Abstract: Conditions for both degradation of glucosinolates to maximize the formation of isothiocyanates and retention of these volatile products once formed were described. The nature and concentration of the breakdown products from enzyme hydrolysis were affected by pH value, temperature, time, moisture and the presence of cofactors. Certain metal ions and ascorbic acid were used to improve hydrolytic rate. β-cyclodextrin, modified starch and pea protein were evaluated as processing aids to preserve allyl isothiocyanate (AIT) and β-phenethyl isothiocyanate (PEIT). Air drying and freeze-drying were evaluated as processing methods to concentrate and preserve the formed isothiocyanates. It is showed that conditions for incubation of horseradish slices taking into consideration AIT and PEIT content were temperature 30℃, pH 6, time 30 min, buffer 5 mL/10 g. AIT and PEIT content increased significantly with ascorbic acid, Mg²⁺ and Zn²⁺ added at a low level. AIT and PEIT levels were increased when myrosinase was used. When β-cyclodextrin was mixed with sliced horseradish, higher AIT and PEIT were preserved. Freeze drying and fluid bed drying contributed more to retain AIT and PEIT.