Pre-treatment of the mash

Equipment for heating the crushed fruit must meet the following requirements  

Most commercial products are a mixture essentially of four individual enzymes pectin esterases, polygalacturonases, pectin lyases and pectate lyases. Depending on the intended use, the enzyme preparations have different contents of the individual pectolytic enzymes. The enzyme preparations are commercially available in liquid or solid form they originate mainly from mould cultures. 

As a general rule, when using enzymes it is important to make sure that they have not been obtained from cultures of microorganisms that have been altered by genetic engineering. 

When crushed apples are treated with pectolytic enzymes the temperature should not exceed 30°C, as otherwise there is likely to be a change in aroma quality (ester-type components of the apple juice aroma, in particular, may be destroyed). It is recommended that the juice be left for about an hour at this temperature. The minimum temperature of the juice for efficient enzyme use is 10°C, but at this temperature the time for which the juice needs to be left has to be trebled in order to achieve approximately the same effect as at 30°C. The enzyme should be added while in the mill. The yield can be increased by up to 10% by using special enzymes. 

Berry fruit is usually treated with enzymes at 50-55°C. This is virtually the optimum temperature for the enzymes. After about 2-4 h there are significant increases in pressability and also in colour yield. If the mash is highly acidic, care should be taken to choose enzymes that are still sufficiently active at low pH. 

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