Discrimination and quantification of the degrees of stir-frying for a kind of instant rice powder based on a colorimeter

A colorimeter was introduced to discriminate and quantify the degrees of stir-frying for a kind of instant rice powder.A discriminant function was established and its reference value ranges for the degrees of stirfrying were calculated based on the L* , a* , b* color space by the method of statistical analysis, which made the degrees of stir-frying be easily discriminated by instrument and figures. The discriminant function of the degrees of stir-frying was built as X = 0.408L*-0.409a*-0.233b*-30.367. The bilateral 90% reference ranges were: stir-fried insufficiently, L* (88.9590～92.1140) , a* (-1.1240～0.5710) , b* (6.3380～8.7870) ; stir-fried properly, L* (79.9690～ 86.1360) , a* (0.8310～2.7300) , b* (12.0380～15.8870) ; stir-fried over, L* (75.1800～77.6330) , a* (3.1740～4.2240) , b* (15.8870～17.2110) .The discriminant function was verified and the coincidence rate was 100%.Due to the linear correlations between the values of L* , a * , b * and the degrees of stir-frying, it was practicable to discriminate the degrees of stir-frying for the instant rice powder with a colorimeter.