Antioxidant properties of isolated compounds from banana rhizome.

UNLABELLED: In this study, we attempted to explore banana rhizome (BR) as a source of natural bioactive compounds. Dried BR powder was subjected to sequential extraction using solvents with increasing polarity and studied for antioxidant activities. Chloroform and acetone extracts were selected for isolation and identification of bioactive compounds because of their high antioxidant properties. Antioxidant activity guided fractionation of these extracts yielded 3 compounds. The spectroscopy studies revealed the identity of isolated compounds as 4-epicyclomusalenone, cycloeucalenol acetate and chlorogenic acid. Polyphenolic compound chlorogenic acid and triterpenoid compounds, 4-cyclomusalenone and cycloeucalenol acetate displayed multifunctional antioxidant activity. PRACTICAL APPLICATION: The isolated compounds namely 4-epicyclomusalenone, cycloeucalenol acetate and chlorogenic acid have demonstrated their antioxidant properties in different in vitro assay models. The present study indicated that the vast quantity of banana rhizome which was incinerated could be a potential source of natural antioxidant compounds. This can also be used in the food, nutraceutical and pharmaceutical industries.

Turmeric powder and starch: selected physical, physicochemical, and microstructural properties.

UNLABELLED: Turmeric powder and its starch were characterized for physical, physicochemical, and microstructural characteristics. X-ray diffractogram indicated that turmeric starch to be of B type. Dried and cured-dried turmeric powder samples showed higher water-holding capacity (3.62 and 4.78 g/g, respectively) compared to isolated starch (1.07 g/g) at 30 °C. Non-Newtonian shear-thinning characteristics were observed with turmeric powder dispersion containing 10% (w/w) solids. A power law model fitted well to correlate the shear-rate and shear-stress data (r= 0.993 to 0.999, P≤ 0.01) for both samples. Apparent viscosities of isolated turmeric starch and cured-dried turmeric powder dispersion containing 10% (w/w) solids were 1.29 ± 0.03 and 7.57 ± 0.39 mPa s, respectively. Microstructure of starch particles showed a smooth flat outer surface. The approximate length and breadth of isolated elliptical starches were 25 and 10 µm while the thickness was about 5 µm. PRACTICAL APPLICATION: Isolation and characterization of starch from an unconventional source like turmeric rhizome indicate a potential application as a functional ingredient in foods and pharmaceutical industries including agglomerated products.