High- and ultrahigh-temperature drying: Their effect on quality and the starch component of pasta

Ten genotypes of durum wheat (Triticum turgidum L. Var. durum) were grown in replicate plots at three locations in North Dakota. Wheat quality, semolina quality, and semolina rheological tests were conducted. Semolina was processed into pasta, which was dried using low temperature (LT) and high temperature (HT) cycles. Cooking quality variables, textural parameters, and pasta color were examined. To evaluate data, analysis of variance with a factorial arrangement using location, genotype, and temperature as factors was conducted. Genotype X temperature interaction was of key interest. Results indicated that, with the exception of the trait of pasta redness (F = 3.60, P ;Four genotypes (Vic, Rugby, Munich, and Ben) were selected from the Casselton and Minot locations. Starch was isolated from LT, HT, and UHT dried pasta and the reference materials, wheat and semolina. Starch physicochemical characteristics were assessed. Analysis of variance was conducted to determine whether there was a significant difference among the temperature treatments and reference materials or among genotypes. Enzyme resistant starch was found to significantly increase in HT (2.27%) and UHT dried pasta starch (2.51%). Amylose content significantly differed among genotypes, but not among drying treatments. Differential scanning calorimetry (DSC) gelatinization enthalpy, onset, and peak temperatures increased; and temperature range was narrower for pasta starches. There was no increase in the amount of amylose-lipid complex formed in dried pasta, as revealed by the second endothermic DSC peak. Starch pasting properties were also assessed. Peak viscosity of LT (340.9 RVU) and HT dried pasta starches decreased (356.9 RVU), while that of UHT dried pasta (398.0 RVU) was similar to semolina starch (381.4 RVU). All pasta starches had a lower final viscosity (394.2 to 447.8 RVU) than did wheat starch (469.3 RVU).