Abstract:
Psyllium husk, derived from the seeds of Plantago ovata, has attracted substantial scientific
interest in recent years due to its notable nutritional composition, functional properties, gelforming
ability, and potential health-promoting effects. This study aimed to provide a simplified
and practical characterisation of commercial Psyllium husk to support its application in
developing or modifying food products. The present study was carried out as the first investigation
in Sri Lanka to examine the physicochemical, nutritional, hydration properties, and some
functional properties of commercial Psyllium husk. According to the research methodology,
physicochemical properties (colour analysis, whiteness, bulk density, and pH) and hydration
properties (water holding capacity, water retention capacity, swelling capacity, fat absorption
capacity, water solubility index, and hygroscopicity) were determined. Functional properties,
which are antioxidant content, volatile compounds, and functional groups, were determined by
DPPH assay, SPME-GC-MS technique, and FT-IR analysis, respectively. Nutritional compositional
analysis was done using AOAC official methods. The average whiteness of dry Psyllium
husk was 64.86±0.61, while the average L*, a*, and b* colour values were 72.06±0.65,
3.22±0.57, and 21.07±0.65, respectively. The bulk density and pH of the Psyllium husk sample
were 504.33±7.51 gL−1 and 5.37±0.05, respectively. The proximate analysis indicated
that carbohydrates constituted 78.43% of Psyllium husk, with moisture at 12.59±0.30%, total
fat 2.23±0.16%, crude protein 1.24±0.03%, total ash 2.12±0.12%, dilute HCl acid-insoluble
ash 0.23±0.02%, and crude fibre 3.15±0.08%. The hydration properties of Psyllium husk included
water holding capacity of 21.73±0.86 g/g, water retention capacity of 9.44±0.64 g/g,
swelling capacity of 20.43±0.94 ml/g, water solubility index of 7.13±0.50%, fat absorption capacity
of 1.05±0.01 g/g, and hygroscopicity of 8.23±0.65% after 5 days and 9.45±0.87% after
7 days. The antioxidant content of Psyllium husk was 26.16±0.19 μg ml−1. The total number
of volatile compounds detected was 13. The SPME technique mainly isolated long-chain
n-alkyl compounds and caryophyllene. Labelled peaks of the FT-IR spectrum confirmed that
Psyllium husk contains complex carbohydrates, including hemicellulose, cellulose, uronic acid
residues, and mainly arabinoxylans. This study clearly shows that commercial Psyllium husk
has valuable nutritional, hydration properties, and functional compounds, making it a highly
suitable ingredient for developing functional and health-promoting food products.
