A common enzyme known as papain is obtained from the green papaya (pawpaw) fruit. Enzymes are proteins that can increase the rate of biological changes such as the ripening of fruit. At the end of an enzyme catalyzed reaction the enzyme itself is unchanged and is able to react again. Enzymes can be generally recognized by the ending -ase. This either indicates the nature of the substance affected by the enzyme (eg carbohydrase acts on carbohydrate material and proteases acts on proteins) or to indicate the nature of the reaction eg transferases catalyze the transfer of atoms or groups of atoms within a substance. Enzymes occur naturally in foods and many traditional food processing technologies involve the use of enzymes. Today, with more advanced knowledge of food science these enzymes can be extracted, concentrated and added to foods during processing (e.g. meat tenderizers). Table 1 describes some of the traditional technologies and the enzymes involved.
One important group of enzymes is called proteases. These are enzymes which catalyze the breakdown of proteins. Chillproofing of beer (ensuring that fine precipitates – or haziness – does not occur in the beer when it is cooled ), tenderization of meat, the production of dough for pizzas and batters for waffles and wafers, are applications of proteases in the food processing industry. The most common of these proteases is papain.