Determination of Calcium Content in Milk Alternatives

Tim and Dan’s Excellent Real World Project

What are we doing?

• To determine the amount of calcium in four milk alternatives (Soy, Almond, Lactaid, Chocolate) and a 1% dairy control

• To compare the calcium levels in each with how they compare to the control and the manufacturer’s claim

(Radical!)

What chemicals do we need?

• Standard Calcium Solution– 2.5 g CaCO3 in 100 mL of

0.1M HCl. Diluted to 1 L

• EDTA Solution– 15 g disodium EDTA

diluted to 1 L

• Calcium Indicator– Hydroxy Naphthol Blue

• 0.5M KOH (to adjust pH)(Hydroxy Naphthol Blue)

How are we gonna do it, dude?

• Combine 5 mL of distilled water, 10 mL EDTA and 5 mL increments of KOH (to adjust pH to approximately 13) to a 125 mL Erlenmeyer flask

• Add 200-300 mg of the calcium indicator and the color should change from clear to light blue

• Back titrate excess EDTA with the standard calcium solution until color changes to violet. This will be the blank titration used for calculations

Sorry about all that writing. Here’s a picture of puppies!*

*drinking milk

But here’s more procedure…

• Repeat the same procedure as previously stated, but substitute 5 mL of milk alternative for the distilled water

• Perform each titration three times for accuracy

(Procedure acquired from Titration of calcium and magnesium in milk with EDTA by Patrick G. McCormick)

Surely there must be data!

Here it is…and don’t call me Shirley…• Mass EDTA: 15.0084 g• Mass CaCO3: 2.5070 g

Distilled WaterTrial Ca

indicator (g)

Sample (mL)

EDTA (mL) KOH (mL) CaCO3 added (mL)

1 .2503 5 10 5 16.70

2 .2535 5 10 5 16.75

3 .2653 5 10 5 16.70

Control (1% white milk)Trial Ca

indicator (g)

Sample (mL)

EDTA (mL) KOH (mL) CaCO3 added (mL)

1 .2673 5 10 5 10.50

2 .2529 5 10 5 10.65

3 .2637 5 10 5 10.90

1% Chocolate MilkTrial Ca

indicator (g)

Sample (mL)

EDTA (mL) KOH (mL) CaCO3 added (mL)

1 .2562 5 10 5 12.72

2 .2569 5 10 5 12.30

3 .2590 5 10 5 13.15

Silk (Original)Trial Ca

indicator (g)

Sample(mL)

EDTA (mL) KOH (mL) CaCO3 added (mL)

1 .2530 5 10 5 11.23

2 .2565 5 10 5 10.40

3 .2628 5 10 5 11.11

1% LactaidTrial Ca

indicator (g)

Sample (mL)

EDTA (mL) KOH (mL) CaCO3 added (mL)

1 .2539 5 10 5 11.72

2 .2553 5 10 5 11.61

3 .2557 5 10 5 12.30

Almond Breeze (Original)Trial Ca

indicator (g)

Sample (mL)

EDTA (mL) KOH (mL) CaCO3 added (mL)

1 .2605 5 10 5 8.50

2 .2551 5 10 5 8.55

3 .2565 5 10 5 8.20

Calculations

Soo…what’d we get?

• 1% - 10.48 %/240 mL• Chocolate – 12.69 %/240 mL• Silk – 11.21 %/240 mL

• Lactaid – 11.70 %/240 mL• Almond – 8.48 %/240 mL

How does that compare?

Manufacturer’s Claim• 1% - 30 %/240 mL• Chocolate - 30 %/240 mL• Silk - 45 %/240 mL• Lactaid - 30 %/240 mL• Almond - 30 %/240 mL

Our Results• 1% - 10.48 %/240 mL• Chocolate – 12.69 %/240

mL• Silk – 11.21 %/240 mL• Lactaid – 11.70 %/240 mL• Almond – 8.48 %/240 mL

In Conclusion

Through our methods, we discovered that the best alternative is the Lactaid

This provides the second most calcium per serving, but the most as a true alternative

It is also the closest to the reported value for the milk alternatives we tested

Silk turned out to be the biggest disappointment, having the largest difference in reported vs. experimental

Error

• An important source of error comes from our calculations. We couldn’t find the density for the Almond milk and Silk so we used the chocolate’s density

• Another source could be the potential of slightly titrating past the equivalence point