| Summary: | 碩士 === 國立中興大學 === 畜牧學系 === 86 === The purpose of this study was conducted to examine cow milk
or reconstituted milk components in goat milk by electrophoresis
method. Based on the varied electrophoretic mobilities of milk
proteins, (s1-casein demonstrated a higher electrophoretic
mobility than (s2-casein. Moreover, since (s1-caseinis is absent
or account for a minor content in goat milk, consequently the
characteristics of goat (s1-casein make it easy to detect
adulteration of goat milk with cow milk. To precipitate more
casein contents, milk proteins were separated by the isoelectric
point of casein at pH 4.6. The casein concentrations in Saanen、
Toggenberg、Nubian、Alpine and Lamancha goats were: 25.46±1.98
mg/ml、22.08±1.29mg/ml、22.68±1.75mg/ml、24.21±1.15mg/ml
、29.13±1.87mg/ml respectively。 Goat or bovine caseins in
the agarose gels displayed three major bands of A、B and C.
Fresh goat milk、reconstituted goat milk(Bate(s or Sentosa)、
fresh cow milk and reconstituted cow milk also dramatically
varied in band proportions after densitometerically scanned, as
following: fresh goat milk, A band 11.98±0.59%、B band
41.41±0.53%、C band 46.62±0.63%；reconstituted goat milk(Bate(
s ), A band 10.38±0.52%、B band 32.25±0.59%、C band
57.37±0.77%；reconstituted goat milk(Sentosa), A band
9.99±0.68% band 36.54±0.79%、C band 53.45±0.47%；fresh cow
milk, A band 54.77±0.64%、B band 8.90±0.42%、C band
36.33±0.38%；reconstituted cow milk, A band 51.32±0.74%、B
band 9.84±0.43%、C band 38.85±0.66%. With the adulteration of
reconstituted or fresh cow milk, the relative area proportions
of A and B bands in fresh goat milk showed a dramatically
change. However, when added with reconstituted goat milk, the
area proportion of A and B bands in fresh goat milk were not
altered. Since the area percentage of A band in goat milk was
closely proportional to the content of fresh or reconstituted
cow milk in casein electropherogram, regression analysis between
the adulterated cow milk content and area percentage of A band
in fresh goat milk revealed a high correlation coefficient(
r2=0.98). The results of this study can be employed to detect
the adulteration of fresh or reconstituted cow milk in fresh
goat milk.
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