• Food Science and Biotechnology
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• v.14 no.5
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• pp.681-684
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• 2005

A maltopentaose-producing amylase (G5-amylase) from Bacillus megaterium KSM B-404 was applied to retard bread retrogradation. Retrogradation rates were determined by differential scanning calorimetry. Gel permeation chromatography determined changes in maltooligosaccharide composition and the molecular weight profiles of carbohydrate tractions. The baking process produced maltopentaose and maltotriose by the hydrolysis of starch molecules into small units. Amylose and amylopectin degradation as well as maltooligosaccharides produced by the enzyme were likely responsible for retarding starch retrogradation. Overall, addition of G5-amylase reduced the starch retrogradation rate, and was as effective as Novamyl(R), a commercial enzyme.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.2
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• pp.316-325
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• 2015

The characteristics of Heunmi (brown waxy rice)-ssuck (mugwort)-injeolmi containing different contents of mugwort over a storage period of 2 days were studied. The pH level ranged from 6.4 to 6.5, whereas moisture rate ranged from 34.4 to 51.4% with different amounts of mugwort. Heunmi-ssuck-injeolmi with different amounts of mugwort showed significantly different characteristics in the texture analysis. Hardness, gumminess and chewiness all decreased, whereas adhesiveness, springiness and cohesiveness increased with greater amount of mugwort added. Colorimeter analysis showed that L-, a- and b-values of Heunmi-ssuck-injeolmi were inversely proportional to the amount of mugwort. Scanning electron microscopy (SEM), confirmed that the stoma size of Heunmi-ssuck-injeolmi was directly proportional to the amount of mugwort, whereas the largest stable stoma size was observed with 30% mugwort. In the control group, retrogradation was preceded by expelling water, known as syneresis, whereas Heunmi-ssuck-injeolmi showed less retrogradation with a higher moisture rate. It is expected that mugwort containing cellulose discourages the retrogradation process. In conclusion, 30% mugwort showed the least retrogradation and was the most preferred in terms of taste with stable stoma over the storage period at $25^{\circ}C$. Therefore, it is appropriate for the manufacture and commercialization of Heunmi-ssuck-injeolmi.

• Korean Journal of Food Science and Technology
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• v.26 no.4
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• pp.370-374
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• 1994

The effect of water activity(Aw) and storage temperature on retrogradation of pregelatinized corn starch was investigated at various temperature of $4^{\circ}C$, $20^{\circ}C$ and $30^{\circ}C$. Samples stored at different water activity, i.e., 0.43, 0.52, 0.75, 0.83, 0.88 and 0.93 by means of saturated salt solutions. The rate of retrogradation was determines. by enzymic digestibility, and evaluated by Avrami equation. The degree of retrogradation during storage showed a great difference around Aw 0.8. At Aw 0.52 and 0.75 at all temperatures, retrogradation occurred slightly. The effect of water activity on retrogradation was much greater at $4^{\circ}C$ than 300. And at Aw 0.43, the degree of retrogradation after 3-week storage was smaller than 3.9%. The critical water activity of retrogradation was inferred as Aw 0.43. At each temperature, the degrees of retrogradation of gelatinized corn starch after 24-day storage were 30% at Aw 0.8 and Aw 0.9, and greater than 50% at the Aw above 0.9. At Aw below 0.8 the degree of retrogradation was about 20%. The rate constants of retrogradation according to Aw showed small differences at $20^{\circ}C$ and $30^{\circ}C$, but showed a great difference at $4^{\circ}C$. The value of exponent of Avrami was 1.0 regardless of temperature and water activity. And the rate constants of retrogradation increased with increasing Aw, but decreased with increasing temperature.

• The Korean Journal of Food And Nutrition
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• v.22 no.2
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• pp.185-191
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• 2009

This study investigated the effects of adding hard and soft wheat flour to Korean rice cakes(Karedduk) to retard retrogradation, by examining texture properties and descriptive sensory qualities after 2 and 24 hrs of storage at $5^{\circ}C$. The hard and soft wheat flour were combined with dry rice flour at levels of 0, 5, 10, and 20%. The texture properties, as analyzed by a Texture Analyzer, revealed that the springiness, cohesiveness, and adhesiveness of the rice cakes containing wheat flour were similar to those of the control, while chewiness, gumminess, and hardness were lower compared to the control. Also, in sensory analyses, hardness was significantly different in the rice cakes containing wheat flour compared to the control after 24 hrs of storage at $5^{\circ}C$. Overall, the instrumental texture properties were highly correlated with the sensory characteristics. These results suggest that adding hard and soft wheat flour to Korean rice cakes(Karedduk) is effective at retarding retrogradation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.4
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• pp.837-844
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• 1999

The textural properties and retrogradation of injeulmi(Korean traditional waxy rice cake) made from various waxy cultivars were examined to compare the varietal difference. Injeulmi made from Shinsun chalbyeo and Whasunchalbyeo were exhibited relatively soft texture, while Taichung Sen Glu I and Yuk donongrimna were shown high adhesivness. Intermediate or long grain rice such as Yukdonongrimna, Hangangchalbyeo and Taichung Sen Glu I had a tendency to be rapidly retrogradatated as compared with short grain rice, Shinsunchalbyeo and Whasunchalbyeo. Amylogram characteristics of these intermediate or long grain rice cultivars were shown high value in consistency and low value in setback. Studies per formed by various cookery procedure demonstrated that injeulmi made from cooked waxy rice was softer and delaying retrogradation than made from waxy rice flour.

• Korean Journal of Food Science and Technology
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• v.20 no.6
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• pp.794-800
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• 1988

The retrogradation properties of waxy starches isolated from waxy rice(Shin sun, Tong il), waxy barley(Suwon # 227), waxy indian millet. waxy millet and Jobs tears(Yullmoo) were investigated. The extent of retrogradation determined by the glucoamyase method during freeze-thaw treatment and storage in low temperature$(0{\sim}5^{\circ}C)$ showed that six kinds of waxy starches were very slowly retrograded. The order of the retrogradation tendencies of these starches were waxy indian millet > Suwon # 227 Waxy millet > Yullmoo > Tong il > Shin sun. Waxy indian millet and Suwon # 227 starches were distinctively retrograded compared with other starches. Retrogradation properties observed during freeze-thaw 30 cycles were similar to those of storage for 30 days at $0{\sim}5^{\circ}C$. Suwon # 227, which has been the only recommened variety in our nation, was composed of 15% of non-waxy starch and 85% of waxy starch granule.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.876-881
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• 1997

The relationship between the molecular structure of acid-hydrolyzed rice starch and the retrogradation rate of starch gel was investigated. The molecular structure of starch was modified by acid hydrolysis with 1 N HCl at $35^{\circ}C$. The molecular weight of starch decreased as acid hydrolysis time was increased. At the early stage of hydrolysis up to 3 hr, the branching point of amylopectin was degraded and thereafter both ${\alpha}-1,4\;and\;{\alpha}-1,6$ linkages were hydrolyzed. The starch gel (50%) stored at $20^{\circ}C$ revealed that the rapid retrogradation occurred during 4 hr of storage which was more pronounced as the hydrolysis time increased. The degree of retrogradation of starch gels after 4 hr storage showed a linear relationship with the yield of hydrolyzate. These results suggested that the retrogradation of starch gel was accelerated by degradation of ${\alpha}-1,6$ linkages with acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.2
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• pp.175-180
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• 2003

Effect of the addition of maltitol to Korean rice cake (Karedduk) on its retrogradation was examined. Degree of retrogradation was also examined in terms of recrystallinity of starch and color change with a differential scanning calorimeter. As a result, retrogradation was suppressed by the increasing addition of maltitol. In particular, enthalpy showed a tendency to decrease at $25^{\circ}C$ rather than at 4$^{\circ}C$ during 4 days. In the gelatinization properties using DSC, onset temperature (To) was shown to increase slightly according to storage time. Maximum peak temperature (Tp) was shown to decrease by the addition of maltitol during 4 days. Melting enthalpy was decreased at $25^{\circ}C$ and 4$^{\circ}C$ by the addition of maltitol. The analysis X-ray diffraction also revealed that retrogradation of the Korean rice cake was suppressed by the addition of maltitol because crystalline region did not appear. The addition of maltitol into the Korean rice cake was found to result in an increase of its qualify or color stability.

• Applied Biological Chemistry
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• v.35 no.5
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• pp.404-409
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• 1992

Hydroxypropylated starches and acetylated starches were prepared by reaction of potato starch with propylene oxide and acetic anhydride, respectively and then degree of retrogradation and swelling power were investigated in different pHs and temperature. The extent of retrogradation determined by glucoamylase method during freeze-thaw treatment and storage in low temperature $(0{\sim}5^{\circ}C)$ showed that modified potato starches were slowly retrograded as the increase of degree of substitution. The order of the retrogradation tendencies in different pHs were pH 4>pH 6>pH 8>pH 10. Retrogradation of hydroxypropylated potato starches were less than that of acetylated potato starches. Swelling power of starches were influenced more by the temperature than by the pH. The order of the swelling power tendencies in different pHs were pH 10>pH 2>pH 8>pH 4>pH 6.

• Korean journal of food and cookery science
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• v.21 no.6 s.90
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• pp.782-793
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• 2005

This study investigated the effect of $2\%$ addition of pectin and alginate on the Physicochemical and retrogradation Properties of Jeungpyun, a Korean traditional fermented rice cake. The volume of batters with alginate and Pectin was significantly larger than that of control. Jeungpyun samples with Pectin and alginate had a larger volume with uniform and smaller cell size. All samples showed largest foaming capability after second fermentation. Foaming capability of the control ($0\%$ addition of pectin and alginate) was significantly larger than that of the treated samples. The amount of reducing sugar tended to increase during fermentation but decreased after steaming, which was due to the increase in hydrolysis of starch. On the contrary, the content of free sugar was slightly decreased during fermentation but slightly increased after steaming. The control contained the largest amount of free sugar after steaming. The microstructure of starch particles after fermentation showed completely dispersed starch granules with air bubbles. After steaming, the structure was sponge-like in all samples. Samples with added alginate and pectin had significantly higher water binding capacity than those of the control. All samples showed noticeably increased solubility and swelling power at $70^{circ}C$ with the control being significantly lower than the treated samples. Retrogradation was measured with $\alpha$-amylase and the retrogradation process of the sample with added alginate and pectin proceeded slower than that of the control. The relative crystallinity was observed through X-ray diffraction method and samples with added alginate and pectin had smaller crystallinity and delayed retrogradation compared to the control. Thus, Jeungpyun with the addition of alginate and Pectin demonstrated improved functionality and dietary fiber addition effect. The storage period of was extended as the retrogradation rate was delayed by the addition of dietary fibers.