Thermal Properties of Starch in Corn Variants Isolated After Chemical Mutagenesis of Inbred Line B73

Abstract

The starch from eight ethyl methanesulfonate (EMS) treated M4 families of the corn (Zea mays L.) inbred line B73 was analyzed using differential scanning calorimetry (DSC), a Rapid Visco Analyser (RVA), a texture analyzer (TA), and scanning electron microscopy (SEM) coupled with image analysis. The eight families were chosen from 144 families previously selected for having starch with unusual DSC parameters. Apparent amylose contents of the starch from the eight families generally were lower than that of the control. According to DSC, starches from mutagenized families tended to have lower onset temperature (T 0 ) of gelatinization, enthalpy (ΔH) of gelatinization, and peak height index (PHI), but broader gelatinization range (R) than the B73 control. Their values for ΔH and percentage of retrograzdation (%R) were clustered around that of the control. Pasting properties from the RVA of the starches from the M4 families also were clustered around those of the control B73 starch, except for the setback values which were lower than B73 for M4 starches. Gel firmness values, as measured by TA, of all the M4 starches were generally lower than that of the B73 starch at storage treatments of one day at 25°C or seven days at 4°C. The stickiness of the gels of the M4 starches tended to be greater than that of B73 after seven days of storage at 4°C. These observations were consistent with the lower apparent amylose values for the M4 starches. SEM and image analysis data revealed no differences among the treatments in granule size and shape. Possibly, EMS treatment altered the genes, affecting internal structure of the starch granules. Starch from the mutagenized families likely had lower bonding forces among molecules and fewer long chains in the amylopectin molecules than did B73. RightsWorks produced by employee of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. The starch from eight ethyl methanesulfonate (EMS) treated M4 families of the corn (Zea mays L.) inbred line B73 was analyzed using differential scanning calorimetry (DSC), a Rapid Visco Analyser (RVA), a texture analyzer (TA), and scanning electron microscopy (SEM) coupled with image analysis. The eight families were chosen from 144 families previously selected for having starch with unusual DSC parameters. Apparent amylose contents of the starch from the eight families generally were lower than that of the control. According to DSC, starches from mutagenized families tended to have lower onset temperature (T o ) of gelatinization, enthalpy (∆H) of gelatinization, and peak height index (PHI), but broader gelatinization range (R) than the B73 control. Their values for ∆H and percentage of retrograzdation (%R) were clustered around that of the control. Pasting properties from the RVA of the starches from the M4

Pasting, textural and thermal properties of resistant starch prepared from potato (Solanum tuberosum) starch using pullulanase enzyme

“…The Difference in textural properties of all sample gels were influenced by rigidity in gelatinized starch, amylose content as well as interaction between the dispensed and continuous phase of the gel which in turn is dependent on the amylose and amylopectin structure (Yamin et al 1999). …”

The physical, chemical and functional characterization of starches from Andean tubers: oca (Oxalis tuberosa Molina), olluco (Ullucus tuberosus Caldas) and mashua (Tropaeolum tuberosum Ruiz & Pavón)

“…Furthermore, Yamin et al (1999) and Singh et al (2003) list the length of the amylopectin chains, the degree of polymerization of the amylose and amylopectin, the degree of association between starch components, the presence of intermediate material and the size and shape of granules as other factors that play important roles in retrogradation during storage. On the other hand, when a starch paste is subjected to successive freeze-thaw cycles, the paste structure is affected because ice crystal growth and dissolution causes redistribution and dilution, which leads to changes in consistency (Hernádez-Medina et al, 2008).…”

Chemometric Analysis of the Gelatinization and Pasting Properties of Long‐grain Rice Starches in Relation to Fine Structure

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