Apple Juice Internal Assessment

Personal Engagement

Apple juice has been a staple drink throughout my life which I still avidly drink today, especially as I have never grown to like soft drinks such as Fanta or Coca-Cola unlike many other people my age. My limited palette subsequently drove my interest in apple juice further, to the extent that my mother and I would make our own apple juice using ones from the apple tree in our garden. It became occurrent to me however that in the mass production of apple juice, a plethora of confounding variables must be taken into consideration to produce the most amount of juice possible at an effective rate. Consequently, upon beginning research to find a topic for my internal assessment (IA), I was provoked by such confounding variables

Enzymes are biological catalysts that provide an alternative reaction pathway that lowers the activation energy and increases the rate of a reaction. Pectinase breaks down pectin, a polysaccharide found in the cell wall of terrestrial plants. It is most commonly extracted by the fungi “Aspergillus niger”, which produces pectinase to break down the middle lamella; A pectin layer cementing adjoining cell walls together, so that it can extract nutrients from plant tissue through the release of hyphae. By opening glycosidic linkages, “pectinase splits polygalacturonic acid into monogalacturonic acid” which softens the plant cell walls and results in the extraction of

Temperature could influence enzyme activity is it provides the enzyme with a higher kinetic energy, thus increasing the rate of the reaction as there is a greater likelihood of a collision for a reaction to occur. Much like pH, too high a temperature denatures the enzyme and inhibits the substrate from binding to the active site. Furthermore, I controlled the concentration of the pectinase added to the apple pulp as a high concentration means that there is a larger amount of the enzyme present and therefore, increases the probability of a successful collision. I kept the concentration the same for all the samples as I wanted to avoid concentration influencing the activity of pectinase and sustain the reliability of the results that would be collected.

Ultimately, my exploration into the role of pH on pectinase’s activity led me to form the question:” To what extent does pH effect the activity of Pectinase when making apple juice”. I hypothesise that the pH will influence pectinase activity and consequently the amount of fruit juice produced. If my investigation leads to contradict my hypothesis, I will have to accept the null hypothesis which is that the pH will have no effect of pectinase activity and therefore not influence the amount of fruit juice