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Effects of Different Salts on Mixing and Extension Parameters on a Diverse Group of Wheat Cultivars Using 2-g Mixograph and Extensigraph Methods

¹CSIRO Plant Industry, GPO Box 1600, Canberra, ACT 2601, Australia. ²Corresponding author. Phone: 61 2 62465028. Fax: 61 2 62465000. E-mail: Barbara.Butow@csiro.au. ³BUTE, Dept. Biochemistry and Food Technology, Budapest, Hungary.

Cations of differing chaotropic capacities (LiCl, NaCl, and KCl) were used in small-scale mixing and extensigraph studies to assess functional changes in dough behavior of wheat cultivars varying in total protein content and HMW glutenin composition. Salt addition, regardless of cationic type, caused an increase in dough strength and stability. The smaller (hydrated) and least chaotrophic cations (Li⁺<Na⁺<K⁺) effected the greatest increase in mixing time (MT) and resistance to extension (R_max) and produced the most stable resistance breakdown (RBD). The effects of different cations on mixing and extensions indicated strong intercultivar variation; differential responses to salt addition were further shown when the cultivars were grouped according to protein content and Glu-1D or Glu-1B genome composition. Increases in dough strength parameters due to the addition of salt were consistently more significant for cultivars showing an overexpression of Bx7 (>12% protein). In the absence of genotypic variation, a significant interactive effect of cultivar type, protein amount, and salt addition was found for all functional dough parameters except extensibility. During mixing, there was a decrease in the amount of apparent unextractable polymeric protein (%UPP) in the dough. This phenomenon was ameliorated by the presence of salt in doughs formed from weaker flours and was most pronounced early on in the mixing process (t = 100–200 sec). Results show the importance of refining 2-g mixograph studies to include salt in the “flour and water” dough formula.