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STOMACH CONTENTS ANALYSIS

STOMACH CONTENTS ANALYSIS. What do you look for?. Drugs Type of food that was ingested: can test for the presence of fats, sugars, proteins, etc.; this will give an indication of the type of food that was ingested

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STOMACH CONTENTS ANALYSIS

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  1. STOMACH CONTENTS ANALYSIS

  2. What do you look for? • Drugs • Type of food that was ingested: can test for the presence of fats, sugars, proteins, etc.; this will give an indication of the type of food that was ingested • Degree of breakdown: food takes anywhere from 2 to 6 hours to pass through the stomach

  3. Carbohydrates • Includes sugars, starches, and cellulose • Function to store energy and to provide shape to organisms • Composed of carbon, hydrogen, and oxygen

  4. Carbohydrates (cont.) • Can be divided into 3 groups based on their size: • Monosaccharides: simple sugars like glucose (blood sugar) and fructose • Disaccharides: double sugars like sucrose (table sugar) and lactose (milk sugar) • Polysaccharides: chains of sugars like starch, glycogen, cellulose and chitin

  5. Carbohydrates (cont.) • Simple sugars are also called reducing sugars and can be identified using the Benedict’s test • Benedict’s solution is a light blue color (contains copper II) • In the presence of a reducing sugar, the Benedict’s solution will change color ranging from green to yellow to red, depending on the amount of reducing sugar present

  6. BENEDICT'S TEST A positive test results in a color change from light blue to orange, green, yellow, or red. A negative test results in NO color change. The solution will remain light blue. • To perform the test, place about 30 drops of your sample into a test tube. Add about 30 drops of Benedict's. Place the test tube into a hot water bath for 5 minutes and observe any changes.

  7. Carbohydrates (cont.) • Starch can be tested for using the iodine test • Iodine is a yellow/orange color • In the presence of starch, the iodine changes color ranging from royal blue to purple to black

  8. IODINE TEST • To perform the test, add about 30 drops of your sample to a test tube. Add 2-3 drops of iodine. Observe any color changes. A negative test results in no color change. A positive test results in a color change from yellow/brown to blackish/purple.

  9. Proteins • Make up ½ of the dry body weight • Structure is a complex molecule composed of 20 different, smaller molecules called amino acids • The presence of protein in foods can be identified using the biuret test • Biuret solution (blue in color) contains copper sulfate dissolved in a strong base • Protein causes the solution to change color ranging from lavender to purple depending on the nature and amount of protein present

  10. BIURET'S TEST • To perform the test, put about 30 drops of your sample into a test tube. Add 2-3 drops of Biuret's. Observe any color changes. A negative test is seen here. The color stays blue. A positive result is seen here. The color changes to purple.

  11. Lipids • Include fats, phospholipids and steroids • Insoluble in water • Functions include: • Provide long-term energy storage • Act as insulators • Important in cell membranes • Act as hormones

  12. Lipids (cont.) • Structure: • Fats: a glycerol and 3 fatty acids • Phospholipids: a glycerol, a phosphate group and 2 fatty acids • Steroids: four fused rings with various side groups

  13. Lipids • Lipids are insoluble in water • The presence of lipids can be identified using the Sudan III test • Sudan III is a pink dye that is attracted to and dissolves in non-polar compounds • Sudan III does not dissolve in water or other polar solvents • In the presence of lipids, Sudan III changes color from pink to yellow/white

  14. SUDAN III TEST • This is the test for lipids. This is a positive test result. You can also do the brown paper test.

  15. Vitamin C • Ascorbic acid, commonly called Vitamin C, is important in the body for collagen production (an important component of bone, cartilage, and other connective tissues) • Vitamin C deficiency results in the disease scurvy which causes bleeding gums and a tendency to bruise easily

  16. Vitamin C (cont.) • High concentrations of Vitamin C can be found in citrus fruits (oranges, limes, grapefruits, etc.), tomatoes, potatoes, and leafy green vegetables • Vitamin C is water soluble and a reducing agent (gives up electrons) • 2,6-dichloroindophenol is a blue color indicator that turns colorless in the presence of Vitamin C

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