The Biology Corner website has an investigation on enzymes (https://www.biologycorner.com/worksheets/enzyme_lab.html) that is well set out and may be suitable for your needs. It does not include the use of detergent; however, you could add universal indicator and some detergent to Part D to achieve the outcome you are looking for. As with all new activities, it is recommended that you and/or your technician trial the activity to ensure that it suits your purposes and is workable.
A few other links that may be helpful are listed below:
‘Factors affecting enzyme activity’, Nuffield Foundation website, http://www.nuffieldfoundation.org/practical-biology/factors-affecting-en... (Accessed February 2019) (some examples of a range of different enzymes and activities)
'Liver Stinks!’, Science Buddies website, https://www.sciencebuddies.org/science-fair-projects/project-ideas/BioCh... (28 July 2017) (an activity testing under different conditions without test tubes)
‘Practical Enzyme Experiments Anyone Can Do’, Practical Biology: science for everyone website, http://practicalbio.blogspot.com/2012/11/easy-enzyme-experiments-anyone-... (November 2012) (a blog on enzymes including 2 activities using the catalase enzyme)
‘The Effect of Hydrogen Peroxide on Liver: Hypothesis, Apparatus, Method’, Schoolworkhelper website, https://schoolworkhelper.net/the-effect-of-hydrogen-peroxide-on-liver-hy... (2017) (some general information)
‘The Liver: Helping Enzymes Help You!’, Scientific American website, https://www.scientificamerican.com/article/bring-science-home-liver-help... (8 March 2012) (an activity testing under different conditions without test tubes)