Freezing induces reversible colour-change in both zeaxanthin-biofortified and yellow sweet-corn

O'Hare, T. J., Calvo-Brenes, P., Fanning, K. and Pun, S. (2015). Freezing induces reversible colour-change in both zeaxanthin-biofortified and yellow sweet-corn. In: T. J. O'Hare and M. E. Netzel, XXIX International Horticultural Congress on Horticulture: Sustaining Lives, Livelihoods and Landscapes (IHC2014): VI International Symposium on Human Health Effects of Fruits and Vegetables (FAVHEALTH 2014). XXIX International Horticultural Congress on Horticulture: Sustaining Lives, Livelihoods and Landscapes (IHC2014), Brisbane, Australia, (73-77). 17-22 August 2014. doi:10.17660/ActaHortic.2015.1106.12


Author O'Hare, T. J.
Calvo-Brenes, P.
Fanning, K.
Pun, S.
Title of paper Freezing induces reversible colour-change in both zeaxanthin-biofortified and yellow sweet-corn
Conference name XXIX International Horticultural Congress on Horticulture: Sustaining Lives, Livelihoods and Landscapes (IHC2014)
Conference location Brisbane, Australia
Conference dates 17-22 August 2014
Convener O'Hare, T. J.
Proceedings title XXIX International Horticultural Congress on Horticulture: Sustaining Lives, Livelihoods and Landscapes (IHC2014): VI International Symposium on Human Health Effects of Fruits and Vegetables (FAVHEALTH 2014)   Check publisher's open access policy
Journal name Acta Horticulturae   Check publisher's open access policy
Place of Publication Leuven, Belgium
Publisher International Society for Horticultural Science
Publication Year 2015
Sub-type Fully published paper
DOI 10.17660/ActaHortic.2015.1106.12
Open Access Status Not Open Access
ISBN 9789462611009
ISSN 0567-7572
2406-6168
Editor T. J. O'Hare
M. E. Netzel
Volume 1106
Start page 73
End page 77
Total pages 5
Chapter number 12
Total chapters 36
Language eng
Abstract/Summary Zeaxanthin-biofortified sweet-corn is a deeper golden-orange colour than regular yellow sweet-corn due to a greater ratio of orange carotenoids (zeaxanthin, β-cryptoxanthin and β-carotene) to yellow carotenoids (lutein, zeinoxanthin). Freshly-harvested zeaxanthin-biofortified and yellow corn-cobs were subjected to freezing 
(-20°C) and assessed for colour-change (hue angle). Freezing kernels at -20°C was observed to significantly reduce hue angle by approximately 4-6°, with decline slightly greater in zeaxanthin-biofortified kernels than in yellow kernels. Frozen kernel hue angle could be predicted by linear correlation with fresh kernel hue angle (r2=0.90). Carotenoid-analysis of zeaxanthin-biofortified and yellow corn confirmed no significant change in carotenoid profile due to freezing, apart from slight changes to antheraxanthin, β-cryptoxanthin and β-carotene. This indicates that colour changes may be due to physical, rather than chemical changes. In order to investigate if cell membrane disruption was the cause of colour change, fresh kernels of zeaxanthin-biofortified and yellow sweet-corn were blended into a slurry, and hue angle measured after freezing to -20°C. Decline in hue angle was similar to that of intact kernels, indicating membrane disruption was unlikely to be responsible. Fresh cobs were subsequently subjected to freezing and subsequent thawing. Thawing to room-temperature resulted in a reversal of hue angle to the original values of fresh kernels. The results indicate that colour change due to freezing may be due to the formation of ice-crystals, possibly interfering with light absorption, as the effect disappeared once the ice-crystals had melted. Rapid freezing with liquid nitrogen had less effect on hue angle than freezing at -20°C, indicating that ice-crystal size may also play a role. The observation of why orange cobs are affected more than yellow cobs remains to be elucidated.
Keyword Carotenoids
Hue angle
Frozen
Thawing
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 0 times in Thomson Reuters Web of Science Article
Scopus Citation Count Cited 0 times in Scopus Article
Google Scholar Search Google Scholar
Created: Tue, 26 Apr 2016, 12:38:16 EST by System User on behalf of Centre for Nutrition and Food Sciences