| Summary: | 碩士 === 國立臺灣大學 === 食品科技研究所 === 84 === The objective of this study was to examine the effect of the
fine structures of rice amylose(AM) and amylopectin(AP) on the
rheological properties of starch gel.Two indica rices(KSS7,TCS10)
,one japonica rice(TNu67),and two waxy rices(TCSW1,HCW4) were
chosen in thr study The fine structure of amylose subfractions(F1
,F2) and unsubfracted amylose were analyzed.The result indicated
that the average chain number of TNu67 AM,TNu67F1 and TNu67F2
were all higer than those of KSS7 and TCS10, respectively.The
iodine affinities of F1 and F2 were lower than unsubfracted
AM.When the F1 and F2 were mixed by weight percentage,its value
of the iodine affinity was equal to those of unsubfracted AM;the
phenomenon might be due to the interaction of F1 and F2. AM with
the higher DPn or AP with the longer ECL would give the higher G''
and the smaller loss tangent in the 3% AM gels or 9% AP gels.
However,AM and/or AP with the high degree of branching and the
lower of DPn made the gel with the smaller G''and randomly
distributed tan delta during retrogradation.The rheological
properties of the reconstituted starch of 3%AM and 9% AP were
also influenced by the DPn and the degree of branching of AM and
AP,and ECL of AP.The lower DPn and higher degree of branching of
AM and AP,and ECL of AP.The lower DPn and higher degree of
branching of amylose and/or AP gave thereconstituted starch gel
with the larger initial tan delta, and final tan delta. The
effect of the fine structures of subfracted AM and AP on its
reconstituted gel properties was similar to those of unsubfracted
AM and AP. Excepted TNu67 subfractions,the reconstituted starch
gels with KSS7F1 or TCS10F1 showed higher G''f than those with
KSS7F2 or TCS10F2.All reconstituted starch gel containing AP of
branching had lower data of DELTA G",but no trend was found in
DELTA G''and DELTA tan delta.
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