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Osmotic dehydration kinetics of biofortified yellow-flesh cassava in contrast to white-flesh cassava (Manihot esculenta)

In recent times, the cultivation, processing and
consumption of biofortified yellow-flesh cassava is of
significant interest to breeders and food processors due to
its relatively high pro-vitamin-A content, compared to the
conventional white-flesh cassava. In light of this, osmotic
dehydration (OD) kinetics of a recently released biofortified
yellow-flesh cassava was compared to that of a whiteflesh
cassava, using salt, sugar, and salt–sugar solutions at
different temperatures (30, 45, 60 C) and fixed cube/solution-
ratio. Water loss (WL) and solids gain (SG) data
were fitted by non-linear regression using four models
(Page, Weibull, Azuara, and Peleg). Azuara model was
most appropriate in describing OD kinetics for both cultivars.
Azuara estimates for equilibrium WL and equilibrium
SG, respectively, ranged between 0.101–0.120 and
0.049–0.094 g/g for salt solution, 0.158–0.212 g/g and
0.107–0.268 g/g for sugar solution and 0.234–0.306 g/g
and 0.189–0.276 g/g for salt–sugar solution. The best
conditions for OD of both cultivars by salt solution and
sugar solution was at 60 C and 45 C, respectively, while
that for salt–sugar solution varied with cultivar. Increasing
temperature increased water loss and solids gain. Salt-OD
conformed to Arrhenius temperature dependence of diffusivity,
but sugar-OD and salt–sugar-OD did not. Micrographs
reveal biofortified yellow-flesh cassava was more susceptible to cell wall collapse than white-flesh cassava.
Extent of dehydration by OD agents ranked: salt–sugar[
sugar[salt. Osmotic dehydration may be useful as a
means of dehydration for cassava prior to drying, and is
especially relevant for the carotenoids-rich biofortified
yellow cassava.

Oluwatoyin Ayetigbo, Sajid Latif, Adebayo Abass, Joachim Müller
Journal of Food Science and Technology