Characterization of rice starches extracted from Indian cultivars.

摘要

Physicochemical, morphological and pasting properties of starches isolated from 4 rice cultivars grown in India were studied. Amylose contents ranged between 4.7 and 30.2%, and were highest in K332 starch and lowest in SR1 starch. Swelling power, water solubility and water absorption capacity of starches increased with increase in temperature from 50 to 90 degrees C at 10 degrees C intervals. Highest swelling and water absorption was found in SR1 and lowest in K332 starches but the reverse was true for solubility. Microstructure of starch granules from different rice cultivars showed the presence of mainly polyhedral granules having an average size in the range 4.0-5.2 mum. K332 contained the smallest granules, whereas SR1 starch contained the largest granules. X-ray diffraction patterns of rice starch from different cultivars showed typical A-type crystallinity. Pasting properties of starches differed significantly. Pasting temperature was highest for K332 and lowest for SR1, while peak viscosity was highest for aromatic rice and lowest for K448 starches. Higher setback was observed in K332 and lowest in SR1.