• Journal of the East Asian Society of Dietary Life
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• v.27 no.1
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• pp.41-49
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• 2017

This study investigated the effects of teff flour on the properties of pound cakes. Five types of pound cakes were made by addition of 0% (Control), 5% (TF5), 10% (TF10), 15% (TF15), and 20% (TF20) of teff flour based on wheat flour. Specific gravity of pound cake batter showed no significant differences among samples as 0.54 (p<0.05). Baking loss was the highest in the control at 5.92% and the lowest in TF20 at 5.27%. Batter yield was the highest in TF20 at 94.73% and the lowest in control at 94.08%. Moisture content was the highest in TF20 at 23.68% and the lowest in control at 21.32%. pH showed no significant differences among samples at 7.61~7.65 (p<0.05). a-values of crumb significantly increased while L-values and b-values significantly decreased with added teff flour amounts. (p<0.05). ${\Delta}E$ values significantly increased with teff flour at 34.32~49.24 (p<0.05). Hardness was lowest in TF20 at $180.60g/cm^2$. Springiness was the lowest in TF20 at 85.37%. Cohesiveness showed no significant differences among samples (p<0.05). Chewiness was the lowest in TF20 at 172.17 g. Hardness more rapidly increased in control at $273.13{\sim}26,123.33g/cm^2$ than that of pound cakes with teff flour. Avrami exponent (n) was the highest in the control at 3.5987 and the lowest in TF20 at 1.2144. In sensory evaluation, flavor of TF20 was higher than that of the control at 4.43. Overall acceptability had a higher score in TF20 than in the control. It is considered that addition of 20% teff flour can improve the quality characteristics and retard retrogradation of pound cake.

• Culinary science and hospitality research
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• v.21 no.4
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• pp.145-154
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• 2015

The quality characteristics of Korean rice cakes (Karedduk) with a mixture of fructooligosaccharide (95%) and AA (acetylated adipate distarch) added, after 2 and 24 hours of storage at $5^{\circ}C$, were investigated. A central composite design was used for arrangement of treatment. Different levels of fructooligosaccharide (95%), 0, 3, 6, 9, and 12%, were added to dry rice flour. In addition, different levels of AA, 0, 0.3, 0.6, 0.9, and 1.2%, were added to the same dry rice flour. The texture properties analysis using a Texture Analyzer revealed that the springiness, cohesiveness, chewiness, gumminess, adhesiveness, and hardness were significantly different. The effect of retarding retrogradation of Korean rice cakes (Karedduk) with added mixtures of fructooligosaccharide (95%) and AA showed an increasing trend as the amount of fructooligosaccharide (95%) and AA increased. Overall, the instrumental texture properties were highly correlated with the sensory characteristics. These results suggest that adding a mixture of 6% fructooligosaccharide (95%) and 1.2% AA to Korean rice cakes (Karedduk) is effective for retarding retrogradation.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.288-293
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• 2004

Differential scanning calorimetry (DSC) was used to study effects of sucrose and gluten on wheat starch glass transition, gelatinization, and retrogradation. Glass transition temperature ($T_{g}$) of wheat starch decreased as the ratio of sucrose or gluten to starch increased. Both peak temperature ($T_{G}$) and enthalpy values of gelatinization endotherm increased or decreased with increasing ratio of sucrose or gluten, respectively. Wheat starch gel with no sucrose and gluten recrystallized up to 4 weeks of storage at $4^{\circ}C$, whereas those with sucrose and gluten completed recrystallization within 1 week. Both wheat starch gels with no sucrose and gluten, and those with sucrose and gluten at storage temperature of $32^{\circ}C$ recrystallized up to 4 weeks, with wheat starch-sucrose-gluten (1 : 0.5 : 0.12) system, which had highest ratios of gluten and sucrose to starch, showing lowest recrystallization. Nucleation and propagation rates of starch gel recrystallization based on polymer crystallization principles can be converted into peak width (${\delta}T$) and peak temperature ($T_{R}$) of retrogradative endotherm by DSC, because higher nucleation rate at storage temperature of $4^{\circ}C$ close to $T_{g}$ showed higher ${\delta}T$, whereas higher propagation rate at $32^{\circ}C$ (close to $T_{G}$) had higher $T_{R}$.

• Korean journal of food and cookery science
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• v.17 no.2
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• pp.156-164
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• 2001

Four different oligosaccharides used to determine their effects on gelatinization and retrogradation of Backsulgies(BSG), Korean traditional rice cake, were cyclodextrin, isomaltooligosaccharide, fructooligosaccharide and maltotetrose, with 3 or 6%(w/w), based on the rice flour. From the Amylograph and blue value data, adding 6% cyclodextrin into the rice flour fastened the gelatinzation process, and delayed the retrogradation in stored BSG at 4$\^{C}$ for up to 3 days, probably due to its cyclic structure. Using rheometer, the hardness of freshly made BSG added with cyclodextrin was significantly lower than that of control BSG, and increased with storage time in all BSGs at refrigerated temperature. When using maltotetrose in rice flour, the hardness of BSG was also significantly low, but slightly higher than that of cyclodextrin. Hunter “L” value in BSG decreased with the addition of oligosaccharides, but the higher the level of oligosaccharide in BSG, the insignificant the Hunter “a”,“b” values of BSG. From the X-ray diffraction studies, the rice flour showed typical A pattern, and the crystallinities of all BSG gave amorphous V type. The highest peaks of X-ray patterns in BSG added with 6% cyclodextrin or maltotetrose were, however, lower than that of the control, meaning the less crystalline, retrograded starch in the former BSGs. Based on sensory evaluation, BSG added with all oligosacchrides were not significantly different in taste, flavor, chewiness, moistness and overall preferences, with slightly darker color with longer storage time, compared to the control BSG.

• Food Engineering Progress
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• v.14 no.2
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• pp.146-152
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• 2010

A Korean traditional food, sulgidduk, was prepared with the supplementation of whole wheat flour (WWF) high in dietary fiber, and its quality characteristics were investigated depending on the WWF content (3, 5, and 7%). There was no significant difference found in moisture content of final products. Colorimetric analysis revealed that L-value representing brightness decreased with increasing WWF content. In texture profile analysis, freshly-made samples did not show measurable difference in hardness depending on WWF content. However, stored samples at 25$^{\circ}C$ for up to 3 days exhibited a decrease in hardness with increasing WWF content, indicating retardation of retrogradation related to WWF addition. Springiness and chewiness values showed decreasing trend with WWF content especially for stored samples. Retardation of retrogradation with WWF addition was also evidenced by observing the increment of time constant calculated from Avrami equation. Analysis of sensory evaluation demonstrated that considering flavor, taste, texture, and overall acceptability, 5% substitution of rice flour with WWF could be a promising formulation for quality product with high nutritional value.

• Korean journal of food and cookery science
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• v.17 no.1
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• pp.29-42
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• 2001

The purpose of this study was 10 investigate the effect of jujube on the physicochemical properties of lnjeulmi during storage. Various lnjeulmi samples were prepared with steamed glutinous rice, glutinous rice flour, or brown glutinous rice flour along with the addition of chopped jujube at 3, 6, 9, or 12% of rice. In sensory evaluation, the more jujube was added, the stronger sweetness and bitterness were obtained. The samples made with steamed glutinous rice gave the harshest texture. Tenderness and moistness of Deachu-Injeulmi were the highest in the samples made with glutinous rice followed by brown glutinous rice flour, and glutinous rice flour, and they were increased with less amount of jujube. The chewiness of the samples made with brown glutinous rice flour' was the highest and the samples made with glutinous rice were the coarsest. The more jujube was added, the redness and yellowness of Daechu-Injeulmi were increased. The moisture content was higher in the samples made with glutinous rice followed by glutinous rice flour and brown glutinous rice flour. The reducing sugar content of samples during storage was higher in the order of glutinous rice, glutinous rice flour, and brown glutinous rice flour, and it was dramatically reduced until 48hr of storag e; however, it was increased a little bit after 72 hr. The degree of gelatinization was reduced rapidly during the first 24hr of storage, and it was decreased in the order of brown glutinous rice flour, glutinous rice flour, and glutinous rice. The springiness and cohesiveness were decreased during storage. The chewiness and gumminess were increased with the increase of added jujube, and they were increased until 24hr of storage, then decreased after 48hr. The hardness was the highest in the samples made with glutinous rice and 12% of chopped jujube showed the least change in the hardness. The more jujube was added, the less change in the hardness of samples was observed during storage, consequently retarded the speed of retrogradation

• Applied Biological Chemistry
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• v.33 no.4
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• pp.277-281
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• 1990

Injeulmi(Korean glutinous rice cake) was prepared without, 5, 10 and 15% of macerated tea leaves for utilizing unplucked low-graded tea leaves. The effect of firming rate by addition of tea leaf was determined using the Avrami's equation in terms of the texture parameters. Hardness of 5, 10 and 15% addition as compared with no addition was decreased gradually. Overall texture was softened in proportion to Increasing the content of added tea leaf and the addition of 5% and 10% were evaluated as the highest score as an acceptable sensory quality. Avrami exponents and time constant obtained from the Avrami's equation applicable for changes in hardness of without and 10% addition during 7days of storage at $20^{\circ}C$, $90{\sim}95%$ RH indicated 1.062, 15.3 and 0.989, 41.6, respectively, as showing the effect of delay on firming rate.

• Korean journal of food and cookery science
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• v.25 no.2
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• pp.170-179
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• 2009

This study examined effects on shelf-life extension and prevention of starch retrogradation in rye-wheat mixed bread (RWMB) samples prepared with substitutions of 20, 40, 60, and 80% rye sourdough (RSD) as well as a control made with the addition of naturally fermented raisin extract. These effects were investigated using mold growth, water activity, and textural characteristics during a storage period of 8 days at $20^{\circ}C$. The activities of the rye sourdough were examined in terms of pH, total titratable acidity, general bacteria, lactic acid bacteria, and yeast counts. As the incubation time of the sour dough increased, pH decreased, while total titratable acidity increased. General bacteria, lactic acid bacteria, and yeast counts increased with increasing incubation time. Mold grew on the external surface of the control group after 6 days and on the surface of the RSD bread samples after 8 days, respectively. With regard to water activity, the control group had increasing activity as the storage period increased. In addition, the 20, 40, 60, and 80% RSD samples had increasing water activities until the 4th day however, these strongly decreased by the 6th day. In terms of textural characteristics, as the storage period increased, hardness increased, while springiness, cohesiveness, and resilience decreased. There were no significant differences in gumminess among the samples. The control, 20, 40, and 60% RSD samples had decreases in chewiness with increasing storage time, however, the 40% RSD sample did not differ significantly during the storage period. Finally, water activity was negatively correlated with hardness (p<0.05). In conclusion, the results indicate that substituting rye sourdough in rye-wheat mixed bread has a prolongation effect on shelf-life, but no effect on the prevention of starch retrogradation.

• Journal of the Korean Society of Food Culture
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• v.12 no.5
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• pp.463-468
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• 1997

Starch plays an important role in textural quality of infant food which is mainly affected by retrogradation of starch during storage. The acetylated rice was prepared and its physicochemical properties were evaluated to improve the textural quality of infant food when added. When the rice powder was reacted with acetic acid with its increasing concentration from 0.1 M, 0.2 M to 0.3 M, the amount of acetyl group and degree of substitution were increased by 0.39%, 0.8% and 1.27%, and by 0.0014, 0.031 and 0.048, respectively. The initial gelatinization temperature of rice paste determined by amylograph was decreased from $79.5^{\circ}C$ of unmodified rice to $67.5^{\circ}C$ of acetylated rice whose DS is 0.048. The apparent and maxium viscosity of rice paste at $95^{\circ}C$ before and after modification were increased from 92 B.U. to 201 B.U. and from 100 B.U. to 236 B.U., respectively, The degree of retrogradation and rate of syneresis were decreased from 28.7 to 18.8 and from 0.47% to 0.25%, respectively with increased by DS from 0 to 0.048. The digestibility rate of rice powder decreased from 9.19 of natural rice powder to 7.54 of acetylated rice powder whose DS is 0.048. In United State, there is no serious problem in total digestibility because only 4% of modified rice powder is added in production of infant food.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.157-161
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• 1978

Physicochemical properties of rice starches from Paldal(japonica type) and Tongil(indica type) were investigated. There were no significant differences in water-binding capacity, blue value and amylose content between the two starches. Paldal starch showed a higher value for-swelling power than Tongil starch. Amylograph data showed that both Paldal and Tongil starches had similar paste viscosities except setback in which Tongil starch showed a higher value. No significant differences were observed for intrinsic viscosity and glucose units per segment between Paldal and Tongil amylopectin fractions. However, the intrinsic viscosity for Tongil amylose was considerably higher than Paldal amylose. The rate of retrogradation of Tongil starch gels at $21^{\circ}C$ was faster than Paldal starch gels.