Question

gelatin is made almost entirely of protein. pineapple contains bromelain, an enzyme that breaks down proteins. for this reason, gelatin manufacturers advise against adding fresh pineapple to gelatin desserts, because the gelatin will not solidify properly. the graphs show the relative activity of bromelain at different temperatures and ph levels. based on the graphs, what is the best way to prepare pineapple for use in gelatin desserts? a. change the ph of the pineapple to 4.5. b. heat the pineapple to 55°c or higher. c. change the ph of the pineapple to 7.5. d. chill the pineapple to 30°c or lower.

Explanation:

Step1: Analyze enzyme activity factors

Bromelain in pineapple breaks down protein in gelatin. We need to find a condition to inactivate bromelain.

Step2: Examine temperature - activity graph

From the temperature - activity graph, bromelain's activity drops significantly above 55°C.

Step3: Evaluate pH - activity graph

The pH - activity graph shows multiple peaks of activity in different pH ranges, so changing pH is not a reliable way to inactivate bromelain.

Step4: Consider temperature options

Chilling to 30°C or lower still allows bromelain to have some activity. Heating to 55°C or higher inactivates bromelain.

Answer:

B. Heat the pineapple to 55°C or higher.