• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.612-618
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• 1999

Physicochemical properties of amaranth starch were compared with those of waxy rice and waxy corn starches. Amaranth starch granules vary from $1.1{\sim}1.9\;{\mu}m$ in diameter and are polygonal in shape. Total amylose contents from waxy rice, waxy corn and amaranth starches were 0.01, 0.03 and 0.07%, respectively. Swelling power of amaranth starch granule was slightly different from waxy rice. The swelling power of amaranth increased at $70^{\circ}C$. X-ray diffraction patterns of amaranth and other waxy cereal starches showed an A-type crystalline structure. Relative crystallinities of their starches were similar. According to pasting properties by Rapid Visco-Analyzer, amaranth starch showed a very high gelatinization temperature $(75.1^{\circ}C)$ and lower viscosity and higher stability than other waxy cereal starches during heating and cooling cycle. Peak onset temperatures (To) of starches from waxy rice, waxy corn and amaranth in DSC thermograms were $58.7{\sim}64.0$, 67.2 and $71.5^{\circ}C$, respectively, and their peak enthalpies were similar. Enthalpy of reheated amaranth starch after 3 day storage at $4^{\circ}C$ was higher than those of waxy corn and rices starchs.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.173-173
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• 2022

In this study, we investigated whether there is another amaranth GBSS isoform in an attempt to characterize the synthesis of amylose in the pericarp. We used I2/KI staining to analyze the temporal and spatial starch accumulation patterns during seed development. The spatiotemporal starch accumulation patterns in developing seeds were observed by staining with I2/KI. Starch granules were observed in the pericarp in the initial developmental stage (3 DAP). A few starch granules were detected in the perisperm in the early-late developmental stage (8 DAP), during which the pericarp starch contents rapidly decreased. Starch granules were distributed throughout the perisperm in the mid-late developmental stage (15 DAP). Similar results were reported for other cereal crops, including barley, rice, and sorghum. Starch granules in the pericarp are synthesized during the early seed developmental stages but are absent in mature seeds. We recently reported that starch deposits in the perisperm of developing amaranth seeds are detectable only after the initial developmental stage. Prior to this stage, the pericarp is the major site of starch deposition. A recent study suggested that GBSSII isoforms are responsible for amylose synthesis in pericarps.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.262-267
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• 2004

Processed foods were developed using amaranth starch and flours. Amaranth seeds were untreated (UT), defatted (DF), germinated (GM), roasted (RT), popped (POP), and extruded (EX1 and EX2). Amaranth flours showed A-type pattern on X-ray diffractograms, while crystallinity was not observed in POP, EX1, and EX2. POP and EX1 showed highest (740.3%) and lowest (38.5%) water-binding capacities, respectively. Transmittances of RT, POP, EX1, and EX2 flour suspensions were higher than those of others. Transmittance of amaranth starch and flours differed with processing methods. RT, POP, EX1, and EX2 showed higher transmittance at $60^{\circ}C$. Initial pasting temperature of amaranth flours by RVA were $68.1-73.0^{\circ}C$, and peak viscosities of GM and RT were 31.6 and 401.1 RVU, respectively. Melting endotherms of POP, EX1, and EX2 were not observed in DSC thermograms.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.252-257
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• 2000

The physicochemical and pasting properties of amaranth starches isolated from five cultivars, Andy, Suvarna, Nu World, K266-1, K432, grown in Korea, were investigated. The shapes of starch granules were all polygonal and size was in the range $1.14{\sim}1.48\;{\mu}m$ for all five cultivars. X-ray diffractograms were shown typical A type diffraction patterns for all amaranth starches. The protein and crude lipid contents of starches were $0.13{\sim}0.23%$ and $0.01{\sim}0.05%$, respectively. The apparent amylose contents ranged from $2.79{\sim}4.35%$ and the water binding capacities were $128.05{\sim}135.80%$. The transmittances of 0.1% amaranth starch suspensions except K266-1 increased rapidly above $65^{\circ}C$, thereafter increased slowely. The initial pasting and peak temperature ranges of five cultivars by RVA were $71.3{\sim}73.7^{\circ}C$ and $81.5{\sim}84.0^{\circ}C$, respectively. The peak and cooling viscosities followed the order : Nu World>Andy>Suvarna>K432>>K266-1. Nu World was shown the highest peak (166), final (103) and cooling viscosities (30 RVU). K266-I exhibited the lowest setback (-38) of all five cultivars. Gelatinization (To) and peak temperature (Tp) of amaranth starches in DSC thermograms were $65.7{\sim}68.0^{\circ}C$ and $70.6{\sim}75.8^{\circ}C$, respectively. Enthalpies followed the order: K266-1

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.10a
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• pp.263-263
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• 2017

• Analytical Science and Technology
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• v.30 no.1
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• pp.1-9
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• 2017

Starch is a mixture of amylose (AMY) and amylopectin (AMP) which are different in physical properties such as molar mass (M), rms radius ($R_g$) and hydrodynamic diameter ($d_H$). The rheological and functional properties of starch are influenced by various factors including the molecular size, molar mass distribution (MD) and the concentration ratio of AMY and AMP. It is also important to analyze proteinaceous material in starch as they affect the flavor and texture of food to which starch is added. In this study, asymmetrical flow field-flow fractionation (AF4) was employed for separation and quantitation of AMY and AMP in starches (Amaranth, potato, taros and quinoa). AF4 was coupled with a multi-angle light scattering (MALS) and a refractive index (RI) detector for determination of the absolute M, MD and molecular structure. It was found that AMP has the M and $R_g$ ranging $3.7{\times}10^7{\sim}6.5{\times}10^8g/mol$ and 84 ~ 250 nm, respectively. Also the existence of branch was confirmed in higher M. In addition, proteinaceous material in starch was analyzed by AF4 coupled with a fluorescence detector (FS) after fluorescence-labeling. AF4-FS with fluorescence-labelling showed a potential for investigation on existence of proteinaceous material and the interaction between proteinaceous material and polysaccharide in starch.

• Korean journal of food and cookery science
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• v.32 no.3
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• pp.253-260
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• 2016

Purpose: To develop fat-free dressing containing a resistant starch (RS) as a dietary fiber, the viscosity and stability of various type RSes prepared from wheat, maize, potato, rice, waxy rice, and amaranth starches were investigated by using Brookfield viscometer. The shape of RS granule in the dressing during storage was also observed. Methods: The viscosity of fat free dressing with different retrograded RS3 (RS3V) prepared from waxy rice starch with 0.1% lemon vinegar and ascorbate mixed solution had higher RS3 that was maintained constant during storage. Annealing and heating prior to cross-linking, and heating after cross-linking increased RS level of RS4 type starches. Results: The viscosities and stabilities of dressings with RS were different depending on starch sources and RS preparation conditions. The heated RS4 (HRS4) increased in viscosity and stability with RS4 addition. Especially the fat-free dressings with HRS4 prepared from rice and waxy rice starches maintained stability regardless of separation after one month storage with only 7% separation after 6 month storages. The shape of RS4 granule in acidic medium of dressing did not change until 6 months. Conclusion: In this study, RS4 made by the rice and waxy rice starches showed high viscosity and maintained stability of the fat-free dressings during storage.