Spent residue from cumin – a potential source of dietary fiber

Cumin has total dietary fiber content (TDF) of 59.0%, insoluble dietary fiber (IDF) of 48.5%, and soluble dietary fiber (SDF) of 10.5%, while the spent residue from cumin (after oil and oleoresin extraction) was found to contain 62.1% TDF, 51.7% IDF and 10.4% SDF. The spent residue also contained 7.7% starch and 5% bound fat. Particle size analysis showed a direct effect on the hydration properties of the fiber. The spent residue exhibited 3.3 g/g water holding capacity, 4.0 g/g water retention capacity and 4.47 ml/g swelling capacity. Scanning electron microscopy revealed spherical starch granules embedded within cell wall material, which upon differential sedimentation gave differently sized starch granules (5.8 μm). Upon defatting the spent residue showed typically a ‘honey comb’ structure, almost devoid of starch granules. Thus, the spent residue from cumin, not having much commercial value at present, can be a rich source of useful dietary fiber and can find food applications. It can be an effective way of utilizing industrial waste from the point of view of environmental pollution from the residues of spice processing industries.