Classes of food nutrient is the basic classes used in the formulation of a healthy diet. The classical six basic classes of food includes: Carbohydrates, Protein, Fat, Vitamins, Minerals and Water. This Part 4 in the series of summarised study notes by Berry Berry Easy on Nutrition for SPM Biology Form 4 students is focussed on the classes of food nutrients. However, this part won’t explain in detail the classes on food but rather be explaining on the general tests conducted in school labs to test the content of foods. Berry Readers will be exposed to the name of tests, reagents used, observation expected and conclusions regarding the identification of classes of food nutrient. So do read on.
[Tips: Most food contain more than one of the classes of basic nutrient. To understand this, you may look at the contents section of your slice bread's packaging. You'll see that it contains protein, carbohydrate, fat, vitamins, minerals and even water (although water might not be stated). So please remember that, chicken meat isn't all protein and rice isn't all carbohydrate. Eat healthy, stay healthy and study hard.]
SPM Biology Form 4 Notes – Nutrition (Part IV)
Classes of Food Nutrients
|Benedict’s test||Food sample + Benedict’s solution (Place in boiling water bath)||The solution turns from blue to green / yellow / brick-red precipitate formed (depend on sugar concentration).||Food sample contains reducing sugar|
|Benedict’s test||Food sample + Benedict’s solution + Dilute hydrochloric acid (Place in boiling water bath) + neutralise by sodium hydrogen carbonate powder||The solution turns from blue to green / yellow / brick-red precipitate formed (depend on sugar concentration).||Food sample contains non-reducing sugar|
|Iodine / Starch test||Food sample + Iodine solution||The solution turns from brownish-yellow to blue-black.||Food sample contains starch|
|Emulsion test||Food sample + ethanol||The fat droplets formed on the surface and the solution become cloudy.||Food sample contains oil (lipid)|
|Sudan III test||Food sample + Sudan III stain||A red-stained oil layer separates out and float on the water surface||Food sample contains oil (lipid)|
|Fat test||Food sample + filter paper||A translucent mark formed||Food sample contains oil (lipid)|
|Millon’s test||Food sample + Millon’s reagent + 1% sodium nitrite (Place in boiling water bath)||The solution turns brick-red precipitate.||Food sample contains protein|
|Biuret test||Food sample + 20% sodium hydroxide solution and 1% copper(II) sulphate solution||The solution turns from blue to purple colour.||Food sample contains protein|
This marks the end of Part 4 of the series of notes on Nutrition for Form 4 Biology students taking SPM in Malaysia. In the next part, Berry Readers will learn all about vitamins. Read all about it to stay healthy.