RAPID PEROXIDASE TESTING FOR RICE “COOK” QUALITY

A second part of the shelf life and product stability equation for cooked rice products is peroxidase. It is more difficult to inactivate than lipase and trace residual activity is common. Peroxidases can also renature and regenerate part of the original enzyme activity under some conditions.

Numerous colorimetric reactions can be used to follow peroxidase denaturation and renaturation during thermal processing. We selected guaiacol as the preferred color generator for its stability and excellent sensitivity without excessive reactivity. More sensitive color reactions for peroxidase exist but they are difficult to use effectively in processing areas because of the presence of rice and other peroxidase positive dust. RICE-CHEK II can be correlated to lab peroxidase tests if appropriate adjustments are made for enzyme-active dusts in the processing plant environment. Consequently RICE-CHEK II, like RICE-CHEK I, can be used to establish in-house standards, to generate quality assurance data and for rapid sample comparisons.

RICE-CHEK II was developed to allow in-plant testing of oxidative rancidity. It does require a short extraction with distilled water (not provided) prior to the actual color reaction. Tests take only a few minutes and are easily run by production personnel without laboratory support.

We think you and your production and quality assurance staffs will be pleased with the ease and speed of RICE-CHEK II.