Green Preparation of Citric Acid Crosslinked Starch for Improvement of Physicochemical Properties of Cyperus Starch.

Abstract

This study was undertaken to assess the properties of Cyperus esculentus tuber starch crosslinked with citric acid from liquid substrates of orange peel derived via the natural solid-state fermentation process; a green approach. The flow properties of the prepared starches were evaluated using standard methods. Water-holding capacity, swelling capacity, moisture sorption capacity, gelatinization temperature using differential scanning calorimetry, morphology, fourier infrared spectroscopy, and pH of the starches were evaluated. Results showed that the pH of the crosslinked starches were lower (3.39-4.07) than that of the native starch (5.25) and the flow profile was found to improve. The crosslinked starches' water-holding capacity (90.67%-96.69%) were higher, whereas its emulsion capacity (15.33) was similar to that of the native starch (15.33). No change was observed in the morphology of the crosslinked starches' granules. The infrared spectra of the native and crosslinked starches showed identical peaks; however, the enthalpy of gelatinization (ΔHgel) of the crosslinked products were found to differ from that of the native starch. Modified starches show propensity of being exploited as binding agents in food and pharmaceutical industries. The green modification process proved to be a valuable addition to the available starch modification processes.