ANALYSIS OF BIODENITRIFICATION CONDITIONS OF RED BEET JUICE USING THERESPONSE-SURFACE METHOD

Microbiological denitrification of red beet juice proceeds under condi tions that are unfavorable for pigments. In this study the effects of pH, accessible oxygen, and temperature on the stability of red and yel low pigments were examined. All three factors examined affect the cont ent of pigments. The strongest effects were exerted by pH and oxygen a ccess in red beet juice. An interactive effect of these parameters on losses of red pigments was observed. At increased pH of juice, losses of red pigment were very high, reaching 60-80% at pH 8.0, whereas loss es of yellow pigments decreased with an increase of pH. An increase of temperature within the range of 25-30 degrees C did not practically i ncrease losses of pigments and did not influence the color of the juic e.