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Harold Corke – One of the best experts on this subject based on the ideXlab platform.

  • Influence of Amaranthus betacyanin pigments on the physical properties and color of wheat flours.
    Journal of agricultural and food chemistry, 2008
    Co-Authors: Fan Zhu, Mei Sun, Yi-zhong Cai, Harold Corke

    Abstract:

    The effect of betacyanin pigments from Amaranthus tricolor and Amaranthus cruentus on chromatic and physicochemical properties of three wheat flours was studied. Addition of Amaranthus betacyanins increased the gelatinization temperatures (To, Tp, and Tc) of all wheat flours without altering their transition ranges (Tc−To). The melting enthalpies (ΔH) were either increased or decreased depending on the types of flour and pigment. Amaranthus betacyanins decreased the peak viscosity (PV), hot paste viscosity (HPV), cold paste viscosity (CPV), setback (SB), and pasting time (PT) of all flours and increased the breakdown (BD). Texture profile analysis (TPA) showed that Amaranthus betacyanins decreased hardness, and gumminess, and increased cohesiveness of all gels, without altering adhesiveness. Chromatic investigation exhibited that A. tricolor and A. cruentus pigments imparted gels with red and orange−yellow hues with favorable color stability.

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  • Extraction and Purification of Squalene from Amaranthus Grain
    Journal of agricultural and food chemistry, 2002
    Co-Authors: Yi-zhong Cai, Mei Sun, Harold Corke

    Abstract:

    Grain amaranth has been suggested as an alternative to marine animals as a natural source of squalene. Oil contents, squalene contents, and fatty acid profiles were determined in 11 genotypes of four grain amaranth species. Although the oil contents of grain amaranth were low (from 5.1% in Amaranthus tricolor to 7.7% in Amaranthus cruentus) as compared to other oil-containing grains, high concentrations of squalene were found in total lipids, ranging from 3.6% in Amaranthus hypochondriacus to 6.1% in A. tricolor. The major fatty acids in Amaranthus oil consisted of palmitic acid (19.1-23.4%), oleic acid (18.7-38.9%), and linoleic acid (36.7-55.9%). A high degree of unsaturation was observed in Amaranthus oils, with S/U ratios of 0.26-0.32. A method to isolate and purify the squalene from Amaranthus oil was developed. After the saponification of K112, the squalene content increased from 4.2% in the crude oil to 43.3% in the unsaponifiables by the removal of the saponifiables. The unsaponifiables were fractionated by silica gel column chromatography to get highly purified squalene. The squalene purity in certain fractions was as high as 98%. Combining the fractions rich in squalene gave a 94% squalene concentrate, with a yield of 90%. The structure of squalene in the purified sample was confirmed by comparison of its ultraviolet spectrum with a standard and from its nuclear magnetic resonance spectra.

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  • Genetic Diversity in Physical Properties of Starch from a World Collection of Amaranthus
    Cereal Chemistry Journal, 1999
    Co-Authors: Harold Corke

    Abstract:

    ABSTRACT Physical and functional properties of starches isolated from 93 noncultivated genotypes of nine Amaranthus species from a world germ plasm collection and an additional 31 cultivated Amaranthus genotypes obtained from China were tested. A wide variation was found in the properties tested among the Amaranthus species and among genotypes within the same species. When comparing starches from cultivated and noncultivated genotypes, it was generally found that amylose was lower; starch pasting profiles were more consistent with higher peak viscosity, lower breakdown, and lower setback; the gelatinization temperature was lower; and energy of enthalpy was higher. Under cool storage, the hardness of cultivated starch pastes was lower and the adhesiveness was higher. As expected, amylose content was a primary factor affecting the physical and functional properties of Amaranthus starch. Compared with reference maize, rice, and wheat starches, Amaranthus starch tended to have lower hot paste viscosity and lo…

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Philip Westra – One of the best experts on this subject based on the ideXlab platform.

  • interspecific hybridization transfers a previously unknown glyphosate resistance mechanism in Amaranthus species
    Evolutionary Applications, 2012
    Co-Authors: Todd A. Gaines, Sarah M. Ward, Bekir Bukun, Christopher Preston, Jan E. Leach, Philip Westra

    Abstract:

    A previously unknown glyphosate resistance mechanism, amplification of the 5-enolpyruvyl shikimate-3-phosphate synthase gene, was recently reported in Amaranthus palmeri. This evolved mechanism could introgress to other weedy Amaranthus species through interspecific hybridization, representing an avenue for acquisition of a novel adaptive trait. The objective of this study was to evaluate the potential for this glyphosate resistance trait to transfer via pollen from A. palmeri to five other weedy Amaranthus species (Amaranthus hybridus, Amaranthus powellii, Amaranthus retroflexus, Amaranthus spinosus, and Amaranthus tuberculatus). Field and greenhouse crosses were conducted using glyphosate-resistant male A. palmeri as pollen donors and the other Amaranthus species as pollen recipients. Hybridization between A. palmeri and A. spinosus occurred with frequencies in the field studies ranging from <0.01% to 0.4%, and 1.4% in greenhouse crosses. A majority of the A. spinosus × A. palmeri hybrids grown to flowering were monoecious and produced viable seed. Hybridization occurred in the field study between A. palmeri and A. tuberculatus (<0.2%), and between A. palmeri and A. hybridus (<0.01%). This is the first documentation of hybridization between A. palmeri and both A. spinosus and A. hybridus.

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  • Interspecific hybridization transfers a previously unknown glyphosate resistance mechanism in Amaranthus species.
    Evolutionary applications, 2011
    Co-Authors: Todd A. Gaines, Sarah M. Ward, Bekir Bukun, Christopher Preston, Jan E. Leach, Philip Westra

    Abstract:

    A previously unknown glyphosate resistance mechanism, amplification of the 5-enolpyruvyl shikimate-3-phosphate synthase gene, was recently reported in Amaranthus palmeri. This evolved mechanism could introgress to other weedy Amaranthus species through interspecific hybridization, representing an avenue for acquisition of a novel adaptive trait. The objective of this study was to evaluate the potential for this glyphosate resistance trait to transfer via pollen from A. palmeri to five other weedy Amaranthus species (Amaranthus hybridus, Amaranthus powellii, Amaranthus retroflexus, Amaranthus spinosus, and Amaranthus tuberculatus). Field and greenhouse crosses were conducted using glyphosate-resistant male A. palmeri as pollen donors and the other Amaranthus species as pollen recipients. Hybridization between A. palmeri and A. spinosus occurred with frequencies in the field studies ranging from

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Mei Sun – One of the best experts on this subject based on the ideXlab platform.

  • Influence of Amaranthus betacyanin pigments on the physical properties and color of wheat flours.
    Journal of agricultural and food chemistry, 2008
    Co-Authors: Fan Zhu, Mei Sun, Yi-zhong Cai, Harold Corke

    Abstract:

    The effect of betacyanin pigments from Amaranthus tricolor and Amaranthus cruentus on chromatic and physicochemical properties of three wheat flours was studied. Addition of Amaranthus betacyanins increased the gelatinization temperatures (To, Tp, and Tc) of all wheat flours without altering their transition ranges (Tc−To). The melting enthalpies (ΔH) were either increased or decreased depending on the types of flour and pigment. Amaranthus betacyanins decreased the peak viscosity (PV), hot paste viscosity (HPV), cold paste viscosity (CPV), setback (SB), and pasting time (PT) of all flours and increased the breakdown (BD). Texture profile analysis (TPA) showed that Amaranthus betacyanins decreased hardness, and gumminess, and increased cohesiveness of all gels, without altering adhesiveness. Chromatic investigation exhibited that A. tricolor and A. cruentus pigments imparted gels with red and orange−yellow hues with favorable color stability.

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  • Extraction and Purification of Squalene from Amaranthus Grain
    Journal of agricultural and food chemistry, 2002
    Co-Authors: Yi-zhong Cai, Mei Sun, Harold Corke

    Abstract:

    Grain amaranth has been suggested as an alternative to marine animals as a natural source of squalene. Oil contents, squalene contents, and fatty acid profiles were determined in 11 genotypes of four grain amaranth species. Although the oil contents of grain amaranth were low (from 5.1% in Amaranthus tricolor to 7.7% in Amaranthus cruentus) as compared to other oil-containing grains, high concentrations of squalene were found in total lipids, ranging from 3.6% in Amaranthus hypochondriacus to 6.1% in A. tricolor. The major fatty acids in Amaranthus oil consisted of palmitic acid (19.1-23.4%), oleic acid (18.7-38.9%), and linoleic acid (36.7-55.9%). A high degree of unsaturation was observed in Amaranthus oils, with S/U ratios of 0.26-0.32. A method to isolate and purify the squalene from Amaranthus oil was developed. After the saponification of K112, the squalene content increased from 4.2% in the crude oil to 43.3% in the unsaponifiables by the removal of the saponifiables. The unsaponifiables were fractionated by silica gel column chromatography to get highly purified squalene. The squalene purity in certain fractions was as high as 98%. Combining the fractions rich in squalene gave a 94% squalene concentrate, with a yield of 90%. The structure of squalene in the purified sample was confirmed by comparison of its ultraviolet spectrum with a standard and from its nuclear magnetic resonance spectra.

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  • Colorant properties and stability of Amaranthus Betacyanin pigments
    Journal of Agricultural and Food Chemistry, 1998
    Co-Authors: Yi-zhong Cai, Mei Sun, Harold Corke

    Abstract:

    Color, spectral characteristics, and stability of betacyanin pigments of 21 genotypes from 7 Amaranthus species were evaluated. Wide variation in color characteristics and significant differences in pigment stability were found as much within as between Amaranthus species. Amaranthus betacyanins, like red beet pigments, were susceptible to temperature and also affected by pH, light, air, and water activity, with better pigment stability at lower temperatures (≤14 °C) in the dark and in the absence of air. Storage stability at 25 °C of dried Amaranthus pigments (t1/2 = 23.3 months) was longer than that of aqueous pigment extracts (t1/2 = 1.04 months), indicating that the dried pigments were stable enough to be used as commercial colorants. The betacyanins from some better pigment genotypes (Cr015, Sheng07, Tr010, Cr072, Cr017, etc.) exhibited brighter red-violet color characteristics and were similar in stability to red radish anthocyanins under selected conditions. These characteristics of Amaranthus pigm…

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