulberry concentrate decreased significantly as the amount of the mulberry added increased, whereas the a value increased. The antioxidant activity, such as the DPPH radical scavenging activity, significantly increased in the Yackwa with mulberry concentrate, unlike in the control. These results might have been caused by the mulberry concentrate, which contains an antioxidant. The ability of the mulberry concentrate to delay the rancidity of the Yackwa was due to its antioxidant activity.

• Journal of the Korean Society of Food Culture
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• v.7 no.3
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• pp.213-222
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• 1992

This investigation was undertaken for the purpose of studying the quality and acceptability during storage at room or refrigerator temperature of Yackwa containing waxy rice flour substituted for 0,10,30,50,70% of the wheat flour. The storage periods were 0,15,30 and 45 days. Chemical composition, composition of fatty acids, and value, and peroxide values of Yackwa were measured. Sensory evaluation was done by a panel of 5 judges majoring in food and nutrition. The evaluation was repeated 4 times. Objective evaluation was done by rheometer and color difference meter. Chemical composition of Yackwa were $5.9{\sim}6.8%$ for moisture, $3.43{\sim}4.09%$ for crude protein, $22.35{\sim}27.65%$ for crude fat, $0.27{\sim}0.31%$ for ash, $15.6{\sim}18.4%$ for fructose, $10.6{\sim}13.7%$ for glucose, $0.34{\sim}1.0%$ for sucrose, and $0.79{\sim}2.37%$ for maltose, respectively. Fatty acid contents of Yackwa were $10.54{\sim}10.73%$ for palmitic acid, $4.12{\sim}4.18%$ for stearic acid, $25.8{\sim}26.9%$ for oleic acid, $51.6{\sim}52.1%$ for linoleic acid, and $0.27{\sim}0.34%$ for linolenic acid, respectively. Acid value and peroxide value of Yackwa during storage showed little change. As a result of sensory evaluation for Yackwa made various levels of waxy rice flour, there were no significant differences in most of characteristics between the samples supplemented with waxy rice flour to 30% of wheat flour at 0.01% level. By the color difference meter, the value of L (lightness) and b (yellowness) were increased by increasing the amounts of waxy rice flour, however, there were no significant differences at 0.1% level between the samples supplemented with waxy rice flour to 30% of wheat flour, on the other hand, the value of a (redness) was decreased by increasing the amount of waxy rice flour. In the textural characteristics, brittleness, and chewiness were increased by increasing the amounts of waxy rice flour, and by lengthening the storage period, on the other hand, resilience and cohesiveness showed vice versa. In the correlation coefficient between sensory characteristics and mechanical characteristics, overall acceptability in sensory evaluation correlated significantly with cohesiveness, chewiness, and the values of L, a, and b in mechanical test in most of samples(p<0.001).