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Advisor(s)
Abstract(s)
The polyphenols have been identified as food components sensitive
to high temperatures; therefore, the application of heat treatments
can lead to a significant reduction in the phenolic content and
also on antioxidant capacity. The objectives of the present work
were to investigate the decrease in total phenolic compounds and
antioxidant activity in pears during air drying at different tem-
peratures and to model the kinetics of those variations. The pears
(cv. D. Joaquina) were dried at 60
◦
C and 70
◦
C in an electrical
drying chamber with hot air at 0.5 m / s. Along drying several
samples were collected for analysis, being submitted to multiple
extractions with methanol and acetone solutions. The phenolic
compounds were determined by the Folin-Ciocalteu method and
the antioxidant activity was determined by the ABTS method. The
results showed that three successive extractions with methanol fol-
lowed by three extractions with acetone solution was necessary for
an efficient quantification of the total phenolic compounds and
antioxidant activity. The decrease along drying was found to be
of about 40% for both parameters and for the two temperatures studied. Furthermore, a relatively strong relation was observed
between total phenols and antioxidant activity. The mathematical
modeling of the kinetics showed that a 3-parameter exponential
decay function was the best function to describe the experimental
data, and the kinetic constants were found to vary in the range
0.0136–0.0444 min− 1.
Description
Keywords
Pear Phenolic compounds Antioxidant ativity Mathematical model
Citation
Guiné RPF, Barroca MJ, Gonçalves FJ, Alves M, Oliveira S, Correia PMR. (2015) Effect of Drying on Total Phenolic Compounds, Antioxidant Activity, and Kinetics Decay in Pears. International Journal of Fruit Science, 15(2), 173-186.