Chemical+Composition


 * Chemical Composition **



= = ("Test tube," ) = We can test for the presence of proteins, lipids and carbohydrates in food by using chemical reagents that react in predictable ways in the presence of these nutrients. The presence of starch can be easily detected by iodine water showing a violet blue coloration. Fehling’s test is used to identify carbohydrates showing a red brick precipitate upon boiling; Biuret test to identify proteins showing a violet color upon adding a caustic soda solution and a copper sulfate solution, and a translucence spot on newspaper to identify lipids. (Jamm, Dagher, Ghorayeb, & Hajjar, 1999) = = = //**hawraa: starch, the test done is iodine test,it shows blue violet color with starch. **// __**//Samia El Kurdi://**__ The chemical substance in potato is the starch. The test done is the iodine test which shows violet to blue color with starch.
 * ==__What is the nature of the chemical substance identified in potato? What is the test done?__==
 * __Alia:__ ** //**Starch. The test is done by adding Iodine water which shows a Violet/Blue coloration with Starch. **//
 * ==**__What does milky lime water indicate?__**==
 * __Alia:__ //Presence of Carbon Dioxide.// **
 * //hawraa: lime water is used to detect the presence of carbon dioxide.// **

__**//Samia El Kurdi://**__ Milky lime water indicates the existence of carbon dioxide.

__**//Samia El Kurdi://**__ The chemical analysis of the organic materials shows their makeup. They are made up of carbon, hydrogen, and oxygen.
 * ==**__What does the chemical analysis of the organic materials show?__**==
 * hawraa: they are made up of carbon, hydrogen, and oxygen.**

__**References:**__
Jammal, N, Dagher, J, Ghorayeb, L, & Hajjar, Z. (1999). Life science first year secondary. Sin-El-Fil, Lebanon: national center for research and pedagogical development.

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