Some physico-chemical properties of smooth pea starches

Structural studies of starches with different water contents

“…For starches from the same species, however, no difference in ⌬T was found in excess water or salt solution (Table IV). In agreement with previous reports, 17,24,37 a shift in T p was found for endotherms in salt solution compared with excess water (Figures 5a and b). This shift was found to be much larger for A-type (7-9°C) than for B-type (2°C) starches (Table IV).…”

“…The exception is wheat starch, which is the only known A-type starch with a T p in excess water that is similar to potato starch. 12,17,24,[31][32][33] A second peak (a-l in Figure 5a) with a higher T p was found for maize and wheat starches, which on cooling and reheating was completely reversible. This indicated that the nature of the a-l peaks was the disruption and reformation of amylose-lipid complexes.…”

“…Depending on the mutant, this may be a narrow transition, similar to that seen in starch from the WT, or a low broad transition. 2,12,17,[22][23][24] This second type of transition is often attributed to mutants containing mutations affecting branching enzymes associated with amylopectin synthesis-for example, mutations at the r locus in pea (Pisum sativum) and the ae locus in maize (Zea mays). 2,19,22,23,25 It is also known that this type of gelatinization is characteristic for starches from peas containing a mutation at the rug5 locus, which is known to affect a starch synthase involved in amylopectin synthesis.…”

“…14,17,[22][23][24]26 Data presented in these reports have shown that starch from WT peas is composed of complex granules in which B-polymorphs are at the centre and A-polymorphs at the periphery of all the granules. Also, x-ray diffraction was used to demonstrate variation for the proportion of A-and B-polymorphs in relatively dry starches from WT and some pea mutants.…”

“…Also, x-ray diffraction was used to demonstrate variation for the proportion of A-and B-polymorphs in relatively dry starches from WT and some pea mutants. 22,24 These approaches were used to pro-duce the data in the present paper together with new approaches that have been developed for determining the structural characteristics of starches equilibrated in excess water.…”