• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.13-18
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• 1988

Retrogradation characteristics of 1% dilute rice starch dispersion were analyzed. The retrogradation was increased with prolonged storage, however, the trend in increase was more conspicuous during the initial phase of retrogradation period. The Avrami exponent, rate constant, and time constant of 1% dilute Chuchong starch dispersion were 0.96, 0.21 $days^{-1}$, and 4.77 days, respectively As the Avrami exponent approaches unity (n=1), it is confirmed that the dilute rice starch dispersion retrogrades following the formation of a rod-like growth of crystals from instantaneous nuclei. When the retrogradation process of dilute rice starch dispersion was traced, the three-dimensional structure of crystals which had different contour from native stach was formed.

• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.638-643
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• 1994

Gelatinization and retrogradation properties of modified starches which were prepared by steeping sweet potato at $40^{\circ}C$ for 2, 4, 7 and 10 days were investigated. The peak temperature of gelatinization and enthalpy of untreated starch by DSC were $53.9^{\circ}C\;and\;1.32\;cal/g$, respectively, but those of modified starch were increased by steeping. In gelatinization by alkali, starches with 2, 4 and 7 day steeping showed higher viscosities than untreated starch, whereas the viscosities of starches with 10 day steeping decreased. The clarities in paste decreased during storage in all starches and decreased in starches with steeping. The degrees of retrogradation by ${\alpha}-amylase-iodine$ method were higher in starches with steeping than untreated starch. The enthalpy of retrograded starches by DSC increased by steeping except 4 day steeping starch. The sweet potato extract containing sugar inhibited the retrogradation of starch paste and the degree were higher in residual starches than in untreated starch.

• Journal of agriculture & life science
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• v.46 no.1
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• pp.153-161
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• 2012

Wheat is a very popular crop in all over the world due to the various use of wheat flour as staple foods, such as bread. As many food products are made from wheat, the property of wheat can be a determinant of the quality of final food products. Staled bread is not harmful to health but is normally rejected by consumers due to the absence of desirable sensory attributes. The phenomena of staling can be increased hardness of bread, the migration of moisture from center of bread to the crust of bread, loss of flavor and etc. The exact mechanism of staling has not been established completely. To delay or prevent staling, either addition of anti-staling agent, such as surfactant and enzyme or modification of wheat component, such as wheat starch has been adapted. The development of waxy wheat made it possible to reconstitute the starch component in bread. When the content of amylopect in was increased in bread, the loss of moisture was decreased and the reduction in softness of bread was decreased during storage. Increased retrogradation of starch did not always accompany the staling of bread indicating that the retrogradation of starch may not be a single indicator of bread staling. To find out the exact relationship between bread staling and starch retrogradation, further research is necessary.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.4
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• pp.601-605
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• 1995

To efficiently utilize not only fresh chestnut(FC) but also wormy chestnut(WC), four types of chestnut starches which were fresh chestnut starch(FCS), fresh chestnut crude starch(FCCS), wormy crude starch(WCS) and wormy chestnut crude starch(WCCS) were extracted from them, respectively. The mooks were prepared with four types chustnut starches and a acorn crude starch(ACS) as control. Sensory evaluation by five points method indicated that the mooks had noticeable differences in smoothness, taste and fragrance, and no noticeable differences in color and texture. The total scores of mooks for sensory evaluation were higher in order of FCS, FCCS, WCS, ACS. Retrogradation properties for the chestnut mooks prepared by five type starches which were FCS, FCCS, WCS, WCCS and FWCCS(mixing FCCS and WCCS with same weighs) were also investigated with the variation in the starch concentration, storage time and storage temperature by hardness of textural properties. The results indicated that when the mooks which were prepared with starches(all but FWCCS), concentration 8% and 10% were storaged for 7 days at 15$^{\circ}C$, there were no variations in the qualities (hardness) of the chestnut mooks.

• The Korean Journal of Food And Nutrition
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• v.16 no.2
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• pp.105-110
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• 2003

The effect of varietal differences of rice starches by amylose content and gel consistency on the retrogradation behavior was studied. The gel consistency test, which is designed to detect differences in the texture of cooked rice of varieties that have a similar amylose content, had been turned out to be useful in this study. Both Suwon 232 and San Li Cun had higher amylose content, but were greatly different in gel consistency values. The results showed that setback viscosity of rice flour measured in a Brabender amylograph was significantly affected by amylose content as well as gel consistency. Increase in the rigidity modulus (E) of rice starch gels during storage determined by using Texture analyzer indicated that amylose content was an important factor in terms of hardness development The study of Avrami kinetics of retrogradation showed that time constant of rice starch gels was influenced by amylose content, but not by gel consistency.

• 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.

• Preventive Nutrition and Food Science
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• v.10 no.3
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• pp.207-213
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• 2005

Molecular structures and functional properties of starches isolated from normal, waxy, and zero amylose barleys were examined. Amylopectins from zero amylose starch had the largest molecular weight $(M_w)$, whereas those from high amylose starch, the smallest. A good correlation between the $(M_w)$ and the radius of gyration $(R_g)$ was observed among amylopectins from various starches, indicating similar polymeric conformation in solution even with the differences in the $(M_w)$. The debranched amylopectin molecules from different types of barley starches exhibited similar profiles, implying that the packing geometry of double helices in the different types of barley starches may be similar. Zero amylose starch showed the highest peak viscosity (326 RVU) in RV A viscograms at lower pasting temperature $(67.6^{\circ}C)$, compared to normal and high amylose starches. Relationship between RVA peak viscosity and amylose content suggested that the presence of amylose inhibited the development of granular swelling of barley starches during cooking. A rapid retrogradation, traced by differential scanning calorimetry (DSC) and strain-controlled rheometry, occurred in the high amylose starch sample during storage, while zero amylose starch showed a very good resistance to retrogradation, indicating excellent storage stability.

• Food Science and Biotechnology
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• v.16 no.5
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• pp.663-674
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• 2007

Starches from different botanical sources differ in the ratio of amylose to amylopectin contents, molecular structures of amylose and amylopectin, granule morphology, and minor-component contents. These structural features result in different gelatinization, pasting, retrogradation properties, and enzyme digestibility of starch granules. In this review, compositions and molecular structures of starches and their effects on the physicochemical properties are summarized and discussed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.6
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• pp.1251-1255
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• 1999

The sugar alcohols are useful alternatives to sucrose in confections because they provide desirable taste but lessen the potential risks for dental caries. The effects of sugar alcohol and their interaction on starch pasting properties were determined by the viscoamylograph with the concentration of 30%, 20%, 10% sugar alcohol in 1% CMC. The disaccharides, lactitol, maltitol, and isomalt, delayed pasting more than did monosaccharides, sorbitol and xylitol. With regard to the solubility in water, sorbitol and xylitol are more soluble than sucrose, maltitol and lactitol are almost equal and isomalt is less soluble than sucrose. Sorbitol and xylitol were highest on gelatinization. But their retrogradation occurred faster than other sugar alcohols. Lactitol and maltitol decreased gel strength more than did sucrose and other sugar alcohols.

• Journal of the Korean Society of Food Culture
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• v.26 no.5
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• pp.521-529
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• 2011

This study evaluated the effects of different levels of malt extract on the hardness, moisture, water soluble starch (WSS) contents, and in vitro starch digestibility (IVSD) of Jeungpyun during storage at room temperature ($25{\pm}1^{\circ}C$) and refrigeration temperature ($4{\pm}1^{\circ}C$). Resistant starch (RS) and soluble starch (non-RS) contents were also evaluated. During storage at both temperatures, hardness increased in Jeungpyuns with the malt extract-added Jeungpyun groups (malt-added Jeungpyuns) exhibiting lower hardness than the control. The rate of retrogradation was faster upon storage at refrigeration temperature. Moisture and WSS contents as well as IVSD of Jeungpyuns decreased, whereas these levels were higher in malt-added Jeungpyuns compared to control. Storage increased RS contents in Jeungpyuns stored for up to 4 days, particularly at $4^{\circ}C$, whereas there was a decrease in RS content after 7 days of storage. However, RS content was lower in malt-added Jeungpyuns compared to control. Soluble starch (SS) contents of Jeungpyuns decreased. However, SS content was higher in malt-added Jeungpyuns than that of control. The reduced hardness and RS content as well as the rate of increase in other parameters of malt-added Jeungpyuns were dependent on the concentration of malt extract. These results reveal that addition of malt extract delayed retrogradation of Jeungpyun, whereas retrogradation possibly increased the content of RS during storage at both temperatures, however, that of RS decreased with increasing level of malt extract, suggesting that the level of malt extract as well as the storage conditions are important for obtaining acceptable texture and retaining the RS content of Jeungpyun, which is known to possess physiological activity.