Abstract:
Palmyrah tuber is a seasonal product of palmyrah palm (Borassus flabellifer L). Palmyrah
tuber flour is used to make starch-based products. However, the native starches have
restricted industrial applications. Therefore, modifications of native starches are carried
out to provide starch products with specific properties. In the present study, three different
starch modification techniques (pre-gelatinization, acid modification and dextrinization)
were used to produce modified palmyrah tuber starches. The physicochemical and
functional properties of the native and modified palmyrah tuber starches were evaluated
and compared. The resultant modified starches were compared with the native palmyrah
starch and a commercially available starch to find out their applicability as a thickener.
The extracted native starch yield was 16.04±0.56%. The recovery yields of modified
starches ranged between 75.90 - 91.96%. The crude protein, lipid and fiber contents of
modified starches significantly decreased compared to native starch (at p<0.05). The
water and oil absorption capacities of palmyrah starches were significantly increased
(p<0.05) after the modification processes. The dextrinized palmyrah starch showed
significantly (p<0.05) the lowest swelling power and the highest average solubility. The
pre-gelatinized palmyrah starch showed a significantly decreased level of syneresis of
its gel. The gelatinization temperature, amylose content (9.2 - 21.69%), amylopectin
content and the whiteness index (92.29 - 95.75) varied among the native and modified
starches. The total phenolic content (0.12±0.00 mg GAE/g) and the antioxidant
activity (DPPH-IC50 value 81.99±0.18 mg/ml) were higher in pre-gelatinized starch.
The sensory scores and the apparent viscosity were higher for pre-gelatinized and acidmodified
starch incorporated soup mixes than the native and dextrinized starch. The
study revealed that the modification processes can greatly improve the physicochemical
and functional characteristics of native starch and the feasibility of the application of
modified palmyrah starch as a thickening agent.
