The JFSS was treated with TA
aGT at 70
C for 1 h in the presence
of 0.1 mmol/L genistin so that the enzyme acted on the partially
gelatinized JFSS. The HPLC chromatogram showed that a genistineCA
complex was produced (Fig. 7A). The formation of genistineCA
was then confirmed by treatment with
b-amylase; in the
HPLC chromatogram, peaks from 6 upward decreased, whereas
peaks 2 and 3 increased (Li et al., 2005). This indicated that the
transfer product composed of different (glycosyl)
-genistin complexes
hydrolyzed gradually (Fig. 7B).
n
To investigate complex formation between lysolecithin and
amylose of the partially gelatinized JFSS, a DSC pan containing the
JFSS and lysolecithin was heated and held at 75
C for 15 min. The
second DSC run demonstrated that the first peak appearing in the
range of 58.4e74.4
C in native starch disappeared completely,
whereas the second peak remained, with a slight shift of onset
temperature from 79 to 82
C. The peak that appeared in the
100e115
C temperature range represented the lysolecithineamylose
complex that was formed between amylose released
from the partially gelatinized starch and lysolecithin (Fig. 2D).
However, in the case of pretreatment with genistin and TA
aGT at
70
C, the onset and conclusion temperatures were shifted to
88.7
C and 97.8
C, respectively (Fig. 2E). These unimodal endothermic
peaks might include genistineCA complex and ungelatinized
starch. The peak melting temperature of the
lysolecithineamylose complex was 106.7
C, whereas that of genistineCA
was 92.7
C. The difference in the peak melting temperature
of the inclusion complex was presumably due to the
interaction between host and guest molecules and also the status of
the complexes. The genistin-CA complex could protect of the guest
molecule from oxidation, heat, and low pH in a food matrix and
may prevent its early release in the gastrointestinal tract, as reported
by Cohen, Orlova, Kovalev, Ungar, and Shimoni (2008).