EFFECT OF FREEZING UPON ALLIINASE ACTIVITY IN ONION EXTRACTS AND PUREENZYME PREPARATIONS

Alliinase is the enzyme ultimately responsible for the development of the flavour compounds in onions and other alliums. Freezing of onions has been shown to result in a lack of flavour and pungency due to the destruction of alliinase activity. It was therefore thought that the e nzyme is susceptible to freezing. However, the results of this paper s how that purified alliinase can be stored at -80 degrees C without any loss of activity. The enzyme also remains active after quick freezing of fresh tissue in liquid nitrogen. Inactivation of the enzyme occurs only after slow freezing or thawing procedures. Results show that cel l proteases are not likely to be involved.