Peter Lorelli
The Effect of Magnesium Supplementation in Fruit Smoothies Peter Lorelli Purdue University
F&N 453 Professor Daniel November 19, 2007
Peter Lorelli
Introduction My reason for studying Magnesium supplementation in fruit smoothies was to prove that sufficient magnesium for optimal nutrition could be added to a smoothie without any effects on the taste or physical properties of the product. A study done at the 1st Department of Neurology in Ankara, Turkey suggests that there is a relationship between serum magnesium levels and clinical dementia that could be useful in the treatment of Alzheimer’s disease. Also according to Advanced Nutrition and Human Metabolism 4th Edition, low intake of magnesium can lead to hypomagnesemia, characterized by NVD (nausea, vomiting, and diarrhea), muscle weakness, lethargy, hallucinations, and arrhythmias. Magnesium in its elemental form usually exists as Mg2+, but this supplemented form exists as magnesium carbonate (MgCO3) which can be digested and absorbed just as elemental magnesium and is less reactive with other substances. As stated earlier, the purpose of this study is to prove that magnesium supplementation in fruit smoothies would not have any effect on the taste or physical properties of the product. Independent variables in this experiment are the varying amounts of magnesium per serving. These include 0 grams (g), 0.1g, 0.2g, and 0.4g per cup of smoothie. The dependent variables are the specific density of the smoothie, viscosity of the smoothie, and taste preference.
Peter Lorelli
Methods The basic design of this experiment involves following a smoothie recipe and adding varying amounts of the magnesium supplement in order to create 4 different products that will then be tested for viscosity, specific gravity, and taste preference. The recipe for making the fruit smoothie is as follows: Mix 240 milliliters (ml) pineapple juice, 120 ml orange juice, 100 g banana (without peel), 240 ml pineapple sherbet, and 190 g mango slices in blender for exactly 30 seconds. Pour the mixture into 4, 1 cup servings; it should make just over 4 cups. To three cups, add 100g, 200g, and 400g of the magnesium supplement. These should be labeled with the following random numbers 141, 234, and 486 respectively. The recipe not containing any added supplement will be labeled 927. Now proceed to individual testing.
Viscosity using linespread apparatus To determine viscosity using the linespread apparatus, use the following procedure. 1. Center the glass plate above the concentric circle grid on a level surface. 2. Place the hollow metal cylinder directly above the smallest circle on top of the glass plate.
Peter Lorelli
3. Fill the cylinder with the smoothie and level off to be sure you are using the same volume of smoothie for each trial. 4. Lift the cylinder, allowing the food to spread. For consistency reasons, allow the same amount of time to spread, and perform the trial in the same location. 5. Quickly take readings at 4 points that are widely separated. Take the average of the 4 readings to determine an average amount of spread. 6. Perform this test 3 times with each variable, for a total of 12 trials.
Specific Gravity Determining the specific gravity of each sample is rather simple using the following equation:
Specific gravity = Weight filled container – weight container Volume Container
All that is needed for this experiment is a scale and a cylinder. For accuracy reasons, use containers and volumes of smoothie that are very close to each other for each trial. Perform this test 3 times with each variable, for a total of 12 trials.
Peter Lorelli
Taste Preference Scale Randomization is the key in performing a successful taste preference test. The four samples are placed in front of the tester and assigned random 3 digit numbers as mentioned above. The samples are not placed in numerical order, and the tester obviously cannot know which number is assigned to which variable. The tester tastes a sample of each variable in whichever order he/she chooses and rates each on the following scale:
Rate each sample by checking the appropriate line. Sample 486 141
234
927
Dislike extremely
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Dislike very much
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Dislike moderately
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Dislike slightly
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Neither dislike nor like
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Like slightly
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Like moderately
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Like very much
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Like extremely
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Peter Lorelli
Discussion As mentioned previously, the linespread method was performed to determine how viscosity would be affected in the smoothie by the addition of the magnesium supplement. According to the Food Chemistry Laboratory Manual, viscosity is defined as a fluids resistance to flow, due to the internal friction of matter. Magnesium supplement was added to the fruit smoothie to see if the composition of the smoothie would change so much that it affected the viscosity of the product, and according to the results of the experiment, it did not. Notice in Table 1 that the average spread (in mm) for each of the four variables varied only 1 mm. The data in Table 1 also shows no correlation between the amount of magnesium supplement added and viscosity of the product. This experiment provided us with evidence that magnesium supplementation does not affect viscosity when added to fruit smoothies. To calculate the specific gravity of each variable, the following equation was used:
Specific gravity = Weight filled container – weight container Volume Container
Peter Lorelli
An example of how this equation would be implemented when taking the specific gravity of the fruit smoothie would be as follows: After creating the smoothie, and adding the appropriate amount of magnesium supplement, you would weigh the container the smoothie will be placed in. This container weighed about 2.2 grams. Then the volume to be weighed is taken in milliliters (ml). Then the amount of supplement placed in the container, inside the pre-weighed container is weighed. If the weight of the smoothie inside the pre-weighed container was 40.8 grams, the container weighed 2.2 grams, and the volume of the smoothie was 40 ml, the equation would as follows:
Specific gravity = 40.8 grams – 2.2 grams = 0.965 40 ml
Just as with the linespread method, there was no significant difference in specific gravity among variables. The average specific gravity measured for each variable did not differ more than 10%. According to the Journal of Food Science, if p
