Detailed studies of the sta
rch p
resent in tube
rs of six accessions of
Pachyrhizus ahipa (ahipa) havebeen ca
rried out using sta
rches f
rom tube
rs of
P. erosus (Mexican yam bean) and seeds of ahipaand wheat fo
r compa
rison. Sta
rch accounted fo
r 56-58% of the tube
r d
ry weight with g
ranulesoccu
rring in a
range of geomet
ric fo
rms and in sizes f
rom below 5
r.gif">m to about 35
r.gif">m (mean about10
r.gif">m in all accessions except two). The amylose content
ranged f
rom 11.6 to 16.8% compa
redwith 16.9% in
P. erosus tube
rs and ove
r 23% in the seed sta
rches. X-
ray diff
raction analysis showedA-type o
r C
A-type diff
raction patte
rns. The chain-length dist
ribution of the amylopectin afte
r enzymedeb
ranching showed a peak at DP11 simila
r to that of wheat sta
rch, but had a less ma
rked shoulde
rat DP 21-22 and contained a highe
r p
ropo
rtion of longe
r chains. Diffe
rential scanning calo
rimit
ryshowed an endothe
rmic peak co
rresponding to gelatinization with
Tmax ranging f
rom 59 to 63
C,which was simila
r to the
Tmax of wheat (about 64
C). The composition of the ahipa sta
rch may meanthat it is suitable fo
r food applications that
requi
re low amylose content and low
ret
rog
radation afte
rp
rocessing.Keywo
rds: Sto
rage tube
rs; yam bean;
Pachyrhizus; food p
rocessing