The Effect of Pectinase on Apples

In biochemistry, enzymes have the ability to speed up chemical reactions. These proteins increase reaction rates and breakdown materials. Pectinase is an enzyme that is often used in the food industry. Breaking down pectin, which is found in the cells of fruits, pectinase increases the amount of juice yielded from fruits like apples. If you are so inclined, you can even test the effects of pectinase on apples at home.

Pectinase aids in the extraction of juice from apples. Pectinase speeds the process by breaking down and digesting pectin, which is found in the cellulose fibres of the apple. Pectin is also found within the layers of the apple's cell wall. The pectinase enzyme breaks down the pectin, causing each of the apple's cells to release greater amounts of juice. Due to the increased yield of apple juice, the food industry often uses pectinase in the production of apple juice.

While the age and type of apple has a lot to do with the amount of juice yielded, the application of the pectinase enzyme allows the juice to flow from the fruit with greater ease. To extract juice from apples, the food industry will press the apples to release initial juice. The apple pulp is then stirred to oxidise any enzyme inhibitors that could potentially slow the reaction of the pectinase. When the pectinase is added, the pulp is heated and the juice flows from the remaining apple pulp. The addition of pectinase yields more juice than simply pressing the apples.

Before pectinase was discovered to increase the extraction of apple juice, the food industry used pectinase to clarify apple juice. When the juice is first extracted from the fruit, it is hazy or cloudy in appearance. Adding the pectinase enzyme reduces the cloudiness of the juice.

You can test the effects of pectinase on apples at home and observe the reaction. However, you should not drink or cook with any of the juice yielded from the apples in this home experiment, as the concentration of pectinase will be too high. You can purchase pectinase from at stores that sell home wine making supplies, or you can purchase it online from a biological supply company. Prepare the pectinase according to the manufacturer's directions.

To complete the experiment, cut two apples into small cubes and place them in two separate glass jars. Add 4ml of pectinase to the first jar, and 4ml of distilled water to the second jar. Cover the top of each jar with cling film. Place both jars in a water bath with water that is 40 degrees Celsius. You can use a styrofoam cooler or a pot for your water bath. Be sure that the jars do not float or tip over due to excess water in the bath. Once 25 to 30 minutes has elapsed, funnel the juice from each jar into two separate measuring cups. Notice that the jar with the pectinase enzyme yielded more juice. You can experiment with the variables in this experiment by adjusting the temperature of the water bath, the amount of pectinase used and the amount of time elapsed in the water bath.