April 18, 2012 at 7:48 p.m.
April 1, 2012
Chemistry, Nutrition Sciences
University of California, Berkeley
We are determining the calcium and lead content in different brands of chocolate pudding, as well as different flavors. Two flavors, chocolate and chocolate fudge, were used as samples. We also had a store brand Safeway pudding of each flavor, and name brand Snack Pack.
Chocolate pudding, while a delicious snack that is loved by many (including ourselves) for its taste, is far from nutritious. However, one of the saving graces of pudding is its supposed calcium content, which is used as a selling feature by many manufacturers. One of the most popular pudding brands, Hunt’s, sells its pudding in single serving “snack packs”, which according to the nutrition facts contain 10% (100mg) of the recommended 1000mg of calcium that should be consumed by adults daily. However, nutrition facts, especially for vitamins and minerals that are present in foods in trace amounts, are notoriously inaccurate, which is why we aim to test for the calcium contained in chocolate pudding ourselves. We hypothesize that our experimentally determined concentration of calcium in the pudding should fall around 2 ppm, which would make it so a single serving of pudding would contain around 100mg of calcium, supporting the manufacturer’s claims.
The contents of each element are to be determined through Atomic Absorption Spectroscopy (AAS).
The procedure for determining the amount of calcium in each pudding involves weighing out 1 gram of each type. Then, each sample is acid digested in nitric acid and sulfuric acid, while being boiled gently. After dilution, the sample is put into volumetric flasks with a calcium standard added to spike it (standard addition). The samples are then put into the AAS and a calibration curve is given.
To determine the lead content, a similar procedure is followed, except that instead of acid digestion, the pudding is put into ceramic crucibles and ashed at a temperature of 500 degrees Celsius.
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