Effect of temperature on the enzyme pectinase in fruit juice production.

Have a little read: ... Effect of temperature on the enzyme pectinase in fruit juice production AIM: To investigate the effect of temperature on the work of the enzyme pectinase in fruit juice production. INTRODUCTION It is stated that temperature has an effect on Enzymes. I am going to investigate this fact using my chosen enzyme Pectinase. This enzyme is used in the fruit juice industry and I am going to use this enzyme to explore the question: How Does Temperature Affect Enzymes? BACKGROUND INFORMATION Enzymes are biological catalysts that speed up the rate of a reaction without being changed or used up in any way. They are protein molecules that are tailored to recognize and bind specific reactants and speed their conversion into products. These proteins are responsible for increasing the rates of all of the many thousand of reaction taking place inside cells. Activation energy is the energy barrier over which the molecules in a system must be raised for a reaction to take place. The use of enzymes lowers the activation energy so the reaction can proceed at a faster rate. ( GRAPH TAKEN FROM REFERENCE 7) A number of factors affect the activity of enzymes in speeding conversion of reactants to products. These factors are; 1. PH: Each enzyme has an optimal pH range that help maintain its normal configuration in an environment which it operates. The tertiary structure of a protein depends on interactions such as hydrogen bonding, between R groups. A change in pH can alter the ionization of these side chains and disrupt the normal configuration and in some case denature the enzyme. A denatured protein can not combine with a substrate. 2. SUBSTRATE CONCENTRATION: At very low substrate concentration, collisions between enzyme and substrate molecules are less frequent and the reaction proceeds slowly. As the substrate concentration increases, there reaction rate initially increases proportionately as collisions between enzyme molecules and reactants become more frequent until further increases in substrate concentration have no effect on there reaction rate. At this point the enzyme is saturated and the reaction remains at the saturation level. 3. TEMPERATURE: More information on this particular factor is going to be presented a little later. Pectin is a molecule which has a structure similar to starch, the only difference is that the repeating unit of pectin is galacturonic acid instead of glucose as in starch. Galacturonic acid has a similar structure to glucose apart from the fact that one of the carbons has a carboxylic acid group (-COOH) attached to it. Pectin is found naturally in fruits, where its function is to help hold plant cell walls together, they are bound together by calcium ions (Calcium Pectate) and are important components of the first layers of a cell wall to be laid down, which is known as the middle lamella. (Picture taken from Reference 7 ) Pectin is found naturally in fruits, where it has the important function of helping to hold plant cell walls together. As a fruit ripens, the plant produces proteolytic enzymes which convert the insoluble protopectin of the fruit to more soluble forms, causing the fruit to soften. When fruits are mashed and pressed to form juices, making it cloudy and causing the colour and flavour to deteriorate. They also increase the viscosity of the juice, making it difficult to obtain optimal yields. For fruit manufacturers, the addition of industrial Pectinase between mashing and pressing causes complete de-pectination so that a good quality, clear juice is obtained which retains its stability when concentrated. (Picture taken from Reference 1 ) Pectinase is the name of the enzyme used industrially in obtaining juice from a fruit. It works by breaking down pectin between fruit cells which 'unglues' them so they can slip past each other, therefore releasing the fruit juice. Pectin forms gels that bind liquid and this is the reason why Pectinase improves juice extraction. Pectinase works by splitting the bonds between the galacturonic acids to shorten the pectin chain. They are widely used in the fruit juice industry to help extract fruit juices. They also have the additional task to help clarify and modify fruit juices. Industrially, Pectinase is made using the micro-organism ERWINIA CAROTOVORA, a soft-rot bacterium. This is a valuable source of Pectinase because the micro-organism is easy to manipulate genetically and the result is a high yield of pectinase which can be easily extracted. For these purposes, it is easiest and cheapest to extract the enzymes from bacteria which can be grown on a huge scale. HOW IS PECTINASE MADE INDUSTRIALLY? This is done using