Identification of Food Constituents Essay

Method (testing for bring down dulcorates) 1. provide 3cm? of whole draw, by apply a pipette or syringe to the test tube. 2. Add 5cm? of benedicks reagent and throw in it in the boiling body of water bath for 8 minutes. Do the identical for semi-skimmed milk and skimmed milk. 3. Once either 3 of the test tubes are go away to cool in the air, observe the comments. It provide be a good motif to set up a float of intensity standards from glucose concentrations of 1%, 2%, 3%, 4% and 5% so that you after part relate the colours observed to these concentrations. 4. A positive result would be from park to yellow to brick-red colour.Method (testing for non- bring down sugars) 5. Make up the same solution as bill 1 but this time, subjoining 3cm? of dilute hydrochloric sharp to break the glycosidic bonds between the monosaccharides. 6. then(prenominal)ce resume 3cm? of sodium hydroxide solution to do in it. 7. Add 5cm? of Benedicts reagent and place it in the water bath for 8 minutes. 8. Once its left to cool, it should nowadays turn brick-red colour. 9. The concentration of a non- decrease sugar can be estimated by outset adding a drop of 10% sucrase (sucrase) concentrate to 2cm?of the solution to be time-tested and leaving for 30 minutes at room temperature. The solution is tested for the aim of a minify sugar. This method is preferred to acid hydrolysis. Method (testing for starch) 10. On apiece of the troika types of milk, nevertheless add a few drops of iodine which is dissolved in potassium iodide solution. 11. The sample should change from browny-orange, to a dark, blue-black colour. Method (testing for proteins) 12. blot 2cm? of the three different types of milks on each(prenominal) tube. 13. Then add 2cm? of Biuret reagent and you should see a proud-violet colour developing.The intensity of it is proportional to the protein content. Method (testing for fats) 14. Add 3cm? of the three different types of milk on each test tube a nd 3cm? of water. 15. Place 1 drop of Sudan III to each test tube and shake mildly to mix. 16. Using a littlescope, a err and a cover slip, identify some(prenominal) emulsion of red fat droplets. 17. Alternatively, you could add a drop of each of the milk on a filter stem and see if in that respect is a pellucid stain for a positive result. Results hold over Solution (Milk)TestObservationsConclusionSkimmedBenedict sludge green (lightest)A sylphlike list of monosaccharides or reduction sugars usher Semi-skimmedBenedictsLime green (lighter)A slight amount of monosaccharides or reducing sugars set up WholeBenedictsLime greenA slight amount of monosaccharides or reducing sugars defend SkimmedInvertaseYellowish-greenHardly any monosaccharides or reducing sugars exhibit Semi-skimmedInvertaseYellowish-greenHardly any monosaccharides or reducing sugars present WholeInvertaseYellowish-greenHardly any monosaccharides or reducing sugars present SkimmedBiuretViolet purpleProtein p resent.Semi-skimmedBiuretPurpleLots of protein present WholeBiuretLight purpleProtein present Conclusion If there were to be a fair amount of monosaccharides to be present all 3 different types of milk, then we would surely see a brick-red abrupt formed when adding the Benedicts reagent. exactly according to my range of colour standards from glucose (monosaccharide) concentrations, the lime-green colour pull up stakesn out from each of the 3 milks trys us that it does contain a tyke amount of monosaccharides (reducing sugars).Adding a drop of sucrase normally should break the glycosidic bonds that are keeping the disaccharides together to form monosaccharides. save my results show that its a yellowish-green colour instead of a brick-red colour after adding Benedicts reagent. This shows us that there is exactly any disaccharides present which I image there would be as lactose, a disaccharide, is mostly present in milks. But this result may have a different view on that. Th e feature that all 3 milks turned purple after adding Biuret reagent assures us that there is protein present.If there is protein present, that means there is starch present too because starch and proteins are polysaccharides. valuation It is noticeable that I havent done the test for starch and fats. This is barely due to the fact that I croak out of time. Using a 5cm? micro syringe would be more faultless than a pipette. When a precipitate is settled, I could have used a principle to measure it out (in mm) instead of just using my eyes. Even better, using tintometer would have provide accurate measurements on the amount of colour present and therefore, give us an indication of how much of the diet constituents were present.