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Download fileInfluence of Temperature and Humidity on the Stability of Carotenoids in Biofortified Maize (Zea mays L.) Genotypes during Controlled Postharvest Storage
journal contribution
posted on 2016-03-03, 00:00 authored by Darwin Ortiz, Torbert Rocheford, Mario G. FerruzziMaize
is a staple crop that has been the subject of biofortification
efforts to increase the natural content of provitamin A carotenoids.
Although significant progress toward increasing provitamin A carotenoid
content in maize varieties has been made, postharvest handling factors
that influence carotenoid stability during storage have not been fully
established. The objectives of this study were to determine carotenoid
profiles of six selected provitamin A biofortified maize genotypes
at various developmental stages and assess the stability of carotenoids
in maize kernels during controlled storage conditions (12 month period),
including elevated temperature and relative humidity. There were no
significant changes in the content of individual carotenoids within
genotypes during kernel development from 45 days after pollination
through the time of harvest. Carotenoid losses through traditional
grain drying were also minimal (<9%). However, the stability of
carotenoids in maize kernels over storage time after harvest was found
to be dependent on both temperature and humidity, with variation observed
among genotypes. Different forms of provitamin A carotenoids follow
similar degradation rates. The genotype C17xDE3
had a degradation rate 2 times faster than those of the other genotypes
evaluated (P < 0.001). These differences in carotenoid
stability under controlled storage were attributed, in part, to observed
differences in the physical properties of the kernels (surface area
and porosity). These results support the notion that effective control
of moisture content and temperature of the kernels during storage
conditions is essential to reduce the speed of degradative reactions.