Detecting starch and sugars in food Essay

objectiveTo detect the presence of starch and sugars (glucose and fructose) in different food sources. compassWe have many a(prenominal) different foods in daily life and many of them contain nutrients like carbonhydrates which are essential to human life.Starch is a polysaccharide, a group of nutrients known as carbonhydrates. Glucose and fructose are monosaccharides, simpler carbonhydrates which are of tenner refered to as sugars.In order to detect the different carbonhydrates center in ranges of food, we used deuce theories in our experiment. Firstly, starch can fight back with one to create a sick product. Secondly, glucose and fructose are trim down sugars which can be psychometric tested by benedicks reagent, because the trim down sugars which contain aldehydes group produce red copper( ) oxide precipitate when react with benedicts reagent.Materials and equipments2cm3 of 1% starch solution, 2cm3 of 1% glucose solution, 10 cm3 of 1% iodine solution, 30 cm3 of 1% Bened icts reagent, thin amounts of different geek of food (mushrooms, potatoes, bread found, honeyed potatoes, lemon, onion, biscuit, cucumber, tomatoes, peanuts,lettus, tomato act, dark jet plane vegetables, milk, cereal), unobjectionable tileTen test tubes, test-tube holder, test-tube rack, Nusen burner, Heat-proof mat, safety glassesProcedures1. Three drops of 2cm3 of 1% starch solution was placed onto a white tile and 3 drops of iodine solution was fited and observed the solor change.2. 2cm3 of glucose solution was placed into a test tube and added about five frops of Benedicts reagent and boiled gently. discover the colouring material change.3. Placed small piece of ten foods in ten test tubes and added one drop of irrigate, three drops of 2cm3 of 1% starch to them on an individual basis and orderly. (mushrooms, potatoes, bread piece, sweet potatoes, lemon, onion, biscuit, cucumber, tomatoes, peanuts) Oserved the color change and made records.4. Placed small pieces of t en foods into ten different test tubes and added one drops of wet, five drops of Benedicts reagent to them in order and respectively. (lemon, lettus, tomato sauce, cucumber, tomato, dark green vegetables, milk, biscuit, cereal, sweet potatoes) And boiled each test tube gently and observed the color change.5. Made a conclusion based on results.Result1.In operation 1, the color of solution changed to blue-black when starch solution reacted with iodine solution. In procedure 2, the color of solution changed to orange-red when the glucose solution reacted with the Benedicts reagent and was heated.2.The plot(fig.1) at a lower place shows what I observed directly after the procedure 3 nutrition sourceColor changeMushroomPotatoesBlue-blackBread pieceBlue-blackSweet potatoesPurple-blueLemonOnionBiscuitBlue-blackcucumber vineTomatoesPeanuts3.Then,the diagram(fig.2) below shows what I observed directly after the procedure 4Food sourceColor changeLemonRed-orangeLettusDark purple-redTomao t sauce orangishCucumberRed-orangeTomatoOrangeDark green vegetableMilkLight orangeBiscuitOrangeCerealOrangeSweet potatoRed-orangeAnalysis1. In my whole experiment, the procedure 1 and 2 were used as testing thoeries to give us a standard to testify whether certain food source contained certain kinds of carbonhydrates. If in procedure 3 the food saturnine color near blue or purple, the food must contain starch inside. Whats more, if in procedure 4 the solution in the test tube turned color near red or orange, the food msust contain reduce sugars glucose or fructose.1. From the information and results I gathered from fig.2, I was able to cypher out whether each food contains sugars glucose and fructose or not. The list was shown below(fig.4)From the diagram above we can clearly see that except dark green vegetables all the foods remained contain sugars glucose or fructose.EvaluationDuring the experiment, our group made some(prenominal) mistakes and I listed them below to evaluate them respectively.1. At the beginning of the experiment, during the process of adding water system to the washing powder solution to 500cm3. We first ingnored the bubbles above and filled the water till the 500cm3 scale but later on we found the water was much more than 500cm3, so we repeated the experiment from the starting come in once again. This time, I controled the water very carefully by pouring it softly along side the walls of the beaker and measuring cylinder to make indisputable theres no bubble made during the procedures. My improvement was victorious and at the second time we added water accurately to 500cm3.2. The color of net solution in test tube 2.5mgdm-3 was as dark as that of the solution with 10mgdm-3and its not consistent with the general trend of other(a) solutions. I considered the whole procedure of our experiment thoroughly and thought of two possible errors. Firstly we could have made that firstly we might add more than 5 cm3 standard detergent soluti on to the test tube. Secondly, because in front using the 1000cm3 beaker to heat the test tube we used 500 cm3 beaker at first then we found it too small to hold sixsome test tubes so we removed two test tubes out of the water and then put them into the bigger container. Maybe one of the two previously heated test tube was the 2.5mgdm-3 one and its darker because it has been heated for seconds onwards others.