• Korean journal of food and cookery science
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• v.17 no.3
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• pp.246-254
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• 2001

Effects of added green tea powder and Angelica keiskei powder on the quality characteristics of Yukwa were examined for the purpose of improving functioanality and variety of Yukwa, and usage of green tea Powder and Angelica keiskei. Dietary fiber contents of green tea powder were 5.2% soluble dietary fiber, 22% insoluble dietary fiber, while Angelica keiskei contained 28.9% soluble dietary fiber, 29.6% insoluble dietary fiber. Expansion rate of yukwa was 3,675% for control and the rates were slightly decreased as the addition level increased. Although Yukwas added 6% green tea and angelica keiskei powder were harder than the others when determined by rheometer, sensory evaluation results showed that hardness and mouthfeel were soft without any significant difference among the control and experimental samples. And internal structure of 4 and 6% green tea powder and those added angelica keiskei at three levels were evaluated by sensory panel as moderately compact. Overall acceptability of yukwa added 2% green tea Powder was the best of all while yukwas added angelica keiskei at three levels were evaluated as good. The results of peroxide value and TBA value showed that green tea powder had stronger antioxidative property than angelica keiskei. In conclusion addition of green tea powder by 2% level and angelica keiskei powder up to 4% would give us beneficial effects in the aspects of functionality and storage life of yukwa without any detrimental effects on the quality characteristics of it.

• Food Science and Preservation
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• v.11 no.1
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• pp.12-16
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• 2004

This study was to investigate the preference test of among 10’s and 20’s in New York, Atlanta, Chicago and Sanfrancisco in USA. Preference of packaging, design, printing, flavor, texture and overall preference surveyed. About thirty percent of the respondents showed high score in packaging among the items. The design and color of Yukwa was 22.0％ and 24.1％ in “excellent”. American did not prefer the texture due to stickiness of Yukwa. However, 92.7％ of the respondents showed high score in overall acceptability of Yukwa. On the basis of this result Yukwa would he developed for residential people’s preference. It is possible to export successfully the Korean traditional snack, Yukwa.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1760-1766
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• 2009

Physical properties of Yukwa base extruded with glutinous rice flour, rice flour, defatted soy flour, and salt using an twin-screw extruder were investigated. The ingredients were extruded at various moisture contents (16-18%), screw speeds (300 & 400 rpm) at 43.4 kg/hr feed rate. Length and specific volume of Yukwa base increased with decreasing moisture contents. Hunter's color L* values of Yukwa base was higher whereas $a^*\;and\;b^*$ values were lower with increasing moisture content. Water absorption index of Yukwa base increased with increasing moisture contents. X-ray diffraction of Yukwa base showed B type moisture content of 16% and 17% while it showed A type moisture content of 18%. Degree of crystallinity and breaking strength of Yukwa base were the lowest in the moisture content of 16% while the lowest value for hardness was found in the moisture content of 16% and of 17% with screw speed 400 rpm for all samples. In the microstructure of cross section of Yukwa base, air cell size was larger and cell wall was thicker as moisture content increased. The sensory evaluation of the Yukwa base showed that color and flavor were not significantly different among samples, while taste, appearance, mouth feel, and overall preference were higher as moisture contents decreased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.7
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• pp.988-993
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• 2012

The objective of this study was to investigate the physicochemical properties of Yukwa bases with different quantities of Soju during long-term storage. We examined Yukwa bases with 5 different quantities (0%, 25%, 50%, 75%, and 100%) (v/w) of Soju after intervals of 10 days up to 50 days at $30{\pm}1^{\circ}C$. The L and a values of all Yukwa bases decreased as storage time increased. The b value of Yukwa bases with 0% Soju increased as storage time increased, but Yukwa bases with 25~100% Soju decreased. The compression and shared force decreased as storage time increased for all subjects, but those with bases of 50% and 75% Soju changed less during storage. The acid values of all Yukwa bases increased significantly during storage. In addition, the peroxide values of all Yukwa bases significantly increased during storage time. Yukwa bases with 0% Soju showed great change of the peroxide value during long-term storage. The peroxide values of all Yukwa bases changed less as the quantity of Soju increased.

• Korean journal of food and cookery science
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• v.18 no.5
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• pp.529-533
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• 2002

Yukwa was prepared with the glutinous rice by the addition of different ratio of pigmented rice (0, 3, 5, 7, 10%) and were steeped for 7 days at 20$^{\circ}C$. No significant differences were found among the samples when the textural properties of Yukwa dough and base were measured using a texture analyzer. But the crispness was decreased with tile increase of the addition level of pigmented rice. The redness (a value) and yellowness (b value) of the dough and Yukwa base were increased and the lightness (L value) was decreased as the addition levels increased. The expansion rate of Yukwa was decreased with the increase of addition levels. The overall acceptability of Yukwa prepared with the addition of 7% pigmented rice was the best in the sensory evaluation.

• Korean Journal of Food Science and Technology
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• v.33 no.3
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• pp.294-300
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• 2001

Effect of bean water concentration and incubation time of Yukwa paste as well as packaging method on the quality of Yukwa was investigated. Quality loss in Yukwa during storage was dependent on the packaging method such as bamboo packaging at $30^{\circ}C$, nitrogen packaging at $30^{\circ}C$ and LDPE packaging at $-18^{\circ}C$. Peroxide value increased with bean water concentration, but showed no significant difference by incubation time. The hardness of Yukwa decreased with the increase of bean water concentration, incubation time, and storage time but showed no significant difference by packaging method. Sensory evaluation after storage for 3 months showed that Yukwa color was significantly influenced by packaging method and bean water concentration. The volume was also significantly influenced by bean water concentration and incubation time. Off-flavor showed significant difference by storage method. Tenderness, taste and overall desirability showed significant difference by bean water concentration. Crispness showed significant difference by storage method and bean water concentration.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1088-1094
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• 2001

The quality of Yukwa added with safflower seed powder (SSP) was investigated using chemical, sensory and mechanical properties, The result of chemical properties showed that degree of expansion of Yukwa were decreased as the amount of SSP increased, while fat absorption increased. Yukwa with 1% SSP was the best in appearance, taste and overall preference of acceptability. Lightness decreased by the addition of SSP, while redness and yellowness increased. Texture measurement showed that hardness was the lowest in the Yukwa with 5% SSP, and cohesiveness was the highest in the Yukwa with 1% SSP. Hardness and brittleness of mechanical properties were positively correlated with the acceptability. The degree of expansion was positively correlated with cohesiveness and springiness. Fat absorption and moisture content were positively correlated with gumminess in the mechanical properties. Yukwa with 1% SSP showed a good overall preference.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.597-603
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• 2002

The analysis of traditional process for a Korean puffed rice snack (Yukwa) is needed to develop an advanced process for Yukwa-making. Steeping and punching (Koarichigi) processes, consume time and labor in Yukwa-making, were analyzed on this study. Steeping of waxy rice at $15^{\circ}C$ for 3 days was required to equilibrate moisture absorption in waxy rice kernel. However, steeping for more than 6 days was required soft texture and small air cell distribution of Yukwa. Protein content at pericarp on endosperm of waxy rice kernel was decreased and starch granule was damaged during steeping. RVA paste viscosity was the highest at 6 day steeping after than decreased. Expansion ratio of Yukwa was increased with the increase in steeping time. Air bubbles in dough after punching were uniformly distributed and kneading energy input was decreased with the increase in steeping time. Soft texture, unique texture of Yukwa could be controlled by controlling steeping time and kneading energy input during punching process.

• Korean Journal of Food Science and Technology
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• v.23 no.5
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• pp.619-621
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• 1991

A partial replacement($0{\sim}30%$) of non-waxy rice(Samgangbyeo, Tongil type) was attempted in Yukwa(Korean traditional puffed rice cake) preparation. The yukwa prepared with the replacement of non-waxy rice up to 20% level was comparable in quality to the traditional yukwa in view of expansion rate, crispness and hardness followed by sonsory evaluation. Continuous whipping machine for making yukwa bandaekee(rice cake) could be successfully introduced for mass production.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.8
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• pp.1181-1188
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• 2014

This study investigated the quality characteristics and antioxidant activities of Yukwa added with 'Donganme' sorghum bran powder and its extracts. 'Donganme' variety has the highest antioxidant activity among sorghum varieties in Korea. The added contents of sorghum bran to Yukwa were 1% and 5% bran powder of 'Donganme' (BPD 1% and 5%) as well as 0.1%, 0.5%, and 1% bran powder extracts of 'Donganme' (BED 0.1%, 0.5%, and 1%). The contents of protein, ash, and minerals of BPD 1% and 5% added Yukwa were higher compared to non-added and BED 0.1%, 0.5%, and 1% added Yukwa. The contents of flavonoids of BPD 1% and 5% as well as BED 0.1%, 0.5%, and 1% added Yukwa increased by 1.6~17.1 fold, and DPPH and ABTS radical scavenging activities increased by 1.8~7.4 fold and 2.3~13.6 fold, respectively, compared to non-added Yukwa. Yukwa added with BED 1% showed the highest antioxidant activity among the treatments, followed by BPD 5%, BED 0.5%, BPD 1%, and BED 0.1% added Yukwa. The expansion ratios of BPD 5% and BED 1% added Yukwa remarkably decreased compared to those of non-added and other treatments. The sensory evaluation values corroborated the results of the Yukwa expansion ratio. The acid values of Yukwa under high temperature storage ($60{\pm}1^{\circ}C$) increased rapidly after 20 days in all treatments, and those of BPD 5% and 1% added Yukwa increased slowly compared to non-added Yukwa. ABTS radical scavenging activities of Yukwa showed little change during storage in all treatments. As a results, addition of sorghum bran below BPD 1% and BED 0.5% was suitable for antioxidant activity, quality characteristics and sensory evaluation.