Biochemical profiling of mucilage extracted from seeds of different citrus rootstocks

Hetero-polysaccharide mucilage was extracted from the seed coats of different citrus rootstocks viz. Rough lemon, Sachtion citrumelo and Yuma citrange for investigating its biochemical and molecular properties. Investigations showed that the mucilage contained (mg/g) starch 3.13–5.04; maltose 3.23–4.31; glucosamine 0.017–0.289; d-xylose 0.059–0.107 and total soluble sugars 8.13–11.82. Specific enzyme activities were 16.98–35.96, 30.60–98.45, 42.00–73.98, 660.98–738.35 and 7.660–19.27 IU mg−1 of protein for protease, amylase, catalase, peroxidase and superoxide dismutase, respectively. Proximate analysis showed 12.85–13.94% moisture, 11.25–14.06% crude protein, 0.31–0.86% crude lipid, 1.31–2.69% crude fibre, 2.95–3.45% ash and 81.48–91.49 kJ 100 g−1 energy. The comparative characterization of the extractable proteins was profiled by SDS-PAGE and quantified using Bradford assay. Structural properties of samples were analyzed and compared using Fourier transformation infrared (FT-IR) spectroscopy.