Degrees of polymerization (DP) by n

Degrees of polymerization (DP) by number for amylose and amylopectin of pearl millet were 1060–1250 and 9000–9100, respectively (Gaffa et al., 2004). The molecular weights of amylose and amylopectin were in the range of 105–106 and 107, respectively (Madhusudhan &Tharanathan, 1996; Wankhede et al., 1979). It should be noted that differentmethods formeasuring themolecular size (e.g., low-pressure gelpermeation chromatography based method vs high-performance sizeexclusion chromatography based one) may give different values for the same sample. To avoid the impossibility of direct comparison of some data fromdifferent studieswhich is indeed unfortunately so common in our global starch research community, systematic studies using the same instrumental setting are needed to establish a comparative database. When starch molecules are subjected to exo-acting enzymes(e.g., phosphorylase a and/or β-amylase), amylose/amylopectin is
hydrolysed from the non-reducing ends and the enzyme action stops close to the branches (Bertoft, 2004). The remnant part is termed limit dextrins (LDs) and represents the internal part of the starch components. The limit value (β- or φ,β-LV) (%) represents the external part of amylose/amylopectin that is removed enzymatically. β-LV (%) of amylose ranged from 78.4 to 93.7%, and of amylopect in 52.1–58.7% (Gaffa et al., 2004; Madhusudhan & Tharanathan,1996; Wankhede etal., 1979). φ,β-LV (%) of amylopectins from four millet species ranged from 57.7 to 59.8% (Annoret al., 2014a). The unit chains of starch component can be categorized into A- and B-chains. The former carries no other chains and the latter at least one chain (Peat, Whelan, & Thomas, 1952). The ratio of A- to B-chain is an
important structural aspect (Bertoft, 2004). When the amylopectin is subjected to the sequential hydrolysis of phosphorylase a and β-amylase to obtain the φ,β-LDs, A-chain can be correctly quantified from the maltose of φ,β-LDs after debranching. The amount of Achains of amylopectins from four millet species ranged from 49.4 to
50.7% (Annor et al., 2014a). The A- to B-chain ratio as ~1 indicates a similar