Digestive Effect of Saliva on Starch PDF

THE DIGESTIVE EFFECT OF SALIVA ON STARCH The digestion of starch begins in the mouth, where it is mixed with saliva containing the ptyalin. Starch is hydrolyzed in several shorter polysaccharides (amylodextrines, erythrodextrines, acrodextrines and finaly maltose which is a dissacharide). Each...

THE DIGESTIVE EFFECT OF SALIVA ON STARCH The digestion of starch begins in the mouth, where it is mixed with saliva containing the ptyalin. Starch is hydrolyzed in several shorter polysaccharides (amylodextrines, erythrodextrines, acrodextrines and finaly maltose which is a dissacharide). Each of these steps can be recognized using an identification reaction with Lugol solution.The final digestion product of starch is maltose and can be identified using the Trommer reaction. OBJECTIVE: To understand and explain the action of salivary amylase and how can we demonstrate its action. Limits in salivary amilase action on starch. Understand and explain the factors which can influence the amylase activity (temperature, pH) Amylo dextrines MATERIALS dextrine Erytho 1. Starch solution 1%0 2. Iodine (Lugol reagent) (contains iodine, potassium and water 1:2:300) 1% Acro dextrines 3. Test tubes Maltogy 4. Graduated glass cylinders dissochride 5. Saliva 6. NaOH 7. CuSO4 10% solution 8. Filter paper PROCEDURE: Take 6 clean test tubes and add 5 ml of starch solution in each tube and 2-3 drops of Lugol solution (I + KI). Notice the colour and keep the first tube (T1) as control. Proceed as follows with next tubes: T2 – add 0,5 ml of boiled saliva. Due to inactivation of ptyalin by heat, there is no colour change T3 – add 3 ml of fresh saliva and wait for 2-3 minutes, then heat the tube to intrerrupt the reaction. T4 – add 3 ml of fresh saliva and wait for 5-7 minutes, then heat the tube to intrerrupt the reaction. T5 – add ml of saliva, wait for 15-20 minutes and then heat the tube to intrerrupt the reaction. T6 – proceed as before and wait for 30 minutes for the complete digestion of starch to maltose. Observe that each stage of starch digestion is related with different colours of the solution:  amilodextrine blue-violet (T3),  erythrodextrine pink-violet (T4),  acrodextrine – colourless (T5). The complete digestion to maltose produces a colourless solution (T6). Test tubes 1 - 6  TROMMER REACTION PRINCIPLE: In alkaline pH and by heating, the maltose reduces the CuSO4 solution in cuprous oxid. MATERIALS 1. test tubes 2. gas burner 3. NaOH 20% solution, CuSO4 10% solution, starch solution 4. saliva PROCEDURE: In a test tube add 3-4 ml from maltose solution and an equal volume of NaOH, homogenize, and add drop by drop CuSO4 solution, obtaining an unsoluble blue precipitate. Boil the precipitate and notice the appearance of a red-cooper precipitate at the bottom of the tube. when heated GE maltose turns Cuson Alkaline NaOH is to make solution Red precipitate Curb if maltose is present A will appear  MINERALS EVIDENCE IN SALIVA CALCIUM (from calcium salts) MATERIALS : test tube, ammonium oxalate 10%, saliva, microscope PROCEDURE: take 3-4 ml of saliva in a test tube, add 3-4 drops of ammonium oxalate. In the presence of Calcium, a white unsoluble precipitate appears at the bottom of the tube. Collect a drop of precipitate, put on a glass slide, dry and examine to microscope. The presence of octaedric cristals is related with calcium oxalate formation. mixed wit ammonium oxalate when saliva containing calcium ions is calcium oxalate Cac On calcium oxalate ions form  MINERALS EVIDENCE IN SALIVA po PHOSPHORUS (from phosphates) MATERIALS : test tubes, gas burner, saliva, HNO3 (nitrogen acid), 12(NH4)2 MoO4 (ammonium molibdate). PROCEDURE: take 3-4 ml of saliva in a test tube , add 3-4 drops of HNO3 and ammonium molibdate in excess. Heat carrefuly the tube and notice the appearance of a yellow precipitate (phospho ammonium molybdate). Na2(PO4)3 + 12(NH4)2 MoO4 + 21 HNO3 = (NH4)3H4[(PMo2O7)6] + 21 NH4NO3 + 10 H2O phosphorTreacts with Ammonium molybdate in presence of HNO form a yellow precipitate A MOO Ammonium molybdate  MINERALS EVIDENCE IN SALIVA KSCN (Potassium sulfocyanate) MATERIALS: test tube, FeCl3 (ferric chloride) 3%, HCl (hydrochloric acid) 10%, saliva PROCEDURE: take 3-4 ml of saliva in a test tube, add 1-2 drops of HC land 1-2 drops of FeCl3. A brick-red precipitate of ferric sulfocyanate appears. The SCN- ion is found in saliva in concentration of 0,01-0,03 mg%. It is an excretory product, resulted from proteic metabolism or fruit ingestion. This is an detoxification mechanism. The SCN- concentration increases in smokers saliva. KSCN in the saliva of non-smokers (left) compared to smokers (right). There is an increased concentration of KSCN in smokers that is identified by a stronger, darker color. Higher naturally found in saliva in E smokers reacts with fechloride Fells saliva FORMS Cyanate Fe SCI Fe SCN