Effect of temperatureThe degradatio

Effect of temperature
The degradation rate constants of cyanidin-3-glucoside and
cyanidin-3-rutinoside both increased with increasing temperature
under all pH conditions (Table 1). The slightly decrease of the degradation
rate of cyanidin-3-rutinoside at pH 6.0 & 165 C may be
due to the low level of cyanidin-3-rutinoside in samples which
was hard to measure. The lowest (8.99  104 s1) and highest
(0.120 s1) degradation rate constants for cyanidin-3-glucoside
were observed at pH 2.2 & 100 C, and at pH 6.0 & 165 C,
respectively, whereas for cyanidin-3-rutinoside, the lowest
(5.33  104 s1) and highest (7.39  102 s1) degradation rate
constants were observed at pH 2.2 &100 C, and at pH 5.0 &
165 C, respectively.
Higher temperatures led to a faster degradation of the two
anthocyanins. An increase in temperature from 100 to 121 C
increased the degradation rate constant by 3–5 times for both
cyanidin-3-glucoside and cyanidin-3-rutinoside, e.g., for cyanidin-
3-glucoside at pH 2.2, the degradation rate constant increased
4.7 times from 8.99  104 to 4.25  103 s1, and for cyanidin-3-
rutinoside at pH 5.0, the degradation rate constant increased 4.2
times from 8.53  104 to 3.56  103 s1. An increase from 121
to 135 C or from 135 to 145 C roughly doubled the degradation
rate constant, e.g., for cyanidin-3-glucoside at pH 5.0, the rate constant
increased 2.2 times from 5.53  103 to 1.22  102 s1 as
the temperature increased from 121 to 135 C, and for cyanidin-
3-rutinoside at pH 3.0, the degradation rate constant increased
1.8 times from 7.64  103 to 1.40  102 s1 as the temperature
increased from 135 to 145 C. An increase from 145 to 165 C
would increase the rate constant 3–4 times, e.g., for cyanidin-3-
glucoside at pH 6.0, the degradation rate constant increased 3.8
times from 3.14  102 to 0.120 s1, and for cyanidin-3-rutinoside
at pH 4.0, the degradation rate constant increased 3.8 times from
1.37  102 to 5.27  102 s1. These observations were in good
agreement with the well-known Q10 law, which states that a reaction
rate approximately doubles with every 10 C of temperature
increase (Beˇhrádek, 1930).
Cyanidin-3-rutinoside showed lower degradation rate constants
than cyanidin-3-glucoside under all conditions, indicating
that cyanidin-3-rutinoside was more stable than cyanidin-3-glucoside.
Rubinskiene et al. (2005) examined the thermal stability of
cyanidin-3-glucoside and cyanidin-3-rutinoside extracted from
black rice and they found that the amounts of cyanidin-3-rutinoside
and cyanidin-3-glucoside were decreased by 35% and 53%,
respectively, after a thermal treatment at 95 C for 150 min. This
could be due to the additional glycosylation present in cyanidin-
3-rutinoside which conferred a stabilizing effect. In general, diglucoside
derivatives are more stable than monoglucosides due to
the protective effect of the bounded sugars through inhibiting
the formation of unstable intermediates which will further degrade
into phenolic acids and aldehydes (Fleschhut, Kratzer,
Rechkemmer, & Kulling, 2006).

ผลลัพธ์ (ไทย) 1:

Effect of temperatureThe degradation rate constants of cyanidin-3-glucoside andcyanidin-3-rutinoside both increased with increasing temperatureunder all pH conditions (Table 1). The slightly decrease of the degradationrate of cyanidin-3-rutinoside at pH 6.0 & 165 C may bedue to the low level of cyanidin-3-rutinoside in samples whichwas hard to measure. The lowest (8.99  104 s1) and highest(0.120 s1) degradation rate constants for cyanidin-3-glucosidewere observed at pH 2.2 & 100 C, and at pH 6.0 & 165 C,respectively, whereas for cyanidin-3-rutinoside, the lowest(5.33  104 s1) and highest (7.39  102 s1) degradation rateconstants were observed at pH 2.2 &100 C, and at pH 5.0 &165 C, respectively.Higher temperatures led to a faster degradation of the twoanthocyanins. An increase in temperature from 100 to 121 Cincreased the degradation rate constant by 3–5 times for bothcyanidin-3-glucoside and cyanidin-3-rutinoside, e.g., for cyanidin-3-glucoside at pH 2.2, the degradation rate constant increased4.7 times from 8.99  104 to 4.25  103 s1, and for cyanidin-3-rutinoside at pH 5.0, the degradation rate constant increased 4.2times from 8.53  104 to 3.56  103 s1. An increase from 121to 135 C or from 135 to 145 C roughly doubled the degradationrate constant, e.g., for cyanidin-3-glucoside at pH 5.0, the rate constantincreased 2.2 times from 5.53  103 to 1.22  102 s1 asthe temperature increased from 121 to 135 C, and for cyanidin-3-rutinoside at pH 3.0, the degradation rate constant increased1.8 times from 7.64  103 to 1.40  102 s1 as the temperatureincreased from 135 to 145 C. An increase from 145 to 165 Cwould increase the rate constant 3–4 times, e.g., for cyanidin-3-glucoside at pH 6.0, the degradation rate constant increased 3.8times from 3.14  102 to 0.120 s1, and for cyanidin-3-rutinosideat pH 4.0, the degradation rate constant increased 3.8 times from1.37  102 to 5.27  102 s1. These observations were in goodagreement with the well-known Q10 law, which states that a reactionrate approximately doubles with every 10 C of temperatureincrease (Beˇhrádek, 1930).Cyanidin-3-rutinoside showed lower degradation rate constantsthan cyanidin-3-glucoside under all conditions, indicatingthat cyanidin-3-rutinoside was more stable than cyanidin-3-glucoside.Rubinskiene et al. (2005) examined the thermal stability ofcyanidin-3-glucoside and cyanidin-3-rutinoside extracted fromblack rice and they found that the amounts of cyanidin-3-rutinosideand cyanidin-3-glucoside were decreased by 35% and 53%,respectively, after a thermal treatment at 95 C for 150 min. Thiscould be due to the additional glycosylation present in cyanidin-3-rutinoside which conferred a stabilizing effect. In general, diglucosidederivatives are more stable than monoglucosides due toผลของน้ำตาลกี่ผ่าน inhibiting ป้องกันการก่อตัวของตัวกลางที่ไม่เสถียรซึ่งจะย่อยสลายกรดฟีนอและ aldehydes (Fleschhut, KratzerRechkemmer, & Kulling, 2006)