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Investigate the Vitamin C Level in Bell Peppers During Various Stages of Ripeness *

Time Required Average (6-10 days)
Material Availability Titration equipment and supplies are needed. A kit is available from the Science Buddies Store.
Cost High ($100 - $150)
Safety Adult supervision required. Iodine solution is poisonous. Avoid skin and eye contact. Wear chemical safety goggles and rubber gloves when handling the concentrated solution. For more tips, consult the Chemistry Safety Guide
*Note: This is an abbreviated Project Idea, without notes to start your background research, a specific list of materials, or a procedure for how to do the experiment. You can identify abbreviated Project Ideas by the asterisk at the end of the title. If you want a Project Idea with full instructions, please pick one without an asterisk.


Vitamin C is a water-soluble vitamin that has many functions in the body. Vitamin C is needed to bolster the immune system. It is an antioxidant that protects LDL cholesterol from oxidative damage, and it is needed to make collagen, a substance that strengthens many parts of the body, such as muscles and blood vessels. Our bodies do not make vitamin C, so we must get it from dietary sources. Citrus fruits, carrots, avocados, and spinach all have vitamin C. Bell peppers, like the ones shown in Figure 1, below, also contain vitamin C. Red, yellow, and orange bell peppers are all ripe versions of the green bell pepper. But how do the vitamin C levels vary among the different colors or ripeness of bell peppers? Does ripeness matter? To quantify the amount of vitamin C, you will need to do some titrating.
Cooking and Food  Science Project bell peppers

Figure 1. Colorful bell peppers. (Luc Viatour, 2008.)

Titration is a chemistry technique used to determine the unknown concentration of a chemical in a solution. For information on how to titrate, consult the references in the Bibliography and the science fair project idea Which Orange Juice Has the Most Vitamin C?. You could use the titration kit from the Science Buddies Store and follow the Procedure for that science project idea, but instead of using orange juice, use a de-seeded and de-stemmed bell pepper that has been blended with water (and then filtered using cheesecloth). You may want to weigh the bell pepper before blending it and adjust your samples so that you use the same amount of each type of bell pepper. This will make it easier to compare your results. For more information about doing a titration, visit the Science Buddies webpage Titration Tutorial: Tips & Tricks for Titrating.

So which color bell pepper do you think will have the most vitamin C, or do you think they will all have similar amounts? Try this science project and do some titrations to find out for yourself!

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Science Buddies Staff. "Investigate the Vitamin C Level in Bell Peppers During Various Stages of Ripeness" Science Buddies. Science Buddies, 10 Oct. 2014. Web. 22 Oct. 2014 <http://www.sciencebuddies.org/science-fair-projects/project_ideas/FoodSci_p039.shtml?from=Blog>

APA Style

Science Buddies Staff. (2014, October 10). Investigate the Vitamin C Level in Bell Peppers During Various Stages of Ripeness. Retrieved October 22, 2014 from http://www.sciencebuddies.org/science-fair-projects/project_ideas/FoodSci_p039.shtml?from=Blog

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Last edit date: 2014-10-10


This next entry is an article that discusses the level of vitamin C as a function of ripeness in a variety of bell peppers.

  • Antoniali, S. et al. (2007). Physico-Chemical Characterization of 'Zarco-HS' Yellow Bell Pepper for Different Ripeness Stages. Scientia Agricola, Vol. 64, No. 1, Retrieved October 8, 2008, from http://www.scielo.br/pdf/sa/v64n1/a03v64n1.pdf

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