3.3. Flour fluidity and morphology
The angles of repose and slide are used to describe the fluidity of
flours. The addition of carrier improved the fluidity of the flours as
indicated by the decreased angles of repose and slide with carrier
(Table 1). In addition, the flour withMDhad significant lower values
in repose and slide angles than those with b-CD and MD/b-CD. The
surface of the reference flour was quite irregular and dented
(Fig. 2A). This can be attributed to the disruption of starch granules
induced by heat. The disrupted starch granules are less compact and
come in larger particles. On the contrary, the surfaces of most starch
granules in flours with carriers were smooth (Fig. 2BeD) and only
a few of damaged surfaces were occasionally observed with larger
particles. This fact reflected the protective effects of carrier on starch
granules. Combined with Table 1 and Fig. 2, it is evident that the
fluidity of the flour is positively related with its particle size and
degree of agglomeration. The higher degree of agglomeration for
flour without carrier resulted from the interaction of disrupted and
sticky regions of starch granules (Goula & Adamopoulos, 2008).