EFFECT OF NEODIOSMIN ON THRESHOLD AND BITTERNESS OF LIMONIN IN WATER AND ORANGE JUICE

The thresholds of limonin and naringin in water and limonin in orange juice were determined in the presence of varying amounts of neodiosmin (NEO), the flavone analog of the bitter flavanone neohesperidin. Up to 40 ppm of NEO in water solution was essentially tasteless, but as little as 10 ppm in water increased the threshold of naringin and limonin 3.5- and 4.0-fold, respectively. Regression analysis showed the relation between limonin and naringin threshold and NEO concentration in water was best described by a power function with similar slope exponents for naringin and limonin. This indicated that increasing concentrations of NEO had a similar bitter suppressive effect for both compounds. The data for limonin threshold and NEO concentration in orange juice was also described best by a power function but with a much smaller slope exponent. Nevertheless, NEO was effective in significantly reducing bitterness in orange juice at threshold and suprathreshold levels of limonin. The addition of 60-100 ppm of NEO to orange juice containing 10 ppm of added limonin reduced limonin bitterness to the equivalent of 4–5 ppm of limonin in orange juice.