Abstracts Book - IMRC 2018

• SB6-P060
FUNCTIONAL AND PHYSICOCHEMICAL PROPERTIES OF
NIXTAMALIZED BLUE AND RED CORN FLOURS OBTAINED BY
EXTRUSION COOKING
Erich Von Borries Medrano 1 , Monica Rosalía Jaime Fonseca 1 , Miguel Angel Aguilar Méndez 1 ,
Cinthya Nathaly Quiroz Reyes 1 , Héctor Iván García Cruz 1
1 Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Legaría, IPN, Laboratorio
de Biomateriales, Mexico.
This research aimed to prepare nixtamalized flours using blue and red corn by
extrusion cooking keeping their functional properties required nowadays in
snacks industry. The extruded samples were formulated according to a central
composite experimental design of two variables: hydroxide calcium
concentration (0.3-0.7% w/w) and moisture content (32-44%).
Viscosity, water solubility index (WSI), water absorption index (WAI) and total
phenolic content were analyzed through response surface methodology (RSM).
While X-ray diffraction and DSC studies were used to evaluate the thermal
properties of flours.
Higher levels of moisture content and the calcium hydroxide concentration lead
an increment in peak viscosity, 167 mPaâˆÂs to 2092 mPaâˆÂs, and
decreased WAI, 5.02 to 3.56 gr gel/gr sample in nixtamalized blue corn flour
elaborated by extrusion. The same levels of variation of hydroxide calcium in
nixtamalized red corn flour resulted in a variation 266.5 mPaâˆÂs and 1348
mPaâˆÂs respectively in peak viscosity and 4.48 to 3.80 gr gel/gr sample in
WAI. This stated that Ca ++ ions interact with starch granules and reach deeper
regions, resulting in granules with better structure, higher gelatinization
temperature and peak viscosity, and moisture content can protect granules
damage.
The polyphenol content measurement showed a reduction compared with
native flours of 2.69 to 1.88 g of gallic acid equivalents/kg in nixtamalized blue
corn flour while the nixtamalized red corn flour had a reduction of 3.18 to 1.85
g of gallic acid equivalents/kg when lime concentration increased. This behavior
can be assumed to the oxidation of polyphenols due to the lime addition but
this reduction is lower than others in flours prepared by the traditional