Colour analysis of syrup from malted and unmalted rice of different varieties

Abstract

The colour of rice syrup produced from flours of malted and unmalted rice of different varieties treated with a combination of starch hydrolyzing enzymes were analysed using CIE-LAB Spectrophotometric colorimeter after being filtered and/or centrifuged. The resulting syrups were processed as filtered unmalted hydrolyzed rice (FUHR), filtered malted hydrolyzed rice (FMHR), centrifuged unmalted hydrolyzed rice (CUHR) and centrifuged malted hydrolyzed rice (CMHR). Results showed that L* ranged from 60.16 to 68.57, a* ranged from 10.49 to 11.13 and b* ranged from 55.34 to 64.56. The magnitude of the colour values was an indication of the intensity of the rice syrup colour. Hue angle (oH*) ranged from 79.08o to 80.36o indicating less yellow in the CIE-LAB colour space and brown colour spectrum in the visible region of opponent colour chart. Total colour difference (ΔE) of syrups ranged from 0.50 to 1.72 for ΔEunmalted while ΔEmalted ranged from 0.49 to 1.76. However, the ΔEfiltered ranged from 5.89 to 11.19 while ΔEcentrifuged ranged from 5.54 to 9.47 indicating that filtration and centrifugation contributed to non-significant difference (p>0.05) in colour attributes (ΔE) of the rice syrup, whereas very distinct colour difference (ΔE) was observed between rice syrups from malted and unmalted samples.