In this study, the effect of ascorbic acid addition
as stabilizer on
degradation kinetics of betacyanin pigments of red beet (Beta vulgaris L.) extract was investigated under different temperature (4, 25,
40, 60oC) and pH (5.5,
7.5, 9.5) conditions. In general, although the degradation of betacyanins seems to follow the first-order reaction kinetics
under all investigated conditions, it was determined that the degradation
kinetics of betacyanins shows a change and indicates a better fit to the second
order reaction kinetics at pH 5.5 with the addition of ascorbic acid and at the
temperature of 4°C. It was observed that reaction rate constant (k) values
increased significantly with increasing pH and temperature. k values decreased
significantly while activation energy (Ea) values increased with the addition
of ascorbic acid. Among all results, the lowest k value was reached at 4oC and pH 5.5 with a value of 0.006×10-3 min-1 in the samples with ascorbic acid, while the highest k value was reached at 60oC
and 9.5 pH with a value of 28.65×10-3 min-1 in the
samples without ascorbic acid. Activation energy value ranging between 53.4 and
87.7 kJ/mol was found to be lowest at pH 9.5. The kinetic of color change was
also evaluated using the first order model.
Bu çalışmada farklı
sıcaklık (4,
25, 40, 60oC) ve pH (5.5,
7.5, 9.5) koşullarında stabilizatör
olarak askorbik asit ilavesinin kırmızı pancar (Beta vulgaris L.) suyu
betasiyanin pigmentlerinin bozunma kinetiği üzerine etkileri incelenmiştir. Betasiyaninlerin
bozunumunun tüm koşullar için birinci dereceden reaksiyon kinetiğini takip
ettiği tespit edilmiştir. Reaksiyon hız sabiti (k) değerlerinin artan pH ve sıcaklık
ile önemli derecede arttığı gözlenmiştir. Askorbik asit ilavesi ile k değerleri
önemli oranda azalırken, aktivasyon enerjisi (Ea) değerleri artmaktadır. Tüm sonuçlar içerisinde en düşük k değerine 4oC’de
5.5 pH’da askorbik asit ilave edilmiş örneklerde 0.006×10-3 dak-1
değeri ile ulaşılırken en yüksek k değerlerine 60oC’de 9.5
pH’da askorbik asit ilavesiz örneklerde 28.65×10-3 dak-1 değeri
ile ulaşılmıştır. 53.4-87.7 kJ/mol arasında değişen aktivasyon enerjisi
değerleri, pH 9.5’ta en düşük bulunmuştur. Ayrıca örneklerin renk değişim
kinetiği de birinci dereceden model kullanılarak incelenmiştir.
Primary Language | Turkish |
---|---|
Subjects | Engineering |
Journal Section | Research Articles |
Authors | |
Publication Date | August 31, 2018 |
Submission Date | December 27, 2017 |
Acceptance Date | June 18, 2018 |
Published in Issue | Year 2018 Volume: 23 Issue: 2 |
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